WM300 Intake Question

[pwrwagonfire]

I am currently doing some work to a 1964 WM300 which my employer owns.
It has a 251 engine in it. Please see the above photo, with the item on the intake, which is wired in one position.
What is this? Should this be locked in position like that? I have never seen this before, as my own truck has a 230 and this is not there!

Thanks in advance!

[Dutch]

The pipe is crankcase ventilation. I believe the item your referring to has to do with the intake heater butterfly flap. The intake sits on top of the exhaust manifold and between the two there is a butterfly valve to regulate the heat to the intake. At least thats my best guess

[joemcc]

WM intake question

It's called a heat riser, there is a flap that redirects heat to warm up the intake manifold for better cold engine driveability. If it's to be wired up, make sure its in the open position or you may have problems with vapor lock when the engine is hot.

[Dutch]

It's not true vapor lock but it is similar like joemcc said. Here is a good explanation of why you want heat on your intake manifold- http://www.langdonsstovebolt.com/tec...take-manifold/

[defdes]

It is likely a better set up, but I deleted mine when I swapped my broken exhaust manifold. It gets about as cold as anywhere else here and as long as I let the truck warm up for a few minutes it does not effect driveability.

[pwrwagonfire]

Thanks for the responses everyone!

I remember seeing it opening and closing with the accelerator on its sister truck, so this all makes sense. We removed the wiring so it'll function as its supposed to.

Head magnafluxed and planed, carb rebuilt, and the truck is now back on the road!


T