I’m doing some prep work for my diesel class tomorrow. The topic will include engine blocks and their use as frame structures. I remember several posts in the past about 8850 engine failures due to the way the engine is mounted to the frame, specifically something about the frame twisting with accessories like dozer blades causing enough block twisting to fail the motor.
I have looked at the JD parts and I do not see any direct attachment of the engine to the frame. However, the engine does not appear to be mounted on rubber mounts either. Can anyone who has or has had one clarify the engine to frame mounting arrangement for me? That is, are the tractor side frames bolted directly to the engine block? It seems to be the case, but I can’t tell from the photos?
Om JD 4wd drives from that era the engine block provided most of the support for the front axle, the side frame bolts solid to the front axle and the engine and clutch housing, the torsional stress from the tractor put too much strain on the blocks, I have an 8650 tractor. I beleive the V-8 mtor used in an 8850 had other problems as well. I’ve always wondered if they would have used stronger side frames and not had so much trouble, I’ve thought about screwing a second side frame against the first to reinforce it, all that would be needed would be longer screws.
It’s really a shame they use the JD 8850 as an example in training, unless it’s to show how bad a tractor can be. The 8850 is on top, when it comes to Deeres. It is a bad tractor. I should add, that I am all green and had an 8450, and I had some problems with the head gasket. The same chassis flex problem.
The side racks were literally just cosmetic, a frame to mount the radiator and the frame to mount the front of the hood so it could hinge up. The engine is mounted on the clutch housing and the front axle is mounted on the engine, so when you put in any amount of torque where the front axle contacted the pivot stops then all the torque was put into the engine block. This was consistent across all 20-30-40-50 series tractors, the engines got a bad rap for being weak and prone to problems when it was the design of the tractor that caused the engine failures.
The 619 became the 10.1 liter engine that was used in the 60-70 series tractors and on that tractor the engine lived very well because it was mounted on the frame rather than the frame. The 955 V8 was used in some construction applications and also held up much better than agricultural applications.