the COMPLETE guide to the Farmall MD, including how the starting system works!

hi i'm pete and welcome to just a few acres farm in this video we're going to take an in-depth look at the farm all md and what makes this tractor so cool and unique is that it starts on gasoline and then after it warms up it runs on diesel and this is quite different from other systems that were used back in the day when this tractor was made manufacturers like john deere and caterpillar used pony motors which were small gas engines that you would start and get going and use them to turn the diesel engine and then when the diesel engine started turning compression would warm up the engine and it would be turning fast enough from the pony engine to get it going but international went a different way and combined a gasoline engine and a diesel engine in the same engine which is pretty amazing in this video we're going to take a look at this tractor stem to stern and i'm going to focus on the general history of this tractor the history of this tractor on our farm the specifications all the pieces and parts of the tractor including a focus on exactly how the gas dart diesel system worked the serial number for this tractor is on the bell housing and it is fdbk which is the model prefix and the serial number is 240953 that makes it a 1950 model my dad bought this tractor in 1983 and he paid 2100 for it it ran well when he bought it and while we owned it we haven't really done anything to it he used it for farming from when he bought it until about 1988 when he quit raising beef cattle and in that time it did pretty much everything on the farm it was our only tractor it pulled the three bottom plow it pulled a harrow at planted corn it ran a nine foot hay vine that baled hay and we had a small new holland baler with its own wisconsin air cooled engine on it and did everything after dad quit farming he pulled the tractor into the barn and didn't get much use after that after 1988 but in 1996 hillary and i moved back to the farm and i used this tractor quite a bit pulling wagons around when we were renovating the house it always started hard especially when it was below about 40 degrees you'd have to crank and crank to get the gas side running and one day i went to start it and it wouldn't start cranking crank wouldn't start we towed it down the road still wouldn't start so we pulled it into the barn and that was probably around the year 2000 and it just sat there ever since when i parked it i hadn't really started restoring tractors yet and about five years later i got the f20 and restored that and i thought well the next project should be this the md so i pulled it into my workshop i pulled the head off of it and then started assessing it for a restoration and i got sidetracked by other things i think i bought some other tractors and got into restoring them so this got put back together put back in the barn and pretty much there it said ever since i've had a lot of interest from youtube viewers on getting this tractor running and i think that's what i'm going to be doing this winter is pulling it in and i think that probably it needs the head gone through i need to send that to the machine shop it needs new piston rings at the very least it's smoked quite a bit it needs new rear main seal the injection pump needs to be freed up the carburetor needs to be gone through so it'll be a fun project when the weather is nasty outside for me to do in my workshop i'm really hoping that that's all it needs because parts for this tractor are hard to find and expensive you're pretty much limited to new old stock parts or custom made parts and it's because only eighteen thousand were made versus about two hundred and seventy thousand regular m's parts are easy to find for regular m's and fairly cheap for this not so much where does this tractor fit in the history of farm alls well the regular m tractor started production in 1939 but the diesel version the md rolled out in 1941 and both tractors were made concurrently until 1952 when they were superseded by the super series the super a the super c the super m etc about 18 000 of these old md's were made during the 11 year production run and this is really kind of too many to make them what tractor collectors consider is rare but compared to regular arms of which they made 270 000 it is quite rare and that's one of the reasons it's so far hard to find parts now because there isn't enough of them to really get after market suppliers to tool up to make those replacement parts and my production numbers don't include all of the m's and diesel ems that were made overseas particularly in britain and actually m's and d slams were made overseas after 1952 and there could be a whole other video on the european and british variants of the m the md was not the first diesel tractor that international harvester made starting in 1934 international came out with the wd-40 which was actually the first diesel tractor that international made and it was a beast it had the same sort of idea as far as gasoline starting and then diesel running but it didn't have a starter so you had to hand crank that monster when international introduced this line of tractors starting with the a and the b and then the h and the m they were revolutionary especially compared to the f series which came right before them and they hired an industrial designer named raymond loewy at this time to design them and i think that their look still holds up today they're really great looking tractors they have an art deco inspired sheet metal design and they're just classic and there's so much iron in these