Hot-rodding the Toyota MGR

[e*clipse]

Ok, I had a meeting with Jesse at High Angle Driveline about making a spool and some halfshafts.

To make a long story short, perhaps I was oversimplifying the problem...

In my case, I'll need a Mitsubishi Eclipse halfshaft to mate with the front wheel's spline. I may get lucky and have a driveshaft from another year Eclipse, or a Mitsubishi Lancer fit that output spline. They all have different lengths - left side, right side, AWD, FWD, etc. etc. This is actually good - it gives lots of options.

Cutting the Mitsubishi Eclipse halfshaft in half and doing the same with a Toyota Highlander, then sleeving and welding them together isn't a particularly good solution. There's a good chance they are heat-treated and the weld has a good possibility of failing in fatigue.

On the inboard side, the Eclipse uses a tripod joint, where the cup is attached to a splined shaft that goes into the differential. Of course the splines of the MGR are not compatible...

Something that has a flange that would bolt to the 4 bolt MGR output would be most desirable. Something that has a tripod joint output and the right spline would be silly lucky.

We all have this problem - we all need some form of halfshaft that can connect to our various vehicle types. Does anyone have any ideas for a shaft with a tripod joint (or other double CV joint) that can bolt to a flange?

It would be nice to solve this problem once, as far as designing and making custom parts.

[Cyruscosmo]

Originally Posted by e*clipse

Ok, I had a meeting with Jesse at High Angle Driveline about making a spool and some halfshafts.

To make a long story short, perhaps I was oversimplifying the problem...

In my case, I'll need a Mitsubishi Eclipse halfshaft to mate with the front wheel's spline. I may get lucky and have a driveshaft from another year Eclipse, or a Mitsubishi Lancer fit that output spline. They all have different lengths - left side, right side, AWD, FWD, etc. etc. This is actually good - it gives lots of options.

Cutting the Mitsubishi Eclipse halfshaft in half and doing the same with a Toyota Highlander, then sleeving and welding them together isn't a particularly good solution. There's a good chance they are heat-treated and the weld has a good possibility of failing in fatigue.

On the inboard side, the Eclipse uses a tripod joint, where the cup is attached to a splined shaft that goes into the differential. Of course the splines of the MGR are not compatible...

Something that has a flange that would bolt to the 4 bolt MGR output would be most desirable. Something that has a tripod joint output and the right spline would be silly lucky.

We all have this problem - we all need some form of halfshaft that can connect to our various vehicle types. Does anyone have any ideas for a shaft with a tripod joint (or other double CV joint) that can bolt to a flange?

It would be nice to solve this problem once, as far as designing and making custom parts.

Hey E*clipse

In my case it won't be a problem for the first go round as the Geo Metro shafts are smaller than the Toyota shafts. The outer CV spider of the Geo is held onto the end of the shaft via splines that have an inside locking ring groove machined in. All I have to do is cut the ends off the Toyota shafts, turn down the OD, machine splines, then a locking ring groove and then reassemble the shafts. The new shaft will be Geo on the outer CV and Toyota Highlander on the inner. The Highlander is wider than the Geo so there is plenty of shaft to use.

I would suggest disassembling the outer CV for the vehicle you are going to use and see if you have the same options. This link shows exactly how the Geo axle is dismantled for boot replacement and inspection. This is not a Geo shown but it is exactly the same build. | Repair Guides | Automatic Transaxle | Cv-joint | AutoZone.com

The six ball bearings in the outer CV are a bugger to get back in place but not impossible. So unless you need to clean and regrease them just pop the shaft out and wrap them up to stay clean. I did some poking around and it appears that the Mitsu CV is built the same way... Check your shaft diameters and see if you can just have the outer end of your stock Toyota shaft modified. All you need is the outer CV for the Mitsu minus the shaft. Get the Toyota outer shaft end resplined to fit the Mitsu spider.

If not then you could simply use an axle from a bigger front wheel drive car that is larger in diameter and longer and cut it down and respline both ends, one to fit the Mitsu and one to fit the MGR. I am not sure how all of them are built but the majority of the ones I have torn down for boot replacement were pretty much the same.

Cyruscosmo

[freebeard]

I was thinking about little mini-adaptor plates milled out of billet disks. The Toyota flange has IIRC four studs on a 6.5" circle and the VW has six bolts on 4". I drew it out and there looked to be 1 1/2" between the hole centers. With the nut on the Toyota stud, there would be a counterbore for the VW bolt head underneath.

Or cut and shut, and then send the parts out for cryogenic tempering. There's also a technique where you spin the two halves in opposite directions and then jam them together until they fuse from the heat of friction. You get good weld penetration that way.

[thingstodo]

Here is a coupler that I have been investigating. This one is sized for 1 inch diameter on both sides, but other sizes are available

Item # C600E-187, Series C600 Keyless Rigid Coupling On Climax Metal Products Company

The coupler itself seems simple to install and uses a similar approach to cut-sleeve-weld. You'd cut, this coupler is the sleeve, then tighten the bolts (as far as I can see).

3200 foot-lb of torque seems beefy enough for my purposes - perhaps not for all projects.

