Smog pump

[Rob M.]

Is this a 1973 smog pump?

thanks,
Rob

[Joe L.]

Re: Smog pump

Is this a 1973 smog pump?

thanks,
Rob

Rob-----


It could be. However, I'd need to see more of it to say, for sure. All that is shown is the backing plate and several of the casting codes. This backing plate was used on 1968-75 pumps. What appear to be date codes may or may not be date codes.

It's even possible that the pump is an "amalgamation" of parts from different pumps if it's ever been through a commercial rebuilding operation.

In any event, I could tell you more about the pump with photos of the aluminum case as well as the STAMPED code found on the aluminum case, usually on a "half-moon"-shaped machined surface.

[Rob M.]

Re: Smog pump

I have some more pictures:

greetings,
Rob.

[Joe L.]

Re: Smog pump

I have some more pictures:

greetings,
Rob.

Rob-----


No, it's NOT a 1973 smog pump, although it will be 100% functional for a 1973 application. The pump pictured was used for 1968 and also for 1969 L-88/ZL-1. This one has definitely been through a commercial rebuilding operation, so the rear plate may not be the one which was originally installed on this housing. However, the rear plate is 100% compatible with this housing and is of the correct casting number.

The only external difference between the 1973 pump and the 1968 pump, as pictured, is the relief valve. 1968 had the valve; 1969-75 (except 69 L-88/ZL-1) did not have the valve. The aluminum casting was identical between the 68-75 pumps, but the 68 had the machining necessary for installation of the relief valve. 1976 and later use a different pump case and different backing plate.

[Harmon C.]

Re: Smog pump

Rob
Is their any numbers on the machined half moon in the second picture?

[Rob M.]

Re: Smog pump

I believe there was only a message saying: "Don't grip in vise".

[Joe L.]

Re: Smog pump

I believe there was only a message saying: "Don't grip in vise".

Rob-----


Yes, that is usually found embossed on the pump housing. However, if you look at one of the reinforcing "ribs", you will see a "half-moon" shaped machined surface. In fact, I can see the surface I'm referring to in one of your photos but I can't make out the stamping. It's the right hand photo and the boss that I'm referring to is the more-or-less rectangular one that's about 1-1/2-2" long. There should be a stamping on this surface. It will be quite small.

[Donald S.]

Re: Smog pump

Rob,

See the attached picture on what the numbers look like. These are backwards becasue the picture was taken in a mirror.
Don