rjr0928

Hello all,

I address you all with my head low and my partner sick. please take a look at my web site to understand where we started at. http://928s.webs.com/

long story short this winter i had to back my 928 to get to table my wife needed, when i went to put her back in and start her i find that the belt had slipped and you know the rest of the story.

to date all work had been done all turned as intended, turned key and started but missing out, timing, electrical no. come to find out today no compression on the drivers side bank

i know you all will need info to help if you would like to, i have posted pics on my web site as we pull the cams to find whats going on. I will have a video web link with audio if you care to view and chime in as we work on what Lee missed when he did all this work.

any input to why zero compression after all new heads valves and much more?

thank you for your time Rich

danglerb

Wild guess you got the timing wrong enough putting it together that valves were bent when the engine was rotated. Leak down test might show the problem more clearly than compression test, but sounds like you need to open it up again and have a look and fix.

Big Dave

If your timing belt slipped off while the engine was running and all you did was reset the belt and timing, you didn't fix the bigger problem. No compression = bent valves. If it's only one side of the engine, you got off easier than most.

SQLGuy

A bit difficult to follow, but it sounds like you're saying you did a valve job and new timing belt, etc, but now you have "no" compression on the driver's side bank. Is that correct?

Is it really 0 compression? If so, that's very scary. It probably means the cams are far enough out of time that other piston/valve contact is happening again and more valve work will be needed.

From your post, it sounds like you're in the process of pulling the cams. Once they're off, you can try shooting some compressed air into the spark plug holes (not sure what you'll need for an extension to reach in there, though). If you hear air blowing back into the intake or out of the exhaust, the head will have to come off again. If you don't hear any air blowing out through these places, you could try double-checking your cam timing and reassembling again.

Good luck,
Paul

JHowell37

The only reason for no compression is cam timing, or the timing belt is not on correctly.

SQLGuy

I'd disagree with that. I had really low compression on my Kawasaki 750 due to bent intake valves that didn't seal well.

rjr0928

Thank you all for the input so far, to recap from the top 1) after finding slipped belt a total valve job was done 2) and all other stuff done we all know to do when the V8 is out water pump rollers belts mounts and other things they tell us to do. the pics i posted on my site of the valves are what they looked like from the first go around and what prompted the work to be done and what it looked like after it was all done . the other pics are at current stage pulling cams. http://928s.webs.com/ the site should be up now and pics on the right side.

Paul, we only did 3 out of the 4 and and 3 were at zero, sad and just not sure what was missed. i know it doesn't have to be much. next is to compress air and find out the outcome. Rich

PorKen

Are the balancer numbers readable from the front, like in this photo?

James Bailey

Please check that the harmonic balancer is correct side forward....or the timing marks are all messed up.

123quattro

Any time I've actually seen a real zero for compression on multiple cylinders was from bent valves.

76FJ55

Is that 0 compression an all 4 cylinder in the driver side bank?

rjr0928

Thank you for all you input!! Todays work found as follows...

http://928s.webs.com/ current pics look in Photo Gallery will be add soon, New News Air air AIR!!!!! If you look at my pics you will see that i dont want to have to pull the V8 again but will do it if its the right thing to do? I pulled it the first time to do all the things you can do when its in. Any reason i cant leave it in to pull the head? i know it will be some work but its all work.

Look like ill have to pass on my AA meeting.... kidding just sick! but oh well

rjr0928

Ps: balancer was correct side forward

SQLGuy

The service manual says that a head can be removed with the engine in place, but that if both heads need to be pulled it's probably overall faster to pull the engine.

76FJ55

I've heard that with the 85-86 engines the egnie has to come out due to the studs the heads mount on. If i'm not mistaken the later cars run bolt instead of stud and t allows for head removal with the engine installed. Not saying it can't be done on an 85, as it seem i've read where someone did it but for the effort it may be easier to pull the engine.