Heating a bare 2F intake manifold (1 Viewer)

[Godwin]

Since installing 3FE exhaust manifolds and losing the 2F exhaust I've noticed that the engine is more prone to rough running when cool to cold. Once the water temp reaches 150F the engine smooths out.

The stock exhaust has a provision to warm the underside of the intake as soon as the engine is running. Plus the stock exhaust manifold should hold heat well. With a header or 3FE exhaust this immediate warming function is lost. A fluid heat riser can be installed with a header but not a 3FE exhaust. Yet this provides no heating of the intake until the water has warmed.

What about an electric 12v heater for warming the 2F intake with the installation of a heating block that would fit within the underside cavity of the 2F intake and be thermostatically controlled? It could be wired for into a switched circuit so that it would only operate with the key on to prevent constant running when the engine was cool. It should offer almost immediate warming of the intake or at least a quicker warming than simply depending on the engine to reach operating temp.

This is only idea because I know about what materials are available in order to attempt putting this together. Feedback?

 

[NeverGiveUpYota]

Can't you install the same sort of thing that is used in a diesel? I remember reading about it years ago w/ my old 60 when I had a lot of trouble starting her in cold weather. A block heater that goes into a freeze plug.

 

[Output Shaft]

Well if you go by Toyota's design of older carbed engines, like the 20R 4 banger used in their late 70's mini trucks, those had a carb and the manifold/intake was heated by coolant. So for the first 5 minutes or so, there wasn't much heating going on to make any difference. I had a 78 toy mini truck and it would always start fine and idled fine and ran forever with zero maintenance. It would even run/start fine up at a ski resort with 20 degree mornings.

Those 12V intake heaters are popular with diesel guys in freezing temps.

 

[LAMBCRUSHER]

I think you're onto something. I'll say, it didn't like the colder than 30* mornings much, but it never kept it from running. I like where you're taking this tho. It wouldn't need much...a juke on that might be to tig a waterjacket to the base of our modified intakes and add a port for a coolant type block heater. even then, I'd rather factory cast over aftermarket tubes, anyday...You're going to take this mod to perfection, J...

 

[RockDoc]

I don't know much for details, but some toyota diesels (some / all of the DI ones) use a glow screen in the intake to heat the incoming air rather than glow plugs. My 7.3 powerstroke has a 12v heater coil in the intake post-intercooler that kicks in when idling cold. Maybe something like this could be installed pre-carb in your intake tract?

 

[NeverGiveUpYota]

glow plugs

, thanks! That is the term I could not remember. They go right into a freeze plug right? I did a bunch of research on them way back when.

 

[SteveH]

What about an electric 12v heater for warming the 2F intake with the installation of a heating block that would fit within the underside cavity of the 2F intake and be thermostatically controlled?

I machined off the bottom of my stock 2F intake manifold to prevent this heat transfer on my '78 FJ40. I now have the same problem you do, which is rough running under load on cold mornings. It was 20F this morning and I had to use the choke to artificially enrich the mixture while driving up a hill away from my house. The engine was clearly having trouble atomizing the fuel, based on how it ran. I did my manifold mod to cut down on hot soak and vapor lock issues, and not for any other reason.

I suspect any 12v heater plate solution would require quite a bit of current, and may not be super reliable in this environment. Do you have any type of 'heat stove' that feeds hot air off the manifold into the carburetor? I do, and that helps, but I have found that simply letting the truck run for 5 min. to warm up helps a lot, too. The 7.3 diesel AIH (air intake heater) is an intriguing idea - don't know if it would work, but probably fairly cheap to set up and test. I may install a GM-TBI setup, and that will fix this cold-weather atomization issue, too.

 

[Output Shaft]

If all of this can be remedied by warming up the engine before driving it, that seems like a simple solution. I don't drive my car until the coolant hits 175-180° anyway... and I have a stock manifold.

 

[gregnash]

Same as @Output Shaft, BeBe gets a full 10minutes of warm-up prior to driving when starting from cold.
There are aftermarket heat risers that I have seen guys put on their 40s when they install headers. Ultimately the way I was taught was that on older vehicles like our trucks, you should NEVER drive it off cold (e.g. it has been sitting for more than 4-5hrs without driving) as it could damage the engine due to oil/lube not being circulated. Whether or not there is any validity to that I don't know but I have never really driven anything (as my own daily driver) that was newer than 95 so I always warm it up first. Also probably doesn't help that during the warmer months I ride a bike to work.

 

[NookShneer]

Something like this work?

KAT's by Five Star 24075A - Hot Pad Heater | O'Reilly Auto Parts

 

[Godwin]

Something like this work?

KAT's by Five Star 24075A - Hot Pad Heater | O'Reilly Auto Parts

That's the idea but 12v not 120.

 

[Gengis]

Just not the diesel intake heater option please. These things glow red hot and have no place on a leakey old petrol carb which may or may not backfire from time to time.

 

[LAMBCRUSHER]

i thought it was bad to warm up your engine- that's what chat said.

 

[RockDoc]

Just not the diesel intake heater option please. These things glow red hot and have no place on a leakey old petrol carb which may or may not backfire from time to time.

Oh come now. They easily mix as well as drinking and posting in tech.

 

[NookShneer]

More like this..

 

[Michael Hanson]

Hi, Excessive idling with cats installed is probably going to shorten their life , Except for a diesel I don't like idling any kind of gas motor for long. Mike