"ccjersey" wrote:

Only hit I get on a search for 9K here on this site is the #12 grader with the D4600 4.25” bore 6 cylinder engine so no connection to the 3 cylinders

The D6100 was the 5.25” bore 3 cylinder that was used in the early Diesel tractors (35 and 40??). I’m not sure on this era of machines exactly when the changeover to the D6600 occurred. But for a long time now, I think most of the D6100 engines have had to be overhauled using the 5.75” bore sleeves and the block modified as needed to fit them.

The D6600 was the 5.75” bore upgraded 3 cylinder and I believe it was first used in the RD6/D6 as well as some of the graders.

Got a couple little JD utility tractors here with a 3 cylinder diesel. One’s a fairly recent (within the last10 years) import from India I think. It’s a really simple tractor without any frills and it shakes pretty badly from the engine. JD has had little 3 cylinder diesels for 40 years or so but I’ve never driven one of the really old ones, just seen them around. We do have one about 15 years old that was a domestic production tractor assembled in Georgia and it seemed to be balanced pretty well. It ran just like any of the other small 4 cylinder tractors, so I know it’s possible to design the engine or tractor or both to run smooth as far as the operator perceives things.

The D6100 was used in the #11 grader 9F prefix. The D6100 was used for about 2-3 years before becoming the D6600 1935-1937.

My 1937 Model 11 is still purring along with the D6600 3 cylinder engine. I bought it from the original owners son and they say it has never been overhauled. ACMOC Chapter 3 has a 3 cylinder D6600 Model 11 grader that sat with the exhaust open for 35 years and we got it running well without pulling the heads. Pony was stuck bad though. I'd say they were a good engine.

interesting feed back y'all...

i've never had a 3 cylinder anything..they were common in snowmobiles at one time(Polaris) and possibly more..maybe some motorcycles and atvs etc...

-i do remember as a young'n....a neighbour had a small tractor, and I ran it for a summer haying......Universal...it was 3 cylinder...i was impressed but knew nothing at the time...just child labour....

Main difference is D6100 is 5 1/4” bore. D6600 is 5 3/4” bore.