Is this the correct OEM dipstick for my '68 L36??? (non air - if that makes a difference) How about the tube??? Your opinions/comments greatly appreciated. Thanks.
-
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Blair-------
I'd say correct and very likely original.In Appreciation of John Hinckley -
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
The dimensions of a 3925520 dipstick are as follows:
A = 17 13/32"
B = 18 1/2"
DaveComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Thanks for the replies back.
Here is why I am confused. My measurements are as follows:
A = 16 7/8"
B = 17 9/16"
Length of blade from stop to tip = 18 1/2"
Overall length from top of handle to tip of blade = 21 3/4"
Measurement between the add and full marks = 3/4"
I have my doubts about this stick being correct for my application. If someone could measure their stick (LOL) to see if the same as mine. (again LOL).
Thanks again for your time, guys.Comment
-
Comment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Blair,
The "A" and "B" dimensions on a dipstick should be relatively close. I would say no more than 1/16" or so. I have compared many of the 50 or so dipsticks that I have collected over the years with the parts catalog dimensions.
My 1968 Corvair-Chevy II-Chevelle-Camaro Parts Catalog (July 1968) lists the 3925520 dipstick for 1966-1967 Chevelle, Camaro (396) models while the 3925599 dipstick is listed for the 1968 Camaro, Chevelle, Chevy II (396) models. This parts catalog does not give the "A" and "B" dimensions.
The 1968 Camaro AIM lists GM # 3925599 as the part number for the 396 dipstick (UPC L35, sheet A4) and described as "GAGE ASM-OIL LEVEL color code (Yellow)".
Based on your photos the plastic insert on your dipstick looks like it might be faded yellow. You might have a 3925599 dipstick, however, more research is necessary to veriify.
DaveComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Blair,
More dipstick research:
Oct. 1969 Chevrolet Parts Catalog, Gr. 1.516
64 Chevelle (8 cyl.)...................................A = 16 7/16"......B = 17 3/8"............3846562
68-69 Camaro,Chevelle, Chevy II (396).......A = 19 17/32"....B = 20 11/32".........3925599
My 1964 Corvair-Chevy II-Chevelle Parts Catalog (Oct. 1963) also lists GM # 3846562 but is described as "single piece".
The dipstick might be a 3846562 "over the counter" dipstick made sometime between 1965 and 1968 but probably not.
I have a Oct. 1968 Chevrolet truck parts catalog and none of the "A" and "B" dipstick dimensions are close to your dipstick.
DaveLast edited by David L.; June 6, 2015, 07:55 AM.Comment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Dave-------
Here's an example of what I'm talking about: I measured an NOS GM #3981088 dip stick, the 70-74 Corvette big block dipstick (I have lots of NOS dipsticks for various Corvette applications but this was the easiest one for me to get at). The carefully measured dimensions from the SEAT (where the dipstick seats on the tube as shown in the P&A diagram) to the marks are as follows:
"A" (full)--------22-5/8"
"B" (add)--------23-3/8"
The P&A Catalog specs are as follows:
"A"-------23-13/64"
"B"-------24"In Appreciation of John HinckleyComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Blair
I think you have the correct dipstick. Attached are photos of the dipstick on my 1968 L71 engine. The colored button has been missing since I bought the car, but I have no reason to doubt it is not original.
John
ds-1.jpgds-2.jpgds-3.jpgComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
John------
The white button dipstick (i.e. GM #3925520) was used in PRODUCTION for a relatively short period of time, from very late 1967 thru sometime in 1969. It was discontinued from SERVICE in October, 1971 and replaced with the GM #3981088 (which also required that the dipstick tube be replaced).
Somewhere, I think I saw that someone is reproducing these white buttons but I don't recall where I saw it.In Appreciation of John HinckleyComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Joe,
I assume that you are not an engineer. The "A" and "B" dimensions of a dipstick are measured from the "ADD" or "FULL" marks to a point in the stop ( a "cup" on these dipsticks) where the upper tube touches when the dipstick is installed correctly. The distance from the bottom of the "cup" to where the tube would touch inside the "cup" section is about 5/8" (see my two photos with the white tape). If you add about 5/8" to your "A" measurement of 22 5/8" you will get about 23 1/4" (or about 23.25") which is very close (0.05") to the parts catalog dimension of 23 13/64" (or 23.20"). Likewise, if you add 5/8" to your "B" measurement of 23 3/8" you will get 24" which is exactly the "B" dimension given in the parts catalog.
With the dipstick upper tube installed on the engine the "A" dimension is from the top of the upper tube to the surface of the oil (which must be level) in the oil pan with the proper amount of oil, or in other words....FULL. The "B" dimension is from the top of the upper dipstick tube to the surface of the oil in the oil pan when the engine is one quart low.
In the top photo the dipstick is pushed into the tube as far as it will go. The bottom of the rubber seal on the "cup" touches the right side of the white tape.
In the bottom photo the distance from the right edge of the white tape to the end of the tube is about 5/8".
BTW, the NOS dipstick with the blue plastic insert in the photos is GM # 3865665 (1975 Vega, Monza).
Dave
Last edited by David L.; June 6, 2015, 09:57 PM.Comment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Blair,
I believe that you did not measure the "A" and "B" dimensions correctly on your dipstick. See the photo that I just inserted on my previous post. You had me baffled with your measurements until I dug out my collection of original dipsticks.
A = 16 7/8" + 5/8" = 17 1/2" (17.50"), parts catalog = 17 13/32" (17.41"), close enough
B = 17 9/16" + 5/8" = 18 3/16" (18.19"), parts catalog = 18 1/2" (18.50"), theoretically off by 0.31".
