How reliable is oil-in-cylinder compression-test trick?

Reply

  #1  
Old 03-08-09, 02:44 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
How reliable is oil-in-cylinder compression-test trick?

My poor car. The end is near. I dread having to give it a funeral. It has been old faithful. The 2.5 liter 4-banger has given me LOTS of trouble-free run time. And with good enough power, especially considering I have the car loaded with about 6-700 pounds tools and supplies. And have to go up and over some hills. Both highway and lots of close-together stop and go signals at 45 mjph (which is hard on any vehicle).

I hate to just go out and get any old other vehicle, as I know this car of mine pretty well. And I have done both front and rear brakes (disc and drum) and have some extra parts left to do more. I said I can change bulbs out quickly. The belts also. It has a coil and distributor, right out in the front open! that has been reliable so I do not have to worry about crank and cam sensors I have the Haynes manual for it. I have read up on it. The car can give it's own codes! The car has gauges. I know where the various parts are. I can get to many engine areas quickly. (I.e., I could change out the unobstructed alternator in minutes. Changing the radiator last year was simple. Stuff like that. My kind of car!

I hear too many horror stories of people having to pay hundreds and hundreds of dollars on their car repairs(my neighbors have!) as a lot of the charges are due to engine areas hard to get to. My one neighbor said they have to jack on the engine to get at rear 3 plugs. Forget that malarkey!! What if you simply want to pull plugs quickly to check engine condition?!

My dad's car I said I can buy. It is one of them where you don't even know where the battery is hidden! Who wants stuff like that?!

Anyway -remember how not all that long ago, when I was mentioning about all the steaming and smoking the car does, but yet I still had good compression? Not any more!! I have noticed now just the last 2 days, that at idle only, the car sort of lopes on 3 cylinders -feeling. And oddly, sometimes worse than others. So this morning I pulled all the plugs at one time, and did a compression test. I got (get ready for THESE readings) - up to 180 psi in #1, 70 in #2, 150 in #3, and about 80 in #4! Ouch. I did test at both totally ustarted cold engine, where it sat unstarted for 1 1/2 days, and was ice cold - and re-tested after engine warmed up. To my surprise, it did not hardly matter, as readings were very close!

The car wants to blue smoke and/or steam the most at plain old idle. Then when I drive it after it is FULLY warmed up - no smoke or steam. But then when I come to a stop, it smokes a little blue plus the steam, etc. (But I did not detect coolant smell, either!)

The car runs smooth when running dwon the road!, and only runs 3-cylinder like rougher when at idle with foot on brake (like at traffic lights).

So for the fun of it, I drive it back in the garage and pulled off plug wires one by one. I was expecting to find one cylinder that had no change. Nope. Each plug wire removal caused the engine to slow. So even with bad compression, they are all still firing off and applying power to the pistons. Obviously though, not evenly. QUITE obviously by the compression readings. I have a very good screw-in gauge, by the way, and it holds readings. Multiple tests were done, to rule out crud holding seat of compression gauge off the plug hole, or something. I even repalced the o-ring. So it indeed is the cylinders, and not the gauge.

So THEN I did the old squirt oil in the bad cylinder test (I did #2), to see if it is the rings or blown head gasket ). I even used gear oil! To my surprise, the compression only went up from 70 or 75, to 80. I'd asay about 1 teaspoon went down in there, as a guess.

So what do you make of my readigng - plus this oil in the cylinder compression test?

I am actually hoping that the real cause of ALL my recent problems with oil loss and coolant loss and bad compression is in the head, worn cam lobes (which it has) and/or head gasket. Because I just might be tempted to redo this (headwork/new gasket), since this is probably one of the easiest cars to do it on (albeit not easy easy, but in relation to those sardines in a sardine can engines, it is. I can have my valve cover off in a few minutes, for example.

What do you think?

................................................................

Update: I just popped the hood and added coolant. It was full this morning(both reservoir and radiator). I have driven the car about 5 miles around town and out on the highway for 20 about. I had to add about 1/3 gallon just now!!To both the radiator and reservioir, combined. And no drops of antifreeze under the vehicle. And oddly I jsut started the car and no blue smoke this time and yes, some more than average steam ,but I cannot detect the smell of coolant! And I sat in the car to feel the smoothness(roughness?) and it feels like it is running on 3 1/2 - 3 3/4 cylinders now. Not all that bad, but detectable. Man this car is an odd one!
 

Last edited by ecman51; 03-08-09 at 03:03 PM.
Sponsored Links
  #2  
Old 03-08-09, 03:10 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
A teaspoon of oil/gear lube wouldn't distribute itself over the top of the piston, then down into the ring cavities. You would need to put a couple of ounces in the low reading cylinders, wait a about five minutes, then slowly turn the engine over without the plugs in it. I normally use a socket on the crank nut to turn it so I don't blow oil all over the car. Catch the excess oil on a shop towel.

Once you've turned it over three or four times you'll have the excess oil out of the cylinders and you can do the compression check.

It sounds like with the compression coming up the 10 lbs or so your problem is likely to show up as worn rings. Unless the cam lobes were completely gone, the compression will still build if you have a seal at the rings/valves/head gasket with no cracks. The 180 and 150 are usable, but all four cylinders would be done in a fixit.

