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Discussion Starter · #1 · (Edited)
I think I found the reason for lack of compression in cylinder 5. I finally managed to get the head off and have a look.

Has anybody else experienced this?

The head gasket seems to be in two halves - still connected in opposing corners. Is this normal?

Also a fair amount of scoring on the cam shaft for cylinder 5 - Central lobe. I suspect it controls the exhaust valves. Will upload a picture of that.

Thanks.
 

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Ouch! That’s ugly. While I haven’t had the Pilot head gasket off, I do think that’s normal for the gasket. Id be looking for any signs that the valve wasn’t moving freely or if there is any carbon causing it not to seal all the way. The scoring on the cam maybe telling you something more. Either way very likely your issue is fully contained in the head and machining / valve job should fix it up assuming the cam is serviceable.
 

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Discussion Starter · #3 ·
Ouch! That’s ugly. While I haven’t had the Pilot head gasket off, I do think that’s normal for the gasket. Id be looking for any signs that the valve wasn’t moving freely or if there is any carbon causing it not to seal all the way. The scoring on the cam maybe telling you something more. Either way very likely your issue is fully contained in the head and machining / valve job should fix it up assuming the cam is serviceable.
Thanks. I am thinking it might have been overdue for a valve adjustment. I just bought it as a project vehicle, so i don't know when it was last done. I will check tolerances. After snooping around the forum, It seems that the exhaust valves tend to get to loose? or is it the other way around?
 

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The other way around......when the valve lash decreases (tight), the valve(s) can not seal properly against the valve seat. Slappy valves are happy valves....with-in reason of course.
 

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Discussion Starter · #5 ·
The other way around......when the valve lash decreases (tight), the valve(s) can not seal properly against the valve seat. Slappy valves are happy valves....with-in reason of course.
Thanks for the correction. Will research this.
 

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Thanks for the correction. Will research this.
Ouch! That cam is toast. You may want to look for a used head in good shape and consider having that gone through. I'd also pull the valve cover on the other bank to see if you're seeing serious issues there too.
 

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Was this engine ever run low on oil?
What was the typical oil change interval?
 

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Discussion Starter · #8 ·
Ouch! That cam is toast. You may want to look for a used head in good shape and consider having that gone through. I'd also pull the valve cover on the other bank to see if you're seeing serious issues there too.
Thanks will do.
 

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Discussion Starter · #9 ·
Was this engine ever run low on oil?
What was the typical oil change interval?
I am not sure. I only just picked it up as a project vehicle. I think it was regularly maintained. I would be surprised if it ran low on oil.
 

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I think the crusty oil is a good indication that the oil wasn’t changed that often, but not enough to break a valve stem. Something got in there and got stuck which in turn, caused the damage you see. A good tear down is in order.....
good luck...
 

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Discussion Starter · #11 · (Edited)
I think the crusty oil is a good indication that the oil wasn’t changed that often, but not enough to break a valve stem. Something got in there and got stuck which in turn, caused the damage you see. A good tear down is in order.....
good luck...
Thank you for your input.

I am thinking that the temperature is too high in the valve cover.

I feel that the sludge on the top of the valve cover indicates that fire from cylinder 5 is escaping from the cylinder and entering the valve cover caviity.

There is no evidence of lack of oil. There is evidence of oil burning in the cylinder.

I suspect that this is oil that is escaping from the valve cover into the cylinder through the burned out valve.

Something got in there and got stuck which in turn

For some reason, something was allowing the valve to remain open too long. I suspect that originally, the valve setting was too large, leaving the
valve open too long.

Heat was able to escape into the valve cylinder. I suspect that carbon started to build up on the valve. This would have led to the burning of the valve, and ensuring that the valve could not seal.

I have ordered a Lisle 36050 Valve Keeper Remover and Installer Kit. I will be getting it tomorrow. I will be able to see what the valves look like.
 

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Thanks for the correction. Will research this.
The other valves and the head actually look really good! Looks like a rodent got in there and bit a chunk outta that valve though. LOL. HTH does that happen? Something got in there?
 

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............For some reason, something was allowing the valve to remain open too long. I suspect that originally, the valve setting was too large, leaving the valve open too long.........
If the valve setting (lash) is too large, the valve will open less/close sooner.

In the pic with the 4 valves.....none of them appear to be fully/properly seating, imho. My presumption is the valve seats in the head(s) have receded.
 
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Discussion Starter · #18 ·
Ouch! That cam is toast. You may want to look for a used head in good shape and consider having that gone through. I'd also pull the valve cover on the other bank to see if you're seeing serious issues there too.
Thanks. One head at a time:)
 

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Discussion Starter · #19 · (Edited)
OK, it looks like mechanical damage to me. None of the other valves 'burnt'?
No, only carbon build up behind and on the other exhaust valves.
I have begun to clean them up.
Provided pictures.

I have begun to clean them up.
I First use a knife to remove the heavy carbon build up,
I Then use a drill with 80 grit then 100 grit sandpaper in water.
 

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