C2 - Heat Riser Valve

[David K.]

Hello to all; I'm about to take out my 65' for the summer season & perform a tune up. I read a section of the GM service manual which pertains to the heat riser valve, and suggests verifying proper operation and the use of GM spray lubricant on it. What would be the current equivalent, since this item is no longer available from GM. Thanks in advance.

[Steve G.]

Re: C2 - Heat Riser Valve

Hello to all; I'm about to take out my 65' for the summer season & perform a tune up. I read a section of the GM service manual which pertains to the heat riser valve, and suggests verifying proper operation and the use of GM spray lubricant on it. What would be the current equivalent, since this item is no longer available from GM. Thanks in advance.

I'd forgotten all about that GM heat riser stuff. We always had that, their EOS, (engine oil supplement) and another product that we used when you had a carbon knock.

My recollection was that it wasn't so much a lubricant as a penetrating oil type cleaner. Lubricant doesn't last long at those temps, it was mostly about getting the carbon out from between the shaft and it's bore and ensuring it moved freely.

WD40 is not a good penetrating oil. It's more of a lubricant. In our shop we use a a product made by Agco that is called Panther penetrating oil. I'm sure their are others that work well, but I've found this to be one of the best I've ever come across. Agco is the parent company for Massey Fergusen, so if you have a MF dealer near you, that's where you get it.

Obviously you're going to be spraying it at the shaft. If it's already stuck or sticking, tap the end of the shaft back and forth while working it in it's normal travel.

Ensure the stop is not bent or broken. With the engine running jab the throttle a couple of times and ensure the exhaust is blowing it open. This ensures that the butterfly has not broken free of the shaft.
Steve

[Jim T.]

Re: C2 - Heat Riser Valve

Others as well as me wire the heat riser valve fully open. The muffler should last longer. The passenger mufflers on my 68 and 70 Corvettes have lasted over 25 years so far

[Stuart F.]

Re: C2 - Heat Riser Valve

Jim;

Let's not go there today so we can keep Davids' thread going for at least today.

Stu Fox

[Larry H.]

Re: C2 - Heat Riser Valve

David,
The current GM product is #88862628. This is a 11 oz. aerosol can of "Rust Penetrant and Inhibitor, Heat Valve Lubricant." Should be available at most GM dealers. The AC/Delco part number for the same thing is 10-4020.
Larry

[John D.]

Re: C2 - Heat Riser Valve

Others as well as me wire the heat riser valve fully open. The muffler should last longer. The passenger mufflers on my 68 and 70 Corvettes have lasted over 25 years so far

I'm with jim. Also no hot start issues due to heat soak of the carb.

[David K.]

Re: C2 - Heat Riser Valve

Thanks guys;

I'll probably leave it on the car and try the GM lubricant. Thank you once again.

David