Cylinder Compression Question

[PDX-84-944]

Greetings.

I encouraged my 15 year old son to get a good project car in order to learn auto mechanics. He found a really great 1984 944 with 90k miles and has been doing minor repairs so far. School is out and we've started figuring out what major work is needed. We know of some pretty big oil leaks at the front end and rear end of the engine and there is some serious shaking at idle. Last night we did a compression test and got 200psi on all four cylinders. 200psi seems a bit high and I'm wondering about carbon build up. The plugs looked great on the electrodes and insulators but there was a fair amount of carbon on the threaded base. You could see a lot of carbon peering through the plug holes on the pistons.


Is 200 too high? Is there any down side to carbon build up? Is
pulling the head the only way to remove carbon deposits?


On other stuff, we are thinking of replacing all the front end oil
seals along with the belts, changing out the clutch (too much slop in the drivetrain) and rear seal, changing out the engine mounts, and possibly replacing the seals in the oil cooler as a precaution. Given this list, would it be easiest to remove the engine? Any other advice would be appreciated.

[Razorback1980]

200 is a little higher than mine. I have an 87 and all cylinders are between 185 and 190. I am not sure what compression ratio Porsche used in 84 but other factors have to be considered as well such as whether it's an ROW car or not. I think I would worry more about the oil leaks and other preventative maintenance items...there is no shortage of those. I'm currently in the process of resealing my entire engine as well. I have pulled mine as I wanted to replace all rubber components as well as all bearings in the motor as I had a oil cooler seal failure. Whether you go to that extreme or not is really up to you. I don't want to have to worry about oil leaks for a few years, so I decided to redo all my seals. The rear crank seal is the one that made me decide to pull the engine really. The rest you can pretty much do with the engine in the car and if you put in a new clutch, you can do that one in the car. Sounds like you have a fair amount of work ahead of you, but when you are done, it's going to be a car to be very proud of.

Here is a web site to read that might point out a few things to check for:

http://www.connactivity.com/~kgross/FAQ/944faq05.html

Welcome to the forum and Porsche ownership.

[nize]

revving it to redline a few times is great for removing carbon deposits.

[fast924S]

200 sounds ok to me, When I check my 87 924S thats What I got 195-200. Giving the list of things you have, I would just pull the engine and do everything from there, It will be alot easier to do once that engine is out. Good luck with everything, When I was 16 me and my dad did the same thing and I learned a ton, 7years later I still have my 87 924S and when to school for toyota ;-)