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Discussion Starter · #1 ·
There's been quite a few posts lately on the position of the header outlets in relation to the body cutouts. Well, I'm in the same predicament. I've tried the various fixes suggested in earlier posts (pulling down the engine mounts, installing the elephant ears, etc.) without much change. Even cursing hasn't helped this time. At FFR's suggestion I removed the headers and measured them in comparison to their master set, and they seem to be OK. So, FFR is suggesting that the machining tolerances on the heads, etc. must be off enough to cause the problem. This I doubt!
My next plan is machine the header flanges at a 3 degree angle which, by my calculations, will remove about 1/8" off one side of the flange and drop the outlets by a little over 1". I may still have to trim the cutouts up about 1/4" to get the appropriate clearance.

Comments?



 

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Header flanges

Dave:

Breeze sells the tapered flange spacers. A lot cheaper and more effective than machining the header flanges. Call Mark.

Breeze Automotive Factory Five Racing

Ron
 

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Head to header taper flange?

OK thanks Ron. I tried calling Mark Friday, but missed him. I didn't see the flange wedges on his sight. Only the ones for the outlet. Will try again tomorrow.

David
Dave: I didn't understand the problem, I guess. I don't know of anyone that has an off the shelf tapered shim for the header flange to head. the ones Breeze sells can be used to move the side pipe up, down or in and out at the outlet.

If you machine the header flange, I think you are going to increase the chance of warping by thinning the flange and it is going to cost a lot of bucks. If you are set on changing the angle at or near to the head, why not just cut a thin slot in the bottom of the pipes, bend them down the correct angle and weld the slot up. That would be almost unnoticeable, cheaper and easy to do. For a machine shop to machine that flange, reweld the stubs, and finish it off will be, I think prohibitively expensive. Just to do the fixture is a major chore.

I think there was a thread on this issue just recently.

Ron
 

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Machining a taper on the header flange shouldnt cause any problems. I did this on one of my customers cars with no adverse affects. Wont affect the coating except where your milling of course. He has many miles on the car with no problems. I took 5.5 degrees off but my problem was much worse. You couldnt even see the upper 2 ports on mine.
Mike
 

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looks like headers made for a 302 block mounted on a 351.
yes it could be the tall deck on the 351.

the other thing is some cyl. heads ports are located not in a stock location
 

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Pipes

I assume youve tried all the other tricks.Shimming the engine mounts, twisting the engine on the mounts, ect.

Try a washer on the top between the flanges ( this only for trial, not permanent) to see how much machining is needed. If a lot is needed, maybe split the difference and do the side pipe flange also.

I assume the pass side is OK.

The Nut
 

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Dave O -

I showed how i went about fixing this issue in this thread. About halfway down the page you should see my photos. It worked great, only catch is you either need to know how to weld or know someone who does and you will be out the price of re-ceramic coating. Entire fix cost about $250-$300, but i dont need to worry about warping or the header-to-head bolts not sitting flush.

http://www.ffcars.com/forums/17-factory-five-roadsters/283053-stumped-mark-4-exhaust-problem.html
 

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Discussion Starter · #15 ·
turbonut48 -I have tried all of the other tricks...at least I think so. I have determined amount of degrees that will do the trick by mounting the header, measuring the angle of the flange at the side pipe end, then loosening and lowering the header until there is clearance at the body cutout and taking another measurement of the angle and subtracting the two measurements.

This condition exists on both the PS and DS, although the DS is a little worse.

evvander11 - I did see your solution and am currently leaning towards doing the same. I have only found one machine shop so far that says they can machine the taper on the flange and they want $170 each flange. And won't guarantee the ceramic coating integrity because of the vibration involved during machining. So, that appears to put me way over the cost of your solution.

Forum vendors- there's a real opportunity here. They are called tapered flange spacers! I know it creates a 2nd potential leak path, but the risk is worth it.
 

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Discussion Starter · #18 ·
First I have heard about the convertible motor mounts. That certainly sounds like a viable solution. Just to clarify, do you mean mustang convertible mounts? Any particular year?
David
 

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Discussion Starter · #19 ·
Searching the previous posts on convertible mounts there seems to be a lot of discussion on whether they actually lower the engine. IF you are talking stock "donor type" mounts it appears that they do make a difference, although how much is unclear. Maybe no difference if you are using Energy Suspension mounts, which I have....they came with the MKIV Base Kit.
 

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Discussion Starter · #20 ·
Update

Problem Solved! I was able to find a machine shop that could machine my header flanges for a reasonable price....it didn't hurt that the General Mangager was building a '32 Coupe! I decided to go with a 4 degree taper on the flange and the result was a perfect drop of the outlet into the body opening. Results shown below. You can see the before pictures in my first posts. Moving forward again!
 
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