Broken head stud 88 carrera :(

EuroZ06 · 06-15-2017, 11:01 AM

Hi guys,

So it started because my clutch wouldnt engage. The local porsche shop told me that the rubber in the clutch fell apart. So he pulled the engine, replaced he clutch and was gonna do valve adjustment, when he saw a broken head stud. There were no signs or symptoms of any issues prior, engine worked flawlessly. Car has 98k miles and seems well cared for.

So another mechanic came by and advised on a whole engine rebuild (he quoted $10k). After careful consideration, i decided that the full engine rebuild is not warranted. So i asked how much to do the head studs and i was quoted $4k for work and head studs, however if exhaust studs break, that will be extra.

I def didnt budget for this (always had a few grand put away for emergency repairs, such as clutch), its really over the top for me.

Is $4k to replace head studs reasonable? He said he will clean the engine and smaller seals are included in the price.

Any advice?

EuroZ06 · 06-15-2017, 11:16 AM

Forgot to add, engine had cirtually no leaks.

Flat6pac · 06-15-2017, 04:43 PM

3.2 guides are probably shot too, valve job included.
Bruce

smokintr6 · 06-15-2017, 06:16 PM

If the heads are coming off, they need rebuilt at that mileage. Get the heads from the mechanic and send them to anchor Atlantic in new Jersey to avoid the markup on whatever clown they have doing machine work.... unless they are using the Cgarr guy from this board, or Steve weiner or some other known quantity.

smokintr6 · 06-15-2017, 06:21 PM

Also make sure that they replace ALL the studs. Personally I used ARP studs, but the supertech kit is worth looking at too. The good aftermarket studs are only marginally more expensive than stock. My guess is adding the head machine work and the better studs you'll be at $6k if they keep their word on the original work. That's pretty fair for a top end rebuild thsee days.

prschmn · 06-16-2017, 03:27 AM

I'd say 4K just to do head studs is a bit high but as others have said it's cheaper in the long run
to consolidate when you have to do that much teardown anyway.
If we knew where you were located you might get some local refferals.
At 90k you don't usually have problems with exhaust studs. Maybe the guy who quoted is a bit heavy handed.

faapgar · 06-16-2017, 06:06 AM

If the shop warns you about broken exhaust studs then they do not know how to use a torch.Find someone else with better hands for your baby.Fred

SCadaddle · 06:25 AM

I'd say 4k is 50 cents on the dollar for a top end as I spent 8k--not including the 1k on having my cylinders plated or the nearly 1k on the clutch assembly parts--- on my 82 SC top end @ 155k miles 5 years ago; that's with me assisting in the tear down, performing all cleaning of parts, and reassembly. The "while you are there" factor is going to kill that 4k budget. The intake valve guides were fine but the exhaust valve guides were marginal. So we replaced the exhaust guides and did a complete valve job. And I went with the factory steel studs on the bottom row only.

It's a tough pill to swallow. Like yourself, a simple "adjust the valves" routine turned into a decision to rebuild the top end once we found a broken stud. They say hindsight is 20-20, so what I would do in retrospect would be to do a compression and leak down test before going any further and make your decision based on that. When you look at the structural side of things, the "bank" of the 3 cylinder heads on each side of the engine are connected by the camshaft housing and become a single structure. IF the broken stud is one of the inboard ones, meaning there is a good stud on another cylinder adjacent to it, from a structural standpoint, at least in my opinion, can't be nearly as bad as one of the studs on the end of the "bank" being broken.

Disclaimer: I am NOT an engine rebuilder, just an owner!

smokintr6 · 06-16-2017, 11:03 AM

To SCadaddle's point.... These cars do routinely run with a broken head stud for a while before it's caught. You might be able to run it for some time with a single broken stud. The biggest gamble you're taking is fretting between the cylinder and the head. You may end up needing a new jug and and a new head if you push it too long. I guess it depends on how hard it is to spend the $6k now, and how much you're "saving" since the engine is already removed for the clutch work. I would probably just do the work now if you can, the car is basically un-sellable in its condition, without taking a big hit.