1970 Formula 400 Water.pump questions
 

Still relatively new here...
Joined in late 24. I have always had trouble posting pictures here, and I know. Its easier if you do it from a computer, but I do everything from my phone. Including other forums where posting pictures is way easier. I had the tapatalk app & that worked pretty good for 3 or 4 months maybe, but each time I try to log in with that now it wants me to jump thru a bunch of hoops & never gets anywhere. Says network down, try back later or something. Ok, end of my rant.

But, I wont be able to post pics with my questions. 🫤

I have a 70 Formula 400, with what I think is the original water pump.
It has a casting # of 30938A & R4 right below that, and a date code of M22.
Is that date code Dec. 22?
And is 30938A a 1969 water pump. My car has a build date of 02A & alot of the engine stampings have Dec of 69 for date codes.

My last question is this pump has 11 bolts holding it on. 2 on the top seem to go thru what is behind the water pump & look as if they thread all the way into the block. The one on the right also holds the bracket that is part of what holds the alternator & power steering pump on. I would like to get those brackets off to clean & paint them while I have the front part of the motor disassembled. That bolt is giving me fits for not wanting to break loose & if it is one that threads all the way into the front of the block, I really dont want to break that one off.

Thanks, Rod

Oh, and I answered my last question. I took the longer bolt out on the left side & can tell it threads into the block. Barely had to put any pressure on that one. One on the right is still fighting me. Even after several times with putting heat to it. Even have the radiator, fan, & shroud out of the way so its not an issue of getting in there.

Bolt is probably corroded where it goes through the timing chain cover. No sure what the solution is. Bolt could possibly break depending on how bad the corrosion is. If that happens the timing chain cover will have to be removed. Good luck!

The water pump casting number should be 9979124. I'm not sure what yours is from, or the year. My '70 Formula has its born-with water pump that we had rebuilt by Cardone a couple years ago (they aren't offering that service any longer from what I understand). Its casting date is C110 and with a build date of 04D on the trim tag. You'll likely bust the bolt, but have you tried tightening it a little before trying to back it out? Sometimes that works, but this is an area of high corrosion, and those bolts take the brunt of the punishment. Good luck!

Dennis

Rod;
Casting numbers can be terrible to try to read;
I believe when a given casting is initially used, they are pretty clear, but as time goes on, they become progressively less and less legible (readable).

The most common casting number of a 1970+ water pump (from my observations) is 488296 (sometimes read as 488298);
Keep in mind that a water pump is a regular service item, and isn't often rebuilt to put back on the car - the core might be sent out to a rebuilder then make it's way back into service, but rarely were these left on the original car.
I believe that this casting number started being used in either late 1971, or early 1972 - but my gut says late 1971.
I believe that this casting number was used right up to the end of Pontiac 400 production during the 1978 model year.

My observation is that almost everything originally casted during the 1970 model year starts with a 9799 - there are exceptions;
According to the Pete McCarthy book (aka: "Pontiac bible") the casting prefixes of 478 479, and 480 showed up during 1970;
One such exception is the 'Formula 400' fender badge - it used casting number 480842.

Because I had been tracking down the best original parts for my car, I have tried contributing to the "1970 only" thread HERE - it's a long thread, and much was seeming to get lost in the back and forth, so I have attempted to condense the key points together in some of the later posts.

Here is a direct link to the singular post which might help you the most: LINK #9799124

Yea my casting number is in the same place as yours(top left) Then bottom left it has the M22 stamp which I assume was a date code. When you google the number 30938A It says its a GM water pump for a Buick or Pontiac from 69 to 81, so I dont know, & there are 30938A WPs on Ebay. One says it was rebuilt by Cardone. The car is pretty original. Matching drivetrain. Alternator is original. Starter wasnt & it had a service replacement Carter quadrajet on it. Water pump looks pretty narly. As does the whole engine bay actually. Im in the middle of cleaning that up. Alternator is out for a rebuild. I found a date code correct Quadrajet that is also out for a rebuild. If this pump was original to the car, I was gonna try to have it rebuilt, but if its not I'll just put another one on it & go from there. Thanks for the response Dennis. I havent been on here to long, but I've read the thread about that Formula of yours, & I know how much knowledge you have about these cars.
I had a thread about my car when I first bought it that has pictures in it. Im gonna bring that back to the top in case anyone is interested in seeing that. Then tonight Im gonna mess with the tapatalk app & see if I can get that working again. Its frustrating not being able to post pictures with these questions.