For that engine, if you're inclined to do the work, I would pull it apart in frame, have a valve job done on it, replace the rings and rod bearings and stick it back together. It may go for another 100,000 miles. If not, you won't have a ton of money in trying.

If you do go that route, get a ridge reamer to take out the top cylinder ridge and hone the cylinders as well as you can.
 
  #3  
Old 03-08-09, 03:51 PM
Member
Join Date: Dec 2001
Posts: 2,538
would just get another car you will get used to it and find you can probably work on your next car also some things will be easier than others but all it takes is time.
if I remeber right this car has like 250 k on it and even if you did replace the engine or do a complete rebuild on it chances are the transmission would be the next thing to go its probably not worth putting the money in it, would shop around used vehicles and see if you can find one you like in good shape the lower the mileage the better.
 
  #4  
Old 03-08-09, 05:08 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Thanks Marbobj for the how-to. I will give that a go. I sort of thought that since I did the oil test with the pistons hot, that it would flow. But now I can understand your method. Sounds good. Sure beats the squirt a couple drops of oil in, which I have heard.

Bejay, No way am I going to attempt the whole engine rebuild as Marbobj mentioned(albeit he was not advising me too). I was thinking that if my problems were related to the head or gasket, that I could make relatively quick and fairly inexpensive work of that.

I picked up an auto publication today and here this guy is selliing this near-luxury car( 76 Ford LTD) he proclaims has no rust and has been stored winters and has only 70, 000 actual miles and he is the 2nd owner and knows the old lady who had it before him, as the original owner. And this car is of the vintage it has a 4-barrel and regular fuel pump (I like that!). It has a 400 Ford engine in it and he said it gets about 16 mpg all around and almost 20 on the highway. I wonder if that is accurate. My decision would be based on mpg since I put on nearly 60 a day. I was thinking that realistically the engine might do 16 on the highway and 13 in town. But what if he is correct? Hmmmmm. I was surprised he only got 3 hits on this car in 5 days!! 70,000 actual miles, no rust?

..........................................

Update: I have been starting my car between posts, keeping it hot. I noticed that it seems to be running not as rough. So I did new compression tests moments ago on the 2 weak cylinders. (I'm like the flash) They were 90 now, on #2 - and 83 on #4.

...............................................

My car has over 270,000 miles on it now. Remember that I baby it. No jack rabbit starts. Trans fluid not burned. Have not had to add any. I do not hit curbs. No downshift to passing gear.

........................................

Any opinions on how cars comparable to Dodge Spirit-Acclaim-Shadow-Sundance is?, and compare to other cars of it's (cheap)type?, like the Chev. Cavalier or Corsica? These cars too seem to be running the streets around here in abundance.

I think you guys know what kind of car I am looking for. I am like my uncle who had a 70's Ford Maverick that got decent gas maileage and got him from point a to point b, and you could work on it yourself. Or like the old Dodge Darts with the slant 6.

I do not want car expenses plain and simple. I do not believe in having to have a car to drive miles for work and then have to pay all my work money out on car repairs, because the car is too complex with too many buried parts. For-get it!!!!That is stupid. If I want car expenses I want to pay for - it be for a 3.5 second quarter miler.
 

Last edited by ecman51; 03-08-09 at 05:22 PM. Reason: added much more
  #5  
Old 03-08-09, 05:28 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
marbobj,

Isn't it almost a given though that on some high-mileage engine, you are bound to bring up the compression SOME with the oil test? But does this prove the major cause then IS the rings?, as opposed to say the head gasket or crack being the real cause?

Part of my problem is every time I recheck the compression, even back to back, I get readings that might vary by 5 psi. How am I to know?
 
  #6  
Old 03-08-09, 06:21 PM
Member
Join Date: Dec 2001
Posts: 2,538
compression will jump greatly with oil while it may come up 5-10 lbs on any car with oil added it will come up alot on a car with bad rings.
the problem with fixing the top end on an engine with that many miles is that the bottom end will usually fail not sure how much life you would get out of it, if it was a head problem and you fixed it you may throw a rod when the bottom end fails the only way to fix it right is a complete engine rebuild sure you can fix a head problem cheap doing it yourself but if the engine fails a week later it probably wasnt worth the money you put in it to fix it but the risk is all yours to take so go for it if you want.
 
  #7  
Old 03-08-09, 07:12 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
Any engine will jump compression some with oil added to the cylinder. The oil will seal the ring gap, which is where the blowby for the crank case comes from. This would usually be 2 to 5 lbs. Adding oil to the cylinder is strictly to check ring wear vs compression loss elsewhere.

Normally when you're checking for ring wear, you have a measurement before the oil is added and after. The only place this will jump the compression significantly (10 lbs up to around 30 lbs or more, depending on where the lack of compression is coming from in the cylinder) is at the rings/cylinder walls. Keep in mind this takes in not only the rings wear and its mating to the cylinder wall, but the condition of the cylinder wall, and the enlarged ring gap. The latter will get larger as the cylinder or rings wear.

