Header leak question.

[siteunseen]

I've noticed a "tick" on my 280 with a 6 to 1 header. Got my hose stethoscope and found the area is under the flange between #2 & #3. 

My question, should I try tightening the nuts while the motor is cold or hot? You guys know more about the science of metal microstructure than me so please advise. Thanks for any replies. Cliff

[Reptoid Overlords]

I'm sure someone will chime in with a more scientific response, but I remember reading that you are supposed to re-torque the exhaust hardware after a few heat cycles..which I have interpreted as cold. 

I believe I have the cheaper version of the same header as you...the MSA paintable 6 to 1(non coated).  I have the same tick, and it gets a little louder when the car is at normal operating temperature.

I will contend, however, that I did "lightly" drop the header last year when I had the engine out of the car, so I'm sure my tick is self inflicted. 

I have replaced the OEM exhaust hardware with studs from MSA, and I have indeed tightened them while hot...but certainly not very much tighter than they were.  It made the tick only barely less noticeable, and preceded go back to the same noise level after another long drive..but again,  I probably have a small fracture. 

So cold is probably safest, hot is ok as long as you are careful not to put too much pressure on your wrist torque wrench. 

 

Edited November 7, 2021 by Reptoid Overlords

[AZDatsun]

I have a tick on my MSA 3-2 headers the paintable type between port 4-5 tried a bunch of different gaskets they always end up blowing out over time. I retighten cold but I just deal with it I guess I could get the header flange resurfaced 

[siteunseen]

I'm gonna try cold. I damn sure don't want to replace the gasket. I can only hear it with the hood open and idiling. 

My anxiety can't get any worse so I'll live with it if I have to.

 

 

[Mark Maras]

4 hours ago, siteunseen said:

I've noticed a "tick" on my 280 with a 6 to 1 header. Got my hose stethoscope and found the area is under the flange between #2 & #3. 

My question, should I try tightening the nuts while the motor is cold or hot? You guys know more about the science of metal microstructure than me so please advise. Thanks for any replies. Cliff

 Nothing too scientific but I'd try torquing it with no gasket, the engine cold and the flange hot (below 1000 f, dull dark red). Torque the leaking area first and then the rest. Keep checking the torque in the leak area as the flange cools. Then remove the manifold, install the gasket and retorque.

[Mark Maras]

 just read your last post. You can try cold but steel bends easier when it's hot.

[siteunseen]

You have way more skills than i do, we all know that, going that deep. I can't even imagine how I would get the flange that hot then back on a cold head without pulling the whole left side off. "Take my wife from me please".

I'm thinking the ambient temp aluminum head's threads will allow me a bit more tightening down. I'm sure it'll do it again sooner or later but I may go with 2 gaskets? Zcardepot.com has the copper diamond ports with injector holes I could probably Dremel out to match the square ports on my N42. Uh...I'm not so sure that's doable now after seeing how close I'd be to the stud holes. Oh well Yellowstone season premire in a minute. Time to veg and watch the Duttons raise hell.

 

 

[Jeff G 78]

I've had leaks on several various headers and I've always retorqued cold.  I've had the best luck replacing the studs and nuts to get a perfect inside to outside tightening pattern just like head bolts.