C2:67 Fuel Sender-Original or Replmt?

[Gerard F.]

Is the fuel sender in the picture an original or a replacement? I got it in an NOS box with the part number 6428065 (1984 box) but the sender had been used and was loose in the box.

The only difference between this on and the original on my 67 seems to be the plastic terminal nuts vs zinc plated on original, and the stamping looks a little deeper then the original.

The 67 AIM calls out part no 6425827. Was this part number consistent with all C2's or were there any design changes from earlier years changing the nuts to zinc plated.

I suppose also that someone could have exchanged the nuts on the replacement with the original ones.

Any information appreciated.

Jerry Fuccillo
#42179

[William C.]

Re: C2:67 Fuel Sender-Original or Replmt?

Sure looks like the real deal to me.

[Joe L.]

Re: C2:67 Fuel Sender-Original or Replmt?

Jerry-----

There were 3 "iterations" of the fuel tank sending unit over the 63-67 period. These are as follows:

E1963----GM #5642797
L1963-64----GM #6425113
1965-1967----GM #6425827

The PRODUCTION and SERVICE part numbers were the same for any given year and each part number was supercessive to the prior for SERVICE. So, that pretty much means that there is functional interchangeability between all. For sure, there is rearward compatibility (e.g. using a GM #6425827 on a 1963 model). There may or may not be forward compatibilty (e.g. using a GM #5642797 for a 1967 model). However, I STRONGLY expect that there is forward compatibilty.

Just what the differences are between each unit, I do not know. So, I cannot tell you which of the above 3 senders this, particular, unit is. However, I do feel pretty confident that it's one of the 3 and it's an original sender. Whether it's a 6425827 and, thus, original for a 1967 is the question and I can't answer that.

In October, 1968 the GM #6425827 was discontinued and superceded by the GM #6428065 for SERVICE. So, the GM #6428065 is a SERVICE-only piece and was never used in PRODUCTION for any 63-67 Corvette. Once again, how it differs from the earlier, I do not know.

You say that you have an "NOS box" with a used sender in it (and, the sender does appear to be used). That's a bit worrisome if you plan to actually use the sender. In general, when folks replace a sender, it's because the one they have installed in the car is not working. In this case, from what you have, it would seem that's what occurred (i.e. someone purchased a new GM #6428065 SERVICE sender, replaced the one they had with the unit from the box, and then put the old one in the box and saved it----I've done this myself many times with parts that were, essentially, scrap). So, before using it, you would need to test the sender for functionality AND HOPE THAT IT DOES NOT HAVE A PROBLEM WHICH IS INTERMITTENT.

[Wayne M.]

Compare with this original in late '65 tank

A bit difficult to visualize with the cam in the way.I have to assume this is a 6425827, as that's what the parts books call for (July '65, Oct 65 and Oct '67). I'm sure the nylon terminal nuts are original.

Excuse the 23 yrs. of Texas and Louisiana grunge.

[Gerard F.]

Re: Compare with this original in late '65 tank

Wayne,

Looks just like the one I have in the picture above.

However the original which came with my late 67 (June 29), has the same stampings but has zinc plated terminal nuts. Wondering if they reverted back to an earlier design with my car based upon supply. Wonder which model John Hinckley has on his (which is close to my 67).

Anyone know when they made the switch from zinc plated terminal nuts to plastic, or visa-versa?

Jerry Fuccillo
#42179

[Gerard F.]

Re: C2:67 Fuel Sender-Original or Replmt?

Thanks Joe for the info. Took a copy of your post for my records.

Your suspicions were correct on the operation of the unit.

I fixed it by carefully cleaning out the variable resistor coil and the contactor point. (I just like to tinker with things).

I found that the resistor coil was loaded up with extra pieces of coil wire which got between the intact coil and insulator, and the case of the potentiometer. In other words, the coil was being grounded to the case and must have been that way from day one.

I also found that that insulation was cracked on the lead which wraps around the contactor point mounting. The fix is in the picture below with Form a Gasket to fill in the insulation cracks. This is probably a common problem with these old senders.


Reassemmbled it and bench tested it with an ohm-meter across the terminals.
It now reads around zero ohms with the float down (empty) and around 90 ohms with the float up (full).

Jerry Fuccillo
#42179

[John H.]

