1970 LS5 w/ A/C Oil Dip Stick & Gauge?

[Carr C.]

The '70 Judging manual is a little vague on the correct oil dipstick for an LS5 w/ A/C. All it says is that it is "about 4 inches longer than the non-air conditioned cars".

Can some one please tell me the correct length vs. the length for a non-air car? Also, any possible indentifying things to look for (like the length from the upper mount bracket to the top), and possibly a part # for the tube & guage?

Any information would be very helpful!

Thanks.

[Tom L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

The original dipstip tube on my 1970 NON A/C LS-5 is 22 1/2 inches long. The bracket is approximately 15 inches up from the bottom of the tube. That number is approximate as the bracket wraps around the tube on an angle. Hopefully someone will chim in on the length for an A/C car.

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

I don't know where this idea that there was difference in dip sticks/dipstick tubes for 1970 LS-5 with and without C-60 comes from. Very early 1970's used the 1969 set-up. This involved a dipstick and tube which were shorter than later 1970. As far as I know, this set-up was used for both C-60 and non-C-60 LS-5, just as it was for 1969 L-36. The dipstick length for this set-up was 19" from the seat to the "add oil" mark. I don't have the exact length of the tube handy, but it was ABOUT 18" long DEVELOPED LENGTH.

Later 1970's, with or without C-60, used a longer tube and dipstick. The dipstick was 24" from the seat to the "add oil" mark. The tube was 24-5/8" long DEVELOPED LENGTH FROM END-TO-END.

So, when did the change take place? I don't know for sure. I'd say about February or March, 1970, though.

[Carr C.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Thanks Joe,

As always you are extremely helpful.

What do you mean by "Developed Length"?

Also, The JG mentions a black tip for 1970, and then changing to red for 71. Is the black tip actually the shorter '69 version, and the red tip the longer late 70 & up version.

Do you have a part number for these?

Thanks!

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Thanks Joe,

As always you are extremely helpful.

What do you mean by "Developed Length"?

Also, The JG mentions a black tip for 1970, and then changing to red for 71. Is the black tip actually the shorter '69 version, and the red tip the longer late 70 & up version.

Do you have a part number for these?

Thanks!

Carr----

The term "developed length" is applicable to parts which are curved. It refers to the length of the piece if it was "straightened out".

I know of only 1 part number ever used for the L1970-74 Corvette big block dipstick. That was GM #3981088. In fact, this piece is still available from GM. I do not know the reason for the difference in color of the plastic buttons that may be observed. However, if there ever was another dipstick used for L70-74, and I am virtually certain there was not, then it was never available in SERVICE at any time. There's no PRODUCTION record of it, either.

[Carr C.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

One last question Joe. What is the part number for the dipstick & tube for the 1969 set up?

Thank You!

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Carr-----


The dipstick was GM #3959158. This dipstick was used only for 1969 and early 1970.

The 1969 dipstick tube was GM #3870324, the same as used for 65-68 big block.

[D S.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

The original 454 oil dipsticks for 1970-1972 did not have part numbers stamped on the shafts. 1970-1971 has only the words ADD, FULL, and an 'M' stamp. 1972, which I'm looking at one right now, has the words ADD, FULL, USE SE ENGINE OIL, and an 'M" stamp with a red button. The loop handle is flattened in the curve on the 1970-1972 issues which is not mentioned in the JG. I believe the service replacements and reproductions, which I also have one in front of me, have much smaller fonts and have part numbers stamped on them with no 'M' stamp and the loop handle is round through the curve.

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Scott-----


Those sorts of details could easily change without a part number change. As far as SERVICE pieces being different, that's a function of when they were manufactured rather than a difference between PRODUCTION and SERVICE. If one had purchased a SERVICE dipstick for a 1970 LS-5 in, say, June, 1970, it would have been the same as the PRODUCTION dipstick in every way.

[Carr C.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?







It looks like they could have either with A/C, and it depends on when it was built. My car is right on the changeover (February 19).



