D. Knapp

Hi, I purchased an 86 944 turbo 9 months ago with 40k miles. Twice in the last 2 months I've hade the exhaust manifold studs nearest the firewall at the rear of the engine break off in the head. Does anyone have any idea as what would cause this?? My local repair shop now wants to drill out and replace the stock 8mm studs with bigger studs, say 10mm. I'm not sure if this is solving the problem or just treating the symptom. What would cause these studs to break off like this. Any info would be a great help!!!
Thanks, Dave

Bri Bro

I went out and grabbed my headers (in the middle of seals/bearing overhaul) and the pipe for 1&4 are connected and the pipe for 2&3 are connected. One thing that bothered me when I first read this was if the exhaust was being placed in a bind, why did only #4 stud break. As soon as I picked up the pipe the answer was looking me in the face. On the 1&4 pipe, the #1 connection has a bellows that will flex under stress. Look at the exhaust pipes, motor and transmission mounts for any sign of damage. When they connect the exhaust, make sure they don't "force" the connections together, they need to look for the reason why things don't align.

I need to clearly state that I have no first hand knowledge of exhaust stud breakage on #4, I am only stating what I would look for.

OVERBOOST

Do you have the old one piece manifold? These do not flex at all. If you do have any preload on the system these studs will break, or manifold will crack. Check your mounts etc.

Paul
<img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />