1 broken Delivar worthy of a tear down?

[LeakProof]

Engine's out of car, trans separated, fixing oil leaks, found the dreaded infamous broken Dilavar head stud (exhaust,cylinder 6, end stud). Non magnetic.
Question? Should I replace 1 or all 12 Dilavar/exhaust studs? (with new steel one's like the intake studs) or should I replace only the broken one, or
should I just leave it. ignore it, forget I ever found it? 107,000 on clock.

Thanks.

Leakproiof.

[carrera turbo]

is the one that broke have signs of rust or pitting on it? do any of the others look pitted. if they do this is probably just the beginning of more broken studs. i would say since the motors out replace them. or do a leak down test on that cylinder and see if head is leaking. if not you could take the gamble and drive as is.

either way its your call and if more break next to each other you could run into big cost later on.

good luck on your decision

cheers ed

[Superman]

Remove the heads and cylinders, and replace the 12 Dilivar studs. Measure stuff while you're there. FWIW, at that point there are not many parts left on the motor. In that situation, I elected to split the case and replace the main and rod bearings, and layshaft bearing. They would probably have lived longer, but they were definitely worn. So were some of my valves. I replaced valves, guides and seals. That was the spendy part.....the valves. Don't ignore it. Replace all twelve. Used factory steel studs, if you can find them. Cheaper. They don't break.

[Porsche_monkey]

^^^ What he said. At the very least do all the studs.

[LeakProof]

Thanks guys for the quick reply and input from your own personal experience. I'm well aware this job could lead to a complete rebiuld and a budget should be considered. If money wasn't a factor this would be an easy decision. I agree the job should be done in the proper manner. Most likely theres more worn parts. Probably valves, guides and bearings. Who knows what else lyes beneath and what other secrets she holds within the aluminum.
I'm a little concerned/confused about addressing the pistons and cylinders? probably have Alusil Perhaps a leak-down test and verification of cylinder make will help.

Thanks.

Leakproof.

[john walker's workshop]

broken studs on the outside heads are the worst ones to keep driving with. do it now.

[KTL]

You're inviting a second teardown if you don't replace the dilavar studs. Relieving (teardown)and retightening (reassembly) of those studs provides a great opportunity to break more of them when the heat cycling resumes.

[Superman]

The engine is already out of the car.

Even if you don't consider anything else "while you are in there," be sure to replace them. Now. Ten buck apiece, probably. There are used ones everywhere.

[Superman]

One more thing. I re-ringed my Alusil cylinders while I was in there. The cylinders and pistons measured as new. No kidding. New spec! It can be done. Just be sure to CLEAN the piss out of the cylinders first, if you re-ring. I mean.....clean them to the point they are basically 'etched.' Do not hone. Do the homework.

[LeakProof]

Well put guys, thanks again. I'm on the phone talking to my engine expert/racing buddy and he mentioned that my driving season most likely came to an end. And to do things right. Take it one step at a time, no rush, and don't contaminate the engine while breaking it down. just in case I don't go 100%. I think he really wants to be involved with this project. He's never worked on a P-car/engine but he builds cars from scratch. He's also a race instructor and has a German last name. I guess I could let him help. Unlike him I however never rebuilt an engine in my life. But consider my self very mechanical. Will post pics with all future questions.

Thanks,

Leakproof.

[Superman]

It's not that hard. The complex part of an engine is the stuff bolted to the outside. The closer you get to the center of the engine, the simpler they are. Yes, be clean. Plug up the orifices and pressure wash it first. Be systematic. Get a box of freezer bags with the white panel on the side for writing.

The one thing I did not do that I wish I had done, for peace of mind, is the balancing. If I had it to do over, I would take all the engine parts, including the flywheel and pressure plate, to a machine shop and ask that they be balanced within an inch of their lives.

[LeakProof]

Thanks, Superman. I been cleaning the engine with engine cleaner, paper towels (four rolls),tooth brush, and compressed air. I do own a pressure sprayer but didn't know if I could safely use it. About 20 hours of cleaning so far (including trans). As far as Re-ringing Alusil cylinders, thats terrific news that you were able to do that. I'm also taken tons of pics, writing everything down, using ziploc bag's, studying the P-books and currently working on my neat/durable labels, with my wifes nifty label machine(better not get it greasy like the camera). Is it likely that things could be that far out of balance as you mentioned?
Thanks for all your help,


Leakproof.

[don gilbert]

i've heard that you could get away with it for a while. Here is my #3 after a while

[LeakProof]

Holy smokes! To put it pleasantly. Definitely don't want to go down that road!
If that doesn't convince anyone I don't know what would. Sold....
I guess I was the only one who needed to be convinced. And convinced I am. Wow.
Moral of the story. What I learned here today. Do not ignore even one broken head stud. Thats 25% less, holding down things.

Thanks,

Leakproof.

[dshepp806]

Do them ALL.....period..


Doyle

[boyt911sc]

Bought a running SC engine with known broken head stud. But during the engine teardown it became apparent that there were more than one broken head studs. See picture below.



My first experience with Dilavar head studs removal was some 12 years ago and took me many long hours removing them. Just recently, the 12 lower cylinder head studs (Dilavar) shown above were successfully removed in about half-hour total. To be precise, it was 35 minutes from start to end.

Thanks to Tom Butler (Tom1394racing) for showing and encouraging me how to do it. Just having the right tools for doing the job makes you feel good!!! Except for the two (2) broken head studs, the other ten (10) could have been removed without pulling the cylinders out. Just to share my recent adventure.

Tony

[Eagledriver]

Is there some kind of damage in the top picture? I don't see it.

-Andy

[N11Porsche]

At least replace the head studs.

My SC had 190,000 miles on the clock and didn't burn oil or smoke on startup I took it to redline everytime I drove it. Just trying to give you an option. Replace the studs and drive it IF it doesn't burn oil or smoke at startup.

[LeakProof]

While now that I slept on it I think I'll have the trans rebuilt, replace all fuel lines,replace 12 lower head studs, fix all oil leaks, replace motor/trans mounts, detail motor and if anything else should arise then certainly address it.
If my work picks up (more income) then perhaps I'll go further
The engine runs fine, no smoke on start up. Eats some oil though.
Was there nothing wrong in Don Gilbert's pic above?
Did I make A fool of my self saying it looked terrible?


Leakproof.

[don gilbert]

no you are correct. So far (and counting) its about 3g terrible. But thats ok, wanted to go through the top end anyway. Just more mach work.