2.6l 6-pot oil in cylinder #6 - Where is it likely coming from?!?!?!?

G'day All,

According to the manual and parts manual the exhaust valves DO NOT have a valve stem seal.

So only the inlet valves have an O ring seal and fit in a grove inside the valve guide.

You do not have to remove the exhaust valves.

Also the manual has the sequence to tighten the cylinder head bolts which may explain why you have a leak from cylinder 6 to 5 and one. 14 bolts are torqued to 50 ft/Lb and 6 bolts are torqued to 30 ft/Lb. Something to be aware of when fitting the cylinder head.

Chris

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Originally Posted by Busted Syncro

According to the manual and parts manual the exhaust valves DO NOT have a valve stem seal.

So only the inlet valves have an O ring seal and fit in a grove inside the valve guide.

You do not have to remove the exhaust valves.

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I was trying to remember whether I had to fit O-rings to the exhaust guides (it was a few years ago.....), I removed the valves to re-seat them.

Because of their location oil is draining away and exhaust pressure isn't trying to suck oil in so probably no need in the exhaust guides.


Colin

Chris you made my day...no, you made my month!!!!!![bigsmile][bigsmile1][smilebigeye] I haven't had time today to pull out the parts manual and determine whether or not the exhaust valves had guide seals. The only reason I was questioning whether they did or not was based on the orientation of the exhaust valves. So mate you have done me a big favor by letting me know this!!!!! The thought of having to remove the exhaust valves with the engine in situ made me nauseous and made my back hurt [bawl]

My brother lives and works in Australia in Queensland. Not sure where all you gentlemen live over there, and I know its a big place, but if I ever get close, the stubbies are on me!!!!!!

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Originally Posted by Busted Syncro

G'day All,

According to the manual and parts manual the exhaust valves DO NOT have a valve stem seal.

So only the inlet valves have an O ring seal and fit in a grove inside the valve guide.

You do not have to remove the exhaust valves.

Also the manual has the sequence to tighten the cylinder head bolts which may explain why you have a leak from cylinder 6 to 5 and one. 14 bolts are torqued to 50 ft/Lb and 6 bolts are torqued to 30 ft/Lb. Something to be aware of when fitting the cylinder head.

Chris

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Originally Posted by matthamilton

Looks like in section 12.29.18 of the workshop manual it does reference the remove of and the refitting of the o-rings. And Gromit you are correct they go into the valve guides. I saw the picture which makes it look like they are place literally on the stem itself against the valve guide. I completely missed this detail and was only looking at the pictures for this part I guess!?!?!?

It also appears that by removing the timing chain and gear and radiator, I can theoretically remove and replace the exhaust valve guide seals in situ!!!!! It also appears that the exhaust rocker shaft is two pieces so I will fab an extractor to assist me since I will not have access to the back of the block to remove the shaft while it is in the engine bay. I really don't want to have to pull the engine again!!!!!!

Thanks gentlemen for all the knowledge! try very very much appreciated!!!!!!

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Couple of tools you can make Attachment 187374 Attachment 187375

I have thought about the smoke coming from the other cylinders. When you performed the compression test you wind the engine over against compression thus sealing the rings against the piston bore. When you performed the smoke test the smoke was bypassing the piston in #6 cylinder, this would then put some pressure in the sump and could cause smoke to come out of all the other cylinder as the pressure is low and from the bottom side of the rings. You stated the cylinders in question had good compression readings, did you find excessive oil in those cylinders when you removed the head if not I would think they are in operational condition. When running all engine have some blowby which is combustion gas bypassing the cylinder rings and venting into the crankcase. As long as it’s not excessive and causing you to burn oil it’s business as usual.

Just something for you to ponder I would have a good look at the rest of the bores and piston crowns if there is no carbon buildup and the plugs were clean I should think the rest of the motor is operational. How the rings aligned is a mystery that may never be answered.
Gippy.

Amazing!!!!! Thank you!!!!

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Originally Posted by 1950landy

Couple of tools you can make Attachment 187374 Attachment 187375

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I tend to agree with you on all accounts. #3, #4, and #5 all had compression in the 150 lbs. #1 and #6 were the suspect ones. #1 was around 108 lbs. I'm gonna pull all the pistons and just give them a good look-see. Might as well since I have it torn down. Cylinders 3, 4, 5 had very little carbon build up and again I agree with your assessment.

Love all the information you and the others are putting out there. Very very helpful!!!!!

I do love this truck and after 8 years restoring her myself, I really want to enjoy this nice fall weather here in Nashville, TN!!!! Had her on the beaches in NE Florida last week and she was a real head turner!!!

Attachment 187376

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Originally Posted by Gippslander

I have thought about the smoke coming from the other cylinders. When you performed the compression test you wind the engine over against compression thus sealing the rings against the piston bore. When you performed the smoke test the smoke was bypassing the piston in #6 cylinder, this would then put some pressure in the sump and could cause smoke to come out of all the other cylinder as the pressure is low and from the bottom side of the rings. You stated the cylinders in question had good compression readings, did you find excessive oil in those cylinders when you removed the head if not I would think they are in operational condition. When running all engine have some blowby which is combustion gas bypassing the cylinder rings and venting into the crankcase. As long as it’s not excessive and causing you to burn oil it’s business as usual.

Just something for you to ponder I would have a good look at the rest of the bores and piston crowns if there is no carbon buildup and the plugs were clean I should think the rest of the motor is operational. How the rings aligned is a mystery that may never be answered.
Gippy.

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That looks a great refurbishment and guaranteed to turn heads.
Great jobs.

Just an update for all those who have weighed in on this thread. I have gone ahead and ordered a proper set of compression rings from the great people at Cox & Turner Engineering in the UK. Might as well remove one additional item as a problem point and use the rings that the engine builders use.

Should have those in about 7-9 days and will begin to put the old 2.6l back together again. New head gasket, new valve guide o-rings and new compression piston rings should have her running well!!!

Back with more as soon as I have an update.

Thank you for keeping us informed on progress.

This is the sort of thing that encourages people to provide help. And also provides a long term resource for others with similar problems.