63-65 chrome oil cap question

[David L.]

Re: 63-65 chrome oil cap question

Here is another photo comparing the chrome cap to a NOS non-chrome cap.

[John D.]

Re: 63-65 chrome oil cap question

NOS caps are service replacements.Cannot go by NOS parts.
I have seen a lot of dimpled oil caps on unrestored mid year fuel injections. I have also see a ton of unrestored units with caps with NO dimple.

I once collected 7 original dimpled caps. All of the caps had plating issues. I took them to a local platers. Had notes on the cap. Instructions in writing and still they removed the dimple so when done my original dimpled caps were junk. Looked like repros.
John

If you are using a repros '63 FI oil filler tube (don't know squat about the carb tubes) your oil cap will not be installed correctly. It will be installed at a different degree. Compare a repro tube to an original. Not even close


PS. Do NOT blast those repro oil filler tubes into your baseplate. You may split the casting and they you are done. THey are TOOO fat. You mustw grind off the chrome etc. I put a piece of tape on the tube about 1-1/4' up from the bottom. They I grind the crap out the tube.
For a 63 FI oil filler tube to be installed correctly you must get it in the manifold as much as possible.Otherwise you will have a hard getting the chrome balance tubes to align.
This stuff is not easy.
If you have a repro tube and a repro cap you will need to massage both the parts. The caps don't begin to fit. You repro guys looking in go try it yourself. Then chirp in here.
Spend the bucks and have your original parts rechromed. Or take some 0000 steel wheel and some polish and use them as is. You don't need all the bling you know.

Sorry to ramble. YOu guys hit a sore spot with me.

[David L.]

Re: 63-65 chrome oil cap question

Enclosed is a photo of a 3828373 oil cap that I removed from a 1964 Chevrolet truck w/283 engine many years ago. The cap has some pitting after I buffed off the rust. The only difference between this cap and the 3828373 cap is chrome plating. This cap has a very slight flat area on the top (1/4" dia. more or less) that is barely noticeable. I sold my NOS caps so I can not compare them.

Dave

[Joe L.]

Re: 63-65 chrome oil cap question

All------


On a part like these caps, tooling wear occurs over time. So, the first cap produced off the tooling might have very noticeable differences from the last cap produced from the exact same tooling.

There might even have been multiple sets of tooling, each with its own unique minor differences from the get-go.

[Doug L.]

Re: 63-65 chrome oil cap question

Hi Guys,
I have a cap on my '64 with a dimple. Original? I can't answer that but everything else on the engine seems to be. When I had the FI unit rebuilt by John D. I sent the manifold (adaptor plate to be precise) and valve covers to be reconditioned. The oil tube and cap were attached to the manifold. John told me to be very careful with the cap because it was original and rare. He warned me not let a chrome plating shop hammer out the dimple before plating.

When I had the car judged in January 2014 I lost points because it was a "repro". Here is a photo.
Doug

[Stuart F.]

Re: 63-65 chrome oil cap question

Sounds like what John D. And others are relating to indicates we have several different things going on;
1) The differences in caps; dimpled and not, repro and not, 63 and others.
2) The differences in oil fill tubes; repro and not, L-76 (carb) and L-84 (F.I.), and again 63 and others.

I can only speak to the 63 L-76 with aluminum intake, AFB, and chrome fill tube and cap. As mentioned before; I had to replace my fill tube twice due to the rolled in fresh air tube first coming loose, then finally coming out (GM had trouble in 63 concluding that rolled tubes are only good for radiators and NOT expansion tanks or fresh air tubes). I don't recall if my first change was NOS or repro, but I bet NOS as it failed too. My second change was probably repro because it is still in place. I still have my original cap and it is not dimpled. I changed it only for cosmetic reasons. Neither cap will tighten fully, I.e. I can, with little effort, turn them to the next tightening position. It does help to have a good cork gasket (fresh), so I change them when the cap starts getting too loose.

Stu Fox

[Gene M.]

Re: 63-65 chrome oil cap question

Sounds like what John D. And others are relating to indicates we have several different things going on;
1) The differences in caps; dimpled and not, repro and not, 63 and others.
2) The differences in oil fill tubes; repro and not, L-76 (carb) and L-84 (F.I.), and again 63 and others.

I can only speak to the 63 L-76 with aluminum intake, AFB, and chrome fill tube and cap. As mentioned before; I had to replace my fill tube twice due to the rolled in fresh air tube first coming loose, then finally coming out (GM had trouble in 63 concluding that rolled tubes are only good for radiators and NOT expansion tanks or fresh air tubes). I don't recall if my first change was NOS or repro, but I bet NOS as it failed too. My second change was probably repro because it is still in place. I still have my original cap and it is not dimpled. I changed it only for cosmetic reasons. Neither cap will tighten fully, I.e. I can, with little effort, turn them to the next tightening position. It does help to have a good cork gasket (fresh), so I change them when the cap starts getting too loose.

Stu Fox

So it appears original caps can be with or with out dimples. Nothing said about draw die marks. The photo of the repop does not appear to have the die marks. But I would suspect all original caps will have die wipe marks along the 4 sides from draw die press operation. Yes, no?

