Hey Guys..
I've got a 1995 850 T5-R with 219000 miles. The car has been running rough
and it seen more water than usual id comming out of the tailpipe. I did a compresion test and found cyl 1 - 5 149, 150, 150, 0, 150
The car still runs but it vibrates like crazy. I had put plugs in several weeks ago and when I pulled them out to test the compression all the plugs looked OK except cyl 4. Cyl 4 plug was like new. Not a mark on it. The idlehat is it that you want. sometimes climbs upward to 4000rpm then will slowly come back down when the engine is warn.
I'm not sure what to do next. Zero compression in cyl 4 but car still runs. Head gasket? burnt valve? Don't remember the car overheating. I love this car and want to keep it. I'll fix it if Its fixable. Where do I go from here.

Hey Guys.

Well I finally took the head off of my T5-R. I wanted to see something drastic pointing me to the problem. I took off the head and found nothing jumped out at me. You can see in the video that the head gasket seemed to be in good shape.
The valves seemed OK. To the untrained eye all seemed well. In the second video I tested the valves by squirting WD40 in the intake and exhaust manifolds to see if the valves were tight. You'll see in the video the #4 cyl leaked while other cyl's didn't.
My plan is to lap all the valves, cleanup the mating surface of the block, cleanup the head and the cam cover mating surfaces, and clean the valves and pistons, intake and exhaust manifold cavities has best I can. Clean all surfaces. Working on a limited budget I would like to do all the work myself if possible. Then new head gasket kit, head bolts, assorted parts that need replacement.(hoses, etc). Also I found some play side to side and up and down in the turbo blades inside he turbo.
I need some advice about where to proceed. What I should and shouldn't do from here on out.

Thanx Guy's your a tremendous resource.
Youv'e got me threw some huge projects successfully.
Flying by the seat of my pants in Mass.

Hey Guys 7/14/2017

Well I took the head off my 850 T-5R. I clean and checked the mating surfaces for true. Everything looked good. Started grinding the valves and found the valves in cyl 4 would not seat. I took the two intake valves from cyl 4 tried them in othe cyl's and they wouldn't seat and I took valves from other cyl's and tryed them in cyl 4 and they would seat properly. This is how I isolated the valves from cyl 4 has the problem. Also just by looking at them you can see they are bent.
My question is . Can I just get a set of valves to replace the bent ones, install them and be on my merry way? Are there any other consideration like valves seats. Other vales seemed to work fine in the cyl that I had the problem with which told me the valve seats were fine. Anyway I appreciate all the tremendous help I've received from the forum. Keep it coming.

With great appreciation
Rick Almeida


Gettin it done with the help of my great support asystem.......

 

Take the head off. Whatever the problem is, the head will have to come off to fix it, so you can safely take that step.

 

Check engine light on? IF so read the code a it will point you in the right direction. But still, it sounds as if the head needs to come off. When you put the head back on, make sure you put a new head gasket on, and DO NOT resue the head bolts. Get new ones as they are one time only stretch bolts.

 

Clean plug would indicate water in the cylinder aka blown head gasket. But, 0 compression would indicate a burnt valve.

Bottom line, its what Firebird said. That head has to come off.

 

Perform a cylinder leakage test to find out where its going. Odds are its head related, as others have mentioned (valves or gasket). Could also be rings though, but it would be unlikely to have absolutely no compression in that case.