break-in & correct timing belt install?


Old 06-20-05, 10:02 AM
Thread Starter
Join Date: Sep 2004
Posts: 238
break-in & correct timing belt install?

The car: '93 mazda protege, 1.8l sohc, 5 spd, 92,800+ mis.

I did a valve job on this car and finally got it back on the road this weekend. Aside from breaking a perfectly good $28 fan switch while installing the t-stat housing and having a 12 year old heater hose leak upon reinstall, the project seems to have gone without a hitch.

What type of break-in should I expect? I cranked it with the injector harness unplugged until the oil light went out. I then plugged the harness in and the car started right up. I let it idle until the cooling fan came on while I checked for leaks. All the while, the car was smoking bad but sounded ok although idling too fast and occasionally surging. On initial drive the car seemed to lack power, smoked a lot under load and seemed at times to be starving for gas. I poked around and found that I had not tightened 1 of 3 ground connections to the head and the smoking seems to have stopped at about 15 miles. Now at about 50 miles, the idle has dropped to about 750 from 950.

The car seems to lack power at low rpm’s. I notice this when going from 1st to 2nd. Now I feel like I am shifting too soon and the car seems to be lugging at about 2000 rpm in 2nd. Therefore, the valve timing is bugging me now. When installing the timing belt, I noticed that the crankshaft had several degrees of play. Since the engine turns clockwise I turned it clockwise to meet the timing mark, but I could turn it several degrees counterclockwise until the crank started to turn. I installed the timing belt and cranked it clockwise many times. The camshaft and crank marks seemed to line up. After complete reassembly, I had to retard the timing a bunch. My pre-disassembly marks on the distributor base are now about 1/8 inch apart. I figured it would be right on. If I had taken out the crankshaft slack going counterclockwise the timing may have been right on my mark. Maybe the timing was off before or the timing belt was not on right. What is the correct way to deal with the crankshaft play? I have not seen this question addressed anywhere.

Why did the machine shop paint my head? The counter guy’s answer was that they always do.
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Old 06-20-05, 01:14 PM
Join Date: Dec 2001
Posts: 2,538
not sure what you would be reffering to when you say there is crankshaft play when installing the timing belt you want all the excess slack of the belt to be on the tensioner side the other side you do not want any slack in the belt when tensioner is tightened it will remove all slack from the belt and if you had any slack on the other side it will likely throw off the marks.
you might recheck timing on a fully warmed up engine at idle speed and folow the manufacturers procedures for setting timing if that doesnt resolve your problem suggest you recheck the timing belt marks to ensure they are ligned up correctly.
the engine should run fine after work was done besides the smoking which sounds normal if any oil was left in the cylinders that could take a few miles to burn out.
Old 06-21-05, 01:33 PM
Thread Starter
Join Date: Sep 2004
Posts: 238

What do I mean by play? The crankshaft pulley unlike the cam shaft can be wiggled a bit before real resistance is felt. This may be from slop in the piston pins, rod bearings and tranny. Just as you said, I discovered that the tensioner when applied to the slack side of the belt can move the crankshaft pulley off the mark.

I will take it apart and recheck. I plan to put a new timing belt and crankshaft seal on in about 2 weeks. I'm still getting the bugs out of this repair. I put a new heater hose on yesterday and taday bought a new t-stat gasket and dist. o-ring. I am taking one leak at a time. I will verify that the new cam shaft seal is holding when I replace the crank seal. Finally I'll put the new vc gasket on. The old slightly leaky one is on now in case I need to get in there.

I 'll check the timing after I replace the dist. o-ring.


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