exhaust stud replacement question

[911fan77]

I know there was a question before on this and I did do a search.

I am replacing my older think flanged heat exchangers for thin flanged SSIs. All the exhaust studs are going to be replaced as they are rusted severely. Looking on Pelican they show two sets M8x20mm and M8x35mm. They also show a new kits for non-corrosive exhaust studs but show M8x22mm (I think). Now I previously read where someone recommended the kit which included the studs, washers and nuts being they were alloy. My question is for a '77 2.7 what size studs do I need for a thin flanged heat exchanger?

Any help is appreciated...
Dean

[Tim Hancock]

Dean, measure an actual stud once removing and add or subtract as needed to accomadate your flanges and nuts/washers. Then buy from an Autozone or someplace like that because I tried to order from Pelican twice for my 79 sc and they never did get the right parts to me (it is not worth the hassle of phone calls, return shipping and weeks of waiting). If you measure your studs yourself, you can then go find some locally that are the right length (and probably cheaper to boot). I can tell you that the lengths listed on Pelican are not O'all length.

I do not mean to trash Pelican, (I have placed orders since) just never again for exhausts studs as the some of the phone sales kids do not understand the meaning of the words "overall total length".

[echrisconnor]

Do you have your engine out and you heads off? I wouldn't even try to replace all my exhaust studs unless I absolutely had to. Invariably a number of them will break and then you'll be drilling or EDMing away. Not a pleasant task and even less plesant with the engine in the car. Rusty is fine. Wire brush them and put things back together.

As for which part is proper, just call Pelican and tell them what you want. It's much faster than asking the forum or taking a guess. The guys on the phone are very knowledable and will take good care of you.

[Tim Hancock]

I agree w/ echrisconner on leaving them if they are not broken, just use plenty of anti-sieze when reassembling. As far as the knowledgable salesmen, well I am sure some must be able to read a tape measure and understand plain english, but I have two packages of unused studs sitting in a box somewhere that proves that not all employees are created equal.

[addictionMS]

just as a data point, I have my heads off, and 8 of 12 sheared and needed to be drilled and timeserted.

Jim

[john walker's workshop]

if you haven't searched the archives on exhaust stud issues, do so. it's recommended to let sleeping dogs lie, and to use a oxy/acetylene torch to heat each nut red before attempting to remove it. if you think any of the old studs is going to come out in one piece, i have some waterfront property in AZ.........

[911fan77]

Well, I am having professionals install them as 1)I have very little time and b) I am a gorilla when I do uninstall/install things. I do know my limitations when working on the car. I have re-done the interior and some of the CIS components but I could see myself getting into trouble on the exhaust part. The mechanic called and wanted me to order 12 studs after they removed the old HEs. Just going by what he said.

[echrisconnor]

Good enough. Just be sure that the mechanic is aware of what he's getting in to. If he busts all 12 studs and then wants $50 each to EDM or drill them out, your overall cost could go up considerably.

Also, know that people do put thin flange HEs on the longer studs. I've heard of washers being used to space things out. Not the prettiest solution, but it could work.

[911fan77]

Yeah, now you guys are scarring me . This had to be the original exhaust that was on it. To boot, since it is a '77 2.7 the guys at SSI are telling me about two different versions of exhaust ports (one at 35,5mm and one at 35mm). So I had to wait until the mechanic could remove the exhaust in order to check the diameter of the exhaust port before SSI would drop ship the exhaust. Talk about a little stress.

The studs were really bad. I went over with the mechanic, in a diplomatic way, about the nut removal using the torch and then unscrewing the nut. I felt confident he had done it before by they way he acknowledged that and mentioned prior experience. I had put PB Blaster on the studs/nuts for several days prior to delivery to the shop. So I felt everything would be done as mentioned on this board in previous threads.

If they are removed, then I really have no problem if they are replaced as long as they are done right. I ordered the kits from Pelican (non-corrosive) for future projects like headers, etc. The main concern was saving the existing studs, although long I could still use thin flange. If that failed I could replace ones that broke. I will be going by the shop later to inquire about the work done so far, etc.

[echrisconnor]

I'm not sure if I'm reading your last paragraph properly but are you changing the plan now to not swap the studs? If so, I'd say that's the way to go. I'm sure your mechanic can get the nuts off and drop your old exhaust. Sure, if he breaks a stud or two in the process, replace them, just don't just go and have them replaced without a good cause.

As for the SSIs. If you haven't yet purchased/received them yet, why don't you just get the thick-flanged SSIs? This is a much better solution than putting thin flanges on long studs.