qball

Went to adjust valves in my 88 coupe and found a broken head stud in the valve cover. Now going to drop motor and have all the head studs changed out, anybody else go through this? What kind of cost am I looking at?


Thanks , any sympathy is appreciated

Tom

emcon5

That sucks. How many miles?

You probably should do the top end while you have it apart. You will have the heads off, the machine work is under $1K, with essentially no additional labor.

Or buy Wayne's book and do it yourself.

Tom

Bill Verburg

I think that all engines right up through the 993 will be susceptible to this problem. They tell me that the fully threaded 993 studs will not allow the propagation of the cracks that are precursors of broken studs, but I installed new studs on my 993 anyway.

I agree w/ Tom that this is a good opportunity to deal w/ the valve guides by updating them to a more durable type. Perhaps even a cam upgrade, depending of course on your need for speed.

qball

Thanks for the info guys, the car only has 70,000mi, but while the motors out I might as well upgrade what I can. The shame of it all is that I've only had the car 2 months and this was missed on the original PPI.

Tom

timlooney

That sucks, the only thing you can do now is make it go faster...

I would go with the top end rebuild when else will you have that kind of opportunity. When it's out make the most of it. I might consider a clutch throw out bearing and seals at that point but then you are starting to talk about some bigger $$$.

Good luck and let us know how it goes.

dial911

For some reason, 3.0 owners seem to get all the flack about broken head studs. 3.2's were also built with Dilavar head studs, so they are just as vulnerable to the problem.

The broken head stud, may or may not have been missed in the PPI. They do break without warning. Always check for a broken stud when the valve covers are off for valve adjustments.

At only 70k, you can probably just replace all the Dilavars, re & re the heads as required, possibly some new rings, re-seal the top-end, and do anything the clutch might require.
A nice winter project.

geo.aigel

This will save you a few bucks: Keep the steel studs. Only replace the divlar studs. No need to mess with anything at 70k unless the car was not maintained properly.

George

qball

Appreciate the input guys, the more info I get the better. Spoke to my mechanic and he estimates 5k to drop motor, upgrade studs ect. While heads are off we'll look at valve guides and last but not least check clutch condition. Not happy but it has to be done.

Tom

qball

Anybody have a ballpark figure on how much this should cost? I want to see if my mechanic is in line.
Thanks
Tom

RANDY P

I've gotten quotes for about $4k and heard others get the same - remove motor, rebuild heads, pull headstuds (lower ones only need) and then reverse. Can't imagine that a 3.2 would cost any more.

Definitely itemize what you're getting before proceeding. Would check one other place if that's the case.

rjp

Bill Gregory

When you replace the studs, use the current Porsche encapsulated steel studs, which are a 993 part number. Also, with the heads off, consider replacing the rod bolts with ARP's or Raceware bolts. Porsche reduced the bolt size on the 3.2L and 3.6L engines, and at continuous high revs, as you'd see on the track, they can let go. Maybe not as important for street usage, however, if I were going to keep my 911 for a long time, I'd do that while the heads were off, regardless of intended usage.

qball

Thanks Greg, I have a list going with all the input I'm getting. I plan on keeping the car a long time and trying some DE events in the future. I found a shop and mechanic I'm confidant in, Mark Tashjian at Formula Motorsports and we'll discuss upgrades monday.

Tom

AZ911

A friend here in AZ has had broken head studs on both his 3.0 and 3.2. The 3.2 cost 4K to fix. I would expect to pay that plus or minus a few bucks

Ed Bighi

Yeah, maybe that is me. I broke the studs in my 88 one day after I bought it. In my 80, they broke about a week after purchase. Not so much bad luck but the result of cars that were from sunny (rainy) Frorida and were seldom driven. They also had sissy previous owners who never knew the meaning of hard driving which would have revealed the problem earlier. In both cases, all it took was a cast iron right foot to break the head studs. In the 80, I replaced just the bottom row of dilavars with new dilavars. That was all that was available back in 92. They have held up fine on that one. On my 88, I again replaced just the bottom row. The steel studs are fine. Leave them alone and reuse them. They won't break. For the bottom, I used the 993 fully threaded micro-encapsulated studs. Don't forget to get some phosphorous bronze valve guides. They last just about forever. I put some in my SC in 82 and now at 210K of abuse, the car still puts out good numbers. Rod bolts are optional. I find the 8mm issue a little overplayed since I have witnessed them break as often as I have seen hen's teeth or fair taxation. Most mechanics I know say the same thing. So it is up to you. As for price, anything around 4K or a little more is a good deal for the job. Don't worry about the price since your motor redone with phosphorous bronze guides will last a ridiculously long time.

qball

Damn Ed,

I thought I had a bad luck story, you got me beat, 2 for 2
Thanks for the tip on the valve guides

Tom