GM 3800 carnage

wwillson

Staff member
Joined
Aug 20, 2003
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Location
Colorado
I was in my friend's shop yesterday and saw this

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First, I asked what was wrong with the motor and how many miles? BAD rod knock to the point that he told his mechanic to shut it off, because he didn't want a hole in the side of the block and have to explain how it happened to the customer. 60,000 miles on the mill.

Second, why drop the whole motor? He said his mechanic dropped the whole assembly out in 40 minutes! He's done hundreds of them and prefers it over trying to take the motor out the top, because it's much faster.

One curiosity to me is the twisted appearance of the balancer shaft

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The water pump had been replaced about 1000 miles before the rod knock started. He speculated that someone used an abrasive wheel to remove the old gasket and some of the debris got into the front of the engine, which lead to a plugged oil orifice and galling in the rod bearing. He put this placard on the top of the motor while I was taking pictures.

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The oil filter was still on the motor, so I asked if I could have it to cut open. The contents may help prove or disprove his theory about the gasket material.

This is what I found in the filter

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All metal and virtually no gasket material. I've cut many oil filters and have never seen anything like this. This is orders of magnitude more metal than anything I've ever seen.

It is possible that the grit from the abrasive wheel doomed this engine. The oil had been changed about 3,000 miles ago.

We are going to take the pan off and get some pictures of the bearings. I'll post them when I get them.
 
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Wow - just a galled journal with a plugged oil gallery caused the balancer shaft to twist like that.

I’m leery about using abrasives on the engine surfaces and especially ones that are part of the oil circuit. GM has harped on this point many times.
 
Similar to the old Mopars: 4 bolts for the K-member, unbolt upper control arms, disconnect torsion bars and a few other things, and lift the body up.
 
He is 100% correct! Using the abrasive disc on the gasket surface even if the old gasket came off in one piece will right after the engine bearings and other sensitive parts. The particles from these disc will go right through the oil/air filter that is why you don't find them.
There is always the guy that claims to use one all the time and never had a problem, that is pure luck and should not to be interpreted as they are safe.

The problem is many DIY and even some pro's have this idea that the gasket surface needs to be " new penny" clean, it does not. It needs to be free of any old material and deposits on the surface but it is common to have some staining where the old gasket was, this is not an issue.
Using these disc is very dodgy, they remove material especially on something made of light metals can damage the original machined surface finish bad enough that it can leak.

If these are used on a engine being rebuilt on external surfaces that are not machined and can be washed and thoroughly cleaned before being assembled its a non issue. I will not use one of these disc on any in service engine, in fact not even around it. These are the disc in any color or grit.

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I cut apart an oil filter off a 1MZ-FE the other day, looked just like that. Tons of metal. It ran fine.

I’m interested to see the bearings from this engine when you get pictures.
 
Will be interesting to see what the damage looks like. IMO, if all bearing surfaces are scuffed, then the OP's premise seems correct. But if only one bearing is bad, then I wonder if it's just plain bad luck.
 
I am a 3800 lover; currently own 3 of them in very roadworthy vehicles. I've never dropped an engine like illustrated, but I've replaced many intake gaskets, valve cover and oil pan gaskets, water pumps, etc....When the interior of the engine is open, I use a plastic razor blade together with a shop vacuum, and lots of clean white rags to stuff into openings. NO POWER TOOLS ON GASKET SURFACES WITH THE ENGINE OPEN. I've used acetone and clean rags on valve cover gasket surfaces. The pictures you've posted are very educational, thanks. For a 60K 3800 to have a rod knock, its certainly been abused.
 
There is no way that debris from a water pump job got into the oil. The coolant and oil are not in the same area. The intake gaskets do look pretty new and I bet that some goon did use those discs to clean the heads and block ends with them.
Chris,

I forgot to mention that the timing chain was done the same time as the water pump.
 
Yeah I have done 5 or 6 different 3800 intake gasket with no issue. I have two separate ones go over 210,000 and my old Buick is with my buddy closing in on 200,000. Either someone one messed up or they just got a bad one.
 
There is no way that debris from a water pump job got into the oil. The coolant and oil are not in the same area. The intake gaskets do look pretty new and I bet that some goon did use those discs to clean the heads and block ends with them.

That was my thought, it has the latest design. I see they did the timing chain too, so yes that could do it.
 

What a fiasco. DIY guy in way over his head. Got my new tools so now its time to take my engine apart, might as well do the tranny too then replace all at once.
 
Our '05 LeSabre just broke. About 240K miles on it, the transmission quit shifting, initially with a torque converter solenoid code, but when it was torn into, it apparently needed more extensive work, the family member we gave it to didn't want to put anything into it. I did the alternator, intake gaskets and associated stuff at about 60K miles. It has been relatively troublefree between then and now.
 
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