bellevillerod 834 #1 Posted April 10, 2020 So somebody school me on the need for the thrust bearing. I am somewhat able to rebuild these small engines and trying to understand this. What purpose do they serve? I get that they stop the crank from rubbing against the small collar on the end sleeve bearing. So how does the use of the electric clutch stop that? The fact that it's mounted against the engine is to carry the pull/weight of the belt? With the conversion i'm trying to do I notice that the crankshaft is longer than most others. If I was to machine a plate, bore it out to carry a ball bearing and mount it to the engine over the crankshaft. would that work? Share this post Link to post Share on other sites
ebinmaine 67,268 #2 Posted April 10, 2020 I don't have all the information you're looking for but I'm curious to see what the answer is so I'm going to follow along.. Share this post Link to post Share on other sites
bellevillerod 834 #3 Posted April 10, 2020 (edited) 16 minutes ago, ebinmaine said: I don't have all the information you're looking for but I'm curious to see what the answer is so I'm going to follow along.. I know there is someone here that can answer my question for me. Problem with the longer crank is the mounting of the electric clutch. All 3 that I have require a shorter crank shaft to make it work. I guess I could make some standoffs to take up the space. But really would like to get away from the electric pto if possible. Edited April 10, 2020 by bellevillerod 2 Share this post Link to post Share on other sites
rayshorses 102 #4 Posted April 10, 2020 The manual clutch has a plate mounted to the crankshaft and the belt pulley is pressed against it by the linkage. the linkage is mounted to the block , so when you engage the pto it puts alot of side thrust on the crankshaft. Without the thrust bearing it would probably push out through the other side . The electric clutch is simply bolted to the block and engages with internal magnets , it produces no side thrust. The manual pto is much wider than the electric one so it needs a longer shaft. Not sure how you could make an external thrust bearing that would be reliable. 5 Share this post Link to post Share on other sites
pfrederi 17,663 #5 Posted April 10, 2020 You are on the right track. Pulleys exert a thrust perpendicular to the crankshaft. That is why a long (1" or so) sleeves bearing on each end of the crankshaft can handle the stress, they have small lips on the ends that can deal with minor side to side movement.. WH manual PTOs push in on the end of the crankshaft. those little flanges on sleeve bearings can't handle it. K series Kohlers used ball bearings not sleeve bearings on the crank. They can handle the end loading, the balls transfer the load to the sides of the race which is a lot bigger than the small lip on the sleeve bearings. At some point WH used B&S engines that didn't have ball bearings on the crank. to accommodate the end loading they put a steel plate over the crankshaft that was against the engine housing/block and was notched against a pin so it wouldn't rotate...Steel plate needed as block were aluminum alloy like your M18. Next came ball bearing then the manual PTO. The bearing stopped the end loading from going against the sleeve bearing in the engine. When I stops snowing I will get you the part number for the bearing WH used. the plate you could easily fabricate.. issue is will there be enough crank left for your manual PTO.... 3 1 Share this post Link to post Share on other sites
bellevillerod 834 #6 Posted April 10, 2020 There is quite a bit sticking out. Thanks for the explanations, I was thinking it was pulling on the crank not pushing. I now understand the problem I'm facing. Much easier to engineer a solution when you understand the problem. anxiously awaiting that part number. Thank you any other knowledge on this I am willing to listen. Stuck around the house, Mi closed my plant for I guess another month. I'm going crazy, been working 7/12's for so long I don't know what to do. Wife is looking like a long tailed cat in a room full of mouse traps. She's afraid I'm gonna start taking the house apart and start fixing it......that never ends well... 1 Share this post Link to post Share on other sites
pfrederi 17,663 #7 Posted April 10, 2020 Looks like you have more than enough room on the crankshaft ...you may have to use a thick plate or some spacers. sorry still snow showers and high winds. Will get bearing # tomorrow... Share this post Link to post Share on other sites
peter lena 8,580 #8 Posted April 11, 2020 agree with the insight above , i would also detail the lubrication needed, using a high temp 550 drop rate grease to insure its life and smooth running , lucas , red and tacky and the heavy duty grease , will cover that , pete 1 Share this post Link to post Share on other sites
pfrederi 17,663 #9 Posted April 11, 2020 Probably more than you want to know but here we go. WH used the flat plate I mentioned on 1100 specials. They also used a thrust washer on C-111 and C-165 twins. The plate 108074 is NLA the thrust washer 106498 is still available but pricey. The used the same bearing in both instances 106499 Which is a Pacamor 6007RS. 1 1 Share this post Link to post Share on other sites
bellevillerod 834 #10 Posted April 11, 2020 Great now I have a direction to go. The plate is a piece of cake to machine, just have to figure out the dimensions. That should not be too hard to do. I will have to locate a good pic/diagram of the assembly of the thrust washer an bearing. The thrust washer looks like it would be pretty easy to machine up also. Will of course have to buy the first one then measure it up. After that I will make up a 1/2 dozen or so. Down the road someone else, if all goes well may want to do the same thing. Good thing is that I can use this as is on some of my other tractors. My old Sears SS16's an SS18's use a different type of pto. It should bolt right into those. Thank you for all your Help!! Going to hook the gas tank up tomorrow and see how she runs. 1 Share this post Link to post Share on other sites
