Engine Placement and Torque Converter Question

[makinbills]

I am new to this page and have a question about engine placement and torque converter setup. My son and I are currently converting a 2010 Yamaha G29 (gas) that has a differential gear box. We are using a Predator 420cc and a 40 Series Torque Converter.

Question 1: We would like to remove the rear bumper and extend the frame in order to mount the engine behind the rear axle and chain it to the Input shaft on the differential. Beside weight distribution, is this okay to do?

Question 2: Is it possible to eliminate the chain and connect the drive pulley of the torque converter directly to the Input shaft of the differential. If so, any suggestions.....

I appreciate everyone's time.

 

[Denny]

What kind of vehicle are we talking about? How heavy? What is the gear ratio of the rear diff? And finally any pictures and why do you want to move the engine back?

 

[jmaack]

golf cart gearbox?

 

[Willie1]

golf cart gearbox?

Yes, a Yamaha G29 is a golf cart.

 

[Redneck Packrat]

...
Question 2: Is it possible to eliminate the chain and connect the drive pulley of the torque converter directly to the Input shaft of the differential...

Maybe with a jaw coupler and mounting the driven of the TC on a jackshaft?

 

[Rat]

Like Denny asked what's the differential ratio?
Depending on orientation I would think you could probably do a belt drive from the PTO to the differential and skip the CVT backing plate altogether.

It really depends on if the differential shaft is keyed.
The differential input shaft diameter (every CVT I've seen uses a 5/8-15mm stepped spindle)
Finding a belt the right length shouldn't be too tricky and you could theoretically raise the engine up a bit should you only be able to get 1/4" on the long side of perfect fit. Never go shorter...EVER

 

[Denny]

Why on earth would you want to mount the engine behind the axle? It will just make the kart harder to turn because of poor weight distribution.

 

[Rat]

Why on earth would you want to mount the engine behind the axle? It will just make the kart harder to turn because of poor weight distribution.

Seat clearance issue.

I did some (mild) digging on the engine/machine... it's a long stroke/Top end but has a lower slung cylinder angle than the 420 (or any garden variety GX clone)
It also appears to be coupled to the transaxle with variator but the PTO also looks to be internally splined while still being a 4 bolt cover as you'd probably expect.

I don't blame him for wanting to keep said transaxle because from what I read the rear brakes are internal to it

 

[ezcome-ezgo]

Hang that engine out back of the axle, won't make a difference in a golf cart in terms of weight distribution as long as it isn't clear of the body work. It would be great to see some pictures of what you are dealing with.

 

[Willie1]

An over simplified diagram to show the concept of locating the engine
where it fits better and using a jackshaft to make the CVT drive line up.
Chain and sprockets transfer power to jackshaft.
Power goes thru jackshaft to drive CVT, CVT belt, and driven CVT pulley to rear axle.
Bonus points - you can now adjust gear ratio with the engine/jackshaft sprockets.

 

[ezcome-ezgo]

A driven pulley adapted to fit the input of the Diff? That's ambitious.

 

[Willie1]

A driven pulley adapted to fit the input of the Diff? That's ambitious.

How so? Most of the gas golf carts I have seen run the driven pulley of the CVT directly on the input of the rear axle.

 

[ezcome-ezgo]

What does the input shaft of the diff look like? Splined? It makes perfect sense, but what are the pieces involved?