I recently rebuilt my 90 C2 3.6 engine with arp head studs and rod bolts new mahl cylinders and pistons with the late model groove. When I installed the arp studs I put them in with permatex threadlocker red.I had Rich at Jacksic Racing do my heads and I also bothered him quite a bit with a lot of questions about these studs.Rich feels that the stock ones are fine for a stock motor.Me being overly cautious and nerotic I decided to put the arp studs in.That was no easy task.I broke one stud taking them all out.Again Rich had to save the day and remove the broken stud and put a time cert in.I used a generous amount of the permatex and I could not get the arp stud to turn in the crankcase.If I wanted to get them out for arguments sake I would have tyo put heat on the crankcase again.I dont know if you put threadlocker or what kind you used,seems to me that something to explore.I tell you this I only have about a thousand mile on my new engine but it is dry as bone and runs well.Hope I dont end up with the same problem as you.Many people swear by these studs.Captek

Use Loctite on the end of the stud, use a nyloc nut on the end of the stud. Screw down into the case, and let the Loctite harden, then remove the nyloc nut...

-Wayne

It sounds like Steve needs to get a timecert or case saver in there first if the observation of his mechanic is correct that the stud pulled out of the thread when torquing it. Not sure if Loctite will save the day here.

I doubt you can install a timecert proberly without tearing down the engine.....

You could try some of the epoxy thats out there some are excellent and once cured they can even be drilled and taped,not that you would want to tap it but rather coat the stud with the epoxy and screw it back into the case and put a heat lamp on and let it sit for a few hours.I,am only suggesting this as a last resort before you tear down the engine.Youve got nothing to loose at this point.captek

I've decided to drop the engine and take a closer look at things with it on a stand rather than in the car. Given the amount of oil blow-by that is concentrated in the vicinity of No. 1 & 2, the complete looseness of at least one stud on No. 1, the p-tech's testimony that several of the studs were loose, and the increasing sound the "exhaust leak," I won't feel confident in the engine unless put an eyeball on the crankcase and cylinder tops. Plus, the knot in my stomach about having to rebuild again, is giving way to the excitement that I "get to rebuild" it again! Kinda sick, but I'll bet some of you understand...

I have the original no gasket configuration. I think there was some sentiment during my last rebuild that there just wasn't enough meat on the cylinder tops to accommodate a gasket channel. Any experience or thought on that?

Thanks!

I had the same deal on my 964 engine.I got a great deal on the cylinders and pistons with the gasket late style.I bought them from EBS Racing in Nevada.Paid about 1,800.00 for new mahl cylinders.and pistons.If your going to rebuild again I would go for the late model cylinders.I agree it is some what interesting doing a porsche engine.Its complicated and at the same time its simple. Its still a lot of work and time.I would want to be certain that there are no kinks this time around.Also I used the dow corning aviation sealer for the crankcase and I put orange silicone around the nose bearing and the braether.I got this tip from Rich over at Jacksic Racing.The loctite seems to thin even though people swear by it.Good luck

First time I have heard of this. What exact type/number are these?

The dow corning is # 730 and the orange silicone is just a 3m silicone sealer.These are good products.The 730 is what they use to seal the aircraft engines,you know its got to be good if its flying.captek

Findings!
 

Engine is out . . . inspection of No. 1 cylinder stud (exhaust/forwrd). The nut was easily removed, but I needed to use a stud remover to get the stud out. Here's what the stud looks like.
http://forums.pelicanparts.com/uploa...1176689976.jpg

I thought the threads were just full of junk, but when I started cleaning the threads - I found a helicoil!! I had no idea.
http://forums.pelicanparts.com/uploa...1176690100.jpg

Here's a better picture of the POS helicoil.

http://forums.pelicanparts.com/uploa...1176690146.jpg

On the exhaust side of the head, you can see discoloration at 2:00 and 5:00.


http://forums.pelicanparts.com/uploa...1176690266.jpg

At least now I know what I'm dealing with.

So assuming I need to put inserts into the case,

1. should all of them be done or only the "bad" ones?

2. case savers or timeserts?

Thanks!

First off was the stud really hard to remove?Second was the nut torqed?I would ask Rich over at Jacksic Racing he is in new jersey but you can ship the case to him,very easy to deal with 908-362-8163.You are running the old style cylinders correct?No gasket maybe thats part of your problem.The picture looks like an heil-coil are you sure its not the aluminum threads?Did you remove all of the studs?Do they all look the same?Depending on how the threads look and how easy they go back in its hard to say to do all of them.But for my pieace of mind I would do all of them and go to the late cylinders,but again ask Rich he will know the guy knows porsches been doing them for about 40 years.Hope this helpsCaptek

that doesnt look like a helicoil, if you look at a cross section of that it is triangle shaped a helicoil is diamond shaped. looks more like pulled threads. as for overtorqueing has your torque wrench been calibrated the click kind are notorious for changing and causing overtourqe. all it would have taken would be to drop it in between doing the banks and both sides would be torqued differently

Steve, see here: http://forums.rennlist.com/rennforums/showthread.php?t=111791&highlight=gasket for some information about gaskets for the early-style 964 cylinders. I am running with this for about 18.000 miles and there is no sign of blow-by. Walt at Competion Engineering did an outstanding job. Cheers,
Ingo

I put a magnet on the "coil" - no attraction.

Thought (hoping) it might be a stainless coil, so I pinched a piece between my thumb and index finger and it crumbled easily. I'll take a close look at the case, but have to agree it certainly does look like pulled threads, though I've never actually seen one.

What next to repair, Timesert or Case Saver?

http://forums.pelicanparts.com/uploa...1176770406.jpg

Timecert for sure those things go in if there done right and you wont have to worry anymore.The case hole gets machined bigger and then rethreaded and then the timecert gets threaded in to the case,if my memeory serves me well.But somehow when yuo install the stud the timecert gets locked in the case.Again I always ask Rich at Jacksic,always quick to help and knowledgable.Captek

I'm betting that something weird happened to this engine case a long time ago before you were the owner. I don't see how you could have caused this to happen, from the events you describe...

-Wayne

Did you remove the studs yourself?How did you remove them?Did you put heat on the base of the stud hole?Captek

Thanks for the vote of confidence, Wayne! The only good thing to happen yet.

Captek: Thanks for your interest on this, too!

Did you remove the studs yourself?
A: Yes, but I've only removed the one that was loosest.
How did you remove them?
A: I used a 10 mm collet style stud remover. (See pics)
Did you put heat on the base of the stud hole?
A: Didn't need any heat. I didn't use Loctite Red.

http://forums.pelicanparts.com/uploa...1176842851.gif http://forums.pelicanparts.com/uploa...1176842859.gif

I,am not sure I understand,you rebuilt this engine and put in the arp studs but when you removed the old ones how did they come out?And when you put in the arp studs you did not coat them with anything?

Got all the heads off today. Also was able to look at the two pulled stud holes - completely smooth... No. 4 head looks like it just came back from the machine shop. Also found wide variety of torques on the head studs on the right side. Some were less than 30 and some were more than 60. I know my torque wrench couldn't have been that inconsistent. I'll post my diagram later.

Captek - My memory is that the ARP studs came already coated on that end, but I might have put a Wurth sealant on, too. You can see what looks like remnants of sealant on some of the studs.

http://forums.pelicanparts.com/uploa...1177301922.jpg