Gas Start Diesels

[DanMD]

Hello,

I am hoping to hear from you guys who have had a fair amount of experience running one of these tractors who can share real world experiences.

I have a '53 SMD that I have completely overhauled and redone. I've always felt it has a strange twitchy governor action while doing anything other than a moderate to heavy load at which point it runs nice and smooth. It also in turn vibrates the sheet metal a fair amount that is in response to the ratty idle. If you take the muffler off you can really hear it and especially at mid throttle. I've tried different injection pumps and injectors and precups and all with no real change. I do not know anyone around where I live who has one to compare it with so I watch a lot of youtube videos and some sound similar to mine and others sound much smoother. It does seem like the regular MD's in general are the smoother running units and my tractor does have the 450 diesel style open face injectors and I was told they sound different. Anyways I recently bought a regular Farmall M and was really shocked at how much smoother the gas engine is at idle and low load conditions compared to my SMD. The gas M also seems to have way more low RPM power.

I was curious if any of you guys who have experience with both a gas and a gas start diesel can share any comparisons that may shed any light on my observations. I kind of feel it is normal as I have replaced everything at least once and no change. The SMD did pull 57hp on a dyno and the IH mechanic said it sounded great to him. But when I use it on light loads like a brush hog or lightly loaded generator, it isn't very smooth unless at low idle. It always just sounds like the governor is way too sensitive.

Thanks,
Dan

 

[caterpillar guy]

Our MD was smooth as an unbalanced engine can be idling. Once wound up like on a mower or chopper it was smoother than at idle. IT will set there and shake idling like it was one of those old 2 cylinder Deere letter series tractors. As for the newer direct start diesels they run smooth at all speeds and idle smooth too. I say unbalanced yet it probably has been somewhat balanced. I do believe if the money was spent to balance parts better it would idle smoother with less shaking to it. IT would probably need the rods and crank balanced to make the most difference in it. As for the governor It never seemed like it was twitchy as you describe it to be. Have you looked at the throttle lever on the side of the pump and does it have the 2 springs one each way with nuts on them. IF so are they real soft tensioned. As part of it as it could possibly vacillate on the springs some . Just a thought.

 

[Brownie450]

We use our 450D mostly on the auger in the fall. We have it idle at 7 or 8
hundred RPM so it is running smooth. Dad would let it idle at the slowest
RPM he could & then had to take the radiator in to the repair shop to have
the leaks fixed. Shaking of the sheet metal at low RPM is just the nature
of the beast. Idle it up till running smooth, & you won't waste that much
fuel.
Jim

 

[rustred]

i have a few of the tractors and have not noticed any shaking tin. i thought the idled pretty smooth. plus slow idling for any diesel is not the best. plus they need to be idled at a faster idle for 10-15 minutes after hard working for them to cool down. yes them governors need to be set by the manual. you sure u have the valves set to spec.? sure sounds like the governor to me , but u say u tryed other pumps so that should eliminate that. wouldnt hurt to do a compression check , yes i know you said its redone.

 

[DanMD]

i have a few of the tractors and have not noticed any shaking tin. i thought the idled pretty smooth. plus slow idling for any diesel is not the best. plus they need to be idled at a faster idle for 10-15 minutes after hard working for them to cool down. yes them governors need to be set by the manual. you sure u have the valves set to spec.? sure sounds like the governor to me , but u say u tryed other pumps so that should eliminate that. wouldnt hurt to do a compression check , yes i know you said its redone.

I’m almost positive it’s the governor. With the cutout side plate installed, you can watch the torque arm quiver. If I grab the torque arm and hold it still it calms down. Following the pump manual, I installed a MD governor and it made a drastic improvement, but at the cost of lost power. Low idle and high idle are pretty smooth, it’s just mid range that is rough. I guess this why i Asking if this is just normal for these tractors. I would be so helpful if I just had another one to operate for 15 minutes. I do know as soon as I load it down it smooths right out. It acts like an over sensitive governor. And I would call it sheet metal vibration, not shaking.

Thanks dan

 

[rustred]

I am sure u are correct and I agree.

 

[cushman]

I am sure u are correct and I agree.

I do not notice any low load instability in the governor of my 400D nor any sheet metal rattle at idle unless I let it idle at below 550 RPM.