Hot-rodding the Toyota MGR

[Cyruscosmo]

Hmm... From the reading I have done I see that the fluid used in those drive units is the same for the transaxle in front so it is ATF and pretty thin. That would make sense since the rotor would get bogged down with a heavier weight gear oil.

Check these out... Electric Oil Feed and Scavenge Pumps It would save a lot of headaches trying to rig belt or chain drives for a pump. They could be set up to activate when the drive unit got over a certain temperature.

Cyruscosmo

[e*clipse]

Chain driven pumps are pretty common. There are quite a few IC engines that use chain driven oil pumps.

In some older machine tools, the chain WAS the pump. A chain moving through an oil bath would carry oil up to some bearings on some lathes.

I haven't seen any exposed or driven off the axle however...

Chains can be fine as critical parts - for example, the timing belt on my TDI engine needs to be changed rather frequently. However, the timing chain (same job) on my Honda Insight apparently never needs replacement.

- E*clipse

Originally Posted by freebeard

Adding a sprocket to one of the drive flanges would reduce the RPMs of the oil pump by the 6.8xx ratio. Although I've never heard of a chain-driven oil pump.

[e*clipse]

About the oil, and oil quality - All three of mine had the oil drained before I got them. I think it's a shipping requirement. All three had something that looked like ATF in them. The one I took apart was pretty clean. When I completely wiped it out with a white paper towel, I found very little in the form of metal powder, etc. I'm trying hard to make sure the rotor doesn't attract metal filings, etc while it sits around my shop. The magnets are very strong and it seems stuff comes from everywhere to stick.

I do all the maintenance on my vehicles, and I can honestly say that the MGR was WAY cleaner than the oil changes from my Honda Insight - both the engine and the CVT. The diesel TDI in my Toyota pickup is REALLY dirty. I rebuilt the R151F transmission on my Toyota truck, and did an early oil change (about 20k miles) and would say that the oil in the MGR was about as clean.

I am seriously considering the super-polishing process that Freebeard mentioned for both longevity and increased efficiency.

For some reason there are 3 or 4 possibilites for oil inlets/outlets. One could easily pull oil out of the drain with some "T" for a drain. There is another tapped hole near the breather on top which would work as an oil inlet, regardless of motor direction.

That bolt you see on the outside is static. I have no idea how it's supposed to work as a vibration dampener - which is its stated job. So, replacing it with some pump drive may be slightly risky from that perspective. Again, I would want to be very sure the pump could handle the motor rpm before trying it.

Also - thanks for the oil pump link. That website has a lot of good info, with some good reality experience info mixed in. If we want to do our own pump or use a pump from another application, there is some good info about what may work.

- E*clipse

Originally Posted by Cyruscosmo

Hey e*clips

I was thinking more along the lines of you having one in pieces already. What do the gears and bearings look like? And how much metallic crud did you find inside the case when you opened it up? if it has held up for over 100K and still looks good inside then I am happy with that. Unless that thing has a one way clutch I am not seeing that rotor has been driven through the gears for over 100K.

Yes... I was wondering about that bolt head and fat washer that can be seen on the outside of the case in that position. Do they rotate with the rotor shaft? If so then replace that fat washer with a toothed belt sheave and there is your oil pump drive. Plumbing is as easy as tig welding on a couple fittings for the oil ports. If you are going to use a positive displacement pump then don't forget a pressure relief valve and you may as well mount an oil filter and cooler.

I noticed in a few pictures that I found that the oil in those gear boxes looked like transmission fluid? Is it that thin? If so a battery powered pump would work and you would only need a couple places to put case fittings.
Cyruscosmo

[Cyruscosmo]

Hey E*clips

From what I can see in your pictures and reading your description the oil is moved via the ring gear into a chamber above the gear set. I can not clearly see the baffle line in one of the pictures but if it is there then the oil spills back into the gear area mainly through the bearings in the main/counter shaft and through the main shaft into the rotor housing for the rotor bearings and to cool the stator.

As you pointed out there is a port drilled to divert a good amount of oil into the rotor shaft. While at rest the fill plug sets the oil level in the unit giving a good indication of the amount of oil it uses. Now the way the gear set and baffles are arranged suggests that while the unit is in operation the majority of the oil resides in that chamber above.

This would make sense as the oil would cause a lot of gear drag otherwise.

Now I have a question for you. Is there a step inside of that main rotor shaft? The reason I ask is that I have had a number of triumph motorcycles over the years and some used the crank shaft as a sort of oil filter. Oil pump stage one pulled oil through a strainer screen from the engine sump and into the frame which was also the oil reservoir/cooler. Stage two pulled cool oil out of the frame and pushed it into the crankshaft. The crankshaft acted as a fine particulate filter by centrifugal force. It has a stepped chamber through the crank pin which had a clean out.

I was curious to see if the main shaft had a step inside of it that they would use to capture any metallic particles before they got to the stator. The last thing you want in there is metallic hair between the rotor and stator.

Anyway I think the oil should be removed from that chamber where most of it is during operation and pumped back into the system at the port where it goes into the main shaft.

What are your thoughts?

Cyruscosmo

[Astro]

Originally Posted by Cyruscosmo

...
Anyway I think the oil should be removed from that chamber where most of it is during operation and pumped back into the system at the port where it goes into the main shaft.

What are your thoughts?

