Securing / Sealing T4 Flange
Thread Starter
Launching!
Joined: Apr 2010
Posts: 285
Likes: 0
From: Sand Springs, OK
Securing / Sealing T4 Flange I have had an issue keeping the T4-Divided flange mount secured, and Sealed up.
The first issue I had- a few bolts backed out, and blew out the gasket.
I replaced the bolts with new grade 8 bolts, and lock washers. Did not use a gasket.
So, I recently had an issue where the Holley EFI is oscillating/hunting to get the AFR nailed down. After working with support, they recommended checking the O2 sensor placement (currently around 6in to 1ft post-turbo), and checking for exhaust leaks.
With it running, I did sense a bit of leakage from the T4 Flange.
So, to my question-
I have been reading, a lot of people seal it up with high temp copper: https://www.permatex.com/products/ga...-gasket-maker/ with good results.
Is, that the recommended approach? Also- what method is everybody using to keep the bolts fastened to the flange? While the bolts did appear to be tight still, the lock washers... well. I don't think they work too well after the repeated heat cycles.
The first issue I had- a few bolts backed out, and blew out the gasket.
I replaced the bolts with new grade 8 bolts, and lock washers. Did not use a gasket.
So, I recently had an issue where the Holley EFI is oscillating/hunting to get the AFR nailed down. After working with support, they recommended checking the O2 sensor placement (currently around 6in to 1ft post-turbo), and checking for exhaust leaks.
With it running, I did sense a bit of leakage from the T4 Flange.
So, to my question-
I have been reading, a lot of people seal it up with high temp copper: https://www.permatex.com/products/ga...-gasket-maker/ with good results.
Is, that the recommended approach? Also- what method is everybody using to keep the bolts fastened to the flange? While the bolts did appear to be tight still, the lock washers... well. I don't think they work too well after the repeated heat cycles.
I usually just used grade 8 bolts and some sort of locking nut. Yeah washers give up the goods after a few heat cycles.
a good hardware store ought to have grade 8 locking nuts. Jet nuts, flex-loc nut or pinch type all work really well.
I try to avoid using gaskets but some stuff you just cant get flat, or sometimes it bows before you get it properly tight. I that case I'll use a stamped steel style gasket.
I've gone as far as using aircraft type safety wire, but that was like last resort fix for some hokey **** done by a previous mechanic
a good hardware store ought to have grade 8 locking nuts. Jet nuts, flex-loc nut or pinch type all work really well.
I try to avoid using gaskets but some stuff you just cant get flat, or sometimes it bows before you get it properly tight. I that case I'll use a stamped steel style gasket.
I've gone as far as using aircraft type safety wire, but that was like last resort fix for some hokey **** done by a previous mechanic
TECH Addict
Joined: Dec 2004
Posts: 2,177
Likes: 627
From: Florida
the last few ive done i used whatever cheap stainless gasket came with the turbos, but I put a thin layer of copper rtv on all 4 surfaces then bolt it together. I have never had turbo flange bolts come loose. I like to use whatever 15mm hex head bolts i have in my "ls engine hardware" bucket with lots of anti-sieze.
I likewise throw the gasket in the trash. If the flange is really flat I just spray them with copper coat, if it's iffy I thin layer copper rtv. Check the flange surface with a straightedge, if it's not flat get it flat. I also tighten the bolts, let the engine run and get hot and tighten them again. Nothing special either just grade 8 flange bolts screwed into a threaded flange.
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Copper liquid gasket works okay on low pressure stuff downstream of turbos. In my experience it blows out too easy under pressure.
These are my go-to guys for gaskets https://www.grimmspeed.com/grimmspee...nifold-gasket/
Been using their MLS gaskets under boost for a long time and was a product tester for a while. You can find these gaskets on amazon too. Extra thick MLS with built in fire ring, not sure what else you could want.
These and STUD the flange for a good seal. Re-torque the studs after a few drive cycles, usually gets another 1/4 to 1/2 turn after fully seated.
Torque spec: TAF
These are my go-to guys for gaskets https://www.grimmspeed.com/grimmspee...nifold-gasket/
Been using their MLS gaskets under boost for a long time and was a product tester for a while. You can find these gaskets on amazon too. Extra thick MLS with built in fire ring, not sure what else you could want.
These and STUD the flange for a good seal. Re-torque the studs after a few drive cycles, usually gets another 1/4 to 1/2 turn after fully seated.
Torque spec: TAF
