Replacing head studs

[rotorhead]

A bit of advice please guys,

I have an 1988 930, it has an oil leak from the join between the #5 cylinder and the block. The leak is bad enough to be refused a roadworthy certificate so I need to fix it.

I am guessing that it is probably a broken head stud (after reading similar posts, but I will confirm it). If it is a broken stud head stud I plan to replace them myself. I would prefer no advice like "while you have it out rebuild the entire engine" as the car has only 30k on it.

I am planning to remove the engine and remove the P&C then replace all head studs with steel 993 studs, then replace the P&C as a unit. I figure this to be the most straight forward method.

any constructive advice is welcome (such as checking the case to see if it needs to be machined, check the valves....)

I have all of Waynes books, the Bentley, the Haynes, and the Factory Worksop Manuals.

Thanks in advance

also, can anyone tell me which gasket kit I will need for this?

[Porsche_monkey]

Why remove the P&C's on a 'good' engine with 30K? What is your compression on the other cylinders?

[hobieboy]

From everything I read & folks I asked, there's a very good chance you'll have to split the case to extract the head stud as high heat is required; particularly if the stud is broken.

Before you do anything, I'd do a leak down to see the health of the top end. And after you opened up the top end, I'd at least check the valve guides, condition of cam & rockers.

[rotorhead]

I had a leakdown done recently and the figures are good for all cylinders (within 2% across all cyls). I believe that there is no problem with the top end (Inspection will tell) I may have a little valve guide wear as I get a puff of smoke on start if the car has sat for a while.

I believe that I have to remove the P+C to change the head studs (source Waynes Books)

Also does an 88 3.3 turbo have Alusil or Nikasil Cylinders?

[hobieboy]

Yes - the P&C needs to come out.

[Porsche_monkey]

Personally, I think you're getting way ahead of yourself.

[rotorhead]

OK that may be true but the oil leak is comming from between the cylinder and the case on the #5. I feel pretty safe in assuming that I will have to remove that Cylinder. I do not know if it is a head stud yet, but I understand that I should probably replace the divilar studs with steel anyhow.

[Porsche_monkey]

If it needs to come apart pull the wrist pins and leave the pistons in the cylinders.

If you post your progress/questions as you go you will find lots of help here.

[Superman]

Wrist pins can be stubborn, so I suggest using heat. They are MUCH easier to remove from a warm piston than a cold one. Once the P&C's are removed, then you'll have access to the stud area. Hopefully they are all long enough to get a pair of pliers on. Use oxy-acetylene. Trust me on this one. Rent a unit if you have to, but don't mess around with flame that's not hot enough. After perhaps a minute of heating, they will come out. Keep heat on them and turn smoothly until it's out.

As much as I hate to say this, you might want to use the current-generation of Dilivar studs to replace. Your engine makes more heat than mine, and those Dilivar studs may be a good application for your engine. Maybe someone understands this better than I.

[john walker's workshop]

you should not have to split the case to remove the studs. just start out renting or borrowing a oxy/acetylene rig so you can get enough heat in the area in a short (30 seconds) period of time, instead of screwing around with propane or mapp gas for hours with mixed results. a good "while you're in there" (sorry), would be some ARP rod bolts, which can be done without splitting the case.

[Porsche_monkey]

I have 12 new dilivars for sale.

[rotorhead]

Sorry PBH you are in Canada, I a m planning on putting a single (Large ish) order in to Pelican to reduce shipping costs.

Superman and JWW thankyou for the tip about the Oxy Acetaline I will do just that. The ARP rod bolts have just gone onto my list (They are mentioned in Waynes book) I did not know that could be done without splitting the case.

Great advice guys

[Porsche_monkey]

What has Pelican ever done for us?

[Wayne 962]

Hmm, lots of questions. Follow the Engine Book carefully, and also check out the Engine Rebuild Wizard:

http://www.pelicanparts.com/cgi-bin/wizards/parts_wizard.cgi?wizard_root=911_engine_rebuild

Other than that, ask your questions here. As I mention in the book, it's best to tear down your engine to see what you've got to deal with, before you get ahead of yourself...

-Wayne

[KobaltBlau]

Raceware might be worth it on a 930. Do your homework on the studs, and if you are able to take things apart before you order the parts you may save yourself lots. Of course it sucks to have the car down for a long time.

[Porsche_monkey]

Look at Waynes book for labor estimates, figure out how many hours/week you can spend, then figure out how long you'll be off the road. I just spent 6 months of 'down-time'.

[Fishcop]

Steve, I've a few good resources and tools (you've probably got the later cam shafts) at my place. Let me know if I can help. Good excuse to come for a drive to Toowoomba!

As an ex-copper, I recall a few of the "roadworthy tricks" that may get you over the line with an oil leak.... Just how bad is it? I agree that you shouldn't get too far ahead of yourself, there may be another issue other than a head stud.

Cheers

[rotorhead]

Wow thanks for the great response guys! As I get into the problem further I'll post more onto this forum.

John, I will take you up on the trip to Toowoomba let me know when you have a couple hours free and I'll be right over

Steve

[Doug Zielke]

Originally posted by PBH
I have 12 new dilivars for sale.

I have 11 "used" Dilavars for sale (cheep).

[Porsche_monkey]

You broke a dilivar? Unbeleivable!!