Header adaptor 21 XM

Hi!

I´m in the process of making an exhaust header adaptor for my 21 XM engine. It will be a short pipe so that I could use a car header. What I wonder is the o/d of the short pipe in the back of engines such as the MAC 21, TT 21, I guess the o/d of the pipe is the same on all engines.

Can anyone help?

Andreas

Im not quite understanding what youre after. Are you looking for an adaptor? I have the XM with an adaptor for a silver bullet pipe. As for the OD, I did do a little porting on the adaptor to open it up a bit to match the port on the motor. Mark at HTB boats have the adaptors in stock.

Scott

Hi

I´m trying to make a part like this for the XM: http://www2.towerhobbies.com/cgi-bin/wti00...=LXAGD1&P=7

Andreas

Check out this link, here is an adaptor

http://home.earthlink.net/~namba707spec/_wsn/page2.html

A consideration should be taken into account making a header the way your

going Andreas. It will be a little harder to get your configuration short enough

for the short pipe length you'll need for the XM's stock exhaust port timing.

If you plan to cut the exhaust port (or raise it), your way might not be a problem.

Also with your method most car header "springs" might not be long enough.

I think the better way is to make a thicker aluminum flange like is shown

at the "707" site(much like the stock muffler flange), thread it for the stock

muffler screws. Use a cut-off piece of tubing from a old car header, dremel

tool an opening in the center of the flange you made to fit the sweeped

tubing. Tweek it to fit the flange opening and J&B weld the two parts together.

I haven't had the J&B weld come apart yet and I don't think it's going to.

It's possible to weld the two parts with a TIG welder but usually the tube

will melt way before the flange and the two parts to be welded have to be

absolutely clean from oil an such.

The other advantage of this type is that you won't ever have to worry about

springs or silicone exhaust header gaskets.

I have some of cut-off car header bends here that are of the 5/8ths inch

OD aluminum tube.

Also: I think Rod Geraghty has made some headers for this motor as well,

so he might the goto guy if you decide not to build it yourself.

Jerry

Hi guys!

Thanks for your answers. I have give this a little thought and it seems to be a better option to buy a complete kit containing header, pipe and fittings.

Andreas

So is there anyone that sells a tuned pipe setup for the OS thats complete ??

ABmods,

Yes, both 707 Specialties and Mark at HTBboats.com. The whole set up will run you about 115 bucks which include an adapter, header and Silver Bullet Pipe.

Scott

you can build a header very easily if you have a few tools...

just need a torch, brasing rod, peice of steel plate, a $0.30 copper elbow from lowes, and a beltsander and drill. These are how Irwin Headers are made. I can post a pic of one if you like.

~James

Pics would be nice, and a link to buy these parts would also be good. Id just like to buy a PROVEN part instead of having to do alot of R&D on a pipe myself.

Here are some photos of the headers that we use. Its very easy to make them. I think the pictures are about as self explanatory as needed to make them. As for links where to get the parts.....well the only part that you buy is the copper elbow from lowes, home depot, hardware store ect. The metal plate is just some scrap peices that most of us have around our shops. take a little time to mark the holes for mounting and make it whatever shape you like. I have found that brasing works the best, we have used silver solder also.

If you dont think you can do this, perhaps it would be better to buy the header and pipe already made.

The one on the left is for a OS XM, and the one on the right is for the K&B outboard.





Hope this helps, James

PS, these are the headers you will get when you pay $85 dollars for an Irwin pipe. You can make these headers in less than an hour, spend about $0.30 cents and buy any pipe only that you want off of ebay for about 40-50 bucks. In fact there is a guy on here now selling Irwin Pro quiet pipes for $25 bucks each without headers.

ABMods said:

Pics would be nice, and a link to buy these parts would also be good. Id just like to buy a PROVEN part instead of having to do alot of R&D on a pipe myself.

Click to expand...

AB, I have one of those on that K&B I've got. We can make those. Mike