Houpty GT

Vice grips and a propane torch. The vice grips did not have much in terms of teeth left by the end, however I was using a small pair because all I had with me was my smallest and largest vice-grips. A mid sized pair should be an improvement. I also put a box-end wrench on the round handle of the vice-grips so I wouldn't have to push as hard. One stud came out very easily and one stud came out very difficultly. This is with exception of the one shorty that had to be welded. As the vice-grips wore and stopped getting as mush grip I started to use my dremel to grind the diameter of the studs flatter on the end were they had broken. This really cut down on any slipping. .

Why do you need to change your head studs if you are replacing heat exchangers? Though some of my studs did not break until I tried to remove the barrel nuts, I only had one cylinder that made a chirping noise under load. There was also no damage to the head or barrels. My feeling with the head studs is that unless you are hearing noise, I would not even bother tearing the engine down for this.

An idea I came up with and would like to see as an option available for others is a weld that can weld a replacement length of stud onto the broken section. This would be much like a spot welder in body shops that welds a nail to the body so a slide hammer can attach and pull out the dent. This process can use either a full threaded length of stud or be cut to size. An insulator can be used to block of the aluminum around the sides of the studs. The proccess would only require removal of the engine and valve covers. It may also be possible to do on the car.

Peter Zimmermann

Please explain, for the benefit of fellow Rennlisters, how you arrived at this...

Actually, once noise is heard that is due to compression loss caused by broken head studs it's too late, and damage has been done. Every engine that I and my mechanics have repaired that had audible compression loss also had damage to either the head, or cylinder, or both.

theiceman

Great info .

My car is a 78 and has the original exchangers... my mistake I was talking about the exhaust studs.. but I think the same principles apply .....i can't even see the barrel nuts or reguar nuts anymore.. they are just a big glob of rusted metal. Although I will of course use the penetrating oil I am not hoping for miracles as I expect to bust em all. well .. after i grow big enough ***** to try it ...

Houpty GT

I got the following prices from Bearing Distributors:
Skf N206EMC3 your cost $73.35 6 days reg ups.
*** N206E.M1 yor cost $89.10 3 days reg ups

Less than half the price for the same bearing.

Pete,
Well I suppose from what I have read that the noise from my exhaust was just a "chirp" while others have had "phat." So maybe I had a smaller leak. If I had a camera I could show you the parts. All heads and cylinders look the same the whole way around.

When people brought you cars with damage, how long had they typically been driving it that way and how loud was it? I would imagine longer and louder. If people learn to recognize the issue and not continue to drive the car then they are not going to be seeing damage.

Iceman: I guess that is what you get for living in Canada, eh? Good luck. Doesn't anyone make a stainless steel exhaust stud set? There is probably a standard stud that will work. They had them for the older Audi's.

Peter Zimmermann

Based on current Porsche retail of $188.83 that's a far cry from "the several hundred dollars" in savings that you claim in post #14. It's certainly not a big enough difference for a Porsche shop to risk their use, especially if the bearings that you found don't arrive in P-car packaging.

Regarding damage to your heads/cylinders the only way to truly know if there is no damage is to put the heads in a fixture on a vertical mill and measure them with a dial indicator. Pictures won't show a small defect caused by burning or warping, and neither can be seen with the eye. The tiniest defect has a good chance of becoming a head leak at some point down the road, usually far sooner than the point where the rest of the engine nears being worn out. The cylinders can be checked by hand-lapping using a precision surface plate and appropriate paper, but this must be done by someone highly experienced with such checks and parts. Good luck with the project.

Houpty GT

I am not sure why you even started to talk about what Porsche shops do or do not. I think it is up to the independants to make that call on their own and the dealers have no choice. As for the DIY, I think $110 is a good savings on a oem part. As for saving several hundred dollars, it is strong possibility on a few of the other bearings. Pelican has several listed for $200-$600.

I will be sure to check my heads and cylinders very carefully.

Peter Zimmermann

I was only trying to make the points that (1) a shop can't in good conscience offer a warranty on a repair done with unauthorized parts, and (2) I didn't see any financial upside to search for a "better" deal. You found the bearing for about $155. Subtract about $80, and you're less than one hour labor, at today's typical shop, ahead. If a shop takes only one hour to locate a "better" deal, they're already worse off than just buying the more expensive one. If your time is worth nothing, well...

