Big AL in VA

That initially was my understanding as well. Use oil and only run the studs down finger tight. After talking to 928 Motorsports in Wisconsin. He gave me this information and his reasoning behind it. I am sorry, I do not remember his rational of using loctite. He did say "The head studs you took out were very hard to break loose wern"t they?" I responded, you bet "they were a b*tch!" The head studs I removed had loctite on them.

Big Al from VA
84 928S2 Euro twin distributor monster

Big AL in VA

Pulling the head studs was very very hard. I spent a lot of time getting them out and cleaning up the threads and holes. A couple of studs needed heat to get them out. With aluminum blocks, using heat can be a daunting experience. Also, if you slip with the stud remover it is easy to gauld the aluminum block. So I perfectly understand those that say leave the old studs in. If this is the first time reusing these studs maybe you will be OK.

Big AL from VA
84 928S2 Euro twin distributor monster

Lizard928

I doubt that the studs will stretch more than they already have, and with already stretched studs it leasens the need to retorque after a few heat cycles which on these engines means pulling the cam housings.

I would worry about replacing the studs IF you were planning on pushing the bar on the internal pieces with massive amounts of cylinder pressures. If you dont plan on doing that, then leave them be.
I have yet to hear of a stud on any of these or the 944 engines breaking from reuse.

Big AL in VA

Food for thought

Would you replace the head hardware if they were bolts and not studs?

I guess I am sensitive to this issue because a friend at the Frenzy did his heads the same time I did mine. The only difference was I changed the studs and he did not.
Now he is having what he believes is coolant leakage at the head. I feel God awful about it because I was the one that told him to reuse his studs. Based upon the huge PIA it was to get my studs out.


Big AL from VA
84 Euro 928S2 twin distributor monster with large valve cut outs in the pistons

BC

You are correct on the studs in a best case scenario Al. But sometimes the prospect of the process stops people from doing it.

Dennis Wilson

Think there is some confusion between the parts/techniques on the 16 valve and 32 valve engines. The studs on the 16 valve engines are not suppose to stretch. That's why they have a completely different torquing technique. Also, retorquing is done without going through a heat cycle so the cam carriers don't have to be installed, removed, then reinstalled.

Keith, I would consider having the machine shop check/resurface the head to cam carrier mating surfaces. These have been known to leak after head rebuilds.

Dennis

928ntslow

Good advice Dennis. Mine were already leaking and I HATE leaks! They looked good and the gaskets were old, but that doesn't mean anything. I can ask him to throw a straight edge over them after he has them apart, but I'm thinking this guy already will do that without my asking...but I will.

He did say the only way he could guarantee his work is if he disassembled the heads completely and started over. He is going to reseat the valves and install new guides. He mentioned that after he adds material to get the head mating surfaces flat again, there tends to be some distortion at the valve seats. With all of this, I can't imagine him not checking the cam box mating surface.

Thanks!

Dennis Wilson

Keith,

Sounds like he knows what he is doing. If he mentions the need to shorten the valves by the same amount as taken off when reseating, let him know the lifters are hydraulic so it isn't required. I would also take the pages (copies) of the spec/tolerances from the workshop manual for his use when checking as it's doubtful he has anything but general information on the heads.

Dennis

Mrmerlin

Dennis thats a great idea to send a copy of the relevant WSM rebuild pages to the mach shop.
Keith In regards to your other question, i would remove the rod caps and check the bearings , yes you should use new nuts, while your in their try to clean out the block girdle oil passage I would bet that its filled with crud, Before you install the timing belt fill the engine up with oil and connect the oil lines with a clear tube and spin the oil pumpwith a drill motor, this will let you see if your pump is primed and hopefully give you an opportunity to see what the oil system has in it before you start your motor

928ntslow

Stan, to be honest, I'm kind of waffling over this, as the engine was never under load and as soon as I discovered the milkshake issue, which I caught within minutes of warm up, I shut it all down.

Do you really think there is that much of a risk in damage based on the condition? I would think an oil flush when I get it all back together and started should be fine. I understand the "better safe than sorry" aspect, but I personally find it difficult to believe that there is any great risk in not doing this. There was no "junk" in the oil pan or any of the oil passages. The pump was a good 5 bars when it was running. Crank assembly and all spin fine by hand and never made any noises when running.

Dennis, thanks for the advice on the specs for the machinist.

Mrmerlin

Keith if you found milkshake in the oil pan then it means the coolant went through the pump, thats how it mixes

to clean out the girdle oil passages is relativly easy( brake cleaner and compressed air) since the pan is off. You might even try leaving the oil lines disconnected and spin the pump this will flush some of the crud out before you start the engine. Definitly remove the oil pump and clean it.
Some one else was talking about loctite and head studs , this is putting the locktite on the stud end that is secured to the block after installing them you should use an extra headgasket and torque the head on and let the loctite cure overnight with a head installed.

Sailmed

Great idea on the loctite cure! I like that
After reading this thread - that's enough for me - the engine is coming out of the $300 car. I don't need to chance a hand grenade the way I drive.
I guess the major difference is that mine had water in the oil for quite some time. I'm going the whole enchilada and changing the bearings too....
Good on ya Keith - it sounds like you were alot luckier than I was
I don't see that much of a differance in between checking the journals - or not and taking chances - I can just hear that rod seizing as I'm passing 3 cars....

Dennis Wilson

Keith,

For safety sake I would at least pull the rod caps and check to make sure no residual water has caused rust/erosion of the journals. While in there, if the journals are clean, plastigage to make sure the clearances are in spec.

Dennis

Bill Ball

How does the water jacket look? If it is heavily scaled, the car will not cool well.

928ntslow

Bill, see post #25. The inside of the jacket now looks NEW, no scaling!