I am repeatedly having header leaks, what gasket do you use and have good success with?

Thanks!!

 

Percy, Seal for Good

 

Dupe Double posted itself for some reason

 

This will usually ALWAYS end up an ongoing saga until you do one thing;

*True/machine the flange of the headers where they mate to the heads.

Sounds like the flange surface has warped.

I dont know what brand you have...it really doesnt matter...fact is, if the flange is not true, it will always create a leak sooner or later no matter what gasket you use....even new they can be warped.

It dont take much to warp them...toqued to the heads in the wrong sequence...stacked at the warhouse wrong in climate changes...assembled wrong when new...ect...

Take them off...bring them to a machine shop and true the flange surface...if done correctly you can use the $5 header gaskets and they will last.
PITA to remove them and get them to a machine shop...it just all depends on how many times you want to r/r gaskets.

$50.00 copper gaskets...they can seal and have the ability to overcome *slight* flange warpage...I think they are made by FelPro, but eventually leak too.

Another old trick is to use "individual tube" gaskets (like regular exhaust manifold gaskets) ...these are cool because they have one bolt hole that is slotted...meaning; you loosen 4 bolts and you only have to remove 4 bolts...hang the gasket in place, re-insert the 4 bolts...hand tighten, snug, then torque all 8 in sequence to torque spec. This also enables you to just r/r the burnt gasket and not undoing the whole header...but it is suggested that you loosen all the header bolts because loosening just one tube, is a leading cause of flange warpage....see where these shortcuts can help or cause problems?

I havent heard of, or used Percy gaskets...but, even at best; a warped flange can make any gasket leak eventually. (I added their link at the bottom since I wanted to know about them too)

BTW---this isnt new (warped headers)...old timers use to double the gaskets to overcome warpage....the smart guys took the headers off and brought them to a machine shop when they noticed the gaskets would continue to burn out in the exact same area as the first set.

Worst case scenario is warped heads-to-headers mating surface (exhaust port gasket surface area)...that requires the heads to be removed and brought to machine shop.
And some machine shops dont take the time to do this when rebuilding heads unless specifically asked for the intake and exhaust areas to be trued/machined.



Percys header Flange Gaskets $44.95

SBC Square Bore

Dont let all this confuse you...just giving you all the info/options of being able to do it right the first time.

GL



Jim

 

Thanks For Your Help!!!

 

Great info Strats-N-Vettes, funny this thread came up because I noticed an exhaust leak on my stang this past week and was trying to decide what to do. I do have one question tho, what causes the warpage on the header flange? I am assuming heat is one cause. Could a supercharger possibly add to the problem? with the increased air flow/pressure under boost.

I got basically a bonestock 5.0, replaced shorty headers with longtube, no cats (shhhh) and straight flow thru exhaust, upgraded ignition/fuel and supercharger far as the engine goes.

 

It dont take much to warp them...torqued to the heads in the wrong sequence...stacked at the warhouse wrong in climate changes...assembled wrong when new...one end of the header un-bolted when hot and not the other end.
Used headers stored hanging on the walls or on the floor during climate changed.
Little kids throwing their brothers or sisters on them pretending they are in jail...no telling.
1/4" flange headers are notorious for EZ warping...el-cheap-0's.
Thats why the high $$ have thicker flanges...less chance of warpage in the future.

Always ask for flange thickness when buying headers, it will tell you a lot about the construction/durability.

but in all honesty; the thickest flanged headers can still be warped when new, or like whats written above.

Not to mention...sometimes cheap gaskets just plain wear out due to no fault at all of anything.




Jim

 

you know make sure your header bolts aren't bottoming out on you.....you may want to check that carefully....try putting each one in and hand tightening it down to make sure it will compress everything far enough

 

Thanks!!

 

I kept having problems too with my dynomax headers. Tried soooo many different types of gaskets, they all leaked eventually. Finally pulled the header off, filed the ceramic coating off of the mating surface, cut the flange between the inner and outer tubes, and used Mr Gasket Ultra Gaskets (filed to fit the head opening) and have not had a leak for years, with multiple removal of the headers and using the same gaskets.

 

I wonder how that works with all coated finishes? Chromed?
Chips or rust?

Seals good, and EZ too.


Edit to add:
I ask because I got chrome hookers to install this weekend...dont wanna do it twice, but dont necessarily wanna cut a 3/8 chrome flange either...hmmmm...

Jim

 

You may want to consider using two gaskets each side. This may be a quick fix to overcome any slight distortion in the flange. If it's badly warped you have to take it to a machine shop. Good luck.

 

I bought my headers from Stan's. 3/8" thick flange, no warpage with that thick of a flange...

 

I kept getting header leaks on my shorties. I would go out for a cruise and if it was a pretty long ride, say 100 miles or so, by the time I got home I would have a slight leak. It never failed that the culprit was a bolt that had backed off. I bought a good set of header gaskets and some Stage 8 Locking bolts. I put the gaskets in and the Stage 8 bolts and have not had another leak since. That has been at least a couple of years. I am a believer in the Stage 8's.

 

I got some Percy's...not bad at the Zone for $37.
Each is a 4pc. gasket made to be removed often...gonna port them tommrow and give them a try.

Will report...



Jim

 

The PO of my car said the header gaskets were always a problem. I put in some Earls Pressure Seal gaskets with Stage 8 bolts and haven't had a problem.