J pipe too close to head

[weldvair]

My engine builder put J pipes on my engine....one of them is about 1/16" below the head & the other is about 1/8" below. I do not know where he bought them but, I feel they are to close to put heat shields on them......are there ones made that drop further below the head?

Don

[sideshow]

I have observed that the more expensive J-tubes have a shape that follows the heater box innards. They drop away from the head and lack the shell for the heat exchanger. CSP has a good example http://www.csp-shop.com/products/Produc ... 5922c/det/

Cheap J-tubes seem to be a straighter design, I have never measured nor cared much. Just try to stop buying cheap crap.

[weldvair]

I did not buy them my engine builder did. Does anyone know where I can
buy USA made that drop away from the head like the one shown ....in steel
not stainless? I want to weld on it so mild steel is better for me.

Don

[weldvair]

can not find any so I will make it......Don

[FJCamper]

Hi Weldvair,

The fix for too-close J-pipes -- which transfer heat to the head -- is to cut a simple sheet metal heat shield that is fastened to the J-pipe.

Cut the shield as a rectangle, and notch it so stainless steel hose clamps will hold it to the top of the pipe so it is between the pipe and the head.

This works very well.

FJC

[Marc]

You might also try loosening the nuts on the exhaust flanges and see if the tubes will shift downward a little. Or (with the nuts tight) remove the header and insert a jackhandle into the J-pipes and tweak them down slightly....a ¼" clearance should be enough to allow for heat shields.
Gas-heater Things come from the factory with undercylinder tin designed for J-pipes, you'll probably want to emulate them.
Something like this: http://i144.photobucket.com/albums/r173 ... G_0134.jpg ....'cept I'd use a softer radius at the top so there'd be less chance of denting the pushrod tubes if something ever smacked up on the bottom.

[Max Welton]

I think the j-tubes sold by Berg clear correctly.

Max

[weldvair]

I got them so I have a little more clearance....I will now make shields like Mark showed....thanks
for every ones help.

Don