I'm sorry, I thought that this thread was about one bearing...

Consult your P-car manual, there are a lot of specifics regarding checking/resurfacing heads.

Houpty GT

Stainless steel exhaust studs:
M8X1.25X32
http://www.arp-bolts.com/Catalog/Cat...talog_0075.jpg
Jegs and Summit both have a set of 16 for about $150

My '81 calls for 30mm length but the earlier SC's call for 35mm according to Dempsey's engine book. Does anyone know what the reason for the change was? Just interested.

www.McMaster.com has M8X1.25X30 stainless studs that are fully threaded for $1.21 each.

Then we just need to figure out a way around the allen nuts.

Peter Zimmermann

The part number for '78/79 heat exchangers is different from that for '80>, so one can only assume that the early units used thicker flanges. It's not possible for gaskets to differ that much, so it can only be the flanges...

BlackPearl

FWIW: I just had a complete bearing replacement on the output side of my '83 SC trans. Here's the breakdown of parts costs on the bearings:

Bearing 915 302 399 05 $274.95
Bearing 999 110 146 00 $174.95
Bearing 999 052 043 00 $109.95

The first bearing set, numbered 915 XXX was pitted and showed signs of heat-stress (blue-ing of metal, etc). It made enough growling sounds to warrant pulling the trans and breaking it apart to see what the matter was. (BTW: I had lots of other stuff done while the engine was out.)

The other 2 sets of bearings were replaced as part of my "track Insurance" for planned future use. I also replaced syncro's where needed. All toll'ed I invested in the future with genuine Porsche parts, with no regrets. I still think I got off fairly low in cost for the re-build (just under $2.4K with everything carefully gone-over) and having a parts and labor warrantee from the shop makes me feel a little more secure going to red-line in 3rd and 4th gear on the tracks of SoCal.

Personally, I'd never go with anything as vital as bearings from an after-market source. There's too much at risk for me, my co-driving wife, and a car I really like to drive. Sure, a few more $$ for OEM, but it's a lot more fun for me to drive home at the end of the weekend in a tight-running car than watching it being towed to the shop for ... replacement of after-market parts.

Now there might be some who disagree with me ... you'll find them waiting for their car to be repaired ...again!

Peter Z.: I'm with you on this one.

Mark Salvetti

I think these specs are reversed. My 79SC has short exhaust studs. I'll always remember, because the used exchangers I got for a great price on eBay had thick flanges, and I had to cut them down with a Sawzall so I could bolt them on. These exchangers also had a short lip that protruded up into the exhaust port (better seal?), and I had to cut those lips off with a Dremel to fit my 79.

The SSI page on Pelican also shows thin flanges for the 78-79 SCs.

If you're going to toss your old exchangers, then I would cut them off with a Sawzall fitted with a metal cutting blade. This will let you access the nuts so you can cut them off a Dremel, saving the studs. Clean up the studs with a rethreading die.

Cutting off the exchangers might be hard with the engine in the car, but if it's out and on a stand, it's very easy.

Mark

INWTARGA

Houpty
Can you list the bearings that you were able to source and the cost. I'm in the middle of a rebuild and have to decide to either replace questionable bearings or leave them due to cost. It sounds like you were able to find OEM bearings from *** and SKF.
Thanks

Houpty GT

I ordered the bearing that I needed from Pelican. I have questions of its accurracy because they have it listed under a different location than the part number dictates. It was half the price of anywhere else. I will let you know if it was correct when I get it. If it is wrong I will return it and buy it from Bearing Distributors. They might be good to get prices from for what you need. Just use the part numbers listed on the bearings.

theiceman

Just catching up to this thread .. the earlier units actually had thinner flanges. I know because I have a set of the later exchangers hanging on my wall as decorations.

Peter Zimmermann

...just guessing based on the post. It's also possible that the longer studs have offset centers and actually go into the head further, and stick out less. Hmmmmm, now if anybody has some heads laying around...

ice: How much difference between the flanges on your car, and the ones on your wall? Let me know, and I'll measure my '82...