I thank you for the knowledge & response sir! Frustrating not being able to show pics with it. Im gonna try to fix that tonight. Yea, I'd be surprised if it was original. Especially since the car spent the first 43yrs or so of its life in Phoenix & San Diego with that hot climate putting more stress of parts like the water pump. If its not original, Im just gonna replace it with another one & go from there.

Agree with @unruhjonny #9799124 is the number for a 1970 Firebird. Very hard to find, but I was lucky and found one for my 70 T/A and even date matched to the engine!

Thanks for that link unruhjonny. Lotta good info on that. I had hoped to post pics of my water pump. Maybe next time. 🤣
Apparently my free time was up with tapatalk & they wanted 99 cents a month for vip status. Ok, fine if it lets me post pics again. Go thur all the signing up/ payment info/ change password/ yada yada yada.
Congratulations! Ur a vip member. 😎 try to log in here with it & still says "network error. Please try again later"
So that I will do, later...

For what’s it’s worth I don’t use the app to get here just chrome. I'm using my iPhone to post this. Heres my old 73 that I wish I still had.

Think I figured this out... Here is my water pump that is on the motor.

Here is the 30938A stamping. Google made it sound like it was an original GM pump. Sounds like there's not many options for rebuilding an original one anyway. So Im ok with that. Thanks for everyone's help on this

Maybe this time...

Flying Dutchman rebuilds water pump pumps. I've had him do 3 for me. Don't expect a quick turnaround but, he knows his craft. Not cheap either.

http://water-pump-rebuilders.com/

i wouldn't spend money on rebuilding a non-original part;
Unless you're chasing points, just buy a good quality replacement (casting number and dates codes will be pretty much unreadable behind the pulley).

to further this discussion;
(because I honestly missed the other parts of your query)

There was (as I have understood it) a water pump change during the 1969 model year which necessitated a TSB to all in use vehicles;
The "snout" on the later 1969 water pump became longer.

The "1970" model year parts were casted in 1969, and would carry the casting number for the 1970 model year part.

You are either misreading your casting numbers, or you have a replacement/aftermarket item in place.

GM used a four digit (occasionally reduced to three digit) date code in the following format:
MDDY
Month = letter
Date = one or two digit date
Year = single digit; final digit in calendar year.

There were also often signifiers indicating if the part was cast on the day or night shift, which casting mold was used, as well as signifiers which elude my understanding.

The following image is the correct part for a 1970 model year Pontiac:

https://forums.maxperformanceinc.com...1&d=1771547057

A dead give away for a water pump having been rebuild is the pulley end;
if it has two bolt patterns, it's not OE - it's been remanufactured.

Here is an image of a later water pump with the common casting number I previously mentioned:

https://forums.maxperformanceinc.com...1&d=1771547057

There should be two long bolts, and two studs that hold the pump in place;
IIRC the studs use fine thread nuts, and sometimes people have replaced the studs with long bolts;
The long bolts can seize in the block, so take care - but worst case is that you may have a little more work to R&R that water pump (which will include a timing housing R&R).

Thanks unruhjonny.
I agree. I'm already in rebuilds on the original alternator & an original date code correct Quadrajet, so Im not heartbroken that the water pump isnt original, lol. I'll replace it with an original looking one & move on to the next obstacle

That is a aftermarket water pump.

Original pump will have factory part number . from memory i think it would be 9799124, and will have a date code close to your other engine parts. ex.: A280 (Jan 28, 70)

Probably late Dec. 69- early Feb.

I could let you know if i come across a date coded pump if you sent me a email or PM. click on my username to do that.

Water pump
 

I believe I have correct part number core if you want you can also email me a contact number if interested.

Here's the original factory water pump from my '70 Judge (03B) with a partial casting number...A070 casting date. So, you can get weird pumps that weren't perfectly cast. It has a cast '2' below the date.

Dennis