danielheren

I was adjusting the valves on my 91' C2 Targa, when I discovered a total of 3 head studs broken off about midway down their shafts. They were just sitting there in the cavity with the spark plug.

I checked to make sure that there were not two broken off from the same cylinder! Luckily they are from three different cylinders (2,5, & 6).

The car has been fine with no head oil leaks (besides a very small amount of weep from 1 or 2 head, that have been there aparently for quite some time).

Can any one help to keep me from freaking-out about this problem. I feel that the next most probable thing to happen is considerably more oil leaking from the affected heads, which I would monitor/notice. Wait until the engine needs a rebuild to address? HELP

Kevin

Daniel;

There is no good news in regards to your engine. Waiting will inflict more damage to your engine. If you wait and warp your heads then you will have to mill more surface material to true the surface up, this will lead to a compression ratio change. If you wait past this point you risk burning a valve and possibly sucking a valve, which you will spend more of your cash to fix. Bottom line save your cash, rebuild the top end, and do the cylinders & head update. The cheapest way is to sent your cylinder and heads to Ollies and have them machine 935 style orings. Good luck

danielheren

Thanks for the advice. Who is Ollie?

Kevin

Ollie's Automotive Machining Inc...(714)558-7334. A Good shop to work with.

Jeff Curtis

Daniel, to add to Kevin's comments, he neglected to basically say, STOP DRIVING THE CAR NOW! You will cause further damage and heartache. Three studs broken is quite a bit.

Ollie's is a great place, they have been performing precision P-Car engine work for several years...and will do it right the first time.

danielheren

Ouch,

Thanks everyone.

Kevin

Thanks Jeff;

If you read some of the past posts. Many people have just had there heads resurfaced with no cylinder update. Spend the money with Ollie's, they have been doing it for a long time, they know what they are doing, they have done work for me in the past. If you don't do the upgrade all you money is thrown out the door when you try to sell your car and people ask if the engine has been updated, and by who? (ie machine shop) If you have big bucks to spend do the factory update. You will also need to puchase ARP or Raceware studs. Hope this helps..

Bill Wagner

Daniel:

The majority of the '91 964s have the cylinder head updates done at the factory. Check your engine serial numbers to see if it's been done. If it hasn't then you may want to take the advice of the other posters regarding the re-machining of the surfaces. It's an alternate to the full cylinder update that costs a lot less and apparently works. If you do have a gasketted engine then you may only need stud replacements (like Kevin said, don't monkey around with the factory studs).

Engine serial numbers where the changeover from non-gasketted to gasketted heads
occured in 1991 as follows:

Manual Transmission: any number beyond 62 M 06836, M64.01
Tiptronic Transmisson: any number beyond 62 M 52757, M64.02

This change most likely took place in the fall of 1990 (unconfirmed by me).

Unfortunately, I seem to be hearing more and more of this occurring now that the cars are beginning to age. Out of curiousity, how many miles are on your car?

Good Luck,

Bill Wagner

cobias1

Hi newbie here..really have enjoyed the flow of info on these cars and knowledge base here..kinda sorta wish i would have found it before i bought my 964. anyhow, was wondering if anyone went with a cheaper set of studs for one and two when did the problem seem to first start occuring with broken studs in these cars in case i go back with factory studs ?? thanks for any replies.

sml

where can I find my engine number?

Makmov

On the very bottom of the case right by the seam where the case splits.

If you have the cover removed or missing it is very easy to see: near the drain plug but on the opposite (driver) side of the case.

sml

Thanks

cobias1

ok..maybe im being silly here...however...which drain plug..I seem to have two for the engine and one for tranny..and the tranny is the only "M" number I can find. just looked again and there are no M numbers under there. only thing I can find is a 964.101.112.1R..seems to be just a part number for the case itself. Any other suggestions ? However, the one near the tranny is an M number M02481 is this the number ? Thanks in advance.

Makmov

I thought I remember seeing mine near the case part number casting, stamped in a flat machined surface.

cobias1

Thanks for the input MakMov, I might take another look at it tomorrow before I have it taken in to have the engine dropped and see how bad the broken headstud damage is. Those were the only numbers that I could find though. Thanks again for the input.