Piston scoring D-21/210/220/7030 engines

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   Thank you, David. Here are two pictures of the current 220 I'm working on. The 1/2" belts are bottomed in their grooves causing fan speed reduction and lower coolant flow which can lead to possible over heating on a warm day at 100% load. The alternator charging at 100% output can also have belt slipping issues. Changing to "B" width belts pretty much solves the slippage problem and especially on 50 year old pulleys. Another problem we have here is someone (not very knowledgeable) in the past has installed a fan spacer that moves the fan forward to within an inch of the radiator. This makes it impossible to work on and air flow is actually reduced, causing more potential engine over heating. This change may have been an effort to combat an over heating engine on a hot day?? One might think moving the fan closer to the radiator core would draw more air thru the radiator, but the reality is that's not the case. Max air flow is achieved when the tips of the fan blades are 50% in and 50% out of the shrouds edge.

Edited by DrAllis - 14 Feb 2026 at 7:20am

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DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 22635	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 14 Feb 2026 at 6:29am
	Thank you, David. Here are two pictures of the current 220 I'm working on. The 1/2" belts are bottomed in their grooves causing fan speed reduction and lower coolant flow which can lead to possible over heating on a warm day at 100% load. The alternator charging at 100% output can also have belt slipping issues. Changing to "B" width belts pretty much solves the slippage problem and especially on 50 year old pulleys. Another problem we have here is someone (not very knowledgeable) in the past has installed a fan spacer that moves the fan forward to within an inch of the radiator. This makes it impossible to work on and air flow is actually reduced, causing more potential engine over heating. This change may have been an effort to combat an over heating engine on a hot day?? One might think moving the fan closer to the radiator core would draw more air thru the radiator, but the reality is that's not the case. Max air flow is achieved when the tips of the fan blades are 50% in and 50% out of the shrouds edge. Edited by DrAllis - 14 Feb 2026 at 7:20am

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AC7060IL Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 19 Aug 2012 Location: central IL Points: 3639	Post Options Post Reply Quote AC7060IL Report Post Thanks(0) Quote Reply Posted: 14 Feb 2026 at 9:29pm
	Yes DrAllis. One fan tip may even have a slight opposite bend to assist that science? A “Centrifugal effect” of airflow is created from rotating fan blades that forces air toward their fan blade tips, where air is then forced along 1” clearance of shroud which allows air to be pushed outward from shroud edges for a more rapid exit. It creates a good constant vacuum where minimal air has no/little chance to recirculate back inward.

Buddy2366 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 14 Jul 2024 Location: ECIL Points: 11	Post Options Post Reply Quote Buddy2366 Report Post Thanks(0) Quote Reply Posted: 6 hours 16 minutes ago at 5:36pm
	Been following this post and learning alot about the 220 tractor/3500 engine. Grew up farming on Allis Chalmers equipment in the 60's-80's. Used to dream as a boy sitting on a dealers lot wishing to someday run a 220. Thank you Dr Allis for your wealth of knowledge. Always wondered why the HP was set on 135, but yet some brochures I have show the 220 pulling an 8bottom on-land plow! With the piston cooling issue, I now understand more why the HP was kept at a minimum. My thoughts on this subject for what they are worth; what was the factory thermostat deg for these tractors? is it water getting too hot or Oil, or a combination of both? Would a more aggressive water pump move more water if one could be designed? How about an Oil pan such as what M & W designed for the JD 4020 with the cooling fins built in? How about a thicker radiator with an extra row of cores. I know a place in Arizona that custom builds about any radiator you can dream up. I know this is all very costly and maybe not even possible, but what does a fresh OH'd engine with minimum hrs cost to rebuild again. A robust 220 snorting 165-180hp with 6-16's would sure make some heads turn at Rantoul, IL in 27! Just my thoughts, so fire away.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 22635	Post Options Post Reply Quote DrAllis Report Post Thanks(1) Quote Reply Posted: 4 hours 58 minutes ago at 6:54pm
	I truly believe that if the piston skirt clearances were left as they were back when the tractor was new (.007" instead of today's .003" to .0035") there wouldn't be this problem. This didn't happen 50 years ago when these tractors were in their hey-day. So, what's changed??? Tighter clearances for number one. Worn out water pump/fan pulley's number two. And 1/2" fan belts that go to the bottom of the pulleys when the belts and pulleys are worn out. This requires constant belt re-tensioning to keep belt slippage from slowing down the fan and the water pump impeller speed. Any extra heat can cause this .003" skirt clearance to get tighter and then there's a problem. A cooler thermostat (180F standard) won't hurt but on a 90 degree day at 100% full load, the temps are still going to be closer to 200 degrees than 160 degrees. As far as the 135 PTO HP rating goes ?? That is what Milwaukee Sales personnel asked for. So, that's what they got. After the D-21 bull gear and axle bearing failures, they sure weren't going to set the new 220 at 160 HP. They hoped the problems at 135 HP would be zero and I think that's what happened.

Buddy2366 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 14 Jul 2024 Location: ECIL Points: 11	Post Options Post Reply Quote Buddy2366 Report Post Thanks(0) Quote Reply Posted: 4 hours 23 minutes ago at 7:29pm
	Do you dare run fully synthetic engine oil in a 3500? How is the engine oil cooled in a 220? Is it possible to run an engine oil cooler in front of the radiator, with a larger radiator to boot? I stand corrected on the custom radiator manufacturing location. Its in Oregon instead of AZ.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 22635	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 4 hours 20 minutes ago at 7:32pm
	The engine already has an oil cooler on it. The engineering goal was to keep oil temps equal to coolant temps as it is a coolant operated type device. I see no problem with synthetic engine oil. Edited by DrAllis - 4 hours 17 minutes ago at 7:35pm

ranger43 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 09 Jun 2019 Location: Huntingburg Points: 167	Post Options Post Reply Quote ranger43 Report Post Thanks(0) Quote Reply Posted: 3 hours 34 minutes ago at 8:18pm
	I have been following this post and I had a scoring issue on my 210 on an in-frame overhaul at around 100 hours. Never ran remotely hot. I did the overall, but spoke to several AC mechanics at the time.... 1997/98 timeframe and they were experiencing similar issues with some overhauls in both AC's and New Hollands. They conlcuded a clearance issue, but thought is was ring gap being too tight. I was/am a very amateur mechanic so I failed to measure ring gap, but never really determined the cause of my failure. I ended up putting in a reman shortblock and never had another issue to this day.