Dave C 911sc

Andrew, what I had to do to find the leak was this:

1. jacked the car up and removed drivers side rear wheel so I could get under the car and be able to see clearly. Support it well!
2. Had my son blip the throttle aggressivly while I held a wadded up towel over the exaust tip.

What I found was a gush of air coming out of the stud access hole in the heat exchanger (the hole you would use to access the hex-head bollt that holds the heat exchanger to the head).
I then looked directly above that hole and carefully put my hand up in the area and could feel and see the leak.

I also have oil leaking from the same area. I will get some pictures this evening.

Dave

aadrew10

Dave, I just noticed my car pops quite a bit when decelerating from a high rpm. Did yours do the same before you found the problem?

Houpty GT

Any news?

My fuel injection just messed up and is running lean. This has also resulted in pops during deceleration. You can have multiple issues with your car. Mine sure did.

aadrew10

I've taken the engine out to replace the exhaust head studs, including one that is broken. Bravo Houpty GT, you were right about the head studs. While taking the exhaust off I noticed a small crack at one of the welds. I'm not sure if it was the cause of the sputtering, so I might put it back as is after I replace the head studs to see if the head studs were the cause of the sputtering sound. Either way I'll be doing some welding work to get a cat on the exhaust and seal up the crack. I also noticed some apparent blow by past the exhaust header gaskets on the right side.

I'm also going to fix up the transmission, with at least a new first and reverse synchro. I'll know what I need to do to it when I get it open and can inspect things. There is a real good Porsche shop here in San Luis, they would be willing to let me get dimensions off any special tools I will need so I can machine them myself at my work or at school.

I also bought an LM1 so I'll check the air/fuel ratio when the car is back up and running, Only adjusting the mixture after checking thoroughly for vacuum leaks and fuel pressure of course.

One thing I'd like opinions on is Carrera chain tensioners. I'm a student right now, so I need to be smart about how much I spend. I know the upgraded chain tensioners are a must have, but I'm thinking the stock tensioners should last me until I get out of school, 2 more years. Then when I have a good job and more disposable income I can upgrade various things on the car. My car has 140k miles.

I've been wishing I had the factory manual for a while, especially for taking apart the transmission. I was surprised to see a google search turn up the factory manual in pdf for free: http://www.cannell.co.uk/911_72-89_W...p%20Manual.pdf

- Andrew

aadrew10

I got the heads off today, and there was considerable blow-by between the head and cylinder. I'm going to re-machine the surfaces on #1 and add a base gasket of the correct width to keep the cylinder height the same.

By the way, BOTH exhaust head studs were broken on cylinder 1. I am confident this was the cause of the sputtering sound I was hearing while accelerating.

If anyone has any re-machining advice please don't hesitate to chime in.

- Andrew

Houpty GT

The Bentley Manual was my preferred reference for the transmission. I used Wayne Dempsey's book for the engine but there are mistakes inside which the Bentley was able to clear me through. I have the factory manual and never use it. I would definitely not pay for one and find it harder to use. It may have better electrical diagrams though.

I fell for all the hydraulic chain tensioner hype. My advise is to use the late style tensioners that came on your car along with a set of the collar locks. Use these until you start to notice noise and when you need to buy a replacement I would purchase the hydraulic tensions since there is not that much of a price difference. The later mechanical tensions did not have the problems that the early tensioners had and the hydraulic tensioners are also known to fail.

If it so happens that you have the Alusil cylinders, they can be refinished unlike popular belief. The manufacturer has a designated procedure. They are not coated like the Nikasil so they are better in respect to being reused.
I did not crack my case since it was work that I did not feel was needed. If the studs were not broken, you would not have considered disassembling you engine.

I think I spent $700 on my tranny, $400 on my motor, and $400 on the chain tensioners. Good luck.