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Cheap manufacturing / Beef with GM
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88delta88



Joined: 09 Jun 2003
Posts: 2407
Location: Canada

Posted: Fri Jun 13, 2003 5:11 pm    Post subject: Cheap manufacturing / Beef with GM  

Has anyone had to replace the Timing gears and chain on thier 3.8L?

I had to, after the chain slipped the camshaft gear and rounded all the teeth. This was a fair sized job, but not hard, just annoying.

Anyways, if you have ever seen the camshaft gear GM put on these motors you would shit. They used an light aluminum gear, with a plastic (teflon?) coating on it to, I would say, reduce noise. This plastic starts to chip and crack after time, and in my case, the plastic was worn right off the gear in some places, making the gear's overall size smaller. The chain worked its way through this aluminum, and finally just slipped.

This amazes me that GM would cheap out on such an important part. Had the valves on my car been zero clearance, as I hear a lot are, I would have been looking at complete engine rebuild following this incident. I only have just over 70,000 miles on the motor, this shouldnt have happened.

Just a beef I had with GM...

Aaron
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Primer Death



Joined: 08 Jun 2003
Posts: 102
Location: Maine

Posted: Sat Jun 14, 2003 7:28 am    Post subject:  

That's GM for you, This is why you hear of S-10 always with their bad cams
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strokercutlass



Joined: 09 Jun 2003
Posts: 379
Location: Wis

Posted: Sun Jun 15, 2003 12:21 am    Post subject:  

the reason behind the synthetic covering is to lessen timing chain noise....most of the V8 olds, and the 3.8's have the synthetic cam gears, as well as alot of the other GM engines as well..chevy used this alot too...just like everything else..comfort was more of a factor than longevity...
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88delta88



Joined: 09 Jun 2003
Posts: 2407
Location: Canada

Posted: Tue Jun 17, 2003 5:24 pm    Post subject:  

Kinda figured this was a common part to have to replace... The replacement chain and gear set only cost me 13.00 from a parts store(and thats canadian dollars!). This wouldnt have been such a bad replacement, if only they hadnt stuck that waterpump in front of it!!! :-)

I like the replacement gears though, completely made of steel. No synthetic crap.
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Primer Death



Joined: 08 Jun 2003
Posts: 102
Location: Maine

Posted: Thu Jun 19, 2003 7:48 pm    Post subject:  

You'll need timing gears and guides too! Anything I'm missing strokercutlass?
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88delta88



Joined: 09 Jun 2003
Posts: 2407
Location: Canada

Posted: Fri Jun 20, 2003 9:34 am    Post subject:  

Yeah the kit came with the little guide and spring aswell... I did this swap a couple months ago...
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86Delta



Joined: 06 Nov 2003
Posts: 281
Location: NJ, USA

Posted: Fri Nov 07, 2003 12:38 am    Post subject:  

it is very strange that you broke the timing chain and you didn't bend the valves. that is how my car was when i got it, broken chain and bent valves. i did the chain and gears twice on my car (again at 200,000 miles as a precaution). i used GM parts (chain, guides, gears) because i heard that in addition to a little more noise (which wouldn't matter to me) the all metal gears may interfere with the cam sensor pick up, not sure if that is true, just what i heard.
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strokercutlass



Joined: 09 Jun 2003
Posts: 379
Location: Wis

Posted: Fri Nov 07, 2003 1:13 am    Post subject:  

have one in the shop right now that took out the timing chain...when it was said and done, only one cylinder had compression...new engine going in tomorrow...there seems to be no rhyme or reason to this..as the last 2 3.8's that came in with dropped timing chains ruined the engine....yet I've had ones that dropped the chain that were saveable...go figure...
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88delta88



Joined: 09 Jun 2003
Posts: 2407
Location: Canada

Posted: Fri Nov 07, 2003 9:54 am    Post subject:  

I dont know how I get so lucky - The gear stripped all the coating off, and the chain just spun free over the gear. I even tried cranking the engine over after it went (not sure what had happened at that point). Is it possible that the cam stopped moving in JUST the right place to avoid bending valves? I've been driving the car completely problem free for almost a year since I did the timing chain.

I did not have to replace anything, adjust anything except the chain and gears!
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strokercutlass



Joined: 09 Jun 2003
Posts: 379
Location: Wis

Posted: Sat Nov 08, 2003 12:08 am    Post subject:  

88..its hard to tell...I've seen the 3.8's go both ways, and i can't say its a difference in years, because the one today was a 93, while the last one that ruined the engine was an 86...I suppose "dumb luck" says it better than anything...lol
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