bending header pipe?

I have a Randy Smity Header-Muffler and I'd like to "unbend" it a small amount so the exhaust is angled just a bit away from the fuselage. Can this be done? If so, how?

>I have a Randy Smity Header-Muffler and I'd like to "unbend"
>it a small amount so the exhaust is angled just a bit away
>from the fuselage. Can this be done? If so, how?

OOPS sorry... make that a ROJETT header muffler

>>I have a Randy Smity Header-Muffler and I'd like to "unbend"
>>it a small amount so the exhaust is angled just a bit away
>>from the fuselage. Can this be done? If so, how?
>
>OOPS sorry... make that a ROJETT header muffler

Well, Randy makes one, too, and I don't think they are that much different, in principle at least (haven't compared them--would be interesting to do so, though). But the header pipe can be bent, at least a wee bit. Just kind of grab ahold of it and unbend it. This is done with pipe ships quite often when you need to "realign" the header a bit.

Depends on how much is a little but you can also re-mill an angle on the mounting face. 1-2deg is not a problem and will yield alot of change at the exit end. Needs to be done on a machine with care but no chance of a major oops and a crimped tube. The clearance holes for the mounting screws can accomodate a little angle--re-spot face under the heads if it makes you feel better.

The material is quite soft tho--it will bend some like Leonard said.

Never tried this but I've been told that packing tubing with sand can help prevent kinks when bending.

NOTE: Remove all sand before running.

FWIW

I have the same problem. I need to have a header with a 1" rise at the front end and 1 1/4" at the back end to fit the thing inside my cowling. I talked to John at Johnston Headers who make Headers sold by Ro-Jett and Randy.

John told me the same thing, that is that the pipes are easy to bend (a bit). I will be giving it a try today or tomorrow. I also talked to Richard Oliver about the same thing. Richard says he has bent a number or headers without difficulty. We'll see.

An alternative, John at Johnston says he will do a custom bend for $5 extra over the retail price for a header. That is my plan "B".

Called Randy about exactly this problem and he told me to do the 'easy bending' trick. worked just fine. I mounted the engine on a test stand with the header firmly attached and just applied gradual pressure until it reached the disired angle. I only needed three or four degrees but it seeme more than willing to go a little further.

One thing worth noting is that I did this to a full length header. If you've shortened one significantly you might need to be a bit more careful.

You can also slip a bicycle seat tube over the outside of the pipe for a little more leverage. This works even if you have shortened your header pipe. I've found that a longer lever arm gives me a little better control.

Ron King

>I have the same problem. I need to have a header with a 1"
>rise at the front end and 1 1/4" at the back end to fit the
>thing inside my cowling. I talked to John at Johnston
>Headers who make Headers sold by Ro-Jett and Randy.
>
>John told me the same thing, that is that the pipes are easy
>to bend (a bit). I will be giving it a try today or
>tomorrow. I also talked to Richard Oliver about the same
>thing. Richard says he has bent a number or headers without
>difficulty. We'll see.
>
>An alternative, John at Johnston says he will do a custom
>bend for $5 extra over the retail price for a header. That
>is my plan "B".
>
>Al

Ron B.
F4Fguy

Al:

For an extra five bucks,sounds like plan "A" to me.

Ron,

Plan "A" it was. I just bent the thing. Bending it myself allowed several tries to get the exact fit that I desired for cowling clearance. I took Richard Olivers's suggestion and simply chucked it up in a vise. I found a ratchet wrench which has a handle which fit snuggly into the header. It has to go all the way down because the bend occurs just where the inside device ends. If you don't get it all the way down to the bend, you will wind up with another obvious bend in the middle of the pipe.

The actual bend happened easier than I expected. I made several adjustments and found a tendency for the cross hatch pattern on the vice to fill with aluminum and become prone to slippage. A steel brush returned the vise to full grin strength.

I used the vise instead of using an engine because of concerns about possibly warping the case. That full length header gives maybe too much leverage.

Anyway, I bent mine 3/8" with surprising ease. I'm sure you can too.