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View Full Version : Heli-Coils in Exhaust Manifold


SVOBoyd
09-12-2016, 11:56 AM
Hey all I bought a used ported E6 and sent it to the machine shop to remove the turbo studs and re-surface the turbo and head mounting areas. When I picked it up the machinist said that there wasn't much of the threads left in the manifold so he put in four heli-coils. What do you all think, will the heli-coils hold up under the heat? Thanks
MikeFleming
09-12-2016, 02:10 PM
Heli-Coils (the name brand) are rated to 600 F MAX while stock 2.3 OHC EFI Turbo engines can reach 1650 F EGT under load. So I would not expect them to last long.

Some folks say they work just fine but there's no engineering reason to expect much life at the stock EGT temp range.
SVOBoyd
09-12-2016, 02:36 PM
Heli-Coils (the name brand) are rated to 600 F MAX while stock 2.3 OHC EFI Turbo engines can reach 1650 F EGT under load. So I would not expect them to last long.

Some folks say they work just fine but there's no engineering reason to expect much life at the stock EGT temp range.

Thanks Mike I was afraid of that. I guess I'll search for a new E6 or maybe one of the Gnari manifolds.
MikeFleming
09-12-2016, 05:24 PM
I think I have a new E6 in the shop somewhere. I will need to look.
brsvo
09-12-2016, 06:26 PM
I have had 304 stainless inserts in more than one manifold and never had one fail.
SVOBoyd
09-13-2016, 08:35 AM
I think I have a new E6 in the shop somewhere. I will need to look.

Thanks Mike let me know what you want for it.
SVOBoyd
09-13-2016, 08:39 AM
I have had 304 stainless inserts in more than one manifold and never had one fail.

I am just worried about the inserts fatiguing due to heat resulting in an exhaust leak. I've had my turbo off twice now for leaks. Once was my fault for using sub par studs.
MikeFleming
09-13-2016, 09:21 AM
They *may* work just fine for a very long time. While it's important to note that the manufacturer of the coil inserts specifically states the MAX ioperating temp for their inserts is 600F, which is 1000F LESS THAN a stock SVO.

Just sayin'.
Mike S
09-13-2016, 12:54 PM
According to the Helicoil website, they do offer them in Inconel.
SVOBoyd
09-13-2016, 05:08 PM
According to the Helicoil website, they do offer them in Inconel.

Interesting thanks for the information!
SVOBoyd
09-14-2016, 06:05 AM
Interesting thanks for the information!

Looks like the trick is finding someone that sells them, all I can find is stainless.