Case savers vs Helicoil in exhaust stud repair?

Joeaksa · 07:36 AM

I am in the final stages of getting the 3.6 back together and running. When we unpacked the motor found two exhaust studs missing, and when they were removed from head, and they took most of the threads out when removed.

Anyone have any input on which is better to use to repair the threads? Was going to put a helicoil in the hole and have used them for years but Bill Verburg mentioned that I might want to try a case saver.

Have never used them nor have any experience with them. Anyone have any experience that they could pass along?

Thanks,

Joe A

Rot 911 · 03-01-2004, 07:35 AM

I am not sure if a DIY'er can do case savers, never done them myself. What I have used is TimeCerts on the exhaust stud holes.

Joeaksa · 03-01-2004, 07:38 AM

Kurt,

Thanks and do you know if timeserts are different from helicoils?

Get the car started? Saw the thread on your starter problem and hoped it was an easy fix.

Thx,

Joe

ChrisBennet · ChrisBennet's Garage

Timesert are a solid insert. The outer thread is "timed" to line up with the inner thread.
A helicoil is just a coil wound piece of wire.
-Chris

dtw · 03-01-2004, 08:17 AM

Once you've installed both timeserts and helicoils, you'll develop a feel for when to use each type.. . I only use helicoils for unstressed, light duty repairs. Timeserts just have a much more confidence-inspiring engagement. The installation of timeserts is also much less 'fiddly' in my experience.

I'd definitely go with a timesert for an exhaust stud - they have to withstand a lot of punishment.

Porsche_monkey · 03-01-2004, 08:21 AM

I just did my own. The PO had butchered the exhaust with hand drilled helicoils (not straight) so I had to go timecerts. There is not a lot of material left when you are done (timecerts are larger than helicoils), but I would have no concerns about using a heli-coil in this application.

A timecert seems to be overkill to me.

KTL · 03-01-2004, 08:35 AM

I'd use a time-sert. Exhaust system goes through alot of heat cycling. Just my opinion.

Plus the time-set locks itself in place. Helicoils can back out when you remove the stud or even the nut.

Porsche_monkey · 03-01-2004, 08:40 AM

Exhaust studs do not pull out of the aluminum head, they break when people try to remove them.

A properly inatalled heli-coil is hard to remove, and it is already stronger than the parent material, why go beyond that?

KTL · 03-01-2004, 09:00 AM

I didn't say the studs break due to thermal cycles. Just said there's alot of heat cycling down there.

I dunno. Time-sert seems like the more precise solution to me, that's all. A solid bushing to accept your new stud seems better than a coiled wire?

And I think time-serts are actually easier to remove than helicoils, no? Not that you'd want to remove one too often. But if you decided to go back and do something oversize instead of using the time-sert, I guess it's good to know.

Zeke · 03-01-2004, 09:18 AM

Quote:

Originally posted by PBH
Exhaust studs do not pull out of the aluminum head, they break when people try to remove them.

A properly inatalled heli-coil is hard to remove, and it is already stronger than the parent material, why go beyond that?

I guess a couple of my exhaust studs didn't want to agree wiht you as they wound themselves out with the rusty nut.

I support the second statement to an extent. I've never had one back out that was properly installed. I use a tiny bit of red loctite and don't install the new stud for a couple days

Porsche_monkey · 03-01-2004, 09:27 AM

Quote:

Originally posted by Zeke
I guess a couple of my exhaust studs didn't want to agree wiht you as they wound themselves out with the rusty nut.

By 'pull' I meant pull the threads out as a head stud frequently does in a mag case. If they thread themselves out that isn't a problem, in fact it is ideal.

Joeaksa · 03-01-2004, 09:47 AM

My main question was the same brought up by PBH above in that I was not sure that there was enough room there for anything other than a heli-coil.

Hmmm... now need to go back to the fastener store and look at the time certs and compare. We use heli-coil's in airplane applications with no problems but then they have to be approved and do not believe that timecerts are yet.

Thx,

JoeA

Porsche_monkey · 03-01-2004, 09:49 AM

It might be okay for aircraft, but is good enough for a Porsche?

Joeaksa · 03-01-2004, 12:37 PM

PBH,

Problem is that if its not "approved" for use in airplanes, life gets very difficult with the FAA. Ferry Porsche and his minions might be difficult to work with but not that bad!

That said, a lot of what we have now in our P-cars was once in or on an airplane, then used with a race car then trickled down to the street cars. Glad it does and wish it would happen more often!

JoeA

Rouxzy · 03-01-2004, 12:42 PM

I had the same problem when changing over to SSI's, 3 studs broke trying to get them out. I went the helicoil route and it's been in there for about 3 years and no problems.
Tom

Porsche_monkey · 03-01-2004, 12:45 PM

One more point: Even the butchered helicoils on my engine stood up fine, I just couldn't stand to see the rest of my engine A1 and these crappy studs sticking out at odd angles.

PS I could post a picture of the helicoil vs the timecert, let me now if you want me to. I have both and my engine is on a stand without an exhaust.

Bill Verburg · Bill Verburg's Garage

Joe, spoke w/ the local shop owner "Timecert Casesavers" 8x1.25 is what he always uses for that repair.