[Mike M.]

Re: 63-65 chrome oil cap question

all of my original caps have the die marks. mike

[John D.]

Re: 63-65 chrome oil cap question

Hi Guys,
I have a cap on my '64 with a dimple. Original? I can't answer that but everything else on the engine seems to be. When I had the FI unit rebuilt by John D. I sent the manifold (adaptor plate to be precise) and valve covers to be reconditioned. The oil tube and cap were attached to the manifold. John told me to be very careful with the cap because it was original and rare. He warned me not let a chrome plating shop hammer out the dimple before plating.

When I had the car judged in January 2014 I lost points because it was a "repro". Here is a photo.
Doug

Doug, Your cap was/is the real deal and not a repro. Not a fake. But as you can see knowledge of these caps is in the learning stages for some and that's just fine. At least this subject has come to light.
I can remember Marlborough Regional around 2006 or so when Dennis Pacy and I were talking about the dimpled caps. Both of our fuel cars had the dimpled caps.
If you have an original dimpled cap and it's not in perfect condition gang clean it up with chrome polish, oooo steel wool and put it on. Don't worry about having bling to impress people. If you give it to a plater then it's history.
I have been getting a lot of unrestored really rough midyear FI's for restorations. Lately a ton of '64's. Next dimpled cap that comes in I will alert you. John D

[Joe L.]

Re: 63-65 chrome oil cap question

Doug, Your cap was/is the real deal and not a repro. Not a fake. But as you can see knowledge of these caps is in the learning stages for some and that's just fine. At least this subject has come to light.
I can remember Marlborough Regional around 2006 or so when Dennis Pacy and I were talking about the dimpled caps. Both of our fuel cars had the dimpled caps.
If you have an original dimpled cap and it's not in perfect condition gang clean it up with chrome polish, oooo steel wool and put it on. Don't worry about having bling to impress people. If you give it to a plater then it's history.
I have been getting a lot of unrestored really rough midyear FI's for restorations. Lately a ton of '64's. Next dimpled cap that comes in I will alert you. John D

John------


I have a strong suspicion that the "dimple" is some sort of "aberration" of the tooling and/or stamping process. I just don't think it was a design feature. For one thing, I can't see any reason for it from a design or functional standpoint. Of course, that does not mean it's not original as it was obviously present on at least some original caps. However, I think it's a real stretch to think that any cap without the "dimple" is not original.

[Edward J.]

Re: 63-65 chrome oil cap question

John, Looking at Doug's oil cap it almost appears like the dome of the cap is really more pronounced and the top is really flat than the others, Could there have been more than one manufacture for these caps. Would like to see a close up of Doug's cap.

[John D.]

Re: 63-65 chrome oil cap question

Edward etal, Definitley more than one manufacturer of caps. If we have learned anything from the million posts here on the DB then we know that GM didn't rely on one manufacturer for much.
I am going to say this gang. At least 3-4 variations of the '63 to '65 oil cap.
At least two variations of the 3714893 Gr 1.758 grayish cap.Listed in a 1980 parts book for 1.40 (plating of this cap not mentioned)
The '893 was painted black (as was the oil filler tube) on early '63's.

The 3828373 cap mentioned next is also listed in the '63 Aims. Sect 6. A 3.00 Oil filter, oil gage and oil filler.
At least two variations of the 3828373 chrome cap that's listed in a 1971 parts book for 1.40
Gasket for the cap: 3723688 $.05 1-1/16" ID X x 1/11/16: OD-cork What do these dimensions mean to you here? Notice the thickness of the gasket is not mentioned. Does the dimension mean the gasket had a hole in the center. But the numbers don't work out as the hole in the center of some of the gaskets is much larger than 10/16 or 5/8".?
I think the center hole is about 7/8".
Jorjorian knows all about these caps so it's his turn please. John

[Stuart F.]

Re: 63-65 chrome oil cap question

You know, I have more than 100 caps in my collection at home. Some from all over the world. My best, though, are the 21 I have in my "Hard Rock Cafe" collection, and then there are the 8 or 9 NCRS caps (some pretty greasy), plus a bunch of just plain "Corvette" caps.

Oh!?! You're talking about "oil caps"!?! gosh, I didn't know where this thread was going.

My only point that I contributed was about the gasket: In my opinion, these cork things have to be changed out every so often otherwise the cap is hard to get closed tightly. It is more liable to keep turning 360 degrees, Leastwise that's been my experience on 63's.

Have a great New Year guys.

Stu Fox

[John D.]

Re: 63-65 chrome oil cap question

I have my original and a couple repos and, of course, they are a little different. There is a slight flat spot on my original. I like to put my cap on so the 4 grip knobs are dialed in square to the engine, not 22-1/2 degrees off like your's Mike. It's way cooler.

Stu Fox

This may have been already mentioned. Mike. Is you oil tube a repro? The way the cap is installed points to that. John

[John D.]

Re: 63-65 chrome oil cap question

In checking my notes I see that Michael Hanson (formerly a heavy contributor here) mentioned that his experience was that he would not expect to see a chrome dimpled cap much after Mid '63.