motor to drive shaft alignment (7117)

[bpg]

Hi,I was wondering how you know if you have good alignment with your motor to the drive shaft? I am going to be installing a kohler magnum in a 1979 7117. Before I do I thought I would ask. Where the KTs simular in dimensions? THANKS

[JR]

All I can tell you is that I just put a Briggs 18hp twin in my 416, and the crank centerline is about 1/2" higher than the original Kohler single. I have no vibration issues at all, and I even had to cut and splice my driveshaft to shorten it about 1.25". The crankshaft and the input shaft on the BGB don't have to be in line with each other, but they do have to be in parallel to each other. As long as you mount the engine flat on the mounting plate (no shimming on either front or back) and you don't move the mounting plate, you should be fine. Just make sure that if you need to drill new mounting holes, be very accurate in laying out the new locations so that the motor stays square in the chassis.

[Ronald Hribar]

I just got a 20hp Magnum mounted in my 7117, everything from the KT-7 mounted on new motor. Motor mounts line up perfectly.

[Al]

Hi, The Magnums are KTs with a different flywheel and cooling fan, cylinder heads with redesigned fins to cool better, electronic igniton, redesigned pistons and rods and some minor oiling changes. Basically the same engine as far as dimensions etc. Al Eden

[maxtorman1234]

quote:

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Originally posted by JR
All I can tell you is that I just put a Briggs 18hp twin in my 416, and the crank centerline is about 1/2" higher than the original Kohler single. I have no vibration issues at all, and I even had to cut and splice my driveshaft to shorten it about 1.25". The crankshaft and the input shaft on the BGB don't have to be in line with each other, but they do have to be in parallel to each other. As long as you mount the engine flat on the mounting plate (no shimming on either front or back) and you don't move the mounting plate, you should be fine. Just make sure that if you need to drill new mounting holes, be very accurate in laying out the new locations so that the motor stays square in the chassis.

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I'd sure want my driveshaft in line. Are you using the driveshaft with flex discs? I'd think it'd be hard on them, but ive never tried it.

[Chris727]

quote:

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Originally posted by maxtorman1234

quote:

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Originally posted by JR
All I can tell you is that I just put a Briggs 18hp twin in my 416, and the crank centerline is about 1/2" higher than the original Kohler single. I have no vibration issues at all, and I even had to cut and splice my driveshaft to shorten it about 1.25". The crankshaft and the input shaft on the BGB don't have to be in line with each other, but they do have to be in parallel to each other. As long as you mount the engine flat on the mounting plate (no shimming on either front or back) and you don't move the mounting plate, you should be fine. Just make sure that if you need to drill new mounting holes, be very accurate in laying out the new locations so that the motor stays square in the chassis.

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I'd sure want my driveshaft in line. Are you using the driveshaft with flex discs? I'd think it'd be hard on them, but ive never tried it.

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I agree. Sounds like if its a 1/2 inch higher it will do some damage, possibly both to the engine and to the BGB input shaft and bearings. I would think somehow you would need to lower the engine 1/2 inch.

[Ronald Hribar]

In this case he is replacing a Kohler twin with a kohler twin. And They have same dimensations. It is not a Briggs and it is not a single cylinder. Same engine different name. It is a direct bolt in. Biggest thing to watch out for. Is different type of ignion. I recommend Al Eden for this.

[JR]

Yes, I'm using the flex discs in exactly the same configuration as original. As far as that 1/2" of misalignment is concerned, over the near two foot span of the driveshaft, I figure it can't be more than a few degrees, likely less than five. If the bearings in the BGB can't handle the small amount of sideload that 3-4 degrees might cause, then they'd have to be pretty poor quality. Same with the ball bearings on the crank in that Briggs I.C. engine. So, no I'm not really concerned. As long as the lubricants in both are kept clean and full, I don't expect any problems. But FWIW, I have quite a bit of experience with this sort of thing. I have degrees in both machine tool and industrial maintenance, and have worked in both the maintenance and lawn equipment fields for most of my life, as well as having experience in a tool and die shop, building tooling and machinery. Then again, I could be all wrong.....I guess time will tell.

[HubbardRA]

JR, I totally agree with you. I have posted the same thing on the site several times. I have a 61 Wards that has spent about 15 of the 20 years that I've owned it, as a pulling tractor. I have had three different engines on it. Same flex disks the whole time. Crankshafts at differing heights. One was nearly 3/4 higher than stock. No problems with disks or any bearings. It came with a B/S 7 Hp and now has a 14 Hp Kohler. I can say for a fact that if you are less than 3/4 inch out of line and keep the shaft of the engine parallel with the tranny shaft, there shouldn't be a problem, at least within the next 10 to 15 years. My tractor had the old "rattle" joints, but I put in a set of used flex disks when I first set it up. I also made the flywheel adapter by using longer bolts and 3/8 pipe spacers. I am running homemade adapters on three tractors currently and have never had any type of driveshaft problems. Nothing magical about hooking up a driveshaft, if you understand how they work. I just caution others to be sure and loosen the rear collar (driveshaft mount) on the tranny and let it move when the bolts at the other end are tightened. This makes sure that the disks are not pulled into tension. This can contribute to failure. They are designed for torsion, not tension.