To get an accurate picture of the condition of the cylinder walls it's better to do a leak down test. This will pinpoint the run of the cylinder the leakage is occurring at. That type of test is usually done before hiring someone to do a complete breakdown of the engine.

As far as the testing you're doing, this variance always occurs to a small amount. The thing you look for in a compression testing of that type is uniformity among the cylinders at a reasonable level of compression. If you are getting 180 one time and 176 the next time the condition of that cylinder/valves/rings is OK. But since you dealing with an engine of very high mileage you wouldn't break that engine open to just work on one or two cylinders, all of them would have to be worked on.

The problem you have is common in deciding just how far to go in the fix. If you did a hired rebuild of the engine you would have more in the engine than the car is worth and it would likely dollar you to death in all areas but the engine, assuming it stays in good shape.

If it was mine and I loved the car dearly, I would do the rings, head, and rod bearings if the oil pressure was good in the engine. If I broke it open and the cylinders on the two weak pistons were beyond repair, I would look for a salvage engine.

You have an advantage in that type of situation if you're able to do the work yourself. If you're not in that position I would leave the engine alone. From what I understand from your previous posting about it, I wouldn't hire a complete end to end rebuild of it.
 
  #8  
Old 03-09-09, 05:03 AM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,575
Well, now we all know why Detroit is in such trouble; it's people like ecman!

We keep ours pretty long, too. Wife's previous car ('95 Camry) was replaced at 175k miles and still running good.

On the cars question, I would own any of the Chevy models you listed ahead of the MOPAR stuff (assuming I couldn't find a good Toyota .

BTW I towed a car into one of the garages couple of weeks ago that was an '03 and had 834 miles on it. The interior still smelled like it was on the showroom floor. The 90+ year old retirement center lady who owned it didn't drive it very much (you think?).
 
  #9  
Old 03-10-09, 05:11 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
marbobj,

I spent the morning getting the valve cover off and cleaning goo off the parts. Turns out there is no cam wear.

Here I thought, froma previosuy observance with the valve cover off some months back, that I had big time camlobe wear. Nope.

Also, lots of oil up there, adsn passageways totally clear that lead back down into the block = good. No signs of wear up top at all!

I rotated the engine by hand, and watched movement, and every camlobe rocker roller follower turned. And like I said, once I cleaned up the goo, which was coolant mixed with oil forming sludge, everything looks good now.

I did your suggested test where you dump sizeavle amount of oil in the cylinder, then spin the engine over to get rid of the excess oil. That does not work. The oil stayed down in there!, and my compression went form 70 PSI cold test in the beginning, to 180! What I did was create less space above the piston, upping the compression ratio. I literally had to reassemble stuff again, to a degree, and then actually run the car - and then took a new test - and it was back down to 70.

I have to use some method to conclusively tell if it truly is the rings, or the head gasket. If it is the rings, also, I am not working on it. This is on cylinder #4. Plug color looks good, believe it or not. Oddly, the cylinder #3 next to it has higher compression of about 120 and that is the one being steam cleaned! Is that a nice clue, or not?

I read about how to do the compression test in my Haynes manual. And they too suggested the leak down test. Any advise on how to do the leak down test yourself? How does one know where it is leaking out? We already know it is going to leak. But under pressure, how can you know if it leaks down from rings or head gasket or valves, or crack?

Regarding the compression test, they said to watch the gauge to see if the first rotation just sits there, and then climbs after that.

Tomorrow I will be back at it again.

IF the head/gasket is the issue, I would maybe fix it, since brakes/stoppinjg is true and excellent, no front end shake/tight front end/no cracked CV joint boots, timing belt looks good, reliable start everytime, easiest car I think to work on.

And how there was no ridge left on cam lobes, and all that oil up top, I am thinking that car has oiled itself pretty doggone good. And if that is true, maybe the rings ARE good. But then I am not sure why the blue smoke that last for a while at codl start up - if that is just valve guides/seals.

I was actually hoping the cam was worn, and not raising open valves and causing oil and coolant to be drawn into combustion chamber under high vacuum. But now I know that is not the case.

Last evening, when I was out on the highway, something let loose(gasket), and it started leaving trail of steam out the exhaust at high engine vacuum. I had to negotiate 2 small towns with spider- in- the- web type cops. So to stop the steaming I applied some throttle, and rode the brake, and this stopped the steam.
 
  #10  
Old 03-10-09, 05:20 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by the_tow_guy View Post
Well, now we all know why Detroit is in such trouble; it's people like ecman!
Oddly -I brought this very thing up to this guy this aft, whose water heater I was working on, and we chatted about cars.

He told me he knows this guy who has a camry with 500,000 miles on it with no engine tear down!

Speaking about long lasting - what is there about a diesel that makes them last say a million miles. Why don't their rings wear out?

On the cars question, I would own any of the Chevy models you listed ahead of the MOPAR stuff (assuming I couldn't find a good Toyota .
Why? Can they get 270,ooo like my Dodge, without lots of major engine trouble?

