Header flange Q's

[turbobitt]

I'm in the process of freshening my engine and found this little snag. When I bolt the header to the head, there is about a .003" gap between the bolts on the outer cylinders on the passenger side header. I'm not sure if a new copper gasket will permanently seal this. I never looked at this in this detail so I'm not sure what to expect. Would they warp from just the bolt torque ? Is this to be expected and acceptable ?

How much gap is to much ? Should I replace the flanges ? This is a stage 2 head with ATR headers modified for a T6 style flange. Any leakage would impact my ability to spool-up.

Allan G.

 

[strongman]

ATR Headers

Just about all ATR Header passenger side flanges need to be replaced. RJC Racing has the correct 1/2" flanges and when having them replaced space the header tubes an additional 1/2" for bolt access. Also, see turbodave231 in the fabrication section for his ATR Header rework.

 

[slamming 6]

Is the flang it self hitting the head bolts.

 

[turbobitt]

Is the flang it self hitting the head bolts.

No, I'm test fitting the header with the head on the bench. I ordered the RJC flanges and debating with myself if I'm going to build another header or change out the flange.

Allan G.

 

[49-blues]

i have an extra set of gaskets & spacers if you need them.

 

[slimtastic]

I'm in the process of freshening my engine and found this little snag. When I bolt the header to the head, there is about a .003" gap between the bolts on the outer cylinders on the passenger side header. I'm not sure if a new copper gasket will permanently seal this. I never looked at this in this detail so I'm not sure what to expect. Would they warp from just the bolt torque ? Is this to be expected and acceptable ?

How much gap is to much ? Should I replace the flanges ? This is a stage 2 head with ATR headers modified for a T6 style flange. Any leakage would impact my ability to spool-up.

Allan G.

.003 gap will be sealed by a copper gasket...hell just shooting 2 layers of high temp spray paint on the gasket surface will seal it (yea i know, stupid but it works)

 

[turbodave231]

I've had my share of blown header gaskets using ATR S2 headers. I've used SCE copper gaskets with safety wired bolts and still blown them out. The passenger side header is not a great design to start with. The header is too close to the VC and you can barely get the darn VC off. The header is hard to bolt to the head and get a good clamp load on the fasteners.

I ended up trashing the entire PS header and starting over. I used RJC's S2 flanges to make my new header.

If you only have .003" warp, they will be OK when bolted up. In my experience, the flatter the flange, the better the seal.

Dave

 

[turbobitt]

Your new looks awsome and would be something that I would like to build if I started over. My current header will pass a .003 feeler gage in some area's when bolted into position. When the header is in it's free state, it is much worse with at least 1/8 out of flat. The bolts will draw it in but has .003 gap between some of the bolts.
Allan G.

 

[turbodave231]

Your header sounds like it is in the same condition as mine before the "slight remodeling" job. I'd either re-flange it and extend the head pipes as Bob A. suggested, or start over on a better design.

Here is a picture of what was left after I started cutting off the parts I didn't like.............

I have lots of time invested in my "remodel" and I hope it pays off this season.

 

[Chevota]

Why use gaskets? Permatex Hi temp copper is all I've ever used with great results.

 

[ijames]

I know this is going to sound crude but if you are probably going to reflange anyway it is worth trying. You can do a decent job of surfacing the flange with a pedestal mount belt sander, and if you cut out the flanges between ports first you might have more luck sealing. That way you only need "locally" flat right at the port, and not flat across the entire flange. Since you have a head to test with off the car so it is easy, and if you will probably cut it all off anyway, why not try it and see if they will seal up?

 

[turbobitt]

I know this is going to sound crude but if you are probably going to reflange anyway it is worth trying. You can do a decent job of surfacing the flange with a pedestal mount belt sander, and if you cut out the flanges between ports first you might have more luck sealing. That way you only need "locally" flat right at the port, and not flat across the entire flange. Since you have a head to test with off the car so it is easy, and if you will probably cut it all off anyway, why not try it and see if they will seal up?

I'm afraid by reducing the thickness, it will warp faster. Flange may not be thick enough to carry the heat away.
Allan G.

 

[turbodave231]

Yes the factory built them without a gasket, but I don't think running without a gasket is the answer for any manifold that isn't 100% flat. I think you need that gasket crush to take up the low spots and seal it up to the head.

Cutting the flange between the cylinders helps, but it isn't the answer either. I've blown out gaskets that way too.


Allan,

One of the ideas I considered, was TIG welding a new RJC flange to the existing flange. By doubling the flange thickness, you could then surface grind or mill everything 100% flat and have enough thickness to keep it from re-warping. It also moves the head pipes away from the valve covers so access to the valvetrain is improved.

I have a single RJC flange left over from my project that I can send you if you want to try it, or take the whole re-flange route. Heck I have quite a few 1 7/8" pipes and bends leftover too. PM me if you are interested.

Dave

 

[turbobitt]

Yes the factory built them without a gasket, but I don't think running without a gasket is the answer for any manifold that isn't 100% flat. I think you need that gasket crush to take up the low spots and seal it up to the head.

Cutting the flange between the cylinders helps, but it isn't the answer either. I've blown out gaskets that way too.


Allan,

One of the ideas I considered, was TIG welding a new RJC flange to the existing flange. By doubling the flange thickness, you could then surface grind or mill everything 100% flat and have enough thickness to keep it from re-warping. It also moves the head pipes away from the valve covers so access to the valvetrain is improved.

I have a single RJC flange left over from my project that I can send you if you want to try it, or take the whole re-flange route. Heck I have quite a few 1 7/8" pipes and bends leftover too. PM me if you are interested.

Dave

Dave,

Thank you for your offer. I already bought the RJC flanges but I think I'm going to cut the old ones off in a bridgprt with a hole saw and re-weld the new ones on. I would really like to start over like you did but money and time is becoming an issue.
Allan G.

 

[TR Custom Parts]

Allan, you going to be up on the Pike Sat nite? Have something you can try if you want before ripping them apart. What size are your exhaust ports? Planning on being at the Panera cruise first and then to the BK cruise.

 

[turbobitt]

Allan, you going to be up on the Pike Sat nite? Have something you can try if you want before ripping them apart. What size are your exhaust ports? Planning on being at the Panera cruise first and then to the BK cruise.

I may be going up tonight but not sure. If I do, it will probably be at the BK cruise.
Allan G.