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Hey, i am gunna thank all yall ahead of time.
ok, so I have an 81 F100, 300 I6 carb. and a manual transmission, atually a three on the tree. I have a motorcraft (i think, its not the origional, but is a direct advance auto replacement) and the electric assist choke. I am wanting to know if the truck would run ok without the hot air system under the carb.
I am rebuilding the motor and in the process discovered that the manifold is cracked rather badly, and is severely rusted. I want to upgrade the intake to use a 550 cfm holley and headman headers, but the headers that i have dont have the hot air attachment. If this works, will it pass NC inspection without the hot air system?
If you look at clifford performance website, you can find they sell a block that coolant flows through to help heat the bottom of the manifold and carb. If you keep the stock aircleaner with the hot air hose going to the exhaust manifold, that will help also.
Passing emissions is not the problem. If you run it with no heat in the manifold or under the carb, it will be very cold natured and not run very well till it's warmed up. If you try to run it in the winter on a cold damp day, it will really give you a fit and keep stalling till you finally get some heat to the carb.
The problem is gas engines will not burn liquid fuel. It has to be atomized into a mist. The carb does this normally, but when the mist hits the cold manifold, it turns back into a liquid. The manifold is heated by the exhaust to create a hot spot, and this keeps the fuel atomized so it runs well when it's cold. That's one of the big advantages of fuel injection, there is no fuel in the intake manifold.
If you look at clifford performance website, you can find they sell a block that coolant flows through to help heat the bottom of the manifold and carb. If you keep the stock aircleaner with the hot air hose going to the exhaust manifold, that will help also.
when i got the truck, the air cleaner wasnt included. Is this the same as one from the small block v8's or is it strait six specific?
Passing emissions is not the problem. If you run it with no heat in the manifold or under the carb, it will be very cold natured and not run very well till it's warmed up. If you try to run it in the winter on a cold damp day, it will really give you a fit and keep stalling till you finally get some heat to the carb.
ok, is there any way to heat the carb without the hot air valve? (is this an egr valve?)
The problem is gas engines will not burn liquid fuel. It has to be atomized into a mist. The carb does this normally, but when the mist hits the cold manifold, it turns back into a liquid. The manifold is heated by the exhaust to create a hot spot, and this keeps the fuel atomized so it runs well when it's cold. That's one of the big advantages of fuel injection, there is no fuel in the intake manifold.
is there any kits out there to use efi from a small block chevy on this motor? I have a chevy that im workin on the has the fullmotor fuel system on it (pre vortec 350), about all thats good on that damn motor. Guess i can make it work
thanks for the lesson on what it does.
also is that big pump thing that is connected to the hot air system necessary? (or is it just robing power from the motor?)
I am assuming the pump thing is the smog pump? If so, you can take it off, it's not part of the hot air system to the carb. If you have inspections though, you had better leave it on there.
Throttle body fuel injection is a step up from a carb, but you still have fuel in the intake, so you still have the same fuel atomization problems, so you still need to heat the manifold for it run right. That 350 chevy has exhaust running up through the intake to warm it up just like your six. The ford system for the six is multi-point, a much better system with a dry intake manifold.