Well John that does bring up an interesting question. I went digging though some of my Cat books and found this... Maybe there is more truth to the Roosevelt argument than I give credit.

It just doesn't sound right, though, Ironman. I can't imagine a company publicly kissing up that much. Having studied a LOT of engine and vehicle manufactorers over the past 40 years, the most likely affliction is "nomenclature schizophrenia." All companies seem to go thru a period when a suit in marketing has a little too much to drink one night and comes up with a "great idea" that has people scratching their heads 80 years down the road.

Look at the product nomenclature evolution. First they had the Spelled Out designations, from day 1 into 1935. Then they divided the line into the gas powered "R" and diesel powered "RD," the "D" being for diesel of course. It's a common sense way to do it. Starting in 1937, realizing 80 percent of the product line was diesel, they rationalized rationalized to "D" because the vast majority of their product line was moving to diesel. Of course some of the product lines overlapped but eventually gas engines were gone and so were the pesky R-series.

Art Rosen is one of my top 10 "Gearhead Heroes," by the way, so if I was going to "wish" and vote my heart about "RD", it would be that. But I live in realville.

John- It's going into Diesel World magazine... about 500K circulation. Been a fulltime freelance writer/book author for 30 years, though I am now semi retired. Can't let you have the story because the magazine will own it when I am done and then it's a copyright issue. Since they usually put the stories online, I can send you the link when they do. Here are links to some of the other Cat work I have done... those that are online anyway.

www.dieselworldmag.com/diesel-tractors/t...-answered-questions/

www.dieselworldmag.com/diesel-engines/the-ships-cat/

www.dieselworldmag.com/diesel-engines/vi...esel-lincoln-welder/

www.dieselworldmag.com/diesel-tractors/t...ttle-caterpillar-d2/

The Diesel 40 with the 5 3/4” bore that was tested at Nebraska was a 5E serial number tractor.

naylorbros wrote:

The Diesel 40 with the 5 3/4” bore that was tested at Nebraska was a 5E serial number tractor.
 

 

 

Which I mentioned above. Both the tests list it as a "Diesel Forty" but was it an RD-6 in reality? Was there a production "gray area" where the Diesel Forty and RD-6 models were blurred? Or was it a labeling mistake made by Nebraska. ?If it was the latter, you'd have thought Cat would've called 'em on it. The theory that floats in my brain is that the RD series wasn't completely rationalized as a model line at the point the tractors were submitted for tests. But yeah, 5E is one of the designations used for the early days of the RD-6. I think this is an important fact to line out and the resources I have available don't do it. Hence, my appealing to the more knowledgeable and better referenced here?

Also, I call your attention again to the differences between test 242 and 243. One is  run at 850 rpm and the other at 1000. Since there are no tests of an "actual" RD-6, I can only go by the official specs, which list 850 rpm. So was the 1000 rpm test an experiment or?????

some might not know the delo range of lube oils were originally developed with caterpillar by standard oil company. and stands for Diesel Engine Lubricating Oil.
chevron the current owners of the delo name have recently grouped all there diesel and heavy equipment oils under that banner.

Yep!

www.dieselworldmag.com/diesel-tractors/t...-answered-questions/

A very interesting article about the development of diesel oils and the need for a one cylinder test engine!!