Header leak

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BOXHEADgumby

BOXHEADgumby

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I've got a 74 duster 318 /727 that I put a set of dougs 453 headers on and summit exhaust system. Had no issues until recently it developed a leak on the passenger side that I cannot seem to get rid of now. I've tried new Doug's gaskets, aluminum gaskets and recently remflex and its still there. Has anyone had this issue the leak is on the middle ports passenger side. Possible warped flange? I also noticed the number 8 tube sits really close to a bump out in the wheel well where the a upper control arm bolts in could it be tight enough that maybe the header is pressing against that bump out when the motor is running and breaking the seal?
Any suggestions or experience would be greatly appreciated.
Thanks.
 
Remflex worked well for me. I just tightened them starting at the middle ports and worked my way out. You also have to be careful not to overtighten with these gaskets.
 
I always cut the flange between the center 2 and the outside ones. They can flex and seal as need.
 
center ports are prone to warp if you overtorque them. Pull them and check the flange for straightness. Also look at the heat signature on the gaskets themselves and make sure there are not any thin spot where the flange is not over the port. I had a set of Hookers and they drilled them wrong, the bottom of the ports were never sealing and would blow out any gasket in about 2 days.
 
Thanks for the info. I am 90% sure I torqued them down backwards and will give that a try as soon as I get a chance and hope I didn't warp the headers.
 
when I install headers I put a thin film of copper rtv around all exhaust ports. It makes it harder to change gaskets out at a later date but it helps seal up any minor leaks.
 
A tube cracked away from the flange is a possibility also.
Use a piece of tubing and stethoscope that puppy down, and what you find will determine what you need to do.
 
My 360 head has a shallow milling gouge that needs a smear of the Copper RTV. Look for any surface imperfections.
 
Backed off the bolts and torqued them center out and it was fairly quiet until she got warm. I also put some of the copper rtv over the known area that the headers were leaking which was very apparent when I pulled the original gasket and it was burned through it looked like it was the number 4 exhaust port as the issue. I also ran a thethescope prior to that and had it nailed down to that area. With the car running once she warmed up I also stuck a hand against both tailpipes and drivers side blewy hand off no problem passenger side however which is the problem side did not, I have a hunch my leak could also be in the collector or where two pipes clamp together. I plan to mess with that today.
Thanks again for the suggestions.
 
The pass. side header is fairly easy to remove,, pull it,, and use a staight edge to check the flange seal surface,,. You'll likely find a poor weld or dip,, some irregularity that should be obvious by the impression/lack of,, in the old gskt,, get the dips welded,, or file down any high spots as nec..

Try to fare out (file) the whole flange flat if poss.. If you do a good job,, a reg header gskt should be sufficient..

cheers

As TB mentioned,, a tube can also crack..
 
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