Noticed when I bought the truck a little over 2 years ago. That the distributor teeth were worn. With 175k I wasn't surprised and replaced it with no issues for about 6 months or 3000 miles. Then it would miss and hesitate. Through much diag and headache I found another worn gear. Replaced under warranty. 14 months and about 5000 miles later. It wouldn't start. Yet again. The gear was worn to the point of braking. Now some people have said the can could be moving. We looked with a scope and the can gear teeth look fine. What I want to know is what could be eating these distributor gears so rapidly. Thanks in advance.

 

Next time u change the gear, have the camshaft retard set to 0 degrees do a little looking around here, u need someone with a capable scan tool (not the cheapy ones) to set it.... This will possibly require u to have to modify the hold down bracket, which Captain Hook explains in one of these threads around here!!!!!! Maybe he will chime in here? If memory serves me right, it can be plus or minus two degrees of zero..... However, if u are a perfectionist u will only settle for zero degrees.....

 

I can see cam retard effecting running condition. But how does it effect the life span of the gear itself?

 

Improper gear lash. The dist. gear should be softer than the cam gear so as to not damage the cam. If the gears dont mesh properly they are not making contact at the proper location on the gear teeth. That is what will wipe out the dist. gear. You must also check to make sure the distributor is fully seated down on the manifold. Besure there is no old gasket or anything built up on the manifold or distributor to keep it from setting down fully on the manifold.

 

How do u check for lash? I know the old gaskets came off and the distro was seated well. (Learned the hard way on other vehicles). Are you saying that can retard effects lash? I thought that was the caps relation to the crank sensors reading. I'll have to see if I can get the pictures uploaded.

 

Above is the first gear when I bought the truck


This was labeled 5 months later on my uploads Lol


And the latest occurrence

 

Something is definitely wrong there. Looks like the distributor is being installed crooked somehow. That or there is a bad tooth or burr on the cam shaft gear. But it is definitely not aligning properly. Are you sure you are using the proper distributor for your year vehicle? I know that sounds messed up but maybe something is not matching up properly with this engine. Is it original? same year as vehicle? ever been replaced?

 

As far as i know, the engine is original, although, the harness does look like it has been moved and stretched to fit. so maybe older block???

One of my coworkers a mechanic for many years, says he has seen the cam stops wear or even the cam gear wear letting the cam move back and chewing on these gears. i thought maybe the oil pump was going making the distro hard to turn?

the distro's look identical to the ones i remove, and as i said above, im sure they are seated, and no extra gaskets.

truck is 96 jimmy sls 2 door bout 181k miles

 

Those pictures are perfect examples, of why u need to set camshaft retard to +or minus 2 degrees!!!!!that's what happens when it is off, now look at the diameter of the distributor shaft, how big is it? & now look at the diameter of the hole in the intake.....see any difference????? The intake hole is considerably larger than the distributor shaft........ When u drop the dist. In , grab the base and wiggle it back and forth in the hole.....by setting the camshaft retard u are aligning the gear on dist. To the cam gear , allowing the gears to mesh properly with each other......eliminating the abnormal wear that u are seeing now on the gears.......

 

Now u have two options here......... Have the camshaft retard set within specs ( which will almost certainly require modding the hold down bracket) or keep replacing gears every so often! The choice is yours