Do you think a relatively high mileage (say 150-180,000 miles) early mid-90's cavalier or corsica would be a good choice? Do these have cranksahrft and cam positioning sensors?, and are these hard to get at and hard to change out? I have a distributor and coil right in the front. I like that. The hall pickup coil is in there and lifts right out.
 
  #11  
Old 03-10-09, 07:30 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
I should have said a couple of ounces = 2 ounces. Your problem is in the rings/cylinder walls of the cylinder that jumped up to 180. If the problem was at the head gasket or the valves, and the amount of oil you put in it sealed the valves or head gasket you would have hydro locked the cylinder/engine.

Now you may have need of another head gasket for water leakage, dunno, but the compression issue is the rings. Now to clarify a point that most bring up shortly after finding this out is why the plug isn't oil fouled. The answer is you can have a compression loss and still have oil control.

The leak down test works like this and requires specialized equipment. First take off the oil fill cap. Then you move the piston of the cylinder to be tested to TDC on the start of the power stroke and fill it with, say, X lbs of compressed air. A second gauge reads the amount of pressure in the cylinder which is actually the back pressure from the cylinder against the second gauge. This is your indexing for the condition of the rest of the cylinder. Think in terms of a regulator for a cutting torch.

Immediately you will have compressed air loss (through the ring gap in a good engine). Then, without killing yourself with this thing, you slowly move the piston down the run of the cylinder. Your piston will pass different points in the cylinder where the air back pressure drops significantly. These represent the points of poorest condition of the cylinder.

Now, you would have specs for that engine to evaluate the results by. I don't know what those are myself.

Also, go back in the text of this thing to the point about killing yourself. You're introducing compressed air into the cylinder. That compressed air will drive the rev of the engine. So hang onto the crank.

I wouldn't let putting in the set of rings by itself concern you. A decent DIY'er can do it.
 

Last edited by marbobj; 03-10-09 at 08:48 PM.
  #12  
Old 03-11-09, 12:52 AM
Member
Join Date: Nov 2005
Location: Charlotte, NC
Posts: 198
A lot of good info in this thread, so I'll try not to repeat what has been said. Sounds like your compression lost is due to a head gasket and not the rings/piston. I would pull the head for further diagnosis. After pulling the head and you notice the cylinder walls are in good condition and still have a cross hatch pattern, then it's safe to assume the rings/pistons are in good shape. I would also pull the rod caps and visually inspect the rod bearings. Rod bearings normally take more abuse than main bearings. At that point you have to decide what and how much you want to invest in the car.

You sound pretty mechanical so a in-frame rebuild would probably be a good idea.
 
  #13  
Old 03-11-09, 05:40 AM
Member
Join Date: Dec 2001
Posts: 2,538
sounds like rings to me also, besides the headgasket/cracked head problem also.
a diesel engine can go alot further without ring problems due to diesel fuel wich does a good job lubricating the cylinders and rings, wich they will still wear but they will typically last alot longer than a gas engine.
 
  #14  
Old 03-16-09, 03:46 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Thanks for the last 3 replies. And especially thanks for marbobj's detailed explanations.

Me and the car are parting ways. Too much risk in partial teardown, with the possibility to discover that not only head work is needed but lower end work also. I'm not up to such a monumental task. Too time consuming - and the overall condition of not only the engine, but car, does not warrant the work.

I found and bought another car just like it. Same color also. Has same miles mine did when I bought it. It has a new engine head on it that has been in the car now for the last 10,000 miles. The car sat for a few months, and yet the thing started right up instantly, when we cranked it up 2 days ago.

Here's the scoop on my ex-91:

On the way home about a week ago, somthing blew. A trail of steam was coming out the exhaust, as I drove down the highway. It had never done that before. When I got home, I noticed that massive air bubbles and water noises were occuring in my reservoir just by me rotating the engine by hand! And then when I ran the car in the garage, fog started filling the reservoir! So either the head gasket blew, head cracked or block cracked. Couple that with the other cause of the blue smoke billowing problem at cold start up. But couple that with the possibly most damning problem of all: The fall off of oil pressure, at times, at idle. That sort of what really clinched it for me.

No way am I taking one of these cheap engines and remove it from car and rebuild it. I'd only be interested in doing such a thing to say a 600 horsepower classic hotrod.
 
  #15  
Old 03-17-09, 09:01 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
That sounds like a good sound decision. We can only get so much out these things - then it's time to put'em to rest. You must have taken very good care of it to have brought it so far. Good luck with your next one.
 
  #16  
Old 03-18-09, 10:49 AM
nightowlpunk's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Nov 2004
Location: Connectitax
Posts: 456
Are you going to use the car with the bad motor for a parts car? Just curious because if you do get into an accident, the body parts should match very well if they are the same color.
 
  #17  
Old 03-18-09, 03:02 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by nightowlpunk View Post
Are you going to use the car with the bad motor for a parts car? Just curious because if you do get into an accident, the body parts should match very well if they are the same color.
I'll get what I can off it (the '91, with the 270,000+ miles on it). I still feel bad about (losing)that car. That one had a better sound and feel to it than the '90 one has. I keep thinking about if that billowing blue smoke in the morning was mainly from the valve guides/seals or if the rings were the problem, as suggested here. I can't get over the fact that up until the very end - up until it finally started to steam on the way home -that up until then, I only had billowing blue at cold-engine idling -and then it would go away completely.

