Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

[Anthony C.]

Re: Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

Put a piece of duck tape over the heat riser actuator and stick the hoses back on . You will never see the tape . This will cut off vacuum to heat riser and keep it open . Just periodically check to make sure the heat riser is open . Only negative effect will be your car will take longer to warm up in cold weather . Good luck 👍

[Larry E.]

Re: Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

Put a piece of duck tape over the heat riser actuator and stick the hoses back on . You will never see the tape . This will cut off vacuum to heat riser and keep it open . Just periodically check to make sure the heat riser is open . Only negative effect will be your car will take longer to warm up in cold weather . Good luck 

Anthony; Got it all fixed by just wiring it open. This is a 66 Corvette which has NO vacuum hoses to heat riser. Fyi
Thanks; Larry

[Duke W.]

Re: Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

On emission controlled Corvette engines beginning sometime in the mid seventies the heat riser valve is controlled by a vacuum motor that I think opens it at some predetermined engine temperature. A neighbor's '77 base engine/TH400 coupe has this system.

I recall it was part of the CCS (Controlled Combustion System) one of the many add-on mechanical systems to control exhaust emissions prior to the general use of EFI and oxygen sensors with a three way catalyst.

Duke

[Anthony C.]

Re: Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

Sorry about that I was thinking C3 mode . Glad you got it fixed happy motoring 🚗

[Owen L.]

Re: Best/Easiest Way To Deacitivate C2(66) exhaust heat risers

I recall GM sold some kind of "heat riser lubricant anti-seize" spray back in the day, but I don't know if they sell it anymore, and don't know of a commercial equivalent that you can buy at a parts store.

Duke