Header 'flange' flatness?
Thread Starter
TECH Apprentice
Joined: Nov 2001
Posts: 350
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From: Lexington, SC
Header 'flange' flatness? I sent out my MAC headers to get ceramic coated ($135 total including shipping both ways through Speed, Inc., FYI) and when I got them back I decided to check and see how flat the flanges were. I failed to check the flanges before I sent them off so I don't know if they were already like this or they got dinged during shipping. I'm not sure of the techincal name, but I'm calling them flanges. I'm talking about the part of the headers that bolts directly to the engine. Anyway, I placed a 12" steel ruler against the flanges and it looks like there is about a .075" gap in one place and about .030"-.040" in other places (eyeballing here). .075" seems waay too much to me. I figure these flanges will conform a little to the heads once you bolt them down, but I don't think they will conform THAT much. Do these flanges need to be perfectly flat or is there a tolerance of some amount? I know a guy that does machine work on a lot of car parts so I may be able to get them perfectly flat, but I wanted to get some opinions here first. Thanks guys.
TECH Enthusiast
Joined: Nov 2001
Posts: 543
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From: Richmond, Va
Re: Header 'flange' flatness? I cant imagine .075 causing a problem, especially after tighten it down.. I suppose what it boils down to is get them fixed so you dont have to worry about it, or put them on and possibly have to take them off and spend the cash anyway. How much spare time do you have?
TECH Junkie
Joined: Nov 2001
Posts: 3,987
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From: Melbourne, FL
Re: Header 'flange' flatness? You shouldn't have a problem. Once you get the headers in place and start to tighten them down, everything should fall into place. Sure, it would be more desireable for the flanges to be perfectly flat, but they usually aren't. There is enough flexibility in the header tubes themselves to take up the ~.075" gap you're talking about.
Re: Header 'flange' flatness? Dude, you've had those Macs for 9 months, get those bad boys on <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Did you have them Jet Hot coated?
Thread Starter
TECH Apprentice
Joined: Nov 2001
Posts: 350
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From: Lexington, SC
Re: Header 'flange' flatness? I know that the header bolts aren't tightened down very much (11lb/ft on one pass 18lb/ft on the next) and I guess that just didn't seem like enough torque to straighten them out. Of course once they heat up some they may bend a little. The worst bend is right on the end of the flange (last cylinder on drivers side)...I wasn't sure if that would make things worse or not. I'd really rather not have them machined since they are already coated, but I don't want to have to take them back off if I have a leak. Oh well, I'll make a decision somehow. Maybe I'll try to straighten them out myself.
Mike: I'm slow ain't I! I've been buying lots of other parts which is why I don't have these on yet. I'm going to try to get them on next weekend. I didn't send them to Jet-Hot, but they were ceramic coated. They look nice!
Mike: I'm slow ain't I! I've been buying lots of other parts which is why I don't have these on yet. I'm going to try to get them on next weekend. I didn't send them to Jet-Hot, but they were ceramic coated. They look nice!