tractors they feel so solid when you drive them different from the kind of spidery look that the f series had the principal market for the md were larger farmers and you have to remember the m was the big horse of the international lineup when it came out this was a big tractor back in those days the only tractor that i know of that international made that was bigger at the time was the w-9 which had a bigger engine and was more of a wheatland tractor but anyway the reason this tractor appealed to larger farmers was because diesel was so much cheaper than gasoline back then back then diesel was half the price of gasoline plus the tractor used a third less fuel total than the gasoline version so when you add all that up it could pay for itself quickly yes this tractor cost about 50 percent more than a regular m did but the fuel savings could pay for itself in less than a year if you were using the tractor a lot now we're going to get into what i consider the meat of this video which is how this tractor starts and runs and to do that i'm going to take the hood off so you can see how everything works all right now that i've got the tractor shirt off we can see what's going on the really cool thing about this tractor is it looks like a gasoline tractor from the left side you've got a carburetor and you've got a magneto and you've got spark plugs but when you go around you look at the right side it looks like a diesel tractor you've got a big honk and injection pump you've got injectors here you've got the fuel filtration system which takes up a good part of the side so this tractor is kind of like a mullet right business in the front pleasure in the back gas on one side diesel on the other when you start the tractor the carburetor is engaged and the magneto is engaged so the tractor is running on gasoline and you run it that way for a few minutes until it warms up and then you switch it over the diesel all you can do on gasoline is idle the tractor there's no throttle control for this carburetor without taking it apart and actually adjusting the butterfly up in here and you can't run the tractor around now it's only meant to do it for a few minutes on gas and then switch to diesel now the magic happens with this tractor via this lever and this lever this is the compression release lever and this is what changes a lot of things in the engine to run on diesel and this is the injection throttle control so when you go to change it over from gas to diesel after it's warmed up you pull on this lever and you pull on this lever both at the same time which engages the injection pump and engages all a bunch of things in the engine that this lever actuates and i'll show you those next now this compression release lever which is forward when you're running in the gasoline position actuates four different things in the engine if you look at the linkage from the lever it runs down under the fuel tank and comes into this assembly right here now from this assembly this lever runs into a rod which goes into the engine and comes up and there's actually a rack that's in the valve cover that opens a third valve in each cylinder so you have the two valves the intake and exhaust valves there's also a third valve per cylinder in this engine and that's the compression valve with the lever in the forward position the compression valves are open and what they do is they expand the combustion chamber in each cylinder so they change the compression of the engine when it's running on gas the compression ratio is about 6.4 to 1 in this engine but when it changes over to diesel and you close that valve and make the combustion area smaller in that chamber then it changes to a 14 to 1 compression ratio suitable for igniting diesel another way to explain it is if you look at this side of the engine here you have the spark plugs these spark plugs are actually in that space that's above the valve that's the compression release valve so when that valve is open there's a chamber that includes the electrode of the spark plug that's exposed and that chamber is what gives the extra area to reduce the compression ratio now the second thing that that lever actuates has to do with the intake manifold that lever rod actuating that also actuates the rack up in the top of the valve cover comes through and ties into the intake manifold and the intake manifold split into two parts so you have this larger one here which is the diesel air intake and then there's this smaller one piggybacked on it that's the gasoline air intake depending on the position of that lever there are two butterfly valves here and here and when the engine is running in the gasoline starting position these butterfly valves are closed so the air from this larger manifold can't get into the cylinders directly instead it's routed down into the carburetor where it's mixed with fuel then it comes back up through this smaller manifold and into the cylinders to burn now when these butterfly valves are opened when you switch it over to diesel then the air flows directly down and comes in through the cylinders because this is a more restricted passage for air to flow in the carburetor is no longer engaged it's probably a little bit hard to see here but here's the actuating rod and it's really hard to see on the camera but there's a rod that goes from the butterfly valve here all the way over to the other end of the manifold to the butterfly valve on the other side the last two things that that lever controls are the magneto and the carburetor that linkage which is up into the air intake manifold here also comes down to the back side of the carburetor