Should the oil cap on the oil filler tube on the front of the motor be painted the color of the motor? (gold) Or should it be the natural metal color. Thanks.

 

Cadmium (I believe) plated if you are entering it in judging competitions.

Whatever color you like otherwise.

- Eric

 

In my engine assembly manual it does not show the cap on the engine on the page it diagrams what parts to paint. But I have heard that even the oil tube went on later and was not painted, does anyone know for sure.

 

I don't know when the oil tube went on, but it was painted.

- Eric

 

My '71 oil tube AND fill cap were painted engine color but I have read (and seen) that in '72 the oil fill tube and fill cap were left natural. Some of the inlinetube cars (restored by Wing's Auto Art I think) have really set a benchmark for correctly restored cars and their '72 W30 442's fill tube and cap are natural, not engine color.

 

Okay, you got me.

Why would GM not paint that one piece, thus guaranteeing that it will become rusty and nasty, especially when they always painted them in previous years?

Weird.

- Eric

 

My old '72 98 had the oil fill painted but cap was not...the '72 98 I have now, neither have paint. I think the oil fill is aluminum so it won't rust.

 

Remember most all the painted stuff was 'flashed' with paint at best. They weren't concerned with long term paint qualityand/or preserving appearances the way we do now and a lot of components were left natural resulting in rust within months. As far as the fill tube, I suspect it was a procedure change where the fill tube was installed after the engine was painted as opposed to previous years when the engine was painted with the tube/cap installed. When completed engines were painted it was very common to have paint on the exhaust manifolds and bypass hoses, etc. or some areas missing altogether. Mass production on an assembly line by human beings left a lot to be desired sometimes.

 

Oh, I know. It just seems odd that they'd leave such a large and prominent piece, right out front on top of the engine, to rust up over the buyer's first few months with the car.

I mean, sure, they didn't try too hard to paint them well, but they did splash enough on there to make 'em look acceptable for the first few years.

- Eric

 

to clarify my engine assembly manual is for 1970 and it does show the filler tube on the engine at time of painting but no cap. I have heard from other "experts" that I have come to trust that this is the way the 70's were done. Painted filler tube, natural cap - for 1970.

 

Which is why I find the idea of an unpainted tube for 1972 so strange.
I've had motors from 1968, 1970, 1976, and 1980, all with painted tubes and unpainted caps.
Why the deviation in '72?

- Eric

 

Every original, unmolested 1970 engine I've seen with an original oil fill cap has had paint on the cap. I don't know why the factory would want to get paint either down inside the crankcase or on the mating surface of the fill tube where the cap screws on, so it makes sense that they were installed before painting.

The paint page in the assembly manual has to be taken with a grain of salt. It shows the intent of the design engineers to paint certain things but keep paint off other things. But ultimately, it was up to the production engineers to decide the best point in the assembly process at which to paint. Ever seen overspray on an aluminum intake manifold? Nope, me neither. Yet the picture shows the manifold installed before paint. Didn't really happen that way.

I can't speak for 1972 engines, but let's just say that many of the restoration details that the gents at Inline Tube have established as "benchmarks" are as much fantasy as fact. I'm not saying they don't make some nice reproduction parts, or that they don't do some nice restoration work. I'm just saying don't believe everything you see or read.

 

so how about the lift hook on a W30 - should it be blue or natural.

 

Thanks everyone for your comments. This is proving to be an interesting topic. My oil tube and cap were both painted gold but I've deceided to strip the cap of paint. I've looked at a lot of pictures of 70 to 72 engine bays and most had unpainted caps. Stevengerard, I believe the motor hoops were all painted. mine are.

 

the 72 442 W-30 i have talked about that i had with 16,000 miles had the tube painted and the cap was not. this was how it left the factory.

 

I'm with Brian on this.....the factory "instructions" are one thing....reality, on any given day, or month, or year could be something completely different. Also agree on his point about the "revisionist history" practiced sometimes.

I've regularly seen original paint '70 motors (big and small) with a painted cap and tube.

I have access to a low mileage '72 W30 and I recall it has a bare tube and cap but I will double check it just to make sure.

This stuff isn't perfectly "cut and dried" no matter how hard you wish it was. There were surely variations and deviations some of the time or changes in the production process that lead to one model possibly not getting painted tubes and caps, etc.

GM didn't care if something slipped out the door unpainted...what were they going to do, fire the engine painter for saving some paint?? Lots of parts on top of the motor survive pretty well without paint anyway....there's no lack of heat to keep the parts dry and if that's not enough there's a constant stream of air blowing across the part to drive off any moisture (the fan in front of the motor).

 

Steven, I'm confused. Last night when I posted I didn't have my Engine Assembly Manual in front of me, so I took your word about the cap not being shown on the paint page. But now I've taken a look at the manual, which I'm pretty sure is the exact same manual you have, and clear as day it shows the cap on top of the fill tube on page 24, the page with painting instructions. The fill tube and cap were installed back on page 22. (The pages in the manual generally show the sequence in which the engine was assembled.)

I can't argue with those who say their car left the factory with the cap unpainted. But I maintain that the unmolested 1970 engines I've seen had painted caps. A couple things to keep in mind:
1/ The caps, like many components, likely had a thin layer of oil on them left over from their manufacturer. I doubt that Oldsmobile sprayed down the engines with degreaser before painting. That's why you see many engine components which show signs of original paint but most of it's flaked off.
2/ Many of these caps were replaced over the years, and the replacements were not painted. The original 1970 oil fill cap -- at least for the Lansing plant -- looks exactly like what you see in the assembly manual and chassis service manual. There were several later styles of caps sold by GM as replacements.

I guess it is possible that the factory changed their process part way through the model year. I doubt the engine was filled with oil until just before it was tested for the first time. I can just picture the guys at the oil-fill station on the line saying to their boss, "Hey, we could save money if we didn't have to remove this stupid cap before filling the engine. Why don't we tell the guys earlier down the line to not install them. We'll install the caps after filling with oil."

 

Doh, I was going by memory, you're right, so I must have been thinking that the cap not being painted were incorrect. Mine was painted but knowing it was a 25 year old car before I got it who knows. My car seemed like it was never a part - though as I worked on it, it was obviously painted at least two times over the years.

 

On my car the tube was painted, the cap was not. Could it have something to do with, where the car was biult? My car was built in Lansing. When I bought my car it had 29,000 miles on it and was almost 3 years old.