The Stovebolt Site Forums The Shop Area Engine Shop Heat Riser on 292 exhaust manifold

I'm looking at one of those 292 replacement exhaust manifolds from THE Company in Iowa. It doesn't have a heat riser. I am planning to put it on a 250 that I use for a daily driver. Will I have any problems with that or could I drill it and put a heat riser out of another manifold in it?
I'm a newbie to this forum and really appreciate the expertise of you veterans! Thanks

It would be pretty hard to install a heat rizor in a manifold without one. The 292 & 250 manifolds are interchangeable. The heavy duty manifolds that are used on the 1 1/2 ton & larger 292 trucks did not come with one. It has a 2 1/2 in. opening & points straight down. Is a new one available with the heat rizor in it?

I haven't been able to find one of the new ones with a heat riser in it. The new one that is sold by THE Company in Iowa doesn't have a heat riser in it. I'd pickup a used one with a heat riser, but I don't know where to find one. I'm worried that without a heat riser you might overheat the intake manifold eventually?

You could install a stainless steel plate with only a small opening between the two manifolds. It would heat but still limit how much. I doubt it would over heat, the valves don't seal 100%, not even 75%, it directs the exhaust down and out more then seal off the intake.

Joe

[quote=Joe H]You could install a stainless steel plate with only a small opening between the two manifolds. It would heat but still limit how much. I doubt it would over heat, the valves don't seal 100%, not even 75%, it directs the exhaust down and out more then seal off the intake.

Joe [/quote]
That sounds like a good idea. Maybe I could drill a few holes - 3'8"? - in the plate. I'm looking for something that will heat up faster when the engine is cold than the plates that are made to circulate radiator coolant under the intake manifold. Do you think I would have to have some machining done to one or both manifolds (the thickness of the alum plate) so they would still align and seal to the head?

Mikie,
Out of curiosity, what is the part number of the manifold you're looking at from THE company? Thanks.

Some of the gasket sets come with a block off gasket, it has steel on side. I have used them in the past, but they always seemed to be burnt through when I remove them.

18 to 25 gauge (.050" to .0219" ) would work with out altering the manifolds. I have had to use two gaskets to get a old manifold to seal with out problems. You may have to buy a new gasket, then cut in apart to sandwich the stainless steel.


Intake Manifold to Exhaust Manifold Gasket
Part Number: FPG 9763
Product Line: FEL-PRO Gaskets

Part # MS9786 Full set including solid gasket.


Joe

Thanks for your reply Joe. I talked to a retired GM engineer this weekend and he said that without a heat riser valve directing the exhaust gasses up towards the intake manifold, the gasses just kind of "drift" up there a little bit.That kind of sounds like my worries about it getting the intake too hot might be unlikely. Maybe you can just leave that passageway open?

You sure can. if you look close at the valve, you will see it doesn't do much at all in sealing off the intake, its just a diverter to get the exh out of the manifold better.

Joe