and then goes into the carburetor and what it does is when you change to diesel mode it locks the float in the up position closing the needle valve in the carburetor so that no more fuel can flow into the carburetor the other thing that happens is the magneto gets grounded out when it switches over to diesel so the spark plugs don't fire anymore so after the tractor warms up on gas you pull back on the lever you pull up on the throttle when you pull back on the lever it closes those valves increasing the compression ratio it changes the take manifold butterflies on the other side it opens them up so air can directly go into the cylinders it locks the float on the carburetor so that no more gasoline is being burned in the engine and it turns off the magneto by grounding it out the throttle lever turns on the fuel to the injection pump so the injection pump starts pumping fuel into the cylinders and away you go on diesel i always fondly remember the thrill of pulling on these levers and the tractor would be putting along on gasoline when it was warming up and then you'd yank on both these levers and the tractor would roar to life it was such a cool feeling what i tend to forget is how hard it was to get started on gas when it was cool in the first place we'd crank and crank on the engine to get her going hook the battery charger up to it tow it down the road whatever i'm hoping that once i go through this engine i can get it better running so that it'll start easier on gas now when you want to shut the tractor down you would turn it back to the gasoline mode before you shut it down so you push this lever back ahead and turn this lever down and it would start running on gasoline again after you ran it on gasoline for a minute you could shut the tractor off and then you wanted to make sure to take this lever and put it back into the diesel position mainly because those valves those compression release valves should be in the seated position against the head so that they didn't warp as they cooled now let's go into detail on all the different assemblies on the tractor starting with the operators platform the first thing is international harvester vastly improved the operator's platform over the previous f series which were kind of uncomfortable to sit on you sit upright on this tractor your feet are flat on the floorboards the seat could use a backrest but a lot of people were used to these old pan seats the gauges are directly in your line of sight the water temperature and the oil pressure gauge there's clutch on one side independent brakes on the other you have this electrical box right in front of you which contains the ammeter and the controls for the headlights this same box was shared between the a the b the h and the m when they were produced you've got a starter switch to unground or ground the magneto and you've got a choke for the carburetor the engine on this tractor had the same displacement as the regular um 248 cubic inches it's four cylinders three and seven eighths inch bore five and a quarter inch stroke rated rpms was 1450 so it's a slow torquey engine now different from the regular ram this crankshaft has five main bearings it's got a main bearing between each cylinder whereas the regular ram only had three main bearings and that's to beef up the engine to take the extra compression ratio that this engine had to bear at its nebraska tractor test this engine developed 35 horsepower on the belt and 31.5 horsepower on the draw bar its maximum pull was about 4 500 pounds this is a complicated engine and the head is especially complicated because you've got the passageways and the holes for the third valves which made it a really complicated casting maybe that's the reason these heads were prone to cracking it's hard to find them these days without cracking them when dad bought this tractor you can see it has a big crack in the head that runs right down through here and somebody brazed it really well it's never been a problem it's never leaked but it was brazed long before we had it i also found when i started to disassemble the engine that the thermostat here had been removed and i suspect somebody did that in an effort to have cooler coolant running through the head to make it less prone to cracking this tractor originally had magneto ignition they were available with a distributor too and this one's been changed over to function like a distributor somebody mounted a coil up here and ran it into the magneto essentially just making it a distributor when i get into the tractor i plan on repairing the magneto to get it working again and as you can see the carburetor sits right above the distributor cap and so if the carburetor releases leaking right onto live electrical connections i never thought that was a real good idea and a lot of md's you'll see there's a drip pan that actually was factory installed this one doesn't have it to keep fuel from dripping directly onto the spark plug wires this starting carburetor is really unique and was made by international harvester i've never seen a carburetor design like this and the main thing that makes it unique is that the intake and the fuel mixed air are on the same side of the carburetor they're both on the top so you've got fresh air incoming down through here it comes into here it does a u-turn as it's mixed with fuel and then it comes back up and into this intake manifold i've never seen a carburetor that works like this i'm hoping that this carburetor is okay that it just needs a cleaning maybe some new gaskets and seals because parts for these aren't easy to find two other unique things on this