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I seem to have the worst luck with header gaskets. header flanges are flat and smooth, i've tried remflex and percys and both blew out in the first day. I've had the best luck with regular felpro gaskets and putting copper silicone on both sides, even then they only seem to last a few months.

Am i dealing with back pressure issues? Car runs great other then the exhaust leaks always occuring
 

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I've been using Stage8 bolts, Ford gaskets and ultra copper and have about 10k street miles with no leaks yet.

Sent from my VS996 using Tapatalk
 

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lol gaskets. I use vatozone replacement bolts, split washers from the hardware store, and red rtv. Never had a problem, ever.
 
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Header gaskets, wtf are those. Back 15+ yrs ago I ran Mopars and gaskets weren't always available at the parts stores, so I ran the "always available" Ulta Copper. All I've used since.
 

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I just use ultra copper rtv also, then you have no gaskets to blow out.
 

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I'm in the same boat, tfs hi ports and kooks 2" SS long tubes, I've been searching for a gasket , just got the headers coated.

is there a write up on using the rtv some where.

whats the right way to do it.
 

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The right way or not , I apply an 1/8th inch bead around the flame, drink a beer , then install .
Never had a leak.
Headers on my 347 in 84 Mustang have been on since 2002 .
 

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I let mine dry overnight other than that, same results.
 

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are you retorqueing after a heat cycle
 

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I always put a bead on the header flange, the aforementioned 1/8" is sufficient, wait about 8 minutes or so, then bolt them on. I will go back and check the bolts, but rarely ever have one loosen up. I think the RTV gets on the bolt threads and kinda helps keep them in place.
 

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I always put a bead on the header flange, the aforementioned 1/8" is sufficient, wait about 8 minutes or so, then bolt them on. I will go back and check the bolts, but rarely ever have one loosen up. I think the RTV gets on the bolt threads and kinda helps keep them in place.
Ok Thanks for the info , I'm going to give it a shot this time.
 

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I seem to have the worst luck with header gaskets. header flanges are flat and smooth, i've tried remflex and percys and both blew out in the first day. I've had the best luck with regular felpro gaskets and putting copper silicone on both sides, even then they only seem to last a few months.

Am i dealing with back pressure issues? Car runs great other then the exhaust leaks always occuring
is this a turbo car?

have you tried header studs?

also what are you using to clean the surfaces as that might be the problem. i've used Klean Strip Prep-all Wax & Grease Remover for years, FelPro 1487 on my turbo setup and header studs and never had an issue.

in my opinion prep is lot more important than the brand of gaskets meaning keeping things clean and not touching the mating surfaces with your hands (treat it like head gaskets).
 

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Y’all skipping past step 1?
If you do step 1, then there probably isn’t a right way, and wrong way? Which my the rule of odds, is probably how 1 guy has success with 1 way. While the other guy on the Internet says it cannot be done that way. Which is probably the leading cause of internet arguments?

Some flanges are flat. Some have a slight warp that can’t really be seen by the eye. Some are warped in the league of On3. No matter what manufacturer of exhaust manifold you go with IMO they all need to be true flat.

Long winded, but here is my step 1.

Step 1:
Slam flanges against Harbor Freight belt sander.
Step 2:
Copper RTV
Step 3:
Drink beer
Step 4:
Install headers with Stage 8 bolts
Step 5:
There is no Step 5

Good luck, your mileage may vary...
 

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Y’all skipping past step 1?
If you do step 1, then there probably isn’t a right way, and wrong way? Which my the rule of odds, is probably how 1 guy has success with 1 way. While the other guy on the Internet says it cannot be done that way. Which is probably the leading cause of internet arguments?

Some flanges are flat. Some have a slight warp that can’t really be seen by the eye. Some are warped in the league of On3. No matter what manufacturer of exhaust manifold you go with IMO they all need to be true flat.

Long winded, but here is my step 1.

Step 1:
Slam flanges against Harbor Freight belt sander.
Step 2:
Copper RTV
Step 3:
Drink beer
Step 4:
Install headers with Stage 8 bolts
Step 5:
There is no Step 5

Good luck, your mileage may vary...
I'm going to do this Saturday , I'll post up how it goes.

Nice … :lol: I see What You Did There!!

I got No Stinking belt sander senior ! :frown2:… but my Kooks are 2 piece flange both sides, only 2700 miles and never over heated. lol.
I'm going to make sure I prep them really good, brake clean , Acetone for the final wipe.
maybe a little thick on the Copper RTV , drink a Brewsky !! 10 minutes later Bolt-em up !!
 

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I run 45-55 psi hotside and don't have any leak issues. I use a little Ultra high Temp RTV off Amazon.

If the header flanges are properly faced they will never need a gasket and never leak, but they have to be faced slightly higher off the head at the bolt holes with the flange a few thousands humped mid way between port bolts. But I mill them.

Then, when you tighten bolts, the centers will pull in tight first. This pre-loads the flange center as the bolts are snugged. This preload keeps the bolts tight, even normal hardware, and it keeps the flange flat even when the tubes get really hot.
 

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highly unlikely that kooks flanges are the issue...
 

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Ok thanks for y'alls advice !


I was going to put my Kooks 2" headers on this past weekend , I tried to mock them up with no gaskets, I was trying to see if I could do the power rack/shaft after installing the headers.

without gaskets my ARP bolts are too long. they are 3/4" long, I had some small washers to put on them, but I want to do it right.

I have TF hi-port 225 heads , whats the gasket and studs I would need?

I'd like to give it a run again next weekend if I can find them.
Thanks for the advice guys
 
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