Technical Heat crossover in iron intake

What is the consensus about heat crossovers? I removed the butterfly on the passenger side manifold, and now that I have the engine out, is it worth filling in the crossover ports? Or will this result in a cold blooded engine?

The idea of exhaust moving through my intake and heating things up just seems wrong......

This is obviously a summer car and the coldest air it will ever see will be 25F I'd suspect.

 

I have been plugging crossovers for 35 years, it's automatic with me. Plug it and don't even give a thought. It's just that more heat that will not boil the fuel.

 

>>>I removed the butterfly on the passenger side manifold>>>

I'm with you. That's all I did cuz it didn't move anymore and the spring was shot. I don't like the x-over either. But mainly because it discolors the intake especially if painted. But I didn't block it except on my flathead. 8^) Jack E/NJ

 

If you do this on an older Chrysler product, 318, 360, 440, you need to change to an electric or manual choke. On these engines the choke stove is in the intake manifold and without the crossover and the damper valve, the choke will never come off.

I still have a damper and open crossover on the 312 in my T-Bird even though the carb now has an electric choke. Old Fords are pretty cold blooded without it.

 

I use to wad aluminum foil up and jam it tight into the crossover ports in the heads on irrigation engines. They were on natural gas. 413 chryslers. Lippy

 

This and a plug made of carefully trimmed sheetmetal. I've even filled the first 2" of the crossover with allmetal then a plug.

 

I was just going to cut a piece of 316 stainless sheetmetal to fit inside the gasket and a bit or high temp silicone.

 

It will make it cold natured and change the exhaust sound.

 

Like my ex wife.

 

I've found MoPars are pretty sensitive about plugging the cross over in the winter, especially the small blocks. This said, I block off the crossover for my Pontiac engine in my 34. Had it in stop and go traffic over 100 degrees with ethanol fuel and it never faltered but it's cranky in cold weather...so am I.

 

I wouldn't do it. It rarely gets as cold here as it does there and FEs tend to be cold-blooded as it is. It was pretty common to find a heated carb spacer on them, Ford added extra heat at the carb. I blocked the heat riser exactly once, never again...

You can pitch the spring-loaded valve though.

 

The picture looks like an FE manifold. Do not block the crossover, especially if you are using an Autolite 4100 Carburetor.

 

Yes, FE 352. Running an Autolite carb, has electric choke. It was an absolutely fantastic running setup, I just don't want to disturb that.

 

I seriously regretted NOT blocking the crossover on a 350 Chevy. The fuel in the carb would boil so easily, because of the crappy gas. And I live in Texas, where it's hot way more often then it's cold.

 

I had a 64 Galaxie once with a 352 and a 4100. Had a spacer plate beneath the carb with the heater hose circuit going through it. I disconnected it and the car did not like it in the winter. The FE manifold is so large that it dissipates heat well, and I never had a fuel boiling issue. If it was a small block my answer would be different.

 

The heat riser valve does not stay closed very long. Fire up your car and watch it. There is a reason the long ram Chryslers setup got removed. My first pickup had a 235 that the heat riser was stuck open below 50 deg. on a damp day the carb would ice up and quit.

 

I would not block off the heat riser passage. With the butter fly valve removed the passage will run much cooler. I feel this is a good compromise. Also if the engine is in a car without a hood the intake & carb will run cooler. With passage plugged the engine will take longer to warm up increasing carbon build up. & engine wear. Greg

 

Cold fuel does not atomize nearly as well as warm fuel .

 

Ford Y-block have 2 different intake gaskets. The truck one had a stainless insert that leaves about a 1/2” hole in the crossover and works great. I’ve removed the flapper exhaust valve and installed a spacer. I also use a 3/8” thick phenolic spacer under the carb. Runs great and doesn’t boil fuel.

 

On my performance pontiac motors I always just put a thin piece of stainless sheet metal between the gasket and intake side and called it good. The gasket didn't care if it sealed to a solid piece of metal or an open port on the intake.

They were cold blooded but once warmed up ran fine.

Also ran 20-50 valvoline race oil in them for years, 20 years in one motor and never had any problems but had more people than I can count tell me this was a big no-no....