JavaJolt78

Hey there fellow C3'ers,

I found this (PIC) in a box of old parts that came with my 78..
Can someone tell me:
What it is?
Where does it go?
What does it do?
Do I need to install it?

Jebbysan

Vacuum valve for the smog pump......if you don't have a smog pump...you do not need it.

Jebby

JavaJolt78

Are you sure Jebbysan?
Car is an East Coast Vette...Never had a smog pump!!
I did find a capped of vacuum line and a plugged up coolant hose that looks like it is from the HVAC cover @ the firewall...

JJ78

Mr D.

Your 78 would have had smog regardless of where it was bought. That item looks homemade and reminds me of west coast stuff they did to get a car to pass emissions back in the 70's. Or some sort of water diverter.

ralphspears

Screws into the intake manifold it is for the heater hose

bmotojoe

That is a vacuum operated hot water shutoff valve, just not the original style that came on a 78.

JavaJolt78

I did find an intake manifold hole that has been plugged..
Would it be to my advantage to install it and hook it up??
FWIW I have never used the heater and the PO had installed two brass shutoff valves??
Your take???

JJ78

JavaJolt78

Ok makes sense even though I've never used the heater and from what I can observe the AC was removed by at least one of the PO's..............

And what's your take?? Leave it off of reinstall it??

JJ78

Jebbysan

Well I got snafu'd on that one! It looks exactly like a smog control valve but Vettes had a one way valve........the one I am thinking of that looks like this were off the 80's model S-10 pickups.....sometimes my brain misfires LOL! Too much swimming around in there......

Anyway....if you have heat shutoffs in the lines already....then toss it back in the box.....it is incorrect for a Vette anyway......

Jebby

interpon

ha
i wrote hot water cut off then deleted it because one side was threaded and not 2 hose ends! So thought it was smog pump..

looks like someone welded the male part to hose end of hot water valve

bmotojoe

My take on the valve you posted, toss it.
These valves came in all sorts of configurations.
Ranco was one of the manufactures supplying GM.
Here is a New-Old GM boxed Ranco valve that looks similar to the one you posted.
LINK: https://www.ebay.com/itm/26507092929...IAAOSwcvFgO84k
75-79 used this style valve, Type H25-177 or a H25-144 will work.
Ranco H25-144 LINK: https://www.ebay.com/itm/25480612842...UAAOSwpd9f1TDg

DWAVette

I would have lost money on my wager - I would have bet it was an early Exhaust Gas Recirculating (EGR) valve!!!

PJO

Original P/N 495613 used with or without A/C 1978

https://www.ebay.com/itm/38410339806...gAAOSwuuFgS77J

JavaJolt78

PJO,
Tx so much for the info..
I am going to find the heater hose and vacuum line that was disconnected and reinstall my valve Into the intake manifold and get it back to OE..
Although my valve has the threaded end as opposed to the pic you sent my guess is that it will do the same job???
JJ78

interpon

holy cow totally different where it goes to dash compared to a 79..79 ridiculously close to exhaust. is that because of AC no AC? not sure of OP
OP why not just get valve for your car?
maybe test your current valve to see if it stops 100% of the water under vacuum first..if not you need to replace anyway... they work good..

minitech

Make sure to test the valve before installing. May have been removed because it didn't work. Also consider where you will get the vacuum line to control it.

minitech

If you fine the vacuum hose, may be a white hose coming out of the firewall, it should be plugged now otherwise it causes a vacuum leak and other things don't work as well. Plug it if it is open with that valve or something else to stop the leak..

JavaJolt78

mini tech..........

Valve works and the vac line comes from the firewall in the area of the HVAC unit..
One thing I did notice is that when I took a closer look at the female end of the coolant line it had a black rubber nipple like a cap off inserted backwards into the female end????
Not sure what to make of that so the project is on hold till I get some feedback!!
JJ78
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Vac line is black, capped and originates from the firewall..No probs with that but the reverse plugged coolant line in question that's what concerns me...Afraid to hook that hose up with the plug removed as it might be like that to keep the heater unit from leaking into the passengers side floor...
yours or anyone else comments...
JJ78

Buccaneer

That's my vote as well.