broken head stud and related damage

[dberman]

I'm doing my first top end rebuild due to a broken head stud. I've attached a picture of the cylinder where the broken head stud was found. The question is the damage on the cylinder such that I need to buy a new cylinder or can this be repaired by a good machine shop.

Also, are there any more tips that will help me determine the types of cylinders I have other than what is in Wayne's rebuild book? I tried the magnetic to the inside of the cylinder and don't feel any pull so I guess I have the Alusil cylinders but I can't find any of the markings that Wayne mentions so I want to be sure.

What are people's thoughts on reusing these cylinders? The car is an '83 SC with only 80,000 miles on it. It ran great until the broken head stud issue. So, I think in general the engine is in good shape. I don't want to spring for new cylinders or pistons if I don't have to.



Thanks,

Dave

[MBruns]

The cyl. is junk, it looks like an alusil KS cyl., they shouldn't be hard to find, the head can have the seal surface machined and the rest matched to whatever the cleanup takes.
It's a common issue when the studs fail.
Mike Bruns JBRacing.com

[jchris]

Sorry to see the damage that you suffered due to the stud. I'm surprised to see how bad that is with just one stud failed. I just replaced the dilivar studs this fall (one was broken). I replaced the rings and treated the alusils with the silicon paste from sunnen. There are enough threads on this subject to keep you busy reading for a week. I decided to risk trying a re ring. Search "rering alusils?" I have about 3k miles on my engine now and it starts well hot or cold no smoke and very low oil consumption (1 quart so far) additionally my fuel mileage is about 18-21 which I believe to be normal. I have no leak down numbers to give or any real hard science. I am on a tight budget and thought it was worth the risk. For me it is a case of so far, so good.

Good luck.

[Eagledriver]

Unfortunatly that cylinder is toast. The good news is that Alusil's are cheap. You'll need to find one with the same height number. It's the number with a tri-angle around it. Alternatively you could put 3 new cylinders on that side from a matched set. You can probably just reuse your rings and pistons with your low milage. It would be worth doing a vavle job when you get the heads resurfaced.

-Andy

[tom1394racing]

While you are at it make sure you replace the lower studs with steel ones.

I can supply studs and a cylinder to match your other (5).

PM me if interested.

[dberman]

Thanks for the information guys. I'm doing some more research now.

[mr.jwhey]

Difficult to say from a photo. Some discoloration of mating surface is normal.

Clean it with a scotchbrite pad and look at it under magnification for evidence of micro-channeling. Inspect the mating surface on the cylinder head. Those can be remachined.

Although conventional wisdom is Alusils can't be reused, my local shop says he has re-ringed many an Alusil with Goetze rings and never had a problem, provided u avoid synthetic oil.

[SCadaddle]

I'm currently going through the same problem with my 82SC with 155k on the clock. Realize I'm no engine builder, but here is what I have been through:

I've read the 28 page thread on re-ringing Alusil cylinders. I've talked on the phone to several engine builders. My engine builder insists that the typical "off the shelf" Goetze rings aren't going to work, the correct rings are unobtanium unless you order them from Porsche and then I was looking at $600+ for a set of rings.

I kept my eyes peeled for a good used set of Mahle pistons and cylinders for a couple of months. Nothing turned up.

I wound up sending my pistons and cylinders to Don at EBS Racing in Reno, they had them Nikasil plated and supplied the new rings to run on my original pistons. About $800 to process the cylinders and about $135 for the set of rings.

We replaced the lower row of head studs with steel ones. Since we had to use a propane torch to heat the case at the lower studs in order to remove them, we replaced the O rings on the 5 case through bolts (10 O rings total--the green ones). We had to heat the case pretty high (350-400F) to get the studs to break loose so I felt it was prudent to replace those being in such close proximity to the heat.

Replaced exhaust valve guides and did a thorough valve job. We've turned the corner and starting to go back together.

I would suggest:

1) At only 80k miles, IF you remove the piston rings by all means keep up with them by placing them in plastic baggies marked with the respective piston/cylinder they were removed from.
2) See #1 above.
3) I'd take Tom up on his offer to supply a single cylinder and studs. I've swapped messages with him in my build and he comes across to me as a straight up very knowledgable fellow.
4) Get in touch with Henry Schmidt. I noticed just the other day he may have some used Mahle pistons and cylinders. Very personable fellow that tipped me off to Don at EBS.

Good Luck!

[mr.jwhey]

That's another combo that flies in face of conventional wisdom. Not supposed to match pistons from Alusil w/ Nikasil cyinders. Most likely you now have Goetze rings running on your pistons, which supposedly don't fit the ring grooves properly.

[Eagledriver]

The Alusil pistons should be ok in Nickasil cylinders. The Nickasil pistons cannot be used with Alusil cylinders. Alusil pistons have an iron coating on them to prevent gualling on Alusil cylinders.

-Andy