Fuel pump date code? David Liukkonen

[Ronald L.]

Re: Fuel pump date code? David Liukkonen

David, also another 40366 66 427 pump - 9J date code. Seeing Heart and diamond stamps tot he left of this, have you seen these?

[David L.]

Re: Fuel pump date code? David Liukkonen

They said it would fit 65-67 and other applications; surprised an AC part out of the box did not have any code in front of the number.

Who is "they"?

[David L.]

Re: Fuel pump date code? David Liukkonen

David, also another 40366 66 427 pump - 9J date code. Seeing Heart and diamond stamps tot he left of this, have you seen these?

I don't spend my life looking at AC fuel pumps. I've stuied them for 20 years which is probably longer then most of the other NCRS members and I'm a little burned out with the date coding subject. It would be nice if others would spend some time and effort studying fuel pumps rather then asking me. I do not know all the answers. I only made a few observations and came up with what I think is a logical conclusion.

I have no idea what the heart and diamond shapes mean.

I believe the "9J" stamping on the 40366 fuel pump may be the 9th day of 1970. That's only an opinion and not a fact.

[Ronald L.]

Re: Fuel pump date code? David Liukkonen

We'll continue looking. Do you have any data to share that we might be able to focus on the breaking this davinci code?

[David L.]

Re: Fuel pump date code? David Liukkonen

The used and NOS 4657 fuel pumps that I have had over the years also had a 2-digit casting for the year inside an untapped hole. There were also anywhere from 1 to 12 radial line segments representing the month of the year surrounding the 2-digit year much like a clock. Here are a few that I have in my research that I have since sold over the years:

Used "4657" stamping with "64" cast w/3 radial line segments (March 1964).

Used "4657EF" stamping (May 1966) with with "66" cast w/ 3 line segments (Mar. 1966).

Used "4657KE" stamping (Nov. 1965) with "65" cast w/10 line segments (Oct. 1965).

Used "4657EF" stamping (May 1966) with "66" cast w/4 line segments (April 1966).

NOS "4657KE" stamping (Nov. 1965) with "66" cast w/10 line segments (Oct. 1965).

NOS "4657GF" stamping (July 1966) with "66" cast w/6 line segments (June 1966).

Used "4657EF" stamping (May 1966) with "66" cast w/4 line segments (April 1966) removed from a complete 1966 Chevrolet 327 engine casting # 3858180, casting date "E186" (May 18, 1966) or possibly "E136" (May 13, 1966) and stamped "T0521HAR" on the pad (May 21, 1966). The "HAR" is for 327 engine w/M.T and Rochester 4BBL carb.

It is with these 4657 fuel pumps that I purchased at swap meets and junk yards in the 1980's that I first noticed a date code pattern.

NOTE: Over the years at swap meets I have seen REBUILT AC 4657 fuels pumps with mis-matched date coded parts and even some with stamped numbers other then 4657. Rebuilt AC fuel pumps are made from an assortment of parts from other AC fuel pumps.

[Scott S.]

Re: Fuel pump date code? David Liukkonen

Very interesting Thread. The code stamped in the flange of the AC fuel pump that came off the '67 (L79) is AI 40503, making it a service replacement from January 1969?

Doesn't the use of an "I" here conflict with the common practice of omitting the "I" in date-stamping?


When looking for a replacement fuel pump, would an NOS AC 64-40433 be safe to use, or am I better off going with a current AC 40503 from a reliability standpoint?

[David L.]

Re: Fuel pump date code? David Liukkonen

Scott,

It is very common for the letter "I" to be used on STAMPED date codes. I have noticed this for the last 30 years ever since I first started doing research on parts. Example: My 1970 Z28 fan stamped "3947772" and "M69" is dated Dec. 1969.

The letter "I" is generally NOT used on CASTING date codes like engine blocks, cyl. heads, intakes, etc. In this case the letter "L" = December.

Dave

[John H.]

Re: Fuel pump date code? David Liukkonen

Scott,

It is very common for the letter "I" to be used on STAMPED date codes. I have noticed this for the last 30 years ever since I first started doing research on parts. Example: My 1970 Z28 fan stamped "3947772" and "M69" is dated Dec. 1969.

The letter "I" is generally NOT used on CASTING date codes like engine blocks, cyl. heads, intakes, etc. In this case the letter "L" = December.

Dave

Dave -

I think you'll find that it's very common practice for the "I" character to be used on GM casting dates, where "L" = December. However, on stamped date codes on GM-produced electrical components (starters, alternators, generators, distributors, regulators, etc.), the "I" character was not used, so "M"=December.

[David L.]

Re: Fuel pump date code? David Liukkonen

John,
You are correct. The letter "I" was used with CASTING dates making "L" = December and the letter "I" was NOT used in STAMPED dates making the letter "M" = December. As least I was half right. I got the correct letters for the month of December. I guess that I just had a "senior moment". Thanks for correcting me.
Dave

[Joe L.]

Re: Fuel pump date code? David Liukkonen

Don,
The 40769 pump (GM # 6470308) did not exist in 1965. It was first issued on the 1970 models. I believe that your pump MAY be a replacement and the "153E" on your pump MAY be the 153rd day of 1991. You could still buy the 6470308 pump (AC 40769) over the counter in March 1991 for $33.80 as per my GM Price Schedule (Mar. 1991).
I believe "Z" = 1986 and the letters start again where "A" = 1987, etc. It's just my theory, not a proven fact.

Dave

Dave------


I don't think that AC was still manufacturing MECHANICAL fuel pumps in 1991. I believe AC ceased making this type pump in ABOUT 1984, if not earlier. After that time, the AC mechanical pumps were manufactured by Airtex or Carter. I would doubt they would use the same date coding system that AC did.

[Joe L.]

Re: Fuel pump date code? David Liukkonen

Dale,

I assume your AC fuel pump is stamped "140Y 40659". According to my research the AC 40659 pump is GM # 6417338. According to Chevrolet Parts History GM # 6417338 was discontinued in June 1971 and replaced with GM # 6470106 (AC 40718). I would normally say your fuel is dated the 140th day of 1986 ("140Y") but it doe not seem to make much sense. In the picture your fuel pump does NOT look 42 years old. Is it the original fuel pump? Was the pump rebuild or replated? Did AC re-issue the 40659 fuel pump? Is it a reproduction? Is this some like of trick question? I have no other logical answers.

Dave

Dave------


Yes, the GM #6417338 aka AC type 40659 was discontinued in June, 1971 from the GM parts system. However, it was around for MUCH longer through the Delco parts system. In fact, I think it was around from the Delco parts system right up until AC stopped the manufacture of mechanical type fuel pumps in ABOUT 1984.

There were also other AC fuel pumps that were discontinued from the GM parts system long before they were discontinued through Delco.

So, why were the pumps discontinued from the GM parts system and yet still manufactured and available long thereafter through the Delco parts system? I have no idea.

[Owen L.]

Re: Fuel pump date code? David Liukkonen

Adding info to this old thread:

This is what I have found for the first letter:
A = Jan.
B = Feb.
C = Mar.
etc...............
J = Oct.
K = Nov.
L = Dec.

This is what I have found for the second letter:
E = 1965
F = 1966
G = 1967
H = 1968
I = 1969
J = 1970
etc................

Dave

I pulled my '67's original (I believe it to have never been apart) 427/390 to have it rebuilt. I have long suspected the fuel pump was likely original as it was ~12 years old when I got the car and it hasn't been changed in the last 45 years I've had it.

The pump's flange stamp is: CG40482
March, 1967, according to David Liukkonen's decoding efforts, which aligns well with my early-May car.