To dampen my zeal for that car, I made a list of other things wrong with the car, such as how the oil pressure at times(another oddity)would fall off at idle, after engine was warm -but it would not do that all the time! How odd. And how it did not have adequate heat. The only reason I knew it had some is from a probe thermometer down in the register. If it weren't for that, you'd say it had no heat. And how the odomoter quit working at 265,093 miles back last October. And the ugly peeling clear coat all over the car. The replacement car does not have that.

The replacement car has the drivers window will go caddywhompus when you crank it down, then it will not go back up til you grab glass and get it back in track. And headlights don't work (not fuses or lamps ). And blower motor does not come on(not on any speed). And rear license plate lights do not work. And the car was used to pull a light aluminum fishing boat out in woods with lots of pine needles with deep layers of pine needles down in cowling and in engine compartment nooks and crannies, etc. This be a great car to take to the edge of a cliff somewhere and get the satisfaction of driving it off.

Maybe in a day or two my attitude will change. I gave $150 for the car and today paid $116 for fuel leak correction work, and had the mechanic keep the car so he could squeeze me in again and redo the front brakes and secure the exhaust system better so it does not clunk around under the car. I could have easily done the brake work, but am currently not in the mood, have regular work to do and am getting over being sick, and my garage is taken up by the '91 carcass (I could back it out if I stick a battery back in it, then gas out the neighbors.)
 
  #18  
Old 03-18-09, 03:08 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by marbobj View Post
You must have taken very good care of it ....
I did ---and didn't - combined. I took it easy on the engine, brakes and front end parts. Put in new radiator and used distilled water 50/50 with coolant. I applied anti-rust and rust conversion sprays on car, poured thinned oil down the door panels, vacuumed out and pulled out leaves/debris from cavities, etc. Car did not squeak, and drove true/no wobbling, and braked excellent and straight, and throttle body/air cleaner area looked brand new.

But as you may recall, I made a game out of seeing how long it go without and oil change, to see if oil companies are just bamboozling us with their claims. I never actually changed the oil in it during the 90,000 or so miles that I actually owned it for. I did change the filter in it once or twice ---near the end.
 
  #19  
Old 03-26-09, 08:31 AM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
To the many of you who have read my postings regarding my old '91 4-cylinder Dodge Sprit, which had that problem of billowing blue and white smoke when the engine was cold, for several minutes, but would not smoke thereafter -at all!

And to those who responded to questions from what I can gather from doing a compression test. And to those who have suggested I either scrap the car or do a TOTAL engine rebuild as opposed to 'taking a chance' on simply rebuilding the top half:

I keep thinking this over. Remember how I posted how even during that awful billowing that would cover acres of land(I've never seen the like of anything like that before), that right while that is going on, if I remove the oil cover cap, absolutely NO vapor of ANY sort would come out? Isn't that a clue right there in it's own right?

If it were the rings, what is the odds that only oil would SUCK into the engine cylinder(s) and burn, on the intake stroke, yet have NO...absolutely not one iota of blowby gas, when it fired after the compression stroke?

Isn't that a HUGE clue that perhaps it is NOT the rings? That of course, we all know that on a car with 270,000+ miles, the rings are bound to be worn(at least some). But what if they are only worn like any engine and not causing the billowing problem?

The reason I ask is, anyone should know that doing a head job on an airconditionless(it was all yanked out so nothing is in the way anymore) 4-cylinder Dodge has to be WAY cheaper than disconnecting the engione/transaxle and attempting a complete rebuild job. If the rings are not the source of the billowing, - then might not it be worth taking the chance to have the head rebuilt (if some mechanic does the work quite reasonable)? Maybe I could get another 75 or 100,000 miles out of that engine?

When old engine rings wear, isn't it not too likely that it would go from showing no signs of problems, to suldden failure within a few miles? Woudn't it be more likely that if there were ring problems, that first it would show up as smoky blowby gases coming out the breather or oil filler cap? And as stated, the car had none. Absolutely none. Not even clear vapor - even though I could feel the wind out the cover hole, when the engine was cold. (Once warmed up you feel alternating wind and suction.)

How would this be for a jury-rig test of the rings?: Fill the cylinders all the way to the plug holes with say a thin oily substance, like WD-40, and then after days, see if any of it seeped past the rings? And if not? ????

Why do I bother with all such stuff and questions?, you might ask? It is from stuff like this in life I have learned great things and have passed on what I have learned to others. And I like tio think outside the box. Adn i wodsu ratehr work less hours and tinker and save money as opposed to do what everyone else does and work yor life away so you can buy complex things that require lots of money to work on, and you are trapped in this viscous frenzy. And I do not take everything I hear as gospel, without proof. Hence - why I did not change oil in 2 vehicles, for 80,000 miles, to see if what oil companies say is true, or if they want your money. My rationale was that if oil coats the metal and forms a barrier allowing the oil to slip along the metal rather frictionless -that even if particles are in the oil, - shouldn't the oil be encapsulated around each particle and still provide a barrier between the oil-particle-oil- cylinder wall, for example?

