Inliners International Forums General Discussion Engines Manifold heater

I am in the process of adding a Clifford intake and exaust on my 250cid Chevy motor, the manifold I have is about 20 years old and has no water heater ports built into it. Clifford has a "hot plate" that goes between the carb and the manifold with hot water running through it they say will do the job. I would like to hear from anyone who has knowledge of this set up.
Thanks.
DD

I don't see this plate in Clifford's current online catalog, but you want heat to the bottom of the intake manifold, not the carburetor - especially with the climate you enjoy in Tucson. The idea is to warm the manifold just enough to keep the mixture from "puddling" as it gets sucked in. If your intake is machined for a heat stove on the botom, you can add a water box there. Check E-Bay or talk to Tom at Stovebolt Engine Co.

I have been and Welding Box to them old clifford intakes for the past two yrs now. For guys who want Water heat.The box is made out of Billet Alum. And then I weld it to the Intake.Is you would like to see one You can Email Me and I'll send you a pic. Hope this helps }[oooooo]

Did anyone run the Clifford manifold without some type of fuel heater. How did it work for you?

I have been running a non heat Clifford for almost a year. I had constant problems with the outside plugs fouling if it even thought of getting cold. I recently added a plate that is made to use headers with a stock intake and retain heat. your intake should have the bosses in the bottem that you will have to have drilled and tapped. I used copper tubing ran from a bung that was premade to my headers into the plate. Been running it about a week and the plugs look great and cold start up time was cut down greatly. Here is a link to the site where you can buy the plate and headers.(EGR Plate aka Carb. Heater) http://www.fastpts.com/cgi-bin/hazel-cgi/hazel.cgi?action=serve&item=hrheader.html

I've used the water heated plate between carb and manifold despite being told about heating the carb vs manifold.
What I did differently was to use a thermostatic vacuum switch from a 70's emission control engine to control a vac operated valve in supply line.
This screws into top of thermostat cover.
I plumbed the water off a 292 lower housing,
(a late 70's van item-has three 1/2" holes and no large bypass-there exists a matching pump)
water passes through an Olds heater shutoff valve modified to take vacuum to open-therefore it fails shut.
I plumbed heater core supply seperately;
the manifold and heater return join at a tee and go back to water pump.
This way I had heat if manifold was shut off.
I believe those vacuum switches should still be easy to find. I think they're marked for temperature they close at. A good parts guy will help. You want the one with two vacuum hose connections.
You want a water valve where the vacuum actuator linkage arm is removable so you can file a new notch and turn valve 90 deg from normal.
I believe the last 250 sixes used a vacuum operated heat riser valve; setup simlar to what I did. Probably what inspired me.
Good points: It worked!
Doesn't involve exhaust system.
Bad points: You have to wait for water to warm- so if you're cold so is manifold!
Oh yeah you should like plumbing........
BTW: Ford used those plates so you see them at flea markets, came in two and four barrel versions, don't know if they're available new.

I ran a Clifford without heat on my 292 with a single Edelbrock 600. Never ran it when it was below freezing, but never had a problem with it when cold or up over 100 degrees. We have to have any vehicle 1965 or newer smogged, and it past with flying colors.

I have plumbed water heat to the bottom of the Offy single 4 barrel intake on my 292. The engine has a 500 cfm carb and tube headers. Heats up fairly quickly from the combination of the water heat and the close-by tube headers. Smooth acceleration for such a relatively large carb; No flat spots, no hesitation and no backfire.

I came across a water heated single 4 barrel Clifford for a good price on Ebay a few months ago. I want to see if there is a noticeable performance difference between the two both in terms of heat and horsepower.

-magic mike-

I live in Tucson, and have run a 292 w/Clifford headers and an Offy intake for 25 years. I needed no intake heat. But I have noticed that the L6 ran a lot better in the High summer.[When the V8s would vapor lock].

Well I sent the "Thermol Plate" back to Clifford thanks to several of your comments. Thanks to this "B" Board I have found someone that can make a part for me that should word. I surely am glad I found you all. This is the set up I have put together, it is ment to pull a small hunting trailer(18') and carry a Polaris Sportsman 500 (850 lbs.)into the mountains of Arizona (10,000 ft). Please feel to step up and tell me if you find a fly in my ointment. I have a 1973 GMC
250 CID from 69 Nova, a Saginaw 4spd. from 78 Camero. The motor has a CompCam 240 duration, recurved Mallory Duel Point distributor, total advance 2800rpm. Clifford headers and intake with Holley 390 cfm 4bbl,stock jetting,

Desert Dove-- I PM'd you.
Brian

whats the difference between Offy intake and Clifford?

The Offy is a little more like the stock intake. But will take a 4b carb. Good lowend power & tork to mid rpms. The Clifford On the Other hand was made for Mid to High Rpm power & tork. Hope this helps.}[oooooo]

I've been running my 250 with an Offy 4bbl set up and no heat under it for a year with no problems.
The car is a hot rod so doesn't see daily use year round but I do drive it on a good weekend day in the winter. When I built the engine I did make up a thin cardstock template for an air box around the header tubes in case I needed the heat.
So far that template is only collecting dust in the shop.

62belair....did you mean that you're using exhaust to heat the manifold. I'm wondering how using the holes in my Fentons to run exhaust to the bottom of my manifold...i have a heatplate but someone said i would need a butterfly vlavue in one of the manifolds? Anybody done a setup with exhaust heat?