Dewitt's petcock; one point deduct

[Dick W.]

Re: Dewitt's petcock; one point deduct

I have worked on several original radiator cars and most had the aluminum hex plugs in them. I dunno if this is typical of all cars or atypical?????

[John Daly]

Re: Joe Lucia: GM # 9424801

gary,
Part number 9424801 is a 1/4" PTF SAE aluminum plug .

john

[Peter L.]

Re: Joe Lucia: GM # 9424801

John - I guess it's not a surprize that its an aluminum plug. I'm interested in knowning the source as to where can this information be found? Is it in the Standard Parts Catalog? Thanks for the info. Pete

[Jim L.]

Re: Dewitt's petcock; one point deduct

Hi All

I have a very original 66 SB with original radiator. Previous owner had car for thirty years. It has an aluminum hex head plug in the drain which I will keep there for judging. JR

[Joe L.]

Re: Joe Lucia: GM # 9424801

Gary-----

This is one that I should have researched a little better before I previously responded. I had never seen an aluminum radiator with a pipe plug instead of a petcock. However, from what's been reported by others and from just a little research I've done, it does look like the pipe plug was used for some period in the 1966-67 time frame.

From what I can tell, the 9424801 is a hex head pipe plug just as John describes it. However, it was never a SERVICE-available piece. I suppose GM figured that, considering the applications for a 1/4" NPT ALUMINUM pipe plug, they wouldn't sell enough of something like this in SERVICE to bother with it. Besides, anyone replacing it for the radiator application would likely replace it with a petcock.

Also, apparently, big blocks during the 66 to early 1967 time period used a drain plug for their copper/brass radiators. This plug was GM #444819. It was a hex head, 1/4" NPT BRASS plug. It was never SERVICE-available, either.

[Robert Jorjorian]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Pete I looked in a 1968 parts book to see the app for the aluminum petcock and its listed as,

GR. 1.229 COCK
60-61 CORVETTE w/H.L. Cam (1st design)
61-64 CORVETTE (2nd design)............(1/4 pipe thd.)(alum.).....3150906

I interpret parts as implying the cutoff was 64 yet as you noted 63-65 AIMs all are called drain assys........interesting info you uncovered, RJ

[Dwight P.]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

My 65 SB has a Dewitts replacement with a typical petcock. Judges at the National in San Antonio deducted 2pts (Chasis #5 Engine cooling system) because the radiator did not have an aluminum plug. Judges said that original radiators came from the factory with an aluminum plug and the dealer was supposed to replace it with a petcock during the recommended maintenance schedule(?).

[Michael H.]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Years ago I bought a few of the 3150906's and they came with a short (2"?) aluminum pipe extension attached to the pedcock. (correct for 6o-62?) The threads on both parts were coated with a black goonk/anti seize. Always thought it was strange that there was never a part number in the book for just the pedcock for 63 and later.

[Michael H.]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Not sure about 65 but I know for sure that my new 64 had the drain petcock, not a plug.

[Robert Jorjorian]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Dwight it sure sounds like those judges think 64 was the cutoff also.
Would you happen to know the judge's name on the plug deduct?

[Dwight P.]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Bob:

Yes, I have the names on the judging sheets, but I am hesitant to publish them on this forum. I hope that everyone including the judges that judged my car and hopfully the judging chairmen will see this discussion and take the appropriate action to correct the Judging guides.

DP

[Robert Jorjorian]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Michael I remember them in 63 and 64 also but I never owned a 64 new so your comment sure adds credibility to the parts book description.
Its odd the 65 AIM shows a petcock and calls it a "BUTTERFLY HANDLE DRAIN ASSY" and gives a torque spec for something that clearly is not pictured as a plug.
Also why is there an AIM torque spec?.....you'd think Harrison would torque it before shipping.

[Michael H.]

Re: Inquiring Minds Want to Know-C2 Rad Drain Asm

Robert,

Yes, very strange that there's a torque spec on a part that doesn't have a part number listed on the page. It's almost as if it were to be final torqued, or possibly removed and reinstalled for some reason. The fact that the part number isn't listed would indicate that the drain was part if the complete radiator assembly, as shipped.

From what we've learned so far, I would agree that 66 was the only year that had a plug instead of a drain.

I've had or seen a ton of new AL radiators over the decades but I've never seen a new one with anything but a petcock.

[Mike E.]

Re: Dewitt's petcock; one point deduct

That's obvious that it's one of Harrison's good ones--40 years old and still working, without ever being drained. I wonder how large a deposit of salts is hanging around the bottom of that one!
My experience has been that (primarily 61-62) many failed in the first 6-7 years, because I've seen oodles of replacements with mid to late 60's dates.
I've also discovered if one has made it this far, it's not likely to become a leaker--just may not cool all that well anymore.
I'm thankful for DeWitt's, even if it means that my 2 NOS 62 radiators have less value!

[John Daly]

Re: Joe Lucia: GM # 9424801

Hi Pete,
The details came from the engineering drawing of the part. I work for GM and for some unknown reason the drawing for this old part is on the electronic database. It was drawn in september 1965.
regards
john