With the new '90 I got, the ex-owner of 15 years said he changed oil every 3000 miles. Guess what? That car, with 90,000 less miles on it than my billowing '91, uses oil, I just learned! (In a few hundred miles, I have already added 1/2 qt.! No billowing or any real apparent smoking, by the way) And as much or more than when my '91 did up until the head/gasket let loose recently, and then all hell broke loose as far as water and oil consumption.

With my old '91 and it's billowing for those minutes in the morning, as you know, I have been suspicious that it really is horrendously bad valveguides/seals, and not the rings.
 
  #20  
Old 03-26-09, 02:39 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
I haven't read all the posts on that engine, but...

In hitting a few of them, though, I believe what you have in the 275,000 mile engine is a leaking head gasket which is the source of the billowing white smoke. It simply seeps water into the cylinder while the engine cools and pressure in the cooling system diminishes. Normally you would have a compression leak going back into the cooling system with the tell tale sign of bubbles, but with temperature variances and different sealing of leak points because of it, you may only see the seepage while the engine is cooling down.

What you described in the latter service days of the engine would support that diagnosis. That is the streaming white smoke coming from the engine on the last trip home, I believe.

I would say no to the valve seals doing it.

You could install a head gasket in it yourself - no mechanic, for a little of nothing. If you're apprehensive about putting in rings yourself, you can go that route. But with the compression test you did before and after the oil in the cylinder trick, I would be looking at two cylinders on their way out needing rings and an engine with 275,000 miles that tells you the rings are over due. If, by chance the compression loss was occurring through the head gasket on the cylinders with low compression you still have the high mileage rings left in the engine.

Also you said you lost oil pressure on the last trip home. That oil pressure issue needs to be resolved before anything else. If the oil pressure collapsed for any period of time a lot more than a head gasket would be needed = not worth fixing.

Once again, I wouldn't put the engine in a shop for a major. Any of the work you can do yourself remains a possibility if you're thinking about putting the engine back into service.

This I can virtually guarantee - if it doesn't say Cummins, Detroit, or Mack on it you will not get another 275,000 out of it after a major.
 
  #21  
Old 03-26-09, 03:58 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by marbobj View Post
Also you said you lost oil pressure on the last trip home. That oil pressure issue needs to be resolved before anything else. If the oil pressure collapsed for any period of time a lot more than a head gasket would be needed = not worth fixing.
Absolutely, I agree. But here is the deal: I did not suddenly lose oil pressure on the way home. I had steam coming out on the way home.

I have had my oil gauge act up for many many months, that after I drove say 20 miles on the highway and get to the first traffic light, with the oil all nice and warm and thinned out, the oil pressure gauge, that would be pointing toward a normal setting, would suddenly nose dive off the charts. Way off the charts. Until I either put it in PARK at the stop light (as opposed to in drive with foot on brake), or took off from the stop and go light. It also behaved this way heading home at night and slowing down to make the various corners to where I live. But this had been going on for months.

But here is what is odd about the gauge: Instead of the oil getting warm-hot and gradually as I drive, show the needle point lower and lower. And then say when at idle in DRIVE with foot on the brake, the oil pressure simply went down a little further - what is so odd is that the gauge would be about at it's normal position, but then suddenly nosedive. That is why I am not 100% certain it is the oil pressure. Why would the gauge act so abrupt? As opposed to gradually lowering (like I woud think should happen)as the engine speed gradually lowered?

My 90 does the same thing! Although, the needle does not drop off the chart. Instead, the oil lamp (an Aladdin's lamp symbol) that flashes on my dash. But with the '90 oil gauge, I notice that the running oil pressure, when warm, is actually lower than even the high mileage '91! In fact, it points right at the bottom low mark. (Actually there is a bold line that says L. Then a space. Then there are 4 division limes. Then a space. And then the bold H line.) Well, the running temperature shows the needle pointing to the bottommost division line! Even though it has 90,000 less miles and supposedly the oil had been changed regularly.

But here is something interesting about that: Why is there no engine clatter coming from the valvetrain (of the '90), when I slow down and the gauge points to the bottom divison line or even a hair under it, when the Aladdin's lamp symbol lights up and starts flickering?

I aim to have a regular oil pressure gauge put on in the place of the sending unit so I can really look at some numbers here.

Yes, it would really be foolish to invest any money actually in either of these engines if it truly is suffering from say bearing failure that is causing the pressure to drop.
 
  #22  
Old 03-26-09, 06:34 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,752
There could be something in the hydraulics causing the oil pressure to do that, but I would suspect an electric gauge/grounding of the gauge first. If it was important to me to figure it out I would put a direct pressure gauge on it. You would definitely have lifter clatter if the low pressure readings were accurate and the pressure stayed low for any length of time.

I would suspect the pressure readings are gauge related. I do think a lot of what you've been seeing is a leaking head gasket or cracked head. The rings would be a separate issue - obviously an important consideration in the future of the engine.
 
