Stigian 1,234 #1 Posted December 12, 2013 Just a quick question Guy's.. How much power can a 8 speed trans handle and how do they cope with a higher revving engine? Share this post Link to post Share on other sites
meadowfield 2,595 #2 Posted December 12, 2013 I would say it is torque that will break the tranny, but if you do run the input shaft faster than 2-3x then you will put more stress on the bearings. Because the gears are straight cut they are stronger, but gave more backlash, and that will generate slightly more cavitation and less lubrication meaning more heat.... Heat is not good on anything mechanical as it accelerates wear. Just my two penneth.......... Using a thinner oil will help with lubrication, but be noisier. I use 10w40 in my C-101 that has an 80mm transmission pulley, so it runs approx 2x the speed of a normal horse. Just what are you thinking? Bike engine? Red line at 16,000rpm. :D Share this post Link to post Share on other sites
Anglo Traction 761 #3 Posted December 12, 2013 Quite a bit of power it seems Ian. Lots of Tranny interest bouncing around at the mo' . Maybe we can start a secret Tranny Rebuild Club at the Shack ?. Here's a link to a recent one that also covers input power - Share this post Link to post Share on other sites
wheeledhorseman 574 #4 Posted December 13, 2013 IMHO agree entirely with Mark about torque being the potential killer here.Probably the weakest point has to be the drive shafts to the rear wheels. The diameter and tempering of them has been designed with a maximum torque in mind e.g. although the transmissions on my 12 hp C and 20 hp D autos look braoadly the same on the outside, the D has larger diameter shafts and stronger bearings internally etc. The shafts have to withstand a significant torsion effect particularly when running in a low gear with heavy load and/or clutch released in an unsympathetic way. The effect is exacerbated if the tyres are in contact with dry tarmac where no tyre slip is possible. Others more knowledgeable than I will doubtless know how drive shafts are tempered to cope with the torsional forces but I know from experience that, even then, punishing a shaft will over time cause longitudinal stress cracks to start appearing in the shaft which if it is not replaced will in the end go bang! What was the highest hp engine that WH used with the gearbox in question? I think that would be a reasonable guide. Andy Share this post Link to post Share on other sites
baerpath 517 #5 Posted December 13, 2013 "Just what are you thinking? Bike engine? Red line at 16,000rpm." I pull with a couple guy's doing that biggest problem they had is shearing off the input shaft. There is a workaround for that though. We hit our stock 8spds with 4500rpm clutch dumps weekly with 30-40hp on pro tires hooked to a 7000lb transfer sled. "although the transmissions on my 12 hp C and 20 hp D autos look braoadly the same on the outside, the D has larger diameter shafts and stronger bearings internally etc." Here there the same 1 1/8 axles in both are they different on your side ? Share this post Link to post Share on other sites
wheeledhorseman 574 #6 Posted December 13, 2013 "Here there the same 1 1/8 axles in both are they different on your side ?" Sorry, Mr Brain was malfunctioning when he told me to say that! - He knows that his owner has used the same seals on both the C-120 and D200 transaxles so yes they're the same 1 1/8 shaft. The later of the Ds I have has plastic sleeves on the shafts which make them look bigger when parked up alongside the C. Apologies for Mr Brains malfunction. Well corrected. Andy Share this post Link to post Share on other sites
Stigian 1,234 #7 Posted December 14, 2013 Thanks guys for the advice.. I'm not thinking of a bike engine with a 16,000 rpm, more like something something with a 6000 max rpm and about 40-ish hp with a few mods.. That's all the clues I'm giving you.... Other than the finished machine would still be capable of a good days work, but would have also have a good turn of speed.. I still need to work out 100% if what I have in mind is possible, I hope so as it would certainly be something different Share this post Link to post Share on other sites
baerpath 517 #8 Posted December 14, 2013 No problem Mr Brain We all know there are differances in what we know and what we type some days. Sounds like a Kohler command they'll turn 6 grand easy and run 40 hp Share this post Link to post Share on other sites
Stigian 1,234 #9 Posted December 15, 2013 Sounds like a Kohler command they'll turn 6 grand easy and run 40 hp Nope, not Kohler.... Or an Onan.. Share this post Link to post Share on other sites
C-101plowerpower 1,605 #10 Posted December 15, 2013 diesel maybe? Share this post Link to post Share on other sites
baerpath 517 #11 Posted December 15, 2013 Little high for a diesel, lets see briggs vanguard will do it, so would a Lambra. Getting close ? Share this post Link to post Share on other sites
Racinbob 11,236 #12 Posted December 16, 2013 A bit off topic here. A Command can sustain 6 grand? I'm assuming not stock? Share this post Link to post Share on other sites
Stigian 1,234 #13 Posted December 26, 2013 Little high for a diesel, lets see briggs vanguard will do it, so would a Lambra. Getting close ? Nope nowhere near close As it turns out the engine I have in mind is proving harder to find at an affordable price than I thought! Looking into "other interesting engine" ideas as a back up plan Share this post Link to post Share on other sites
