new member question. I have an 96 850 turbo with 236k, computer chip stainless exhaust, bilsteins, konis, and bar tying front shock towers together. Until Sat ran wonderfully. Slight hesitation at 55 mph, no noise, check engine light went on and started to miss. code read cyl 4 misfired, changed plug, (old one oil fouled), still missing. Checked compression, none, other cylinders fine, car is not smoking as a broken ring would indicate. Is this a common problem? burned valve, something more simple, hopefully, any suggestions?

 

If you can, do a leak down test. It will pin point why there is no compression.

 

I am not expert in any way, but I would check 4th injector for leek or elect contact. Also check wire to 4th plug, rotor ....

 

Or air intake leak to 4th cylinder.

 

its not a spark issue if he has no compression people....

it sounds as though it is a valve spring...

 

My vote is a burnt valve.

 

Thanks, thats what I was leaning toward. How hard is it to change a head on a turbo? I assume the head should be replaced with a reconditioned one. Anything special about taking it apart. First time in a Volvo engine.

 

If you didn't overheat it and blow the head gasket you can likely just lap in a new valve. I have found a good source for a rebuilt head at Clearwater Cylinder heads in Florida.

http://www.cylinder-heads.com/

The site is down at the moment that I am posting.

Figure on a new head gasket kit and all new head bolts in either case. Some guys say that you can get one re-use out of the head bolts but I wouldn't risk it - in the scheme of things it isn't that much money when compared to all of the rest of the stuff you would need to buy all over again if they fail.

...Lee

 

It is not all that bad just take your time. You can drop a new valve in and lap it and go. I would still have it shaved to make sure it is flat though.

I also agree new headbolts.