[JohnFornaro]

Guys: Let me ask this question. It was stated above, that as long as the engine shaft, and BGB shaft are parallel, it doesn't matter (within at least 1/2") whether or not they align. So the question is this: is the angle between the mounting plates and crank shaft the same on both the Kohler and Briggs engines? I would think that in all cases, the crank shaft would be parallel to the mounting plate of the engine, and any desired angle would be accomodated in the angle of the mounting plate of the tractor. If so, then if all the other dimensions are ok, and the crankshaft is no more than 1/2" (someone comment on this dimension) higher or lower than the original engine, one can freely interchange Briggs and Kohlers. Of course, driveshaft length must be modified as required.

[HubbardRA]

John, Brand doesn't matter. The mounts on the bottom of the engine are parallel with the crank on all of them, unless it is a totally special configuration. I have an AC 716H that came with a 16 Kohler, but now has a B/S 10 Hp in it. I have a 61 Wards (Simp 700) that came with a 7 Hp B/S and now has a 14 Kohler in it. I have an AC 7XX chassis that came with a Kohler and now has a 13 Hp B/S in it, so I call it a 713S. I have also had to make spacers for all of them to hook the driveshaft to the engine. All of them run smooth and I have never had a bearing or flexplate problem with any of them. When I said the shafts must stay parallel, I was referring to the comments that I have heard before that people wanted to put spacers under the front of the engine so that the crankshaft will point toward the BGB. This can cause a vibration. A U-joint or a flex plate, when compensating for an angle will create a pulsation in the driveshaft. If the joint on the other end of the driveshaft is sitting at the same angle, but opposite direction, it will take all of the driveshaft pulsation out. This is why the shafts must be parallel, so the angles are always equal and opposite.

[JohnFornaro]

Rod: Thanks. It only made sense to me intuitively that the crankshaft and engine mounting plate should always be parallel. So, from my viewpoint, I can repower my 7116 with anything that fits. The Kohler Commands require the frame to be cut, as in my newer Sovereign. But other engines, depending on their dimensions may fit without frame cutting..... Then I have to deal with ignition systems, and driveshaft length, and mounting plate hole spacings & height. So are these the key issues with repowers? Is there another thread which discusses ignition systems? Thanks

[HubbardRA]

Those are the problems. I mounted a Cub Cadet engine in my 61 Wards for a while. I had to make engine mounts because the Cub engines do not have a flat bottom and are made to go down between the frame rails. The bolt pattern on the flywheel was different, so I made a flat plate with holes for both the Cub pattern and the Simplicity pattern. I put two long bolts thru the holes for the driveshaft, then bolted the plate to the engine. I could use a thin open-end wrench to hold the heads of the driveshaft bolts to tighten up the assembly. I have made spacers out of tubing, and I have used a stack of washers for spacers, to hook up driveshafts. Just be sure to loosen the set screws on the rear driveshaft collar so that it can move while tightening up the front end, to prevent the flexplates from being put into tension. Fore/aft tension on the flexplates can cause failure. Ignitions are either magneto or battery ignition. Most Simplicities were magneto ignition, many AC tractors with Kohlers were battery ignition. The ignition switches are interchangeable between the two types and still available, if you need to change to the other type. There are also a couple ways to hook the ignitions up without changing the switch. Throttle cable hookup can sometimes be a pain. I have made several types of hook-ups, and modified some others just to get the throttle to work properly. Fuel line routing can also be a pain sometimes. If I can be of help, PM me with your questions. By-the-way, here is a picture of my 61 Wards puller with a 12 Hp Kohler from a Cub Cadet mounted in it. This is the one with the homemade engine mounts and the driveshaft adapter plate. It withstood the rigors of tractor pulling with no problems. Pardon the way the picture looks. I had to drop it to 16 colors to get it to upload to the server.

[BLT]

The Simplicity driveshaft set up with its discs will take lateral movement (back and forth) to accomodate the engine crankshaft thrust. They will handle by design almost no angularity as you can't have both like you do with a universal joint and driveshaft. That is why it is important to keep everything losse when you mount an engine and roll the engine over a few times. This will help center everything up in a relaxed state and then you can tighten things up.