I pulled my intake off today to clean, glass bead and paint tommorow. the heat riser is sealed up in the closed position with what looks like pumice on top of it. (heat insulation?) The manifold I have prepared for my dutra duals has no heat riser valve or flap in it. should I make a thick steel plate to close off the gap between the two manifolds? I"m really happy with the way the car runs. I assume that no heat riser flap is going to give me fuel boiling problems. do they make new heat riser flaps?

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64' Valiant Signet 5.9, 64' Dart 170 moredoor 3.7, 67' A100 3.7, 00' Dakota SLT 4.7

Howdy,

iIn March this year I got into my "manifold heat riser obsession" (see thread). I got a Mopar counter friend to run a Parts Direct search for me, and bought all the flaps, springs, shafts and pins that were listed in the US at the time. Reason is I like parts on the shelf and there were suprisingly few of these parts in the country. SO as to whether "they" make them now, I don't think so, but for sure they can be hard to get. Arizona parts at 480 966 6683 has some complete kits left at about $50 each including shipping (March prices) and if you want a kit or a part, PM me. Now that my Dutras are humming along and I only need one more engine on the shelf, I would let a few parts out of stock to a fellow slanter.

rock
'64d100

I'm not really interested in making it functional. the old one isn't and the car runs fine. I just figure I still need it closed in place for the car to run right. I guess my real question is if it isn't in there at all am I going to have problems?

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64' Valiant Signet 5.9, 64' Dart 170 moredoor 3.7, 67' A100 3.7, 00' Dakota SLT 4.7

Yes you will. When the temps go below 50*, you will experience sever carb icing problems. An inline engine needs some form of heat for the carb.

In my case, I completely removed the flapper valve. I ran my car for 2 1/2 years in that condition. For 3 months out of the year the car ran OK, the rest of the time, icing problems. I could literally touch the base of the carb after a hours drive and it would be cool to the touch. I could literally open the hood on my car and watch the frost form around the base of the carb during sub 50* weather.

I solved my problem by installing a water heated base plate when I update to a Motorcraft 2100. Drivability problems are a thing of the past. Gase mileage has gone from a best of 18 - 19 mpg to 20 - 23 mpg.

I ran my car without a flapper valve for several years also (completly removed like Kesteb did), but never had any drivability problems. The only reason I didn't have icing problems is because I ran the stock air cleaner with warm air coming up the tube (that attaches to the air horn on the air cleaner) from the stove around exhaust manifold. I have replaced the flapper-less manifold with a newer manifold with a functioning flapper valve and have also noticed an improvement in milage....oddly enough the same as Kesteb!

Hi 64,

Glad to see a couple other members got you straight so fast! MY application is a little different because I use an offenhauser intake, but I tried flapper and no flapper...that is why I scoured the US to get a flapper. It aids mileage and general running around here in NC, where temps over a year generally range from about 10 to 100 degrees.

rock
64d100

Where I live it doesn't really get below 50 degrees. it would be pretty rare if it did. San francisco has pretty moderate winters. it's not unusual to have colder days in summer. I dont see how the flapper plate permanently in the closed position is going to rob the intake of heat, it's still sitting on top of the exhuast manifold. and the manifold on my car right now has the riser flap stuck closed. it runs like a top. granted I haven't owned the car through the winter. If I do have problems with the flap stuck closed through the winter I will be the first to admit that I was wrong. I'm worried about boiling the fuel more then freezing it.

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64' Valiant Signet 5.9, 64' Dart 170 moredoor 3.7, 67' A100 3.7, 00' Dakota SLT 4.7