Why Is My '39 Engine Black?

[JRHaelig]

As I begin a weather-slowed scrub down of my '39 Business Coupe I have found that the engine is black instead of grey.

 

The serial number is a year appropriate number, and I learned that factory replacement engines were black, but I don't see any "R" for replacement stamped on it.

 

I also thought a previous owner just painted it, but the decal remnants are on top of the black and there is no gray apparent on any layers flaking off.

 

Was the "R" not always present on the replacement engines?

[Pete Phillips]

I see evidence of gray engine paint in your photo. Gray is the proper color for '39, and black is the primer or under-color.

It's also possible that your engine was an early dealer replacement engine before Buick started up the (R) engine replacement stamp use, which began during World War Two when they weren't selling new cars.

But your valve cover definitely had gray paint at one time, according to what I see in the photo.

Pete Phillips, BCA #7338

[Glassesguy]

Agree with Pete on engine color and black primer/undercolor. My original 39 Special engine valve cover and pushrod cover have paint acting in the same way. Same has been true with other 37 to 41 Buicks I have worked on over the last 43 years. Recently I used parts cleaner solvent to remove a bunch of old gunk from a 38 engine pushrod cover. Same result. I find it interesting,though, that the black paint on these sheet metal parts is smooth and shiny. One would expect the finish to be dull. I have no doubt these sheet metal parts were primed at the stamping plant before being sent to the engine assembly area where they were bolted to the engine and painted as a unit. Your engine does not appear to be a replacement unit. If the oil dipstick enters the crankcase at its junction with the oil pan below the distributor, you can be certain it is a correct block for your 39. The dipstick was changed to a location at the rear of the engine above the starter for 1940 and later blocks.