292 inline 6 Chevy Question

I have a inline 6 292 Chevy on my modified project (http://www.jalopyjournal.com/forum/showthread.php?t=331800&showall=1), with a 2 carb Offenhauser intake and a Langdon's Stovebolt splitted headers.
My question: The offy intake can be heated, using the hot water from engine. Is this necessary ? Or can I run it without the intake heating system ?

 

Are you planning on running it in the winter or cooler weather...then yes it is necessary, if its just for running around in warmer weather you'll get enough heat off the headers to keep the fuel from deatomizing.

 

thnaks. It's a modified, and I plan to drive it without windshield, so, no, no driving during hard winters !

 

You can also add a bung to the exhaust manifold and plumb ome exhaust heat to the intake. You can do without the heat, but it may take longer to get warmed up and you risk the carbs icing up a bit when it's cooler out. Try it. You can always plumb it later if you decide you need it

 

In my opinion you should consider plumbing the water through the intake. In your application you appear to be running the engine fully exposed, no hood or surrounding paneling to retain engine heat and very little, if any, will transfer to the the intake from the header. Further, carb icing occurs in the venturi, where the pressure drops, and on humid days carbs can ice even at very pleasant outside temperatures.

Exhaust heated manifolds warm faster than liquid heated, so warm up will be slower with water, but, I believe, better than no heat at all. For street applications, smooth engine operation trumps maximum performance potential.

Ray

 

Perfect timing as I'm looking at this same issue in my near future. Plumming the water seems pretty straight forward, water in - water out.

How does the exhaust route if a bung is added as Hellfish suggests?

Empire32, hope you don't mind my asking dumb questions on your post.

 

I would consider heat mandatory. Just plumb like you would your heater core if you had one.

 

Just like the water. Heat in, heat out... sort of. Some of the Fenton headers for 235s have the bung. Then you need to buy/make a plate for the bottom of the intake to plumb a pipe in and one out (like for water heat)... or maybe just one in. I guess it would be like a stock set up (at least on a 216/235/261) where the intake is bolted to the exhaust and when cold the exhaust gasses go straight to the intake and heat it; valve shuts when warm enough. Some 1/2" pipes wouldn't carry as much heat, nor would a valve close them off. You're basically just sending up a pipe to carry some heat, like those to thermostatically controlled chokes.

 

Any time ambient is below 45 with any humidity whatsoever, without heated intake manifold you will get carburetor ice on an inline with downdraft carburetor/s. It is most prevelant in the first few minutes of running, like start it up, drive down the lane, stop at the sign or light, bingo, it dies. Bummer. Exhaust heated is better than water heated for obvious reason.

 

This is interesting. I have the samoe deal with my 235 w/ fenton headers. One of the bungs is easy to get to. I wonder if just one would do the trick.

 

I dont know man My 60 chevy is running a pretty stout 250 six cylinder with split manifolds from night prowlers and an aluminum offenhauser 4barrel intake with a pretty good size cam and I didn't hook any heat up to my intake and the motors been in my car for close to ten years like that. I drive it year round snow, Ice, floods, you name it. I havent had any problems. Mine dies everyonce in a while anyway I think cause I don't have a stall converter behind it like I should. Plus I'm running to High of gears for what I'm suppose to be running.

 

Oh and the car is my daily driver also. Theres lots of people on the hamb here that know of my car or have seen the stupid crap Ive done in it with that motor. HaHa.

 

I would definitely heat the manifold or you can/will get a backfire when accelerating ad beat the heck out of every gasket on the carbs.

Years ago when smog stuff started getting added by the factory I removed the heat riser tube from the exhaust to the air cleaner and had a backfire every time I accelerated in cold weather in a sealed engine compartment.

 

Very helpfull treat!

I found this helpfull too!

WHY YOU NEED HEAT TO YOUR INLET MANIFOLD - by Tom Langdon​

 

thanks a lot !

 

I sometimes wonder....Did anyone hear this?

 

I've got that same set-up on a 250, Tom Langdon said it was a must, he's the man, works awesome, you won't be disappointed

 

I'm pretty sure you can get that water neck to fit your 292, most stuff is interchangeable on the 250 and 292, heater line is just pipe-threaded and a black malable tee

 

years ago we did some testing and found we got better times with heat then with out.

 

From the looks of your picture, it would be easy to fab up a strap-on stovepipe from the front header casting up to the bottom of the intake manifold. Might wrap it with some header tape is all??

I know my stock '80 C/10 250 6-banger has one on it going to the breather thermostat air preheat flapper valve.

pdq67

 

I've been running a 2 x 2 intake setup on my 305" Ford powered Willys coupe since 1989. It has no heat provisions to the intake. I don't use the car in winters. But for the other three seasons it works just fine.