BB Water Pump Date ID

[Howard P.]

I have a # 3856284 BB Water Pump which has a date code of L284. I know the "L" is December however I do not know how to translate the 284. Can anyone please advise how to translate this number ? The pump at the top where the "GM" is cast has a 4 in front of this. I beleive this is a vendor code but am not sure.

Thanks

[Grant W.]

Re: BB Water Pump Date ID

I have a # 3856284 BB Water Pump which has a date code of L284. I know the "L" is December however I do not know how to translate the 284. Can anyone please advise how to translate this number ? The pump at the top where the "GM" is cast has a 4 in front of this. I beleive this is a vendor code but am not sure.

Thanks

Hi Howard
You have a Dec 28th day of 64 So I would assume it would be for an early 65 B/B car. 4 number would probably the casting shift? Thanks, Grant

[John H.]

Re: BB Water Pump Date ID

Howard -

The "28" is the 28th of the month, and the "4" is the year; the "GM4" is the foundry pattern number.

[Wayne M.]

Re: BB Water Pump Date ID

....You have a Dec 28th day of 64 So I would assume it would be for an early 65 B/B car ...

Howard -- very rare early BB pump, as Grant describes. Also look for the thick, perfectly flat backing plate, the panhead screws with star washers, and the bypass fitting without a raised bead. This pump is an E-5-5 cast (May 5th 1965) but these features should also apply to yours (if it hasn't been re-built).

[Howard P.]

Re: BB Water Pump Date ID

Thanks very much Grant, Wayne and John. You have been most helpful to me as I thought I was not translating the info correctly with my ID of December 1964.

Wayne as you pointed out this pump is what you describe though the pan head screws have been replaced by hex fasteners usung the external star washer. To me the hex fasteners look authentic witha recess in the head.

Thanks again

[Joe L.]

Re: BB Water Pump Date ID

Thanks very much Grant, Wayne and John. You have been most helpful to me as I thought I was not translating the info correctly with my ID of December 1964.

Wayne as you pointed out this pump is what you describe though the pan head screws have been replaced by hex fasteners usung the external star washer. To me the hex fasteners look authentic witha recess in the head.

Thanks again

Howard-----


A lot of times commercial rebuilders will re-use fasteners. However, when they strip down pumps, the components, including fasteners, are cleaned and put into bins for use in "building up" rebuilt pumps. So, it's quite unlikely that all the screws on a rebuilt pump will be exactly the same as to configuration and/or headmark. On the other hand, NEW GM waterpumps used in PRODUCTION or available in SERVICE USUALLY have "matching configuration" fasteners. Not ALWAYS but the vast majority of the time.

So, if your fasteners are matching in configuration and headmark, the chances are it's the original, first-run pump. If the fasteners are mis-matched, chances are it's been through a commercial rebuilder's operation.

It would be very interesting to know what yours are or, especially, to see a photo of the rear of the pump. It might help establish that hex head fasteners were used on some big block waterpumps a lot earlier than most of us think they were used.

[Howard P.]

Re: BB Water Pump Date ID

Joe

I will take a pic of the rear of the pump however This pump was just rebuilt and I did not see it prior to the rebuild process as the individual I purchased this from had it rebuilt.

I have no information on the prior history of this piece

Thanks for your information