Hi all, I have a Fiat AD7C bulldozer with a blown engine, and I have decided to go down the route of repowering. Not the easiest, but either that (due to engine design flaws and failure) or scrap it, which I am loathe to do. I am putting a Kubota engine in, and due to the position of the water pump (which is lower than the original engine) I am unable to fit the fan onto the water pump, as the fan's arc will not allow coupling of the front-mounted hydraulic pump. The original fan is a 20" diameter steel pusher fan, and I am looking at putting a couple of 10" fans side by side onto the radiator. Is there any reason why an electric fan system wouldn't work? This engine is a bit longer then the original so space at the front is at a premium as well. Dozer weighs around 9 tons, angle blade and rippers. Original engine 80hp 5.4 litre 4 cylinder. Replacement 120hp 5.8 litre 5 cylinder. Will definitely be turning the fuel down to match the original, I would have gone 4 cylinder however I was extremely limited in engine options due to design as the seam has to be around the crankshaft centreline to fit into the sump (only options were Kubota, Fiat and David Brown), and the largest 4cyl would have been too small, better to go bigger, less stress on the engine. Thanks in advance for your input.
My only thought is how much hp did it take to turn the original fan and how much power do the electric fans have? If they're considerably less, you're probably gonna have trouble. Interesting project, though.
Just a thought. If you made a mounting bracket for the the fan so it's in the correct position then use a serpentine belt to drive the waterpump,fan and alternator. Would you have enough room to do this? From what I've been told electric fan motors don't tolerate dust.
FWIW My Fiat Allis 12-g loader had qty (2) fans shaft driven in the back....long shaft. Just sayin'
Thanks for that - good point about the dust. I wouldn't be able to nor does it have the room to add an accessory pulley with a fan - also it is setup with twin A section V belts. The water pump sits 100mm lower - if I shortened the fan blades a bit it may clear - you can see the blade in the 3rd photo (marked orange) but would not be on centre with the radiator. The engine is on wooden blocks that are the right height, before I make up the steel plates to bolt it onto the sump. The main issue I have had is that the oil pump will not let it clear the sump - the original pump was driven off the timing gears - this engine's pump is skew driven off the camshaft. We will be using a hydraulic pump off the timing gears with a higher oil flow. The bulldozer is at the neighbours, and we brought everything from the clutch housing forward, so it can all be fabricated at home, then taken over and bolted in.
Only thing I can tell you is that you will need to have a lot of alternator to be able to run fans to cool it. There was a whole fleet of Cat D7R Dozers at Syncrude that had cab mounted air cooling fans that ran off an extra large 24 Volt alternator to keep the fans going. The rads were above the cab with the coolant being pushed up there by the engine. Some simple math : A 10 inch pipe is 1/4 the volume of a 20 inch pipe. Would be the same with your cooling fans, will not be enough with just two 10 inch ones. If you could push coolant to a large roof top unit with hoses up to it and lots of alternator to power it, it would work, but engine would have to run fast enough to keep the alternator at high output. Very hard to re-engineer something like you are about to do. Simon C
Thank you for that - will be calculating cooling area etc to see what is required, that is a good point re two 10". As far as re-engineering I am doing it partially to take my engineering to the next level, and to increase what I am able to do. It will be getting a different alternator - the engine being 12v and the dozer being 24v, it will be an upgraded ampage at any rate.
Another way is to use hydraulic driven fans, a number of machines use them but you'll have to know the flow requirements in order to get the fan speed. I had a Haldec fan cooling a hydraulic radiator mounted on a limb razier that worked well.
Well, repowering with a cylinder more is always a must... This machines as many others came with a crank belt driven fan for a reason, and the reson is heavy duty building. In my opinion u either go crank driven or hydraulic driven. Considerations, what is your rad pack cooling? just engine coolant ? or TXM oil and Hydraulics? climate? machine was assembled for 50ºC to -20 or so environment temp... u can also play that. If it was my project i would build a Suport for Fan spindle and kept it crank driven, after the assle of swapping a motor , no reason no to spend a couple more in puleys. HYD driven fan is the next aceptable, basically besides complexity it add a lot of cash to the system, as u need a dedicated pump and motor to match speed , unless u able to fab your own controler based on cooling needs, in that case u can use main hydraulics pump. New equipment, many use hyd driven fans , with speed on demand... but that need a lot of electronics The JD4045 engines are not available in your region? or perkins 1000?
Was the original (OEM) motor a Fiat 8045 four-cylinder 3.7 litre (223.94 ci) ?
Are there other water pumps available for that engine that would raise the fan up?
I would shorten the blades of the engine driven fan, before I would go electric. I don't think it would hurt at all, the engine driven one- being off center of the radiator. We run electric cooling fans on some hydraulic coolers, and we are lucky to get more than 2 years of run time before they go bad. If it has a shroud, you can trim it if you need to.
What is with the spline in the front of the damper/balancer/ pulley? I never liked driving a pump off the front of the crankshaft, it changes the tune so to say and bad things can happen to the pump drive as well.
Well, the largest 4 cylinder was a bit small displacement! I don't disagree with keeping the crank driven, if I can I will. I really like hydraulics, but hydraulic really is too sophisticated (and expensive) for an old machine like this, and if I used the main pump, it would likely make the fan stop working when the hydraulics are being used (correct me if I'm wrong, whether someone has a diagram for how it would work on a open centre hyd system). Our local tractor wrecker has a large selection of tractors he is wrecking (over 10 acres) and I spent several hours going over every make and model available, and due to the limitations where it needs to bolt onto the sump, there aren't many options. I did seriously consider the JD 4045, there are plenty around, but that would have involved a complete redesigning of the clutch housing/sump, so had to leave it. The motor here is about ideal, it is 4" longer then the original, but no 6cyl would fit, and this did. There is no room for more pulleys. Radiator is only for the engine coolant. There is a small cooler for the main clutch oil. Engine will be only 80-90hp, and the radiator core is 550x600mm. Thank you
That's the main hydraulic pump drive shaft, and what it ran originally
Unsure, there is a water gallery that it sits under on the cylinder head, which would restrict modifying that, not a bad idea though
No, that was before they came out with Fiat or Iveco engines, this had a OM CO 130 that was 5.4 litres. There were plenty of those 3.7L, and a 3.9L (that 3.9 was my best 4cyl option) engines at the wreckers, but they would not produce the needed torque.
I think that is a pretty good idea and possibly doable, and probably a whole lot less than going electrical. Simon C
Well, I´m not fan of 4 cyl´s unless they´re CAT3304, but that is another type of beast. I can´t see what is the problem for the fan... just build a suport for a bearing and fan spindle, in the right longitudinal alignment, also u can align it with the water pump puley , in the end u just need a longer belt... U can also build a closed loop hyd system for the fan... but u´ll have to hook the fan spindle in the right alignment. Regards
I agree, and if I can I will. I too thought that it was doable until I test fitted the radiator, and found that the water pump will be just about, if not, touching the core... The answer will be to move the front pump support forward 4-6". Then I will be able to add another pulley onto the crank (there was one there before but had to be removed). I'll see what room there is for making and mounting a spindle above the water pump.