Cyruscosmo

That would allow you to increase the rate of oil delivery to the main shaft and on to the motor. Handy for increasing the cooling to the motor.

But it does rely on the gearset lifting the oil into the chamber.
If the motor was reversed and the gearset ran the opposite direction then it wouldn't work. It would be good if the oil pump setup worked for both senario's.

If the oil pickup was changed to the sump where the gearset picks up the oil then it might work for both senarios. There may be the possibility of the gearset running short of oil if the oil level gets too low for it to be able to pick it up. The oil pickup would need to be designed so that it left a minimum amount of oil in the sump for the gearset to lift. Maybe a pickup similar to the fuel pickup in a motor bikes fuel tank. It leaves a "reserve" amount in the tank unless the fuel tap is turned to reserve.

So what do you think, a "reserve" pickup from the sump area? Would it work for both motor directions as well as keep the gearset lubricated?

[e*clipse]

I'll second the "pulling from sump" option, because it would allow spinning the motor in either direction.

The oil in the sump isn't dirty, like an IC engine's sump. At the same time adding a magnetic, inline filter would probably be wise. I added one to my Insight's CVT oil system, just because it's a heck of a lot easier to change that filter than the OE ones. Of course it makes sense to add a really overkill oil cooler as well. Again, for the value they provide, coolers are pretty cheap.

I think the Triumph's use of the engine and frame in the oil system is really cool.

The MGR's motor shaft doesn't really have a step machined into it. However, there's a spline on the gearbox side of the motor shaft that interfaces with the first stage of the drive system's gears. This set of gears is also hollow, so in a sense, there is a step. The shaft inner diameter is smaller on the gearbox side, larger on the motor side.

E*clipse

[Astro]

Originally Posted by e*clipse

I'll second the "pulling from sump" option, because it would allow spinning the motor in either direction.
The oil in the sump isn't dirty, like an IC engine's sump. At the same time adding a magnetic, inline filter would probably be wise. I added one to my Insight's CVT oil system, just because it's a heck of a lot easier to change that filter than the OE ones. Of course it makes sense to add a really overkill oil cooler as well. Again, for the value they provide, coolers are pretty cheap.

And the bigger the oil cooler the bigger the total oil volume which gives the system a lot more thermal inertia. Takes longer for a peak load to raise the total oil temperature. Should tend to even out the thermal peaks. Also adding a thermo fan that comes on above a certain temperature would be good insurance. A small thermo fan doesn't weigh too much.

Originally Posted by e*clipse

I think the Triumph's use of the engine and frame in the oil system is really cool.
E*clipse

Agreed, it may also stop rust inside the frame and act as a signal for any frame damage. A hairline fracture of the frame may go unnoticed until disaster occurs but oil dripping on your nice clean garage floor will likely be noticed and the fracture located early on.

[freebeard]

So what do you think, a "reserve" pickup from the sump area? Would it work for both motor directions as well as keep the gearset lubricated?

The term you are looking for is 'dry-sump': Dry sump - Wikipedia, the free encyclopedia

Maybe with the relatively low cooling requirement I could implement my dream of a corrugated copper skin radiator.

[Cyruscosmo]

LOL ok I can see that neither one of you has had a Triumph motorcycle because the blasted things leak everywhere. Well at least the old ones did... The only old bikes I have had that did not leak was the Moto Guzzi's. The bike I have now does not leak a drop. It is parked in the living room on my hard wood floor. ;-)

If you look at the baffles in that gear box you will see that once it is in motion the oil is pretty much in the chamber on top. There would be no "sump" to collect the it from. The ring gear would pull it up top faster than the pump could suck it out.

If the gear box was run in reverse then the oil would build up near the oil fill plug which would then be the oil suction side. Either way the oil return would be the port to the main shaft.

The MGR's motor shaft doesn't really have a step machined into it. However, there's a spline on the gearbox side of the motor shaft that interfaces with the first stage of the drive system's gears. This set of gears is also hollow, so in a sense, there is a step. The shaft inner diameter is smaller on the gearbox side, larger on the motor side.

As for metallic particles maybe it relies on that chamber up on top to trap them? I find it hard to believe that unit has over 100K on it and almost no metallic powder in it. Maybe the gears have already been hardened and polished? Even if the rotor is not energized it is still being driven by the vehicles forward motion. What would the RPM be doing 60 on the freeway? Talk about over drive!

The oil in the sump isn't dirty, like an IC engine's sump. At the same time adding a magnetic, inline filter would probably be wise. I added one to my Insight's CVT oil system, just because it's a heck of a lot easier to change that filter than the OE ones. Of course it makes sense to add a really overkill oil cooler as well. Again, for the value they provide, coolers are pretty cheap.

I already have the perfect set up for cooling. It is an oil cooler with attached thermostatically controlled fan. New in the box never used! Couple that with a remote mount spin on transmission oil filter and it's perfect.

I am pretty sure that unit will drop in the front of my Geo as is. I can't wait to get my hands on one... Grrrrr

Cyruscosmo

[Cyruscosmo]

Originally Posted by freebeard

The term you are looking for is 'dry-sump': Dry sump - Wikipedia, the free encyclopedia

Maybe with the relatively low cooling requirement I could implement my dream of a corrugated copper skin radiator.

That would look really nice... These guys could make that happen. Radiator Cores | The Brassworks

Cyruscosmo