The pricing (about $175 each) seems attractive enough to try it out. I just haven't gotten around to buying them and trying them yet.

[AlexanderB]

its kinda similar to a collet adapter I've used on a smaller scale (model airplane, 1kw BLDC engine to proppeller), they work pretty well. Looks good.

I hope that wouldn't upset the balance of a drive shaft too much though..

[e*clipse]

Thank you - everyone for the ideas and suggestions.

Last night I spent some time looking at mostly OE and race type options. The good thing seems to be that, for the most part, the auto industry has settled on a pretty common design for the half-shafts.

This helps a lot for the idea of splining a shaft differently on each end to fit different manufacturer's pieces.

I was thinking about going with parts from cars that are commonly raced - this will give lots of repair part options beyond the usual questionable quality big-box store parts. For example, here is a company that specializes in driveshafts for race cars:
The Driveshaft Shop | Home page

One think I noticed is there are a LOT of Mitsubishi options. In addition to the Eclipse, the Lancer, 3000GT, and EVO's share parts. Here are the rear driveshafts for my car:
The Driveshaft Shop |
This looks like it would be pretty easy to modify for another end, like CyrusCosmo suggested. In this case, the splined end goes into the rear differential, and the 4 bolt pattern end bolts up to a stub on the wheel side. The bolt patterns are friggen' close to the MGR, but don't match. This may be an adapter flange opportunity.

The other one that caught my eye is the Porsche half shaft:
The Driveshaft Shop | PORSCHE 1995-1997 993TT Manual 1000HP Level 5 Axle Kit - Porsche - Import Axles

It seems very similar on the inboard side to the VW half shaft:
The Driveshaft Shop | VOLKSWAGEN 1999-2005 Golf / GTI / Jetta / Beetle (VR6 / 1.8T) 5-speed manual (exc. 337 chassis) Basic axle (no warranty / not a racing axle) Level 0 - Volkswagen - Import Axles

Ignoring prices for a moment (yes, I know you can get one of these from Autozone for ~$70) Check out the 6 bolt pattern on the Porsche and VW. Freebeard: would you know what those bolt patterns and pilot diameters are?

By going to Porsche/VW/Mitsubishi axles, there would be a lot of good quality replacement parts available. Since CVT's are wear items, especially at high speed (the grease can cook) it would be nice to be able to get parts.

If the bolt patterns are somewhat compatible, it might be possible to do what Freebeard suggested and make an adapter between the MGR and a VW/Porsche CVT.

BTW, I have one of the 4-bolt MGR flanges sitting on my lap. The stud circle diameter is 94.75mm, or about 3.73" - much smaller than 6.5". If the 4" 6 bolt pattern matches the axle I linked to above, then an adapter may be a little tricky in that the bolt patterns are very close.

[thingstodo]

Originally Posted by AlexanderB

I hope that wouldn't upset the balance of a drive shaft too much though..

This site lists the 14 inch tires I'm using at 902 revs per mile EV Calculator

At 60 mph, that give me 902 rpm. So around 1000 rpm.

Anyone have ideas on how to measure vibration under 1000 hz, that is cheap and that I can mount on a car axle?

[Cyruscosmo]

Originally Posted by thingstodo

This site lists the 14 inch tires I'm using at 902 revs per mile EV Calculator

At 60 mph, that give me 902 rpm. So around 1000 rpm.

Anyone have ideas on how to measure vibration under 1000 hz, that is cheap and that I can mount on a car axle?

Why do you want to measure vibration? Balancing a drive line costs about 30 bucks.

Now if you are doing an experiment you can use a couple hose clamps to do a temporary balance.

Set the car on blocks attach two hose clamps to the drive line and set them tight. Run the car and if it vibrates rotate the clamps away from each other until it goes away. Then wrap the clamps with electrical tape to hold um in place.

I have had to use this method a few times getting four wheelers out of the mountains after field repairs of drive lines.

But if you just want to measure vibrations you can use one of these. https://www.sparkfun.com/products/9199

Cyruscosmo

[freebeard]

I need to reproduce my work— maybe the VW was 6.5". When I looked around, all the transaxles I have are swing-axle (except the driver) so I held a tape measure up to someone else's part.

[thingstodo]

Originally Posted by Cyruscosmo

Why do you want to measure vibration?

To see if it needs to be balanced, I guess. I have no experience, so I want to measure stuff

Balancing a drive line costs about 30 bucks.

Oh. Maybe I should just get it done, but I'd like to know what is 'OK' and what is 'TOO MUCH'.

Now if you are doing an experiment you can use a couple hose clamps to do a temporary balance.

Set the car on blocks attach two hose clamps to the drive line and set them tight. Run the car and if it vibrates rotate the clamps away from each other until it goes away. Then wrap the clamps with electrical tape to hold um in place.

Cool. That sounds like something that even I could do.

But if you just want to measure vibrations you can use one of these. https://www.sparkfun.com/products/9199

Thanks for the link. Looks promising. Not sure how to mount that. On the nearest wheel support while the car is up on jacks, then run the motor?