  #23  
Old 03-26-09, 10:49 PM
Member
Join Date: Nov 2005
Location: Charlotte, NC
Posts: 198
Sounds like you're not willing to part with the old 91, even though you purchase a new 91. Oil in the cylinder test only indicates if you have a problem in the bottom end (piston/rings) or top end (valves/head gasket/cylinder head). After re-reading this entire thread, in my opinion you have two problems.

1 - The billowing blue smoke at cold start is definately a indication of worn valves guides and/or seals. Especially if the blue smoke goes away shortly after the engine is driven.

2 - Since the oil in the cylinder test didn't significantly affect your compression readings, your problem is in the top end. Either valves, headgasket or cylinder head. Since you've already cleaned sludge (oil and coolant mixture) from the inside of the valve covers and have added 1/3 gallon of coolant after a 25 miles drive, you definately have coolant and oil mixing some where.

Even though it's a high mileage engine, your botton end appears to be in good shape. What you should do is pull the head for a look-see. If after pulling the head you notice the cylinder walls still have a cross-hatch pattern, the rings and pistons are in good shape. After pulling the head you might notice a obvious valve face that's broken. Also, closely check the cylinder walls for any cracks. This could be a possible location where you're getting water in the oil. To further check the condition of the bottom end, drop the oil pan and pull a couple main and rod caps to inspect the bearings. Doing this and you'll be $0 invested, just time.

After you have confirmed the condition of the bottom end, then you can decide if you want to proceed with repairing the top end. Be forewarned, with that many miles you will probably need all new valves and guides in the head. What you can do is call a machine shop and ask how much would it cost to completely rebuild the head with new valves and guides. Then call a parts store and check the price for a complete head gasket kit. Again, at this point you're $0 invested.

Most machine shop will pressure check the head in the quote that's given for the rebuild. Check to make sure the rebuild quote includes pressure checking the head. Now this is a area where you can be given an unexpected cost, a crack head. You can either replace a crack head with a salvage head or repair the crack head. Most heads crack inbetween the valves. I've had heads with cracks in those area repaired and look as good as new. Since you mention you can turn the engine by hand and produce bubbles in the reservoir, I would say it's a headgasket problem more so than a crack head or block.

The oil pressure light is probably associated with a sensor or harness problem. As stated, low oil pressure will give vlave clatter and/or rod knock. Installing a mechanical oil pressure gauge to check oil pressure and before tearing apart the engine is definately a good idea.
 
  #24  
Old 03-27-09, 03:48 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by CandiMan View Post
Sounds like you're not willing to part with the old 91, even though you purchase a new 91.
I'm a sentimental guy. One of my downfalls. But I am still mulling it over. I may advertise it for about the price of salvage, tell new buyer the truth, and tell him if he wants, he might 'chance it' by doing just the heads, if he is a gambler.

Oil in the cylinder test only indicates if you have a problem in the bottom end (piston/rings) or top end (valves/head gasket/cylinder head).
But you see; you used the word "only", and yet you included the lower and upper engine. The idea of adding oil to the cylinder is to see if it is just the rings, and not the upper end.

After re-reading this entire thread, in my opinion you have two problems.
I agree.

1 - The billowing blue smoke at cold start is definately a indication of worn valves guides and/or seals. Especially if the blue smoke goes away shortly after the engine is driven.
That is what I have heard. And it does go totally away.

2 - Since the oil in the cylinder test didn't significantly affect your compression readings,....
I have to stop you there. No. it went from like 70 without the oil, to 180 with the oil!! 180 is at least 30 psi over factory new engine specs! But here is the deal - I was told to add sizeable amount of oil and crank over the engine to allow excess oil to fly out the plug hole, and then to do the compression test. Trouble is - at moderate rotational speed of the engine, all that oil did not come out! The piston dome is still well below the plug hole! I had lots of oil still in that cylinder when I did the compression test, and I think that all I did was reduce the clearance in the same way one would do if you had the heads shaved and you upped the compression! I am afraid I learned nothing from that type of oil injection test. I think what you need to do is somehow, with some squirting tool of the right kind, try to flood only where the top ring is at the cylinder wall only, without building up piston dome height with oil - and then do the compression test. That is my logic, anyway.

.....your problem is in the top end. Either valves, headgasket or cylinder head.
That is what I have been hoping.

Since you've already cleaned sludge (oil and coolant mixture) from the inside of the valve covers and have added 1/3 gallon of coolant after a 25 miles drive, you definately have coolant and oil mixing some where.
Or not necessarily mixing, but burning the coolant. I do not notice oil on the dipstick. But regardless, we know we have a head or gasket issue of some sort

Even though it's a high mileage engine, your botton end appears to be in good shape.
You're the kind of preacher I like listening to.

What you should do is pull the head for a look-see.
My problem is the easiest way is to pull the head with the intake and exhaust manifold still attached (even recommended by Haynes), as then the rusty-seized bolts are a non-issue back there facing the firewall. But my problem is the car is currently parked in a hoistless garage (mine), and I have to somehow get the exhaust manifold disconnected at the "donut" gasket.

If after pulling the head you notice the cylinder walls still have a cross-hatch pattern, the rings and pistons are in good shape.
Okay.

