63 Radiator drain valve question

[Edward J.]

Does any one know if Dewitts radiator drain valve reproduction is correct? my understanding is that the complete valve is suppose to be aluminum ?? Thanks Ed

[John D.]

Re: 63 Radiator drain valve question

Ed, I am pretty sure that the 63 radiator doesn't have an aluminum plug but as you said it has an aluminum petcock.
I don't know about the repro but knowing Tom I bet it's a nice part.

[Richard G.]

Re: 63 Radiator drain valve question

I took some pictures of my 1962 dated 63 radiator's petcock.
I can't confirm if it's original but I know it hasn't been messed for the last 41 years.
I scratched up the material so one could guess at the material. Looks like brass nipple, a steel wing nut and a brass nipple on the end.
Rick

[Harry S.]

Re: 63 Radiator drain valve question

Here is one of Dewitts, Aluminum except for the thumb turn. I put a magnet on it.

[Richard G.]

Re: 63 Radiator drain valve question

It appears mine was replaced. Dewitts wouldn't go through the trouble to make them aluminum if they didn't come that way from GM.
However I can see where the life of the valve may not be as long as a brass one. Likely why mine was replaced. I am running a Dewitts radiator but never really looked closely at the supplied valve.

[Joe L.]

Re: 63 Radiator drain valve question

It appears mine was replaced. Dewitts wouldn't go through the trouble to make them aluminum if they didn't come that way from GM.
However I can see where the life of the valve may not be as long as a brass one. Likely why mine was replaced. I am running a Dewitts radiator but never really looked closely at the supplied valve.

Richard-------


GM says that the original petcock was a GM #3150906. In SERVICE this petcock is supplied with an extension. However, in Corvette PRODUCTION it was not used with the extension. I have an NOS example of a 3150906 and I can tell you that the petcock is configured virtually identical to the DeWitts reproduction. The plug and tube are aluminum while the finger-hold is steel.

There's an important reason for this with aluminum radiators and it's the same reason that the aluminum radiator mounting is designed to insulate it from any contact with non-aluminum components of the vehicle. That reason is the prevention of galvanic (dis-similar metal) corrosion. In fact, looking at your petcock there appears to be considerable corrosion in the surrounding area. This is likely galvanic corrosion due to the brass petcock.

[Richard G.]

Re: 63 Radiator drain valve question

Yes it looks bad and it is bad. Just kept the old radiator as a reference. Nice reference as I had the Dewitts replacement dated the same as the original. The JB weld that was on it in 78 when I purchased the car is still there. It leaked there also. One of the reasons it wasn't driven for all those years.

The tag on the top of the original radiator was different than the one supplied by Dewitts. Also some minor difference at the top hose kick out. Other that that its almost perfect. I was happy to be able to acquire such a nice radiator after 50 plus years.
Rick

[Gerald C.]

Re: 63 Radiator drain valve question

Radiator petcock.jpg

Okay..Bubba strikes again! This is the petcock location under my 63 radiator. I guess Bubba didn't like the petcock, so he put a headless hollow bolt in it's place. I used a small drill so that I could drain the cooling system. Easy out's just spin. I know the petcock has a tapered fitting so I need help with getting this "bolt" out without messing up the internal tapered threads. Also, does anyone know the thread size at the top of the internal fitting off of the petcock? I want to properly drill out the opening so that I can put the correct petcock in.

Thanks for everyone's thoughts and ideas.

[Harry S.]

Re: 63 Radiator drain valve question

Don't drill it out, use an easy out since you already drilled a hole to drain the coolant.

This is an example of what to use.

Try--> https://www.harborfreight.com/screw-...RoC9BQQAvD_BwE

[Gerald C.]

Re: 63 Radiator drain valve question

Thanks Harry. I'll keep increasing the size until the "bolt" comes out easily with the easy out. It's worth a shot. Thanks. I would think I shouldn't have to rethread the hole. Do you know the tap size for the petcock?

[Harry S.]

Re: 63 Radiator drain valve question

Do you know the tap size for the petcock?

Sorry, don't know. Do you have a spare to install.

[Joe L.]

Re: 63 Radiator drain valve question

Thanks Harry. I'll keep increasing the size until the "bolt" comes out easily with the easy out. It's worth a shot. Thanks. I would think I shouldn't have to rethread the hole. Do you know the tap size for the petcock?

Gerald------


The thread size is 1/4" NPT (National Pipe Thread).

[Gerald C.]

Re: 63 Radiator drain valve question

Joe,

I believe the fitting has a tapered thread. I'll use the 1/4" pipe tap.

Thanks

[Gerald C.]

Re: 63 Radiator drain valve question

Well success! I used the 1/4 NPT tap and 1/2" drill. I drilled out the hole with sequentially larger bits until I got to the 1/2". Drilled it out and poured water through the system to flush out the filings and excess metal chips. I caught the water in a white bucket and sure enough, metal filings were in the water! I intend to do it again tomorrow to be sure. I installed the new petcock and it went in very smoothly.

Thanks everyone for your ideas.

Jerry