New CV Rear Design

[Rick S.]

I started a thread on this a couple years ago on MBN.
I'm finally getting back into it again. I'll be adding photos of the actual unit here and update the model as it comes together. The UG has sparked my interested in this project again. This uses type 4 cv's.

[trojan]

Nice one Rick. I love how the design allows you to better centralise the motor. With much respect, I honestly believe the idler is a bad idea, engine braking alone hammers the shit outta them . Cannot the housing be disigned to remove it?

[Rick S.]

Because this design is low in front it allows some motors to be placed more rearward.
The idler would lift the chain clear of the motor's case. It has 3 available positions and it's not for tensioning the chain. It is a removeable option.

What gets tore up on the idlers?
The one I've used is a hardened 13T Martin Sabertooth with altered bore and uses dual 5/8 id bearings.
It's also mounted in double shear and is keyed into the housing. I figured I actually overbuilt this area. 

http://i148.photobucket.com/albums/s2/RickS_2nd_Piranha/New%20CV%20Rear/sprockets008.jpg

http://i148.photobucket.com/albums/s2/RickS_2nd_Piranha/New%20CV%20Rear/sprockets002.jpg

[Camel]

I started a thread on this a couple years ago on MBN.
I'm finally getting back into it again. I'll be adding photos of the actual unit here and update the model as it comes together. The UG has sparked my interested in this project again. This uses type 4 cv's.

Hey Rick, pardon my ignorance, but what is this 'UG' that you speak of?  And why has it sparked your interest?

Camel

[Yoshi]

What gets tore up on the idlers?

My problem was always the bearings.  Having a sprocket so small, with such small bearings means it spins faster than the crank, (and no oil bath like the crank bearings) and I always had bearing get so hot they would seize (this was a 600 cc powerplant mind you), then bend/break the idler, then pitch a chain.  The bigger the sprocket, the better off you are since it slows down the speed...

[Yoshi]

How much are you gonna be asking for that unit, and how wide from flange to flange?

[Doug Heim]

Ive been using 15s with no problem. I use the same heavy bearings Rick mentions. good quality and not cheap.

[Rick S.]

The unit is 7-1/4" flange to flange. It will have alot of options.
Price would vary depending on how it were ordered. I will probably only sell it in kit form, which will keep the cost down.
Quite a few pieces are folded and you'd need at least a 75 Ton press brake to do it yourself.
I have it worked out with 3 different axle length options. Each length has custom a arms to match. The arms are all worked out to take full advantage of the cv angles and plunge.
Just set your upper and lower limits shy of binding and you're good to go.
Total plunge on the axles is less than 1/8"
Axle length options are 16-1/4", 18-3/4" and 21-1/4". The 16 and 21 assemblies can be purchased off the shelf new or re manufactured. (These are standard Porsche axle assemblies, just drop them in.) the 18 3/4" is a VW Bus axle with the Type 4 Porsche cv's.
Overall width outside of tires from 65 to 75".
Travel between 11 and 16+" depending on what axles are used.
7/8" eccentric axle throw means you'll never need to use a half link.
Idler can be 13 to 17t if needed. The two single row sealed bearings are rated to 4000rpm each. (FYI Mcmaster-Carr and G&G single idler bearings are rated to 1000rpm)
Suspension rods are also an option on all widths. and skid plates are included.
Uprights too, and wheel hubs, with whatever lug pattern you need.

[Rick S.]

Camel,
UG is the new cad program I'm learning at work.
This is the 3D program that GM uses. Similar to Solidworks, but way more powerfull, from what I've been told. Not a program that you can easily run on your home computer though.
And very expensive. 

[trojan]

Cheers Rick, the ones I've seen eaten were 10 tooth. Both the bearings and the idler are eaten in 1 hr of thrashing. I expect the idler is chewed after the bearings start to go.

[Reidy02]

Very nice Rick, well done, I like it, I like it a lot!!

[Rick S.]

Thanks, I'm getting ready to build a new frame with this rear unit.
I'm also using a new front design on this build.

[Boostinjdm]

Quite a few pieces are folded and you'd need at least a 75 Ton press brake to do it yourself.

how'd you arrive at the 75 ton number?  did you find a formula somewhere?

[Rick S.]

Just a rough figure I was given by a guy at work that knows their capabilities.
75 ton would fold a 1/4 x 18" piece 90 degree to a 1/4" inside radius.
I used a 100 ton at work but had inquired about purchasing a smaller press for my home shop.

[Reidy02]

Cool have you drawn anything up yet Rick? What does it look like.