After pulling the head you might notice a obvious valve face that's broken. Also, closely check the cylinder walls for any cracks. This could be a possible location where you're getting water in the oil.
I do get a temper if I waste my time on stuff. And if I got that far along and found that. Well, I have a sledge hammer in the trunk and I might........

To further check the condition of the bottom end, drop the oil pan and pull a couple main and rod caps to inspect the bearings. Doing this and you'll be $0 invested, just time.
All that kind of work is something I'm trying to avoid. I'm not 20 anymore, and do not have the ambition with engines I once did with late 60-early 70's hot rods that were fun to work on. This Spirit is just some device to get from point A to point B. And I have already worked myself to death in this life, physically and mentally. I'm a mechanic, electrician (you would not believe how and where I found the 3-way power outage 2 days ago - I refuse to be beaten by any snafu), plumber, sheetrocker/mudder, builder, remodeler, appliance repair man, HVAC man... internet forum adviser ....an endless list. I think I will just put a pressure gauge on the engine and see what it reads. If bearings are bad, the oil pressure is supposed to get bad.

Be forewarned, with that many miles you will probably need all new valves and guides in the head. What you can do is call a machine shop and ask how much would it cost to completely rebuild the head with new valves and guides. Then call a parts store and check the price for a complete head gasket kit. Again, at this point you're $0 invested.
Yes, I would absolutely follow this advice, for sure.

The oil pressure light is probably associated with a sensor or harness problem. As stated, low oil pressure will give vlave clatter and/or rod knock. Installing a mechanical oil pressure gauge to check oil pressure and before tearing apart the engine is definately a good idea.
The old 270,000 mile 91 sounded like a clatter trap. It has valve clatter and I have evn wondered it if I am hearing piston slap. But here is the deal. Remember how I said the oil gauge would nose dive way below L, at times? At times -which is odd in it's own right. But, the lesser mileage '90 (the newer one I now am driving) also shows the gauge get low after the engine is warm -also at times. BUT - the valvetrain, nor anything, clatters at all. This has a 10,000 mile brand new engine head on top. But if weak oil pressure were occuring, as documented by the oil light flickering at stop and go lights -again, sometimes only...... BUT, the gauge will read right on the bottom mark or just below it!.... Yet, no engine clatter! Hence, I am thinking that if I am getting erroneous gauge info for the '90...... Maybe it is also erroneous for the old '91!, and all that clatter has nothing to do with oil pressure, but simply worn valve lash adjusters, let's say. Also, the old '91 had lots of oil up in the top of the head, which seems like a good sign. Another good sign is the cam lobes have no outer ridge mark on any lobe (as Haynes manual shows for wornout cams), the lobes look and feel brand new as do the roller rockers.
 
  #25  
Old 03-27-09, 08:58 PM
Member
Join Date: Nov 2005
Location: Charlotte, NC
Posts: 198
You've been in this buisness long enough to know mechanics, plumbers, electricians, contractors, farmers, carpenters, and machinist all have their own opinion even though they all have the same interest in mind. You have not lost anything with your old 91, what do you truely want to do with that vehicle? Sentimental or not, sometimes we have to cut the string and move on.

From your discription it sounds like a user friendly DIY kinda car. Which is a perfect vehicle for someone who's interested in learning and fixing a engine.
 
  #26  
Old 03-28-09, 12:22 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by CandiMan View Post
You've been in this buisness long enough to know mechanics, plumbers, electricians, contractors, farmers, carpenters, and machinist all have their own opinion even though they all have the same interest in mind. You have not lost anything with your old 91, what do you truely want to do with that vehicle? Sentimental or not, sometimes we have to cut the string and move on.

From your discription it sounds like a user friendly DIY kinda car. Which is a perfect vehicle for someone who's interested in learning and fixing a engine.
Maybe I could donote it to the highschool auto dept. We have some locally where they have won awards at troubleshooting contests and stuff. It be a real kicker though to see that they fixed it up and someone else was driving MY vehicle around.

Although why should I complain when the ex-owner of my current car sees me driving around HIS vehicle for $150.
 
  #27  
Old 03-28-09, 12:53 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,019
Just to throw in something I read recently (PM..PS? not sure)..no idea if its true or been stated here before.

You should only use about a teaspoon of oil (I'd guess that would need to be adjusted for the engine size), and inject it with a syringe of some sort. I have a couple of irrigation syringes I got from the vet that I guess would be perfect, since they have long curved plastic tips.

And you should also remove all other plugs so that engine gets max cranking speed.

Just throwing that out there.
 
  #28  
Old 03-28-09, 02:17 PM
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Originally Posted by Gunguy45 View Post
Just to throw in something I read recently (PM..PS? not sure)..no idea if its true or been stated here before.

You should only use about a teaspoon of oil (I'd guess that would need to be adjusted for the engine size), and inject it with a syringe of some sort. I have a couple of irrigation syringes I got from the vet that I guess would be perfect, since they have long curved plastic tips.

And you should also remove all other plugs so that engine gets max cranking speed.

Just throwing that out there.
Good advice, I'd say. I should stop at the vets. I know the one lady good.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes