Header leak problem

[Hallaian42]

Does anyone know a good way to stop header leakage? I know that seems like a pathetic question. But my headers were leaking pretty bad (from the port area). You can hear the "pat pat pat" sound comming from them. I ended up taking every off...intake manifold and all....cleaned and taped the threads....put a new gasket...tightended everything back up and the dang thing still leaks. It sounds even worse now. I looked at the old gasket and you can tell thats where it had been leaking from. Any suggestions to what the problem is and what i should do? I was thinking about just taking it to a muffler shop or something and see if they can just fix it. Thank you

Steve

1972 240z

77 L28 F/I engine

[2ManyZs]

Well, the first thing I would do is to check the header flange to see if it is warped. Take the header off and use a straight edge across the flange to see if it is warped.

Second, look to see if there is any welding slag around the port or ports that are leaking. If there is, take a wide flat file and try to file the port flat.

Third, use a good quality gasket, I have had good luck with the gaskets that are covered with foil, not the paper gaskets.

Third, when you have it back on the car, see where the leak has been developing, and check the mounting bolt closest to it. If it is one of the bolts that has the large washer under it to clamp down on the intake and exhaust, see if it is at an angle. Sometimes the flanges are not even, resulting in a loose flange. If it is not tightening evenly on both the intake and exhaust you will develop a leak for sure, you could try shimming it with a flat washer cut in half it the flanges are uneven.

Make sure all the mounting bolts are tightened evenly, if possible try to torque them all to about 10ft/lbs.

[Ed]

I have a MSA 6-1 header and it leaks too. What kind do you have ? At first it didn't leak but after a while the "special" gasket started to develope pin holes. I called them on this and they sent me another "special" gasket. The first one looks kind of like paper. The new one is more of a composite type material. I haven't put it in yet.

I have been doing some homework on the subject because I don't want to have to replace it again. Check the flange thickness on your intake manifold, is it the same as the exhaust manifold? If not you will need to modify the washers in order to put the same amount of pressure on both manifolds. When you had your header manifold off did you check for smoothness on the face? Sometimes there is some weld spots that portrude. Another thing is to check the manifold face for straightness, use a straight edge. I have heard of other guys using the stock exhaust gasket (the one with the metal center) with good results. You can also try a copper based high temp silicone to help the seal. Hope that helps.

[ZmeFly]

dont waste money on a cheap gasket. it will only cause you headaches. also to add a little. once you put your new gasket on, after few days of driving, retorque your nuts once again.

when i put my new gasket on, just out of curiosity, i had checked and mine had loosened up..

james

[Hallaian42]

What brand is the best kind of gasket? And where can i get one? I'll do anything to get rid of this exhasut leak. By the way...if the header is warped , like at the flange or so...is there a way to fix it or should i just order new headers right now?

[2ManyZs]

MSA should have the header gasket for about 8-9 dollars, ask for the preformance header gasket, part number 15-2525for 70-74 with carbs arnd square ports, 15-2526 for 75-76 with square ports and FI.

It will depend on lot on how much the flange is warped (if it is at all), lay a straight edge across it and see if there are any gaps, if there are gaps, if they are say 1/16th of an inch or less, you should be able to re-use the header with no problem. As long as you use a good gasket and torque it correctly. Any more than that and you might have to either have it straightened or buy a new header. :disappoin

[spudz]

I used the stock type gasket from my import

parts store. I then took the copper high heat sealant and put a bead on both sides of the gasket

before installing. It has been holding up fine for

me. The first time I intalled it I didn't use the

copper sealant and had leaks.

Also I used anti seize on all the mounting studs and bolts. It is much easier to get the nuts back

off later.