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Discussion Starter #1
Car is a 91 E34 3.6...not had the motor long and car suddenly started to missfire and generally run bad.
After some investigating found the compressions on 4 and 5 to be nearly none existant..all the rest 160+psi.
Im suspecting[and hoping] headgasket blown between the cylinders,but car has no other obvious symptoms of headgasket failure..ie..water/oil contamination,water use or overheating..??????
Another thing is the car did have a rebuilt top end including a new headgasket approx 30k ago including having the head skimmed[so the receipts tell me!!]

Any suggestion here would be greatly appreciated..

oh and anyone any experience of removing the head of one of the beasties???...:D

TIA
Gary
 

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Get a leak down test done aswell.

Hopefully its just your head gasket and you wont need a bottom end rebuild.

I can see a rebuild going into thousands and thousands. Might aswell find a replacement low mileage engine.
 

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Gary,

It's one of these three problems 1) broken piston ring (very unlikely), 2) blown head gasket, or 3(the most likely cause) completely worn valve guides in the no#4 and no#5 cylinder, yes worn valve guides will cause a cylinder to lose all of it's pressure and result in misfires for both cylinders, a easy but costly fix is to remove the head, replace the worn valve guide (might as well replace all the valve guides while the head is off), then reinstall the head, is the car burning more oil than usual as this is also a sign of worn valve guides or piston rings. Hopefully this helps.

Garcia
 

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Cyrus said:
How costly is changing the head gaskey on a 3.6? And Why?
If you're not experience with timing changes and head gasket I wouldn't recommend it for, the costly part is finding a good mechanic/shop to do the work

Garcia
 

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Discussion Starter #6
Wouldnt the valve guides wearing produce a more gradual fault??The car doesnt use a drop of oil and as soon as this fault occured,i havent really driven it much..This problem came on more or less instantly..looks like the head is coming off anyway at a minimum..The best guide i can get a the moment is between a £1000 and £2000 depending on the fault bein with the head only..bottom end problem=just more cash...

Oh dear..bread and jam for christmas i think..
 

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Alpinaman,

Your last message just jarred my memory (I had a particular problem on an old pontiac engine, yes I know there's a big difference between the two, but there are many similarities) I had the same problem, no cylinder pressure in #7 cylinder, car didn't burn any oil, no cooling problems, after pulling the head I found a bent valve, because the bent valve couldn't properly seat against the head all the cylinder pressure was escaping through the intake valve. Leakdown test will help isolate whether it's a bent/burnt/ or cracked valve, or piston ring problems, hopefully it isn't gouged cylinder walls (an entire block replacement), best of luck.

Garcia
 

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Discussion Starter #8
Ta mate..Bent valve?bloody hell..dont like the sound of that..Must be a reason to have a bent valve??Timing chain jumping??..god knows eh...reckon i will know whats happening in the coming week...i can feel myself puckering up at the thoughts goin through my head!!!!

Cheers

Gary
 

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alpinaman said:
Ta mate..Bent valve?bloody hell..dont like the sound of that..Must be a reason to have a bent valve??Timing chain jumping??..god knows eh...reckon i will know whats happening in the coming week...i can feel myself puckering up at the thoughts goin through my head!!!!

Cheers

Gary
Alpinaman,

Let me restate (sorry for raising your blood pressure, heart rate), not a bent valve but a valve that isn't seating properly against the head valve surface.
I hope it's something minor.

Garcia
 

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Discussion Starter #10
Ahhhhh..i realise what ya sayin now..was gonna try and soak all the valves with injector cleaner in situ,to see if clumps of carbon were holding the valves open??..Was a last ditch attempt really..Can do without the huge expense its gonna cost..I originally bought the car for 6k..was an ok example..just bits of paintwork letting it down..So ended up having a full colour change on the car to Avus blue with silver kit..then had the car fully re-leathered..new screen..new 19"Breyton alloys..now it looks like another few k will be involved..Will be up to £15,000 soon...bloody hell..I better not think to hard about this!! ha ha..

Thatnks for ya kind words G..
Gary
 

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Gary,

Just try to forget about the amount of money that already invested in the car and think about all the fun you've had with the car, at least ya didn't waste it on beer (the no return liquid). All M5s are like the opposite sex, sooner or later they're going to cost you. Really can't put a price on the fun factor.

Garcia
 

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Probably a head gasket. If they blow between the cylinders you will not burn any water or oil. Sometimes you will get a crossfire and it wil lscore the block, so don't drive it mroe than you have to in this condition.
 

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My car suffered a broken valve last year during the Memorial Run.

I fixed it myself with some help from experts in the Yahoo group.
Total cost was about 3-400 Euro. (one new valve, one gasket set, and i took the head to a specialist so he could install the new valve).

So it does not have to be expensive to fix these engines :)
 
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