I had a 394 engine rebuilt by a engine rebuilding shop. It was later installed in a 1964 Olds Dynamic 88 that was restored. The restorer told me that the lifters chattered and I have should have the rebuilder recheck the engine. The restorer said the lifters chattered the first time they started the engine and continued up until the time I picked it up. I drove it back to the engine rebuilder and he told me that he wasn't sure what caused the chattering noise (could be the wrong oil, wrong gas, wrong first time start-up process). During engine testing he found that one of the cylinders lacked compression. Any ideas what could be the problem?
Thanks

 

I would assume that the engine rebuilder is the one that has the answers...

 

If the lifters were clattering they were probably not adjusted properly which would cause the valves not to open and close properly causing a lack of compression. Just my guess.

 

Sounds like a defective engine builder to me. There's no need to guess he needs to fix what ever is wrong.

 

Don't let your engine builder off the hook on this one. He needs to take responsibility on this issue.

 

X2!!!
It's not cheap to buld an engine. So if a pro shop did the job, there better be a warranty, cause it sounds like this one hasn't even turned 100miles. From your description alone, I would have probably trailered it over.

Make sure that they don't damage the resto work you did to your car. If they screw it up, I'd be letting them know in advance that they'll pay for that too!

 

Not likely he would, unless he removed a valve cover to find out.

My first guess: He does not know that reground cams have a smaller base circle, and the difference is normally made up by using a longer lifter or pushrod.

And it could be that the air in the tires needs to be changed.

Poor valve and/or piston ring seal, a broken piston, or a blown head gasket? Doesn't matter much, because everything points to an error by the rebuilder. Any reputable shop would have already had it corrected, at no charge.

This story illustrates, why one should never "price shop" for a machine shop.


Olds did not use adjustable valve trains.

Norm

 

Norm, you crack me up.
Take it easy on them.
Jim

 

Your 394, like the rest of Olds engines has a non adjustable valvetrain.The difference is that the 394 and earlier engines use shaft mounted rockers. I haven't checked, but the rocker shaft stands might be on upside down. They may be offset enough to give you the clearance for the clatter. Also remember that they feed the oil to the rocker arms through one of the stands. As far as the no compression, I would think that could be another totally different issue. Valve stuck or bent, valve seat not ground right, or a ring issue on that cylinder. Hope this helps.

 

Yes, more stable than the newer designs and, if properly maintained, would be less likely to cause any valve lash in a 100,000 mile engine.

But this is a "fresh" engine that was rebuilt by a "professional".

In the day, this was the "shadetree" method of curing (not causing) the propblem.

Both shafts are fed through the stands. If the oil is not there, the fault lies with the assembler.

And as the last step in the QC chain, the person who assembles the engine assumes responsibility for the finished product.

Norm

 

Thanks for all the input. So far, further investigation shows the piston in the cylinder where there was low compression is scorched on the side of the piston and the cylinder shows some friction marks from the piston. This low compression cylinder is the back cylinder on the passenger side of the engine. The rebuilder is going to further disassemble the engine to see if he can determine the exact cause. There looked to be oil flow to the cylinder so lack of lubrication didn't appear to be the issue. I told him that obviously there was an issue with the rebuild anmd it appears with this piston. The engine had only about 200 miles on it and had been making the lifter chatter noise from the first time it was started. He is coming around to the fact that this is pointing to his fault and has agreed to fix the problem on his own dime. The lifter chatter noise may be an unrelated issue from the piston and he has admitted the lifters need to be replaced as well. After all this, the rebuilder still contends that using regular oil to start the engine contributed to the problem. His argument is that the EPA made all the oil manufacturers remove all the zinc from their oil in early 2008 and therefore this "zinc-less" oil did not adequately protect the engine. He feels that had I used Brad Penn oil to break in the engine we probably wouldn't have a problem. I told him that there was no way I was going to believe that the wrong motor oil caused this issue. His other position is that he wasn't present when the engine was started up and he therefore can't verify that it was started up properly and that something didn't happen at intial start up that caused the problem.
I should say that all this guy does for a living is rebuild engines. He has been in business for years and has a crew of about 10 full time employees that tear down and repair/rebuild engines. He has a reputation as one of the best in our region and that is why I went to him in the first place.
Well again, thanks for all the input and ideas. I really appreciate having the group of experts that are part of this forum to bounce issues off of for advice and your opinions.

 

Crappy oil usually just flattens out the cam, and does not cause piston damage. something else was wrong.

I do agree with the Brad Penn oil though.

Regular 10-30 and a bottle of zddplus will probably ruin your cam.

Been there done that, got the t-shirt.

Never a problem with "the green oil"