Oil in Exhaust Options

[Mikemo44]

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,

[Mikemo44]

Here is a video of the cylinder in question:


https://www.youtube.com/watch?v=wH9bmmlLreE

[rhodyguy]

Spent valve guide?

[Superhawk996]

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.

[porschetub]

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.

[Mikemo44]

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.

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.

[Mikemo44]

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!

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.

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.

[Superhawk996]

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.

[930cabman]

Oil ring(s) stuck?

[Artfrombama]

Am I seeing a gap around the intake valve guide?

[porschetub]

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.

(IMG:style_emoticons/default/agree.gif) That guide is worn and the valve stem as well , they wear until the excess clearance causes poor heat transfer to the head ,then end result is burnt or snapped valve .
Still makes me wonder why you have good compression on #2 and are burning so much oil ,that indicates oil control ring is compromised but the compression is still holding in there...maybe that is rubbish but food for thought ? ,certainly not normal.
Cheers.

[wonkipop]

funnily enough there is a Morris J Van in the workshop at the moment.
owner has had it since the early 70s. he bought it when a metropolitan bakery here in north antarctica sold the fleet. very popular with university students in the early 70s.
kind of like a proto VW bus fad before the bus fad.
you know the cars @porschetub ? sort of thing bound to have been in NZ too.

anyway.

it was spewing oil out everywhere. huge amounts through the crankcase breather tube (that thing designed to deliberately cause motor cycle crashes until it was outlawed in the late 60s). as well as any other crevice in its various nooks and crannies.

yet.........

compression test said it had compression despite every indication it had something beyond the normal limits of blow by.

(IMG:style_emoticons/default/biggrin.gif)

the head came off on wednesday night.

and lo and behold there was a vision of pure f$%)ness in the form of 4 pistons with not burnt through tops. no there were burnt out holes at the edges. all four. which has to have caused some carnage in ring territory below.

and out came the story.

it overheated. when it was unwisely taken up the freeway from metro north antarctica to some provincial research camp about 100 miles away. this is a vehicle that is barely capable of cracking 35 mph. got flogged up the freeway. got warm-ish. got oil poured down its throat to get it to the base camp and then got similar quantities poured into it to get home. and some water. and some more water.

we have determined/confirmed its also cracked its head.

the pistons have not come out yet. so we cannot tell just what state the rings are in.

but it had compression. and acceptable leakdown.

it just did not have anything else indicating it was of sound mind and body.

maybe this 914 is doing something similar.
though it if was and was to do with rings, i am sure oil would also be ejected elsewhere.
pcv valve would be in distress?
so.....if not it has to be that valve and guide.
sure spitting a lot of oil out, not your normal worn VW valve guide symptoms,
which are much milder. big puffs of smoke at start up and thats it.
i think it might be the culprit.

------

owner reports J van overheated. i would say it got well and truly baked.
it still drove mind you. got to the workshop here under its own power.
and............a lot of oil. both burned and ejected. (IMG:style_emoticons/default/biggrin.gif)