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Oil System Help


lg_rebel's Avatar
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09-20-02, 04:18 PM   #1  
Oil System Help

I actually have a couple of questions. I havea 13 HP OHV Briggs engine 28000 series that I have been racing. It came off of a White mower, posibly designed just for that company's mowers.

1 Lately, I have been getting blowby back through the crankcase vent tube into the air filter. It sounds like extra compression, but I've done nothing to it and I don't know why it just all of the sudden started.

2 I tore the engine apart in an attempt to find the problem ( with no avail ) and decided since I was there, I might as well put new rings in it. However, I don't know what the ring gaps should be and i don't want to risk breaking one and wreaking havoc internally.

3 The engine I have is not full pressure lube and I was wondering how the oiling system worked.

Any help would be greatly appreciated.

 
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Fisher's Avatar
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09-20-02, 08:17 PM   #2  
Fisher
The original problem may have been just a blown head gasket.

 
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09-20-02, 11:57 PM   #3  
Hello lg_rebel!

Fisher may be right about the head gasket. On the OHV engines, if it is blown, it can let compression into the crankcase, and oil into the cylinder.

The oiling on this engine is done by an oil slinger. It is part of the governor flywheight assembly. The plastic "gear" that slips onto the end of the camshaft with the flyweights also has tabs around it that dip the oil and sling it all around inside the engine.

I don't have the ring-end gap specs on hand at the moment. A repair manual will tell you...and you should definitely be using one if you are working with the engine. You'll also need several other specs...like valve lash, head bolt torque and pattern, connecting rod bolt torque, etc...


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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09-21-02, 07:41 AM   #4  
Thanks for the help guys, I'll give it a shot. As far as manuals, I've got two, one copyrighted sometime in the 60's and another that covers to 1992. But I've got nothing for OHV. Every other time I work on one I've used what's close to what I've got and so far, so good. Guess I'll have to find a new one somewhere. This is the first time I've messed with an OHV engine. I was really surprised that the oil slinger assembly oiled the OHV system. It was hard enough to believe that they could oil a flathead good enough. Oh well, I guess they're just animals. Thanks again.

 
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09-21-02, 03:15 PM   #5  
mikejmerritt
I'm going to toss in a thought here so here it comes.....Original problem was intake valve to tight. That will cause the very symptom you were having. In that you have torn it down and going back together the valves will be set properly so we may never know if simply setting the intake lash would do the trick but I bet my new M$ Optical Mouse it would....Mike

 
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09-23-02, 10:37 PM   #6  
Mike may also be right.

If it helps...the ring gaps are:

for 28E70,28N700,28P700, 28Q700: ring gap limits are:

Top compression ring: 0.025 inch
2nd compression and oil ring: 0.030 inch

for 287700:

Both compression rings: 0.030 inch
Oil ring: 0.035 inch


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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