How bad could this be?

[98GTW]

My '77 has some sort of head stud issue. February 2002 we discovered 2 of the head mounting nuts off their studs and a couple of others loose, with some indication of leakage at the head from one cylinder. Worst fear was the studs had pulled.
We were able to torque them to spec without pulling the studs out, so I've been hopeful that I'm in the clear.
When I put the car up earlier this month, I asked the shop to check the heads and re-adjust the valves, just to keep tabs on the situation. A couple of the same nuts were loose again. Again they accepted full torque without pulling out.

What am I looking at here? Stretching studs? Studs slowly pulling? Ill-fitting nuts that won't stay tight?

FYI, the car's got just over 100K miles, 14K of them mine since I bought it 9/2001, thermal reactors replaced at some point, though I have no idea when.

What else do I need to know or to do to diagnose and repair this problem?

Thanks,

[sammyg2]

Sounds like a classic case of the studs pulling the threads out of the magnesium case.
The fix is a complete rebuild, it is detailed in Wayne's engine rebuild book.

[Superman]

Yep. Not only that, but I believe the heads and cylinders have been whacking each other enough that the mating surface is not longer flat. I believe that's why the nuts will continue to work themselves loose. So, flycutting the heads will also be necessary.

FWIW, I found damage (actually, John found the damage) to at least three of my heads, though only one head stud had broken. I think this was a penalty for not retorquing those nuts as part of the new car breakin procedure.

[98GTW]

From everything I've gathered here I'd conclude that this engine is not an ideal candidate for a rebuild.
On top of that I'm not sure I can justify the expense of a rebuild or another engine.
This whole line of thinking isn't leading me to any happy conclusions. Can someone offer something uplifting here?

[Superman]

I drove mine for about 50K miles before deciding to fix it. Particularly if each cylinder has at least three secure nuts on it, you might want to just drive it.

[sammyg2]

If you decide to rebuild that 2.7 with all the right upgrades (case savers, carrera tensioners, etc) it will be a very good engine that should last almost forever. Sure it will be expensive but the peace of mind knowing you have a fresh engine will all the bad things taken care of is worth quite a bit. Figure about $2.5k to $5k if you do most of the work yourself.

Another option is replacing it with a used 3.0, 3.2, or 3.6 but you end up spending more that the rebuild and you end up with a used engine that may need it's own repair soon.
If it were me I'd bite the bullet and fix it right once.
Mid year 2.7 cars get a bad rap but after the "issues" are addressed they are one of the best 911s for the money.

[nostatic]

if you rebuild it right, it should run for another couple hundred thousand miles, and you'll know exactly what is up with the engine. If you do a swap, unless that engine is well documented, you're getting another mystery.

There is a saying from the Bar exam prep schools: Do it once, do it right, never do it again.

[vash]

dave, i am pretty much in the same boat as you, although i didnt have loose hardware floating around behind my valve covers. i got my car to run, and i plan on driving it around until it (the car) lets me know otherwise. my sick self, is actually looking forward to rebuilding the 2.7, which in my mind feels like the "holy grail" of rebuilds. with the right books, and this forum, i am feeling pretty confident. these people are nice! i have even seen tools loaned out, sight unseen! talk about faith. the funding is trickier, does my house really need double paned window?

cliff

[ruf-porsche]

Originally posted by 98GTW
From everything I've gathered here I'd conclude that this engine is not an ideal candidate for a rebuild.
On top of that I'm not sure I can justify the expense of a rebuild or another engine.
This whole line of thinking isn't leading me to any happy conclusions. Can someone offer something uplifting here?

eBay the 911, although if you been reading the threads on selling a 911 now is NOT the time to sell. If you had any stocks before 9-11 did you sell once it started to go down or did you ride it down to the bottom?

Cut your loss before your loss increase.

[Pat S]

If you do a swap, unless that engine is well documented, you're getting another mystery.

