Torque Converter

[gone_fishin]

nicely done, too

thanks for the first really good gander i've had at this stuff...it looks to be the future solution to the "noisy gearbox" symptom thatsdax reported on, maybe?

 

[sergio riveros]

The torque converter tav2 30 has a built in jackshaft about 1 foot apart from the engine sproket, you can not place the jackshaft anywhere in this case since the driven unit goes on the backplate provided by the kit, the advantage of the kit it is that is cheaper and makes the job easier by not requiring a separate jackshaft.
Well if you did not use the back plate I guess you could place the jackshaft anywhre.

In the case of the torque converter 20 and 30 series, it consist of 2 units a driver clutch that goes in the engine sprocket and a driven unit that goes in the jackshaft.

So technically a jackshaft is required (it is built in the kit, tav2 30), what I meant to say when I said a jackshaft was not required, it was that an additional jackshaft to the one in the kit is not required, and in the case of the other torque converters a jackshaft is required for the driven unit as is in the case of series 20 and 30.

In fact in the tav2 30 kit, the belt to chain it is a jackshaft that is built in.

The reason I believe a large sprocket might be needed is that the torque converter provides a ratio of 2.7:1, which can be increased by using the large sproket, for example the ratio using a 36 tooth sprocket at low speed would be 2.7 x 36/10 giving a ratio of 9.7:1, with a large sprocket it would be 2.7 x 55/10= 14.9:1 which is more torque for low end, for high speed 36 tooth might provide too much speed for the bike using a 6.5 HP engine, unless another jackshaft in addition to the one the torque converter uses is used. That will also work, but would be more work installing.

In comparison the gear box in our 2 strokes are about 4.1:1 ratio which is a larger ratio than 2.7:1 that is the reason for the large sprocket.

So in conclusion by using the torque converter we are using a jackshaft.

Well when I get the engine, and the torque converter arrives I will test with different sprockets.

 

[gone_fishin]

...which i saw clearly in 'mpg's ad. thanks, sergio, for getting me back on track. seeing it in that light opens the door for the mad inventor in my mind.

looks like rear sprocket would be where the final ratio is obtained, and easily done.

i'll be looking forward to some real-life reports 8)

who started this crazy thread, anyway? greeeat topic 8)

 

[dr_clabo]

GREAT ! Can't wait for pics of the working finished unit....... !

I hope that collectively, we can do slightly better than our forefathers.....

 

[gone_fishin]

who'da thunk i'd come up with an engine worth having a closer look at this topic

i have this: http://www.motoredbikes.com/viewtopic.php?t=1899

but i want to keep this topic going...

i've read what we have & some of the good links. i know what the converter does, i'll deal with the chain-secondary after i swamp this out...

this converter is compatible with my engine, i have a question or two

is that sprocket in it's proper place? it doesn't appear right to me, so i'm asking.

if i need more "offset" can i simply use a longer shaft for the driven end?

is reenforcement required or will the baseplate suffice?

 

[lotsa_mpg]

is that sprocket in it's proper place? it doesn't appear right to me, so i'm asking.

if i need more "offset" can i simply use a longer shaft for the driven end?

is reenforcement required or will the baseplate suffice?

Yes, the sprocket is in it's proper location. This pic is of the newer units that have been available for a couple or three years. The older versions used a pressed steel backer plate instead of the cast one on the new version. The old versions had the sprocket sitting on the other side of the backer plate....which might have worked better in some applications....however the pressed steel plates had a real tendency to crack which is likely why they changed it to the cast aluminum set up. You won't need any reinforcement.......I know of a few guys using these on some pretty crudely constructed karts around here and nobodys had any probs with them breaking. I'm not near my shop right now to check to see if a longer shaft could be installed in the driven end, but I really don't see any reason why it couldn't be done.

Pete

 

[lotsa_mpg]

I just realized why you may have thought the sprocket was not sitting properly....the photo does show the clutches considerably out of line with each other and perhaps you may have thought the sprocket was causing the secondary (aka driven clutch) to sit higher than normal. The reason they are out of line is that the primary (aka drive clutch) is just resting on the backer plate in the picture....whereas it would normally be sitting higher because it would be mounted to the engine crankshaft.

Pete

 

[lotsa_mpg]

One other thing I figured I should add is that these Torque -a-Verter kits are assymetric set ups......that is to say, the clutches are made in such a way that one sheave on each clutch is almost perfectlty flat and the other has a fair bit of an angle to it. On all snowmobile clutches (and most other torque converter belt drive applications) both sheaves are angled. I believe Comet builds these this way for the smaller engines just to make them more compact to fit into cramped applications and I guess they feel that having only one sheave angled is good enough for the lower powered engines (I think they are rated for up to around 7HP or so). The only thing you have to keep in mind is that on these Torque-A-Verter kits, the drive belt must only go on one way because it too, is angled on one side and almost completely flat on the other.

Pete

 

[SlicerDicer]

so how will bicycle wheels hold up to one of those?

 

[Egor]

I like those drives, but not how it adds to how wide the power pack is. I found a pic a few years ago of a good looking bike but with no pedals so not a MoPed, see what you think! Have fun Dave