Should I have my heads rebuilt?

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Old Sep 2, 2008 | 06:33 AM
  #1  
54olds's Avatar
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Nothing new beats an Olds
 
Joined: Aug 2007
Posts: 94
From: Illinois
Should I have my heads rebuilt?

As many of you know I've posted a few threads regarding my 54 olds 88 and some of the engine problems I've been experiencing. Here's a brief summary:

* Burns oil (light blue smoke at start-up and while running.)
* Motor starts OK when cold, oil pressure at around 30 pounds.
* After warmed up, motor wants to stall, especially when put in drive.
* Oil pressure drops to about 10 at idle after warmed up.
* Compression tests showed all cylinders around the 107-115 range.
* Leakdown tests had a lot of air escaping out the oil filler tube.

I know air out of the filler tube is supposed to indicate bad rings, but that doesn't jive with the compression readings I got. I've been told it could be valve guides and seals. I have checked for vacuum leaks and found none. I have put the old girl up for the season, and I'm planning on taking the heads off and having them re-done at a machine shop.

Is this the right course of action to be taking at this point? I have no plans on driving her until next year, so I have plenty of time to decide what to do.

Thanks!!
Old Sep 2, 2008 | 06:54 AM
  #2  
joe_padavano's Avatar
Old(s) Fart
 
Joined: Mar 2007
Posts: 50,770
From: Northern VA
Originally Posted by 54olds
As many of you know I've posted a few threads regarding my 54 olds 88 and some of the engine problems I've been experiencing. Here's a brief summary:

* Burns oil (light blue smoke at start-up and while running.)
* Motor starts OK when cold, oil pressure at around 30 pounds.
* After warmed up, motor wants to stall, especially when put in drive.
* Oil pressure drops to about 10 at idle after warmed up.
* Compression tests showed all cylinders around the 107-115 range.
* Leakdown tests had a lot of air escaping out the oil filler tube.

I know air out of the filler tube is supposed to indicate bad rings, but that doesn't jive with the compression readings I got. I've been told it could be valve guides and seals. I have checked for vacuum leaks and found none. I have put the old girl up for the season, and I'm planning on taking the heads off and having them re-done at a machine shop.

Is this the right course of action to be taking at this point? I have no plans on driving her until next year, so I have plenty of time to decide what to do.

Thanks!!
The very simple test is to run a compression test dry (after warming the engine) then squirt a little oil in each cylinder and run it again. The oil serves to seal the rings, so if the compression raises significantly with the oil, you need rings. If not, you need the heads done.
Old Sep 2, 2008 | 07:04 AM
  #3  
Olds64's Avatar
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Joined: Jul 2007
Posts: 18,196
From: Edmond, OK
light blue smoke at start-up
This is a sign of bad valve guide seals or valve guides. However, your compression test looks pretty good. I would do the test like Joe says and see what kind of results you get.
Old Sep 2, 2008 | 10:09 AM
  #4  
54olds's Avatar
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Nothing new beats an Olds
 
Joined: Aug 2007
Posts: 94
From: Illinois
Originally Posted by joe_padavano
The very simple test is to run a compression test dry (after warming the engine) then squirt a little oil in each cylinder and run it again. The oil serves to seal the rings, so if the compression raises significantly with the oil, you need rings. If not, you need the heads done.

I neglected to mention that I did do that on a couple of cylinders. There was no change.
Old Sep 2, 2008 | 04:54 PM
  #5  
joe_padavano's Avatar
Old(s) Fart
 
Joined: Mar 2007
Posts: 50,770
From: Northern VA
Originally Posted by 54olds
I neglected to mention that I did do that on a couple of cylinders. There was no change.
Rings tend to wear uniformly from cylinder to cylinder (which implies this is a valve problem), but you still should do them all.
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