The Stovebolt Site Forums The Shop Area General Truck Talk Heat Riser is Stuck

My heat riser is stuck but I don't know what position it's stuck in. Would someone look at the picture here:
http://home.hawaii.rr.com/calabash/hrv.JPG
and tell me if it's open or closed. I'm hoping for open.

Thanks,
Rich

I would be curious also. Mine is stuck but am not sure in what position. I've tried everything I know to free it up and it looks like pulling the exhaust manifold would be neccessary. That ain't gonna happen soon. . . .

If the flat surface on the bottom of the weight is horozontal it is closed. If it is at a 35-45 degree angle it is open. You often can free it up by applying penitrant & hammer it back & forth.

use a torch and cut the butterfly out .weld up shaft holes.if it was stuck closed ,you would be burning up your valves in time

Wouldn't it be easier to fix it right? Mine was frozen solid. I kept workin' it with penatrant and tapping it with a small hammer. Now it works perfect and it does what it was meant to do.

Yes,but most of them are worn ,and leak giving you that sputter sound. Rich being from Hawaii and no winters.I would say no need for that.It just helps the engine warm up a little faster.Plus when removed no problem ever.Enjoy the sunshine,Happy truckin in your beautful state. If you remove the manifold I sugest maybe putting a split manifold on. Man they sound pretty

May I suggest that you take the manifold off and clean it out from the inside.

Mine was stuck and the spring holder was broken so I did a switch with another I had.

The stuck one had considerable carbon build-up that was causing the seizing.

Setting the heat riser to rights made a world of difference in early start up driveablilty.

Thanks all.
As dan-pa mentions, here in Hawaii I have absolutely no need for the function that the heat riser serves. If it is frozen in a position that is not doing any damage and not effecting the perfomance adversly, that is where I would want to keep it.
Aloha,
Rich

That one in the photo is in the open possition.

Open to let exhaust flow out right?

Right. When it is closed it directs the exhaust up around the base of the carb. & then flows out.

split manifold Go for it.duals exhust.bad to the bone.got a manifold setting on the hill side.Postage would cost much.So find another manifold and torch.Make a split manifold.If you want some kick *** ,put a 4 barrel on that 6 poper and it will come alive

Hey Wrench--
open....closed...which way should it be before you start the engine?? I replaced my heat riser spring not too long ago. I put it on while it was closed (flat bottom of weight horizontal) but it never seems to open (flat bottom of weight at 35-45 degree angle) after the engine heats up.

should I re-install the heat riser spring with the valve open, so that when the engine warms to temp., the valve will close??

Chuck

NO! Normally they aren't adjustable, but it would be closed when cold, open after the engine warms up

It opens when the engine is accelerated. The butterfly is off center so the pressure from the exhaust opens it. The hotter the spring gets the least tension & it opens sooner.

Back when crack was that place above a plumbers belt, we used solvent and a hammer to loosen heat risers. Rich even on a tropical island the heat riser should be allowed to heat the base of the carb until the engine warms up.

I just noticed that the heat riser valve (HRV) spring on my 72 burb 292 is broken.
Any place to get the spring or something close or the HRV? Searched the web no luck

I would not hammer it around.
I did that and the weight moved on the axis so it was impossible to know how it was. Being stubborn I spent hours that ran into days on it and finally got a new manifold (used) with spring etc. It worked fine in winter.

A little penatrating oil and tap it left to right and so on until it comes loose. Don't try to tap the counter weight up and down you will break the pin which holds it in place and then you don't know what position it is in. A little paitence and persistance goes a long way and most times doesn't break anything in the process.