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> Oil in Exhaust
Mikemo44
post Aug 4 2025, 10:11 AM
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Hi All, I have burnt and unburnt oil coming out of the exhaust on cylinder 2. Compression and leak down tests were both good. Looking for suggestions on how oil could be getting in/exiting the exhaust? Some searching suggests a worn exhaust valve guide?

The car doesn't have an exhaust on it, so I am able to put eyes on the exhaust port.

Thanks,
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Mikemo44
post Aug 6 2025, 02:58 PM
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Here is a video of the cylinder in question:


https://www.youtube.com/watch?v=wH9bmmlLreE
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rhodyguy
post Aug 6 2025, 04:22 PM
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Spent valve guide?
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Superhawk996
post Aug 6 2025, 06:32 PM
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Compression test - you’re clearly burning oil

That could either be coming past rings or pulled in through a valve guide. If compression is good then it’s all the more likely the oil is pulled past valve guides.
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porschetub
post Aug 6 2025, 10:55 PM
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QUOTE(Mikemo44 @ Aug 5 2025, 04:11 AM) *

Hi All, I have burnt and unburnt oil coming out of the exhaust on cylinder 2. Compression and leak down tests were both good. Looking for suggestions on how oil could be getting in/exiting the exhaust? Some searching suggests a worn exhaust valve guide?

The car doesn't have an exhaust on it, so I am able to put eyes on the exhaust port.

Thanks,

What the results of both compression and leak down tests, one mans good can be others mans not so good .
Have you done a valve clearance check/reset ? ...pointless doing the above checks otherwise .
Watched the vid and that cyl is burning a lot of oil sadly hence my comment on what your results on the tests were .
Cheers.
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Mikemo44
post Aug 7 2025, 08:23 AM
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Compression on all 4 cylinders ranged btwn 115-123 psi. Only performed leak down on Cylinders 1 and 2, showing approx. 7-8% loss. I have checked and rechecked the valve clearances 3 or four times.

I have the engine out and waiting on a valve spring compressor tool to arrive today to take a look at the valve guides.

Appreciate the help. Will report back once I get the valve disassembled.

QUOTE(porschetub @ Aug 6 2025, 11:55 PM) *

QUOTE(Mikemo44 @ Aug 5 2025, 04:11 AM) *

Hi All, I have burnt and unburnt oil coming out of the exhaust on cylinder 2. Compression and leak down tests were both good. Looking for suggestions on how oil could be getting in/exiting the exhaust? Some searching suggests a worn exhaust valve guide?

The car doesn't have an exhaust on it, so I am able to put eyes on the exhaust port.

Thanks,

What the results of both compression and leak down tests, one mans good can be others mans not so good .
Have you done a valve clearance check/reset ? ...pointless doing the above checks otherwise .
Watched the vid and that cyl is burning a lot of oil sadly hence my comment on what your results on the tests were .
Cheers.

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Mikemo44
post Aug 7 2025, 12:00 PM
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Quick update. I removed both exhaust and intake valves in cylinders 1 and 2. The exhaust valve in question was the only one that was difficult to remove, extremely difficult. It moved freely until the ribs at the end engaged the valve guide. I had to use a punch and hammer to get it through the guide.

There was very little play in any of the valves.

With compression good, leak down good, value guides don't appear to worn/loose, I'm not sure where to go next.

Below are a couple images, red arrow pointing to the problematic exhaust valve.

Much appreciate the feedback!

Attached Image Attached Image

QUOTE(Mikemo44 @ Aug 7 2025, 09:23 AM) *

Compression on all 4 cylinders ranged btwn 115-123 psi. Only performed leak down on Cylinders 1 and 2, showing approx. 7-8% loss. I have checked and rechecked the valve clearances 3 or four times.

I have the engine out and waiting on a valve spring compressor tool to arrive today to take a look at the valve guides.

Appreciate the help. Will report back once I get the valve disassembled.

QUOTE(porschetub @ Aug 6 2025, 11:55 PM) *

QUOTE(Mikemo44 @ Aug 5 2025, 04:11 AM) *

Hi All, I have burnt and unburnt oil coming out of the exhaust on cylinder 2. Compression and leak down tests were both good. Looking for suggestions on how oil could be getting in/exiting the exhaust? Some searching suggests a worn exhaust valve guide?

The car doesn't have an exhaust on it, so I am able to put eyes on the exhaust port.

Thanks,

What the results of both compression and leak down tests, one mans good can be others mans not so good .
Have you done a valve clearance check/reset ? ...pointless doing the above checks otherwise .
Watched the vid and that cyl is burning a lot of oil sadly hence my comment on what your results on the tests were .
Cheers.


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Superhawk996
post Aug 7 2025, 12:29 PM
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Going to try to offer some constructive advice without being critical.

There is a lot of discussion here without measured numbers. Ie subjective.


To measure properly you need a split ball gauge and a micrometer. A less accurate way to measure is to use a dial indicator and measure at the valve head (at approx valve lift) and wiggle the valve side to side. Take 1/2 if that measurement and that is a rough approximation of your valve to guide clearance.

The fact that you had to hammer the valve out is a bad sign. Likewise compare that valve stem to the other. Notice a difference?

That cylinder has been burning oil for a while based on the build up in the combustion chamber. Not sure if it is the lighting but the cylinder with the problem - the intake port appears to be wet looking? What is that. Look for head cracks around the valve guide.

The fact that there appears to be RTV around the cylinder to head interface is another bad sign. Not sure what that RTV is doing there.

What does the cylinder bore look like? Since you have it torn down at this point - I would actually pull the cylinder and inspect the rings to make sure you don’t have a cracked ring.
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930cabman
post Aug 7 2025, 02:56 PM
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Oil ring(s) stuck?
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Artfrombama
post Aug 7 2025, 05:57 PM
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Am I seeing a gap around the intake valve guide?

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