Jonnylightening
Well-Known Member
Anyone have pics of their heat riser block off or deletes? I'd like to get rid of that. If at all possible I'd really like to cut it off and weld a plate or something of that sort.
Slant heat riser block off/delete?
- Thread starter Jonnylightening
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You cut the butterfly shaft in 3rds and get it out of there along with the butterfly flap. (sawzall)
There are steel bushings that are left behind in the cast iron manifold that can be easily welded shut with a wirefeed welder.
There are steel bushings that are left behind in the cast iron manifold that can be easily welded shut with a wirefeed welder.
Charrlie_S
Well-Known Member
Actually that's the second worst thing you can do. You will have heat to the bottom of the intake at all times. Not as much as if the heat riser were in the full heat position (worst thing), but exhaust will still be at the intake. What I did was put the "flapper" in the no heat position, then welded around the flapper to seal it to the exhaust manifold. I used Spray weld, but braze will work.
I made a block off plate for mine out of some fender sheet metal. Blasted it, primed and painted it with 2000 degree VHT paint and assembled it with the gaskets from Remflex. I also sprayed it liberally with Copper Coat. Has no problem cold starting. Idles in about 20 seconds and runs fine. With headers, there's zero contact there anyway, so the argument that is somehow has a negative effect is a moot one. Even the Dutra duals have no provision for it using both pieces. Lastly, if Chrysler thought it aided performance in the least to have manifold heating, then why didn't they include it on the Hyper Pack? They did not.
Charrlie_S
Well-Known Member
For performance, I agree the heat to the intake is not desirable. But in most (and I stress "MOST") cases, intake heat improves drivability and economy.
Not exactly the same situation, but when I built my draw thru turbo slant, I had to add heat to the bottom of the carb adapter. Initially, without heat the bottom of the adapter would frost up at idle, and fuel would "puddle". Engine idled like a supercharged gasser (had that rolling idle). I added hot water from the heater connection to the bottom of the adapter, and that cured the idle problem. Above idle there was enough air/fuel velocity to keep the fuel from dropping out of suspension.
Not exactly the same situation, but when I built my draw thru turbo slant, I had to add heat to the bottom of the carb adapter. Initially, without heat the bottom of the adapter would frost up at idle, and fuel would "puddle". Engine idled like a supercharged gasser (had that rolling idle). I added hot water from the heater connection to the bottom of the adapter, and that cured the idle problem. Above idle there was enough air/fuel velocity to keep the fuel from dropping out of suspension.
kesteb
Well-Known Member
Removing the heat riser is a waste of time. Without it your carburetor will start to ice up in under 50* of damp weather. Welding a plate to the top of the exhaust manifold to "shield" the intake is also a waste of time. The purpose of the heat riser is to force the exhaust gases up against the bottom of the intake, without it, the exhaust flows smoothly out the exhaust pipe.
Removing "heat" from the carburetor makes sense when the carburetor sits in the middle of a large heat source such as a V8. With a inline engine the carburetor is several inches from the heat source and needs "heat" to help atomize the fuel for distribution.
The "Hyper Pak" didn't have provisions for a manifold heat source because it was an over the counter dealer option for off road performance activities. If you talk to anybody that has installed the manifold, you will find that they are miserable for daily driving and take forever to heat up to properly distribute the fuel.
Removing "heat" from the carburetor makes sense when the carburetor sits in the middle of a large heat source such as a V8. With a inline engine the carburetor is several inches from the heat source and needs "heat" to help atomize the fuel for distribution.
The "Hyper Pak" didn't have provisions for a manifold heat source because it was an over the counter dealer option for off road performance activities. If you talk to anybody that has installed the manifold, you will find that they are miserable for daily driving and take forever to heat up to properly distribute the fuel.
My car idles in 20 seconds and is ready to drive in under 50 degree weather. I have the electric choke adjusted so it slams completely open and I don't even have it wired up. I'll be glad to shoot a video if you like.
I agree there are places it may be needed, but even in PA it will get up to temp with the manifold heat blocked off. Some folks on here act like the manifold gets zero heat using a block of plate. I made my plate out of a piece of fender. Sheet metal. I guarantee you there's still some heat transmitted to the bottom of the intake. It's sittin on TOP of the exhaust manifold, for God's sake! lol
kesteb
Well-Known Member
I have a perfectly good manifold that I removed the heat riser from. It was a pain in the *** when I was living in the Seattle area. For about 9 months of the year, the weather is cool damp air under 50*. Carburetor icing is the result. Now that I live in the Columbia Basin area, I would not use it either. They have an actual winter here, last week the temperature was -5*. And I am sure that the carburetor icing would have been just as bad.
If the heat riser was not needed, the factory would have removed it. Removing the heat riser would have risen their profit margin. And the automobile manufactures are all about the profit margin.
Most people are still operating under Hot Rod circa. 1970 crap. Remember they were the ones that first published that flipping the pistons would gain 10hp in your Chevy 283. I think they made the same claim for removing the heat from the intake. On a V8 they are right, on an inline they are not.
And ever since, it has been an article of faith that you need to remove heat from the intake.
If the heat riser was not needed, the factory would have removed it. Removing the heat riser would have risen their profit margin. And the automobile manufactures are all about the profit margin.
Most people are still operating under Hot Rod circa. 1970 crap. Remember they were the ones that first published that flipping the pistons would gain 10hp in your Chevy 283. I think they made the same claim for removing the heat from the intake. On a V8 they are right, on an inline they are not.
And ever since, it has been an article of faith that you need to remove heat from the intake.
My Offy dual 1 barrels and Dutra Duals have no heat riser and will right up and be ready to go in a minute or two down into the 50's as well.
66 Valiant wagon
Well-Known Member
Why are you wanting to remove it? That's what we should be asking? Is it inoperable?
67Dart273
Well-Known Member
Says the guy from the warmest and driest part of the U.S.
I can still remember a sand buggy at the NAS Miramar auto hobby shop in the early 70's. Had a hot rod sheet metal / tube manifold, and I don't remember whether it was a corvair or VW engine. You blip the engine ON A 100 DEGREE DAY and there was ICE under the carb cavity.
I was waiting with anticipation for someone to make that comment!
BillGrissom
Well-Known Member
Decades ago, the heat riser in my 1969 Dart was rusted stuck and the flapper gone. I knocked it out and put a bolt in each hole with a captive nut on the inside of each (nut w/ washer face w/ teeth to bite in), I recall stainless steel. They were still there years later when I had to take off the exhaust manifold again. That was in Atlanta and don't remember any cold weather start issues or overheating when driving.
dave ellis
Well-Known Member
I have a setup to block off the heat to the manifold along with hoses and a valve to be able to turn it on and off so you can put on in the winter you could probably use it
Slantsix64
Well-Known Member
i always block mine off cut a square piece and weld it in, then have it 1/4 of an inch gap under the intake so its not touching, guess what my intake still gets hot from the exhaust ports right next to the intake ports. Still needed a thick heat insulator gasket t help with heat soak, no matter what im always getting my intake warmed up, especially with aluminium intake, with or with out the heat riser.
Rug_Trucker
Love my 3.8 Buicks
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Hooker had a riser tube with a plate for the intakes..............
dave ellis
Well-Known Member
The setup that I told you I have is for running hot coolant to the underside of the manifold with a valve to block it off in the summer. I would also suggest heat wrap on your exhaust runners. If you would like to go to the coolant route to set up is yours for the ship
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