This is precisely why I rebuilt mine. I did it in 3 months, my first ever full rebuild of any engine and the cost for parts, tools and machine work ended up just over $4K and that was doing ALL the labor myself (I'm guessing hundreds of hours of labor). I can't imagine anyone doing a rebuild for under 3K. So yes, dropping in a 3.0 probably could have been cheaper, but now everytime I drive it I feel pride in knowing I built it and when things do go wrong I know exactly why and where to look.

BTW I have no idea how long the PO drove my car with 6 pulled headstuds. I was sure several of the heads where toast, but the machine shop cleaned them up and found no real damage.

If you want to see my expenditures list, just let me know.

Pat

[47silver]

sam is right if you can afford it rebuild it, plus your engine will match the car.... the 75 2.7 that i have was done right and (knock on wood) is like a stone with great power and accelleration. the rebuilder put in the chain tensioners, new exhaust (carrera type), valve job, case savers, new studs, p/c and new clutch about 10000 miles ago.. the engine uses a quart of oil about every 1500 miles, and leaks very little oil,,, the sound is great and the car starts immediately (replaced the points with pertronix) 6 months ago and fixed a bad battery ground a week ago.

gary

gary

[Jim Richards]

From everything I've gathered here I'd conclude that this engine is not an ideal candidate for a rebuild.
On top of that I'm not sure I can justify the expense of a rebuild or another engine.

If you really enjoy your 77S and can invest $7-8K in the engine, you should do it. It'll give you many good years to continue enjoying your car. Otherwise, take ruf-porsche's advice.

You could rebuild your engine into a high-compression 2.7RS with Webbers' (or PMO's) and have a real screamer. Or, look for a well documented replacement engine (3.0, 3.2, 3.6).

[Martin Sellers]

98GTW,

I've had a similar problem with my 70 911T, it's a 2.2 but the problem sounds almost identical. I posted a few questions on the board about a "compression hiss" and got some great instructions from Otto and Hatari on this board. Bottom line is to re-torque the heads everytime you do a major service. Otto suggested retorquing to 27 lbs. Anyway I did and the problems solved on the old girl. I had some reservations about the 27 lbs but it solves the problem. Anyway, if your head gaskets aren't burned through it should solve the problem. if so , well you need to rebuild anyway.

Good luck,

Martin Sellers
Fallbrook, Ca.

[azasadny]

98GTW,

What did you end up doing? How did things turn out? I may be facing the same situation...

[98GTW]

Originally posted by azasadny
98GTW,

What did you end up doing? How did things turn out? I may be facing the same situation...

The problem was discovered in February 02. The studs and case survived re-torqueing then and I've continued to drive her.
When I put her into storage for the winter I had the valves adjustment checked as precaution. The studs are still holding and haven't pulled. She's running strong and I'm keeping my fingers crossed. I think I've put on 6K since the initial discovery.
After following the wonderfully detailed and helpful thread that documented Randy's transmission rebuild , I think I'm ready to tackle the engine and transmission rebuild when the time comes.
I hate the idea of taking her off the road for the time I'd need to do the job, but I'll figure out something.

[kach22i]

I experienced an increase in oil leakage after getting the valves adjusted. I attributed it to the shop changing me synthetic oil.

However now that I understand that the head studs are behind the valve covers I have new concerns.

Is it typical for a shop to tighten up or check the head studs on a full tune up/valve adjustment?

What happens if they over tighten?

Would pulling the engine alone (moving it around) mandate stud re-torquing?

Note: I had to take the car back three times for work not done right, and doubt that I will ever go there again. The owner has done his best to take care of the problems, but I was not expecting the results I got.

[azasadny]

Dave,

Sounds like things worked out well.

kach22i,
My oil leaks have increased as well as the loud exhaust "leak" sound on acceleration, so those are "classic" signs of pulled/broken head studs. I don't know what shops do to the studs during valve ajustment, I guess they don't touch them unless you pay extra $...

[kach22i]

I have just been reading that fuel additives/cleaners will cause the oil leaks to go crazy.

No more for me, I am becoming very conservative with what I do with the car.