Heat Riser Question

[Rob M.]

I would appreciate the collective experience of the TDB on the pro's and con's of wiring the heat riser valve open. Also, if the concensus is that it is best to wire it open, then what's the best way to do it?

Thank you in advance

[Edward J.]

Re: Heat Riser Question

Rob, I would say yes, this will help alleviate some of the heat under the carb., with ethanol gasoline the lower the temp. the less likely you will have driveability problems and hot restart problems.

[Michael W.]

Re: Heat Riser Question

If the heat riser is operating properly it will do no harm.

[Rob M.]

Re: Heat Riser Question

If the heat riser is operating properly it will do no harm.

The heat riser is operating without any issues. I'm just curious what the possible issues could be with moisture, etc. The car is driven somewhat regularly (every few weeks - 6 weeks tops) for at least a 10 mile cruise (to get everything up to temp), however it's still only 500-1,000 miles a year.

[Michael W.]

Re: Heat Riser Question

I'm just curious what the possible issues could be with moisture, etc.

The heat riser has no effect on moisture one way or the other. It can jam open or shut due to moisture but that would usually only occur on a neglected car.

[Frank D.]

Re: Heat Riser Question

I live in Orlando and both my C1 and C2 heat risers are wired open with stainless steel aircraft safety wire.... There is no downside here in the deep South (e.g. "faster" warm-ups are not required)..

[Joe L.]

Re: Heat Riser Question

I would appreciate the collective experience of the TDB on the pro's and con's of wiring the heat riser valve open. Also, if the concensus is that it is best to wire it open, then what's the best way to do it?

Thank you in advance

Rob------

The primary benefit of wiring open the heat riser or, even, eliminating it using a spacer, is preservation of the right side muffler. If you happen to have installed NOS mufflers, then you definitely want to wire open or eliminate the heat riser. If you have aftermarket mufflers or stainless steel mufflers, there's not a lot of benefit.

[Rob M.]

Re: Heat Riser Question

Thank you for the post. That is what I was wondering. I do not have NOS exhaust on the car, so I'm not too worried about it.

Thanks again

[Greg W.]

Re: Heat Riser Question

Rob, If you do not have NOS exhaust on the car or not if not st

[Greg W.]

Re: Heat Riser Question

Got cut off ,If not stainless the right side will rust. Wired mine open and can tell a big difference . Un wire it to judge though.

[Gene M.]

Re: Heat Riser Question

Wire it open will just carbon up and not move eventually but will always be an obstruction.

Just remove the plate, shaft, weight, and spring then fill holes.

[Donald O.]

Re: Heat Riser Question

Remove the plate (or butterfly flapper) with a Dremel cut-off wheel. When re-installed it will look, feel and react as if it had never been altered. No deducts in judging either.

Don

[Donald A.]

Re: Heat Riser Question

Remove the plate (or butterfly flapper) with a Dremel cut-off wheel. When re-installed it will look, feel and react as if it had never been altered. No deducts in judging either.
Don

Yes, that is what I have done, no way to identify the modification once installed

[Timothy B.]

Re: Heat Riser Question

Just keep in mind the heat riser is there for a purpose, the plenum likes heat for fuel vaporization. It's important for heat and vacuum to gas the fuel so you don't have to run a richer mixture. I know ethonal gasoline can be a PIA but I think the problem is more heat soak after shut down. I leave my heat riser functional and have not experienced any problems while the engine is running but the wire is attached if I need to open it and that does make a difference in the temperature of the manifold.

IMO, a shield under the carburetor to extend beyond the float bowls to deflect the heat would make a big difference. I think GM used a shield in later years and probably for that same reason, they also kept using a heat riser.

[John D.]

Re: Heat Riser Question

Wired mine open on my 67 L79 years ago. Dont drive it in the cold NE weather so there are no issues. The biggest advantage has been a huge reduction in fuel percolating out of the carb after a long drive making hot starts difficult.