stevebo-(Moderator) 8,351 #1 Posted September 4, 2019 This is Brennanbo Stevebo's son i'm having login problems, anyway, i'm building a rat rod out of a c101 with 14 hp and 8 speed rear end. I'm running a hydro engine pulley and looking for opinions on the smallest trans pulley I can run. I'm looking to speed up as much as possible. I am thinking 3" at biggest. Does anybody have the id of the shaft and key size? Any links online to a pulley that is 3" or smaller that would fit? 1 Share this post Link to post Share on other sites
ebinmaine 68,365 #2 Posted September 4, 2019 I ordered an engine and transmission pulley off of eBay a year or so ago when I was trying to get the mongrel 1267 to drive right. There may be more than one shaft size available for eight speeds throughout the years so you probably should measure yours to be very sure. You should have decent luck finding a pulley as small as 2 or 2.5 inch. Keep in mind when you go to install all this the belt guard is also your belt guide and that may have to be modified a little bit like I did to mine. Love to see pics of what you're up to. Definitely sounds interesting. 1 Share this post Link to post Share on other sites
SALTYWRIGHT 859 #3 Posted September 4, 2019 STEVE IF YOU GO SMALLER THAN 3 INCHES THE BELT WILL SLIP. MY RAT ROD HAD A JACK SHAFT SO I WAS ABLE TO CHANGE PULLEYS TO ANY SIZE. RUSS 2 Share this post Link to post Share on other sites
wallfish 17,080 #4 Posted September 4, 2019 (edited) Hey Brennan, you can get steel pulleys at tractor supply that go pretty small. The ID is 5/8". Or get a cast pulley here https://www.surpluscenter.com/Power-Transmission/Pulleys/Finished-Bore-Pulleys/2-45-OD-5-8-Bore-1-Groove-Pulley-1-BK24-B.axd Do not use any pot metal pulleys. Just send me your dad's credit card # and I'll order them for you 46 minutes ago, stevebo said: I'm looking to speed up as much as possible. Funny. As much as possible would need the use of a jack shaft between the engine and transmission. Basically the jack shaft will need 2 pulleys, One is a smaller pulley which comes from the engine, the other is large and goes to the trans and the trans pulley is still smaller. You can get the pillow block bearings at the link posted above along with V belts and more. When speeding up the trans that much use motor oil instead of gear oil in the trans. Adding a idler pulley near the trans pulley to force the belt to go around the drive pulley as much as possible helps keep belt slipping to a minimum. Let me know if you want a drawing. Don't forget to modify the steering and certainly do not use WH tie rods. Edited September 4, 2019 by wallfish 4 2 Share this post Link to post Share on other sites
Pullstart 63,096 #5 Posted September 4, 2019 @stevebo @Brennanbo we’ll need pictures of this Rat Horse! 2 1 Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #6 Posted September 4, 2019 Here are a few pics as of now. 3 5 Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #7 Posted September 4, 2019 38 minutes ago, wallfish said: Hey Brennan, you can get steel pulleys at tractor supply that go pretty small. The ID is 5/8". Or get a cast pulley here https://www.surpluscenter.com/Power-Transmission/Pulleys/Finished-Bore-Pulleys/2-45-OD-5-8-Bore-1-Groove-Pulley-1-BK24-B.axd Do not use any pot metal pulleys. Just send me your dad's credit card # and I'll order them for you Funny. As much as possible would need the use of a jack shaft between the engine and transmission. Basically the jack shaft will need 2 pulleys, One is a smaller pulley which comes from the engine, the other is large and goes to the trans and the trans pulley is still smaller. You can get the pillow block bearings at the link posted above along with V belts and more. When speeding up the trans that much use motor oil instead of gear oil in the trans. Adding a idler pulley near the trans pulley to force the belt to go around the drive pulley as much as possible helps keep belt slipping to a minimum. Let me know if you want a drawing. Don't forget to modify the steering and certainly do not use WH tie rods. John, Steve here...what is the size of the key? The tractor supply Pulley had too wide of a keyway. They would fit a 3 speed tranny key but the 8 speeds are smaller Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #8 Posted September 4, 2019 Share this post Link to post Share on other sites
ebinmaine 68,365 #9 Posted September 4, 2019 That tractor has a nice downward tilt. Did you folks flip the axle? Share this post Link to post Share on other sites
wallfish 17,080 #10 Posted September 4, 2019 (edited) 26 minutes ago, stevebo said: Steve here...what is the size of the key? I don't remember but you can file down a larger key for the pulley size to fit in the trans shaft. Think I used a high profile woodruff key and filed it to fit https://www.mcmaster.com/woodruff-keys Edited September 4, 2019 by wallfish 2 Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #11 Posted September 5, 2019 45 minutes ago, ebinmaine said: That tractor has a nice downward tilt. Did you folks flip the axle? Sure did 1 1 Share this post Link to post Share on other sites
953 nut 55,786 #12 Posted September 5, 2019 Hope those front spindles are secured by more than a snap ring! Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #13 Posted September 5, 2019 22 minutes ago, 953 nut said: Hope those front spindles are secured by more than a snap ring! I took the spindles out and I drilled a hole the size of a cotter pin and then I put the biggest cotter pin I could find in and then I flipped the axle 1 Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #14 Posted September 5, 2019 27 minutes ago, 953 nut said: Hope those front spindles are secured by more than a snap ring! Got that covered!! Drilled and pinned 1 1 Share this post Link to post Share on other sites
SylvanLakeWH 25,949 #15 Posted September 5, 2019 13 minutes ago, stevebo said: Got that covered!! Drilled and pinned Very cool so far! Could you post a few pics of how you did that? Doing a build now (C-85, 95, 105...)and giving some thought to flipping axle and lower profile tires... Share this post Link to post Share on other sites
stevebo-(Moderator) 8,351 #16 Posted September 5, 2019 11 minutes ago, SylvanLakeWH said: Very cool so far! Could you post a few pics of how you did that? Doing a build now (C-85, 95, 105...)and giving some thought to flipping axle and lower profile tires... I will. Need to get some pictures. I just drilled and installed cotter pins. 1 Share this post Link to post Share on other sites
Ed Kennell 38,669 #17 Posted September 5, 2019 More food for thought. Frame flipped and second frame added under the flipped frame. The flipped top frame is cut out and the engine is mounted on the right side up lower frame rails. Front axle is on top of the flipped top frame. Custom midmounted clutch with hand and foot control. If required, belt tension can be increased with the hand lever. Belt support pins to replace belt guard support. Fixed idler pully added to push the belt down to increase the contact on the tranny pulley. I bought my smaller tranny pulley from HF, but I think it is 4". 3 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,096 #18 Posted September 5, 2019 The 8-speed pulley key 937221 is a #6 Woodruff 5/32" x 5/8" Garry 1 Share this post Link to post Share on other sites
littleredrider 409 #19 Posted September 7, 2019 I don't remember the sizes, but back when I had my L/R I swapped an 8-speed into it, and used like a 2 or 2 1/2". Belt sure didn't slip lol, if not careful it would do a wheelie..... Share this post Link to post Share on other sites
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