I would like to ask a question.
Does the thermostatic spring-loaded plate in the exhaust manifold have a useful function? Can I get away with not having a plate to block exhaust gases?
Thank you.
Kionga

 

Hello Kionga.

This search should bring up some useful info:

https://www.google.com/webhp?sourcei...t%20riser%20do

Basically though, the heat riser allows exhaust heat to warm up the underside of the intake (there's a sticky at the top of the forum explaining the importance of underside intake heat).

Then, to keep it from getting TOO hot, the spring turns the plate to limit the exhaust heat so it doesn't boil out your intake/carb.

As with most components on the engine, if it didn't have a useful function, the engineers wouldn't have designed it to be there and Ford wouldn't have paid for it.

 

Thanks for the reply.
I currently have a HD exhaust manifold for F600-700s without the thermostatic mechanism. Will it be a major minus? How did the F600-700s get on without the mechanism?
Thank you.
Craig

 

Where do you live? Cold winters make that valve more important than it is here in Seattle. What year is your engine? Carb? EFI? You're not offering much input. The all-purpose answer here, as so often in life, is, "Well, it depends . . ."

One of the best warm-up gizmos of all is a plug-it-in-at-night engine heater.

 

I'm sorry. I did not mean to be vague.
I live in Melbourne Australia. It can get down to 32 F during winter for a short time in the early mornings.
It probably isn't that necessary where I live to have a diversion valve for the exhaust gas.
Thank you.

 

I am having a problem visualizing what you are saying.

Are you saying that the HD manifold allows exhaust gasses to contact the bottom of the intake all the time - or - the HD manifold has no provision to get any heat up to the bottom of the intake at any time?

If it is all the time then, yes, you will have problems with vapor lock and other fuel handling issues.

If no heat is getting to the intake you may be OK with just the engine compartment heat, depending on the engine bay confines.

 

I believe that the HD exhaust manifold has an open space where exhaust gases come into direct contact with the stock intake manifold.
If I was to use an Offy C-series manifold instead of the stock intake manifold, would I (a) be able to bolt the Offy C intake up to the HD exhaust manifold, (b) have a potential over-heating problem and vapour-lock, (c) overcome potential heat and vapour-lock by using a coolant by-pass at the base of the Offy C intake?
Thank you

QUOTE=The Frenchtown Flyer;16360634]I am having a problem visualizing what you are saying.

Are you saying that the HD manifold allows exhaust gasses to contact the bottom of the intake all the time - or - the HD manifold has no provision to get any heat up to the bottom of the intake at any time?

If it is all the time then, yes, you will have problems with vapor lock and other fuel handling issues.

If no heat is getting to the intake you may be OK with just the engine compartment heat, depending on the engine bay confines.[/QUOTE]

 

Put a thin (.050) stainless steel block-off plate between the intake and the exhaust connection to minimize the heat the intake will see. If you think you need more you can always add metering holes to it later. But I don't think you will.

 

That is a great idea! Thank you for your advice.