'72 TCS Spark Control Solenoid

[Kevin Morris]

Any '72 owners and/or judges with knowledge of this solenoid, your answers would be appreciated. This solenoid is on '72's only, and is mounted to a stud sticking up from one of the intake manifold bolts on the passenger side, inboard of the passenger side valve cover. It is a vacuum solenoid that feeds/monitors vacuum from the carb to the distributor. My car was suppose to have it, but when I bought it, the solenoid was missing. I located one through Corvette Central and received it today. Question is...there appear to be three vacuum ports on this solenoid, but only two vacuum hoses. On the front of the solenoid is a "T" shaped fitting, with two of the ports. One is for the vacuum line coming from the carb, and the other I believe is for the vacuum line going to the distributor. On the backside of the solenoid is another port, which I do not know the purpose for. Anyone know?

Kevin #39927

[Joe L.]

Re: '72 TCS Spark Control Solenoid

Kevin-----

You're correct; the vacuum fittings on the forward portion of the solenoid are for the distributor and carburetor. The forward facing port goes to the carb and the side facing port goes to the distributor. The rear of the solenoid should have blade electrical connectors which is where the solenoid gets its "instructions" to interrupt the distributor vacuum advance signal.

I am not aware of a vacuum port on the rear of original solenoids. I wonder if this is an original solenoid or a replacement of some sort. Is there a number 1114451 on it anywhere? This is the original PRODUCTION and SERVICE part number for the 72-only solenoid.

[Kevin Morris]

Re: '72 TCS Spark Control Solenoid

Joe,

Again, I just did purchase this from Corvette Central. Who knows where they got it from...an aftermarket vendor perhaps? There IS this stamped on the front side of the solenoid "DR1114451". The fitting coming off the back of the solenoid, unlike the plastic ones on the front side, is metal like the casing of the solenoid itself.

Kevin #39927

[Joe L.]

Re: '72 TCS Spark Control Solenoid

Kevin-----

You've got exactly the correct solenoid. "DR" represents Delco-Remy and the part number following is exactly the correct one for a 72. I don't know what the rear port is for. Hopefully, some other 72 owner or afficionado can provide the answer.

[Sal C.]

Re: '72 TCS Spark Control Solenoid

The rear port should have a rectangular foam "filter" glued to it. No vac hose was attatched here.

[Gary S.]

Re: '72 TCS Spark Control Solenoid

The rear port on the solenoid has a black foam filter over it. This is right above the blade connector. The other ports on the front of the solenoid are as Joe describes.
Gary
72 LT1

[Patrick H.]

Re: '72 TCS Spark Control Solenoid

Yep. Open to the atmosphere, but I have yet to see a replacement with the foam in place.

Gary, is your e-mail functioning?

Patrick

[Kevin Morris]

Re: '72 TCS Spark Control Solenoid

I put the solenoid in place tonight and then drove the car. WOW, does it make a difference! The car idles at 800 rpm (right where it should), instead of 1000-1100, it also does not miss and stumble as much as it did before. Thx to Patrick Hulst for pointing out this solenoid, or the absence of it, as the potential cause of my idle problems.

Sal and Gary, thanks much for the info. regarding the foam filter. Unfortunately, the solenoid did NOT come shipped to me with this filter. Do either of you know where I can get one?

Kevin #39927

[Kevin Morris]

Re: '72 TCS Spark Control Solenoid

Anyone know where I can get one of these filters??

Kevin #39927

[Patrick H.]

Re: '72 TCS Spark Control Solenoid

I made one (or 4) out of a small piece of black porous filter/foam used for PCV or similar as found in a blister-type pack at AutoZone. I cut the appropriately guessed-at size, and glued it in place.

Real high-tech.

PH

[Kevin Morris]

Re: '72 TCS Spark Control Solenoid

Hey....whatever works! Thx again for the info. Patrick.
Kevin #39927