Re: Compare with this original in late '65 tank

Jerry -

I think (but don't know for sure) that mine's original (has the "S" and "I" stampings, and is suitably crusty), and it has the nylon terminal nuts. June 8th build, #20401.

[Mike M.]

Re: Compare with this original in late '65 tank

Jerry,

I just checked the one I removed because it had failed and has the stampings and also the nylon terminal nuts. Apr. 8th #114570

[Rick S.]

Re: Compare with this original in late '65 tank

Jerry,
I replaced my original sending unit in the spring and my car is half way between yours and Johns. I will check the garage in a couple of days to see if I saved the old unit. My problem is that I don't want to be likened to my wife, who saves everything, so I most likely tossed it after looking at it for a month.

Rick

[Joe R.]

Re: C2:67 Fuel Sender-Original or Replmt?

Hi Jerry:

This is a subject I have been trying to clarify. I have heard that some judges look for the "correct" markings on the sender, but I do not know which of the two versions I have is correct for 1967, and I am not sure what markings the judges are looking for.

I have samples of two different versions of C2 senders. It is possible that either of versions I have might be considered acceptable, since they both have the "S" and "I" markings and they both say, "AC Made in USA." The current service replacement from GM and the current reproductions do not have these markings.

Included here are five photos, but since I can only make one of them display automatically, I attached the first one and then provided image links for all five photos below.

The five photos highlight the following differences between the two versions:

VERSION 1:
a) Upside down stamping of "AC Made in USA"
b) Small foot on reinforcing support for tube (inside tank)
c) Tan float that is 3.0 inches long

VERSION 2:
a) Rightside up stamping of "AC Made in USA"
b) Large foot on reinforcing support for tube (inside tank)
c) Black float that is 2.5 inches long


These are clearly two different designs that differ by more than just the orientation of the "AC Made in USA" stamping.

The sender that was in my car, which I believe to be the original sender, is a Version 1 design. However, I can't be certain it is the original sender since I am not the original owner of the car.

Note that the sender in your photogtaph appears to be a Version 2, although the plastic nuts differ from the metal ones on the Version 2 sender that I have here.

I'd be interested in any feedback that others on this board may have regarding these two designs. In particular, I'd like to clarify what the judges are looking for and whether either of the senders shown here would meet those criteria.

[Gerard F.]

Getting interesting, here's version 3

Joe,

Here is the inside of the one at the top of this thread, the one similar to your version 2 but with the plastic terminal nuts:


Note the difference in the size of the insulators at the terminals inside. They are much smaller then your version 2 with the zinc plated nuts on the outside.

The float is the same as your version 2:


Now what I think is my original (back on the car), with the zinc plated terminal nuts, had big heavy black hex insulators inside, similar to your version 1 as well as heavy black insulators outside under the hex nuts.

As Joe L. says there were 3 versions of the original production fuel senders and I think there were also probably variations of the replacements. I would tend to think that the plastic nuts and lighter insulators were later in production and the heavy insulators and zinc plated nuts were earlier. (Just from the standpoint that GM liked to cut costs)

I think when they got to my late 67 they ran out of the newer models and substituted an earlier model. (I have a few other anomolies on my car.)

Or was it, "Just pick one out of the bin" with different vendors.

Interesting, Joe you ought to write a story on this one.

Regards,

Jerry Fuccillo
#42179

[Wayne M.]

Inside, mine's like your version 3

Matches grungy exterior view posted by me (same thread, above) Similar fiberboard insulators at terminals; note how terminal studs are "star peened" like horn rivets.

I repeat that this is on a late '65 (the next one the factory installedd was on a '66 )

[Gerard F.]

Looks like I got an original

in a 1984 replacement box.


And now it even works.

Jerry Fuccillo
#42179

PS $46 + $10 shipping on ebay, eat your heart out guys.

[Donald T.]

Third Version?

Here are some pics of the sender that was removed from my late 65. It has elements of both of the versions Joe listed. It has the "AC Made in the USA" right side up, like Joe's version 2. However, it has the small foot and tan float like Joe's version 1. It does not have the nylon terminal nuts. Also, the green filter sock is a replacement, the original was black.




Fuel Tank Sender Pics

[Rick S.]

Re: Compare with this original in late '65 tank

Jerry, Unable to locate the old unit but I did find the box of the NOS unit I bought.
Rick