Looks like it could go either way on which is "correct" for a car with my build date. I'd like to know what a NCRS judge would say to this?

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Carr------

The external configuration of the Corvette oil pan did not change in any significant way over the 1965 to 1974 period. However, there were several dipsticks used over the period and 2 different dipstick tubes. The first tube, GM #3870324 was used from 1965 through E1970. This tube was used with the following dipsticks:

1965-E67----GM #3860316

L1967-1968---GM #3925520

1969-E70----GM #3959158.

Each of the above dipsticks superceded the previous for SERVICE. So, the 3925520 became the SERVICE dipstick for 1965-E67 applications and the 3959158 became the SERVICE dipstick for 65-68 applications. This indicates that GM considered each dipstick to be functionally equivalent to its predecessors.

The only difference between the dipsticks are differences in the measurement from the seat to the "add" and "full" marks.

These are as follows:

3860316= 17-13/32" to "full" mark----18-1/8" to "add" mark

3925520= 17-13/32" to "full" mark----18-1/2" to "add" mark

3959158= 17-13/32" to "full" mark----19" to "add" mark

Exactly why GM saw it necessary to change the placement of the "add" mark is not known to me. However, the fact that each dipstick became supercessive to the former strongly implies that the change was not due to an actual change in the configuration of the oil pan. Perhaps, they just found out that they had gotten the calibration wrong and corrected it (twice). Or, perhaps some changes in the internal baffling of the pans affected the "add" mark. Changes in internal baffling did occur about 1969 or 1970. However, there was no change that I know of between 1965 and 1968 while two different dipsticks were used over that period.

My OPINION of the relationship between dipsticks and "colored plastic buttons" is as follows:

GM #3860316= "salmon" button

GM #3925520= white button

GM #3959158= red, green or black; maybe any of these; I'm not sure

The L70-74 tube was GM #3981089. All L70-74 used this tube. It was used only in conjunction with dipstick GM #3981088. This dipstick and tube is SERVICE for 65-E70 Corvette PROVIDING that the tube and dipstick are used as a SET. One or the other CANNOT be used with any of the 65-E70 parts.

GM's "official" specs for this dipstick are:

GM #3981088= 23-13/64" to "full" mark and 24" to "add" mark

My empirically determined (i.e. measured) dimensions of a KNOWN GM #3981088 (that part number actually stamped on the dipstick blade) are as follows:

22-9/16" to "full" mark and 23-5/16" to "add" mark.

Why the difference? It may be that the GM specs are based on DEVELOPED LENGTH rather than FUNCTIONAL LENGTH. Remember that there are 2 "waves" in the upper part of the dipstick. If "flattened out" (which is what developed length is based on) the dipstick would be longer. Using developed length for a dipstick is asinine but that doesn't mean they didn't use it. If so, the earlier dipstick specs I mentioned might also be based on developed length which would mean that "as-measured" specs would be different. I do note that the difference between the "full" and "add" marks is about the same for both the official and "as-measured" dimensions for the 3981088.

[Carr C.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Joe,

Just curious, but what is the oil pan part number and specifications that would have been used with either the E70 or L70 dipstick?

Was it 4 qt, 5 qt, and did the tube go directly into the pan, or into the block and then into the pan?

Thank you.

[Joe L.]

Re: 1970 LS5 w/ A/C Oil Dip Stick & Gauge?

Joe,

Just curious, but what is the oil pan part number and specifications that would have been used with either the E70 or L70 dipstick?

Was it 4 qt, 5 qt, and did the tube go directly into the pan, or into the block and then into the pan?

Thank you.

Carr-----


The 1970 pan was GM #3977591. As far as I know, it was used for all 1970 Corvette big blocks. This pan became the SERVICE pan for 65-69 in January, 1970. That fact also strongly implies that the 3977591 was used for all 1970 Corvette big blocks.

All Corvette big block pans were 5 quart (+ 1 quart with filter change). ALL big block pans, Corvette or otherwise, use a dipstick tube that mounts into the oil pan. NONE use a block mounted dipstick.