side of the engine this engine actually has a dipstick that you unscrew and it is a bulletproof dipstick the regular amps just had the regular oil check petcocks but for some reason the diesel's got this dipstick and it also has an hour meter that's mounted off the distributor drive on a regular m the governor would be here and they didn't usually come with an hour meter but a lot of the md's for some reason came with an hour meter and you read the hours right here on the plate and it is so dirty i can't read them but i think that's cool the injection pump on this tractor is a big honker it was made by international harvester in-house and it's an in-line pump versus the later rotary pumps like the rosemaster pumps that you see on later international tractors these things i hear are a bear to get to work on because parts are hard to find i'm hoping i just need to clean this up maybe partially disassemble it to get it freed up the air cleaner is an oil bath type with an oil reservoir on the bottom and a screen up in here i've explained how these work in previous videos something interesting about oil bath air cleaners they were really efficient they were pretty good at filtering out dust and intake air but what happened is as tractor horsepowers got larger this actually expanded exponentially so that with a big modern tractor you'd practically be carrying a 55 gallon drum on the side of it as an oil bath air cleaner so they fell out of favor for that reason and people started going to paper elements on to the fuel system this tractor has two fuel tanks it's got a really small gasoline starting tank here and a larger diesel tank here the gasoline tank has the usual sediment bowl and the glass is busted off this sediment bulb a sediment bowl here and a fuel line run into the carburetor and then on the diesel side of the tractor you've got fuel line piping coming down from the fuel tank it goes into a pair of filters here you've got a coarser and a finer diesel fuel filter like modern tractors have and then you've got a water trap sediment bowl after those in line and then it's off to the injection pump this tractor has a pressurized cooling system it holds about six and three quarter gallons it is both pressurized and driven by a water pump the water pump is driven off the fan pulley the electrical system on this tractor is 12 volt as opposed to the usual six volt systems other regular ms battery tray under the fuel tank 12 volt starter generator on the other side of the engine and lights which were kind of a new addition for international harvester they're very hard to find on the older f series tractors starting with the letter series tractors there was what's called a lift all hydraulic pump which is a belly pump that was incorporated into the design it's quite common on h's and m's so the belly pump is driven off of the lower transmission counter shaft here which means that whenever you push in the clutch the hydraulic pump stops working it's not live hydraulics originally these tractors were one-way hydraulics which means you only needed a single hose out to your remote cylinder so the hose would pressure the cylinder to raise under pressure but the cylinder retracted under gravity when dad got this tractor he converted it to two-way hydraulics by running a single hose up to a hydraulic valve so that he could get down pressure for things like plowing the transmission on this tractor has five speeds forward and one reverse it has a road gear which is fifth a fast fifth gear the transmission case includes both the transmission up front and then the final drive the differential and bull gears in the back it has a 540 rpm pto and it has a belt pulley up here this belt pulley is missing the pulley but here's the mechanism both the belt pulley and the pto stopped when you push the clutch in this tractor has brake drums on either side of the transmission one here one on the other side this is a cover the drum is inside there's a band that constricts around the drum to stop the tractor there's independent brakes pedals so that you can help steer the tractor by using the brakes independently this tractors rear tires are 14.9 by 38 diameter rear tires the front tires are 6.5 by 16 inch diameter this tractor could come in either the tricycle configuration that you see here or a wide front with an international wide front end they also came with a single front wheel for cultivating in narrow rows as far as hitch goes this was a pulling tractor this was pretty much the only type of hitch you could get from international at the time it's just a simple u-shaped drawbar and it could have a drawbar like this extended off of it which anchors under the bull gear housing in the transmission here international wouldn't come out with its two-point hitches until the mid-50s and the number series tractors so that's my tour of the farmhole md this is a really meaningful tractor to me we used it when i was in high school and i really enjoyed running it with any luck i'll pull it into the garage this winter get her running and we can use it to rake hay and tow wagons next year i hope this video was informative i hope you liked my tour have a great day and i'll see you next time

Channel: Just a Few Acres Farm

Views: 131,111

Keywords: small livestock farm, small farm life, farming, farm, homestead, just a few acres farm, antique tractors, international harvester, farmall md, farmall md history, farmall md gas start system, how to start farmall md, farmall md engine, farmall md walkaround, farmall md features

Id: 7yuHIu1IfPw

Length: 21min 43sec (1303 seconds)

Published: Tue Jul 28 2020