Lex_GTX

A stud pulled out of the head which is causing a pretty nasty exhaust leak. I am going to insert a Time-sert but it's an awkward area to work in.

The vehicle is a higher mileage (130k miles) but the engine has been resealed with new gaskets top to bottom, new hoses, belts, etc. recently. I would rather not pull the head to do this job but if pulling the head means doing it right then I will go this route.

The head gasket is not currently leaking and I don't know when it was the last time it was replaced. The engine has strong compression (145 in all cylinders) and less than 2% leakdown in all cylinders.

However it is using a good amount of oil (1qt per 1000 km - 600 miles) so if I am going to pull the head it might not be a bad idea to refresh it as well.

My preference is to leave everything intact on the head and deal with a blown gasket if/when it happens and just add oil as needed. The car does not smoke. However this exhaust leak has to be dealt with since I have put a lot of work into the car - bit by bit over the last few years - and this is one of the final pieces on the mechanical end that needs addressing at the moment.

Thanks in advance!

lee101315

The original valve guides are definitely going to have excessive play by 130k, so it wouldnt hurt to pull the head, send it to a machine shop, and have everything rebuilt.

MarkRobinson

I did exactly what Lee said because of a broken stud. I was surprised the exhaust valves were even closing there was so much burned oil draining into the chambers from the exhaust valves.

Mark

Lex_GTX

Thanks for the replies guys. I assume a lot of the oil consumption is from worn guides and seals in the head.

What is a fair price for refreshing the 951 head? I am not looking at port work, just guides, seals, valve job. Are there any special tricks to these heads aside from being careful with the exhaust port coating? Is it worth sending this to a 951 specialist like Lindsey or are most shops capable of successfully undertaking this?

Also aside from replacing the head gasket, head nuts, exhaust studs, nuts, gaskets, and intake gaskets is there anything else that should be replaced? All gaskets on the engine were replaced very recently including cam tower and rear cam tower seal.

Black51

Dealing with a blown HG is not a thing I'd recommend when you're in the middle of nowhere, the temp gauge starts bouncing up and down, and the car shuts down, with a wall of white smoke bellowing out the back of your car. Ask me how I know.

It sounds like you do need to pull the head anyways, so this will give you a fully refreshed engine, top to bottom!

Now's a good time to do belts, and front end seals if you haven't already too.

Not sure where you are located, but try to find some local shops and get a quote. You can also look at taking it to a 944 specialist like Lindsey Racing. Their prices minus shipping is right on their site. A simple refresh with no upgrades is reasonable.

Tom M'Guinn

I'd start with a helicoil for an exhaust stud. It's more than strong enough, and if it fails (or something goes wrong) you have enough material left for a timesert.

Lex_GTX

Is it much easier to install in the car than a Time sert? Have you done this? I have read that helicoils fail and pull out but I am interested in a method not involving pulling the head this summer.

Tom M'Guinn

I've not done a helicoil for an exhaust stud while the head is on the car, but with the headers removed it should be straight-forward, though you may need a 90-degree drill attachment. The nice thing about helicoil (in addition to being cheap and easy to get) is that you don't need to remove much metal at all before re-tapping the hole. This makes drilling a breeze and always you to go to bigger inserts if something goes wrong. I've used dozens of helicoils in aluminum and have never had one pull out.

Lex_GTX

For those that have done this repair with the head in the car and manifold removed - any insight? What right angle drill extension did you use?

Lex_GTX

Bump for more people that have done this repair on the car and your experiences.