I believe that your dipstick is an original 3925520 dipstick made in 1966, 1967, or maybe 1968.
To measure the "A" and "B" dimensions more accurately:
1. Measure the length of the tube.
2. Insert the dipstick into the tube as far as it will go.
3. Measure the distance from the bottom end of the tube to both the FULL and the ADD marks.
4. Add each of these measurements to the total length of the tube to get the "A" and "B" dimensions.
The "A" and "B" dimensions on original 1963 and older dipsticks can be accurately measured directly.
DaveLast edited by David L.; June 6, 2015, 10:35 PM.Comment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Joe,
I assume that you are not an engineer. The "A" and "B" dimensions of a dipstick are measured from the "ADD" or "FULL" marks to a point in the stop ( a "cup" on these dipsticks) where the upper tube touches when the dipstick is installed correctly. The distance from the bottom of the "cup" to where the tube would touch inside the "cup" section is about 5/8" (see my two photos with the white tape). If you add about 5/8" to your "A" measurement of 22 5/8" you will get about 23 1/4" (or about 23.25") which is very close (0.05") to the parts catalog dimension of 23 13/64" (or 23.20"). Likewise, if you add 5/8" to your "B" measurement of 23 3/8" you will get 24" which is exactly the "B" dimension given in the parts catalog.
With the dipstick upper tube installed on the engine the "A" dimension is from the top of the upper tube to the surface of the oil (which must be level) in the oil pan with the proper amount of oil, or in other words....FULL. The "B" dimension is from the top of the upper dipstick tube to the surface of the oil in the oil pan when the engine is one quart low.
In the top photo the dipstick is pushed into the tube as far as it will go. The bottom of the rubber seal on the "cup" touches the right side of the white tape.
In the bottom photo the distance from the right edge of the white tape to the end of the tube is about 5/8".
BTW, the NOS dipstick with the blue plastic insert in the photos is GM # 3865665 (1975 Vega, Monza).
Dave
Dave------
I'm not an engineer but, believe it or not, I was able to figure this out anyway. Of course, I measured the dipstick from the point that it seats on the tube to the "add" and "full" marks. That is the point that is equivalent to the seat shown in the P&A catalog diagram.
On a big block dipstick the seat is nowhere near as deep into the bell as the dipstick you have pictured. As a matter of fact, it's only about 3/32" deep but, as I mentioned above, I took that into account in my measurements. The seating point is just about coincident with the flange on the end of the bell. Like I say, I was able to figure this out even though I'm not an engineer. Incredible but true, nonetheless. In case you're wondering, I am ABSOLUTELY CERTAIN that the dipstick was pushed onto the tube absolutely as far as it would go so the seating point was absolutely established.
Below are photos of a 70-74 big block dipstick and dipstick tube, GM #3981088 and GM #3981089, respectively.
On a big block dipstick, the length of the bell is right at 9/16". If one adds that length to the measurements I obtained and considering that the seat point is right at the flange on the end of the bell, then one gets measurements very close to the ones shown in the P&A catalogs. A long time ago, I came to the conclusion (which I forgot about in my earlier responses) the convention for measuring the "A" and "B" lengths shown in the P&A catalog for at least big block dipsticks is taken from the TOP OF THE BELL (which is FAR above the actual seat of the dipstick) to the "A" and "B" marks. Why this is used, I have no idea. Once again, believe it or not, even though I'm not an engineer I was able to come up with this hypothesis.
By the way, even though I show the tape in the photos, I didn't need to use the tape to figure out where the seat actually is. I used the tape only for illustration purposes as you did in your photos. I was able to figure out where the seat was without the tape even though I'm not an engineer.
Of course, the dimensions and seating point described are for the 3981088 dipstick. However, I'm pretty confident the same would hold true for the 3 earlier Corvette big block dipsticks.
Sorry the last 2 photos are out of focus, but they illustrate my point, anyway.
DSCN3126.jpgDSCN3127.jpgDSCN3128.jpgIn Appreciation of John HinckleyComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Joe,
I must apologize for even mentioning anything about being or not being an engineer. It just seemed to me that when I dug out my collection of dipsticks and dipstick tubes the dipsticks made since the mid 1960's have a "cup" (or "bell" as you call it) as a stop. When I took your measurements and added the distance (about 5/8") the tube was inserted into the "cup" on one of my dipsticks the number came out to be very close to the parts catalog dimensions. Looking at your photos the "cup" (or "bell") looks about the same size as the one in my photos. It seems like like there might be some kind of obstruction or possible slight defect in the "cup" of your dipstick. It also seems like the tube and "cup" are not straight in your first photo and this is why the distance is only 3/32".
Once again, I do apologize. I know that you have collected and studied parts in this Corvette "business" for many years and that you are considered by many, as well as me, to be an expert.
DaveComment
-
Re: *** 1968 l36 engine oil dipstick - your opinion needed ***
Dave------
No apology necessary as no offense was taken. Actually, it gave me an opportunity to emphasize how non-engineers can still figure a few things out. It also reminds me of an incident that happened a LONG time ago in the early days of my working career. My boss was the senior engineer and I was a fairly green environmental inspector. One day I was in my boss's office and he told me that there was an opening for an associate engineer and he wanted to know if I was interested. I was shocked and I told him I was not qualified and reminded him I was not an engineer but a microbiologist. He told me I knew more about engineering than any of the engineers on his staff and the job was mine if I wanted it. I didn't take it, though, since I figured I'd be getting in over my head. Plus, I loved what I was doing.
I'd be extremely interested if folks out there with big blocks with original dipsticks would measure the seat depth of their dipsticks in the tube. It's very easy to do and they could use the tape method you showed.In Appreciation of John HinckleyComment
Comment