Oliver 70 Engines

molinegb · Sep 27, 2023

Oliver used two or three different motors in 70's. What years were the 5 gear used with mag on right side? Believe spark plugs on opposite side. Later models had
distributor on opposite side and plugs on mag side. What parts are not interchangeble? Gears, block. crankcase? heads pistons crank?

Welding man · Sep 28, 2023

I am no expert on these engines by any means, but I have had 3 of them apart in the last month. I just rebuilt a 3 gear for a friend of mine. His Crank had no counterweights in the center. My 5 gear does. The heads were the same and so was the cam as far as I can tell. Some had 5/16 valve stems, some had 3/8 in stems and springs were different. He needed a connecting rod due to one of his had spun the rod bushing. There are 3 right hand and 3 left hand rods. It takes 2 different rod bearings. I used a rod from a 5 gear to replace his. Governors are different. His had had an overbore kit installed at some point and rings were easy to find. There is a thick and a thin wrist pin bushing. One of my 5 gear motors had flat top pistons, one had dish tops. I won't be using either one. I still have 2 5 gear engines disassembled and one 3 gear complete. I am hoping to have enough parts to build one very good pulling engine.

molinegb · Sep 28, 2023

Heard bearings can be tough to locate. Rings ?

tom upton · Sep 29, 2023

I believe the 5 gear ended sometime in late 38 or early 39. My 38 is a 5 gear and my 39 is a 3. 5 gear mags are on the left side as sitting on tractor. 3 gear engines are on right. Spark plugs are on left side for both 5 and 3 gear engines. The 3 gear engines just had a tube that plug wires go thru to carry them around to the left side. Not sure what parts are not interchangeable.

molinegb · Sep 29, 2023

1940 70 3?

Oliver 70 Engines

molinegb

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tom upton

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