83 replies to this topic

[Tremelune]

Welp, the engine's out. I really wish I had drained the oil and more of the coolant before moving it around. When I removed the axles, no oil drained. When I tilted the motor back and forth, the oil started coming out quite a bit...Coolant came out of the disconnected hoses...blarg. I read to just leave it in. Had to take the hood off, too...

 

It seems like it would have been easier to just drop the subframe, but everyone seemed to think it wasn't...I feel like having a 2-post lift changes that equation quite a bit.

 

Some shots for posterity:

 

 

 

 

 

 

 

[Tremelune]

Subframe out and on a bench next to the motor to take some measurements. I drew a Very Professional diagram of what is where, focusing mainly on the axle location and centerline...It's not a slam-dunk, but for how tight this engine bay is, it really fits pretty well.

 

My intention is to bring the whole car to a race shop so they can hack up the subframe and fab up some mounts, but I wanted to be reasonably sure this was feasible before involving the pros. It looks like it will be, with caveats. I'm happy to tear up the Mini subframe, but I don't want to redesign the suspension, so the pickups points are important. The AC compressor is right out; I think it can be put anywhere and there ain't much room where it is.

 

The axles will fit, centered, between the axle holes in the subframe, (though some slight relief will probably need to be grounded out). I'll likely enlarge the axles holes to ensure they can be installed. The Leaf has the axle output behind the motor just like the Mini, so that's nice.

 

The caveat is that I can't center the axle line front-to-back, because the reduction gear housing will stick out an inch or two passed the rear of the subframe, and the steering rack lives there. I'm hoping I can get away with 1-2" of misaligned axles (and I hope there is space up front before the subframe turns into the front grill)...I don't know what the repercussions are for them to be off-center (increased joint wear?), but I do want them at the same length/angle to mitigate torque-steer.

 

 

 

 

 

 

[Tremelune]

I wish I knew more about the aftermarket subframes. Specifically, how they are in terms of ride quality, suspension geometry, and compromise? Are they a clear upgrade, or just what was necessary to fit in a larger engine? I'm building a daily driver that will probably never see a track or an autocross, so I'm hoping for the smoothest ride I can get (with of course as little compromise on motion control as possible)

 

Keeping with the stock Mini subframe, I have access to all the improved parts offered for these cars, now and forever (HiLos, various coilover options). It also gives me easier comparison with other cars on the road ("Hey my car is doing this weird thing, anyone know why?").

 

If I went with a Minitec subframe, there would be enough space to mount the motor directly centered on the axle line. I would also get coilovers and nice brakes, greater alignment adjustment(?), but they would be somewhat more proprietary than bog standard Mini stuff...With all-metal mounting points, it looks like a lot of bumps and vibration would be transmitted into the cabin. The track on the Minitec subframe is only 1/2" wider than stock, but I often hear about excessive scrub radius and torque steer on these cars...Maybe it's because everyone puts on the widest wheels they can...? 

[Tremelune]

Aight, it's time to fit the motor...I'm attempting to block the subframe up so that it's perfectly "level", but I'm not sure what to use as reference points. Are these shock towers dead level, or could there be wild variation...? Presumably the front and rear crossmembers are level...?

 

I read somewhere that there was a factory spec for where the wheel hub centers should be relative to the chassis. Is that something I would find in the shop manual?

 

 

 

Edited by Tremelune, 24 October 2019 - 05:58 AM.

[danie garry]

Aight, it's time to fit the motor...I'm attempting to block the subframe up so that it's perfectly "level", but I'm not sure what to use as reference points. Are these shock towers dead level, or could there be wild variation...? Presumably the front and rear crossmembers are level...?

 

I read somewhere that there was a factory spec for where the wheel hub centers should be relative to the chassis. Is that something I would find in the shop manual?

 

 

 

 

 

 

 

i would check the level from the top of the big oval section as that's where it'll mount to the body, the bit you have the level on at the moment is more likely to be out considering its welded in and it doesn't actually mount to anything

i doubt it'll be too far out but it might be something

Edited by danie garry, 25 October 2019 - 07:17 AM.

[Tremelune]

Humbug. I think using the stock Mini subframe is out. The final bit was the axles. There simply isn't enough room to get the axles in and out with the motor in place (and there's no way to remove the motor with the axles in place).

 

The rearward motor position is the critical measurement...The axles will always be at an angle when rotating with this swap, which will accelerate wear, I expect. I don't see any way around that without cutting the body and/or moving the steering rack. Even if the subframe were completely cut away, the body of the car is directly behind it, and the steering rack directly behind and below as well.

 

The axle holes can be enlarged to sneak the axles through (maybe 1/2"), but not at the angle that they need. The boots might also rub the edges. The Leaf motor will be about an inch further back than what is in these photos when dropped into place, but that's it, and it's not enough to keep the stock subframe without really mangling it...I don't see any way around it without changing the suspension pickup points, and I'm just unwilling to do so. 

 

Education is expensive.

 

So. New plan is to pick up an Allspeed subframe designed for a Nissan G10/G13. I like that they use the stock suspension, have been around and steadily improving for years, are made with square tubing (which is easier for me to work with than round), and are pretty well proven in terms of strength and handling.

 

Compromises:

 

- It might wind up being $2k and two months to get this thing to California.

 

- The lower arms must be replaced with somewhat proprietary "spherical" lower arms. This will increase NVH a bit, but allow for greater alignment adjustment and handling precision.

 

 

[Ethel]

I take it the shafts fit where the rag's stuffed in? If so, I can't see that you'd have much option other than to mount it forward as the steering rack will be in the way.

 

I reckon 99% of us will agree Min's are best sprung on rubber with a solid mounted subframe, like god (or Issigonis) intended.

 

 

 

 

Added.....

 

looks like it's all final drive cover forcing you forward. What's the rolling diameter of the Leaf's wheels you'll be replacing it with approx 20 inches.

[DamoMini]

Following this. Where abouts in CA are you?

[Tremelune]

I'm in Hollywood, near Bojack Horseman.

 

The gearing works, if I can get the motor to spin to 10k RPM. With a tire diameter of 19.5-20.5" you get something like 80mph as a top speed.

 

 

Do the solid mounts transfer much road noise? I've become wary of any mounts that aren't rubber due to NVH concerns. It does seem to make sense to keep the whole suspension rigidly mounted to the car, though...
 

 

I haven't quite done the research on the springs/shocks yet. I'm inclined to just go with a the softest donuts I can find, and a quality set of shocks. I've read that coilovers can have a smoother ride than the donuts, though, and that is something I'm after (but I don't want this thing to wallow around turns). LA has potholes, yo, and this car can't get too far from it...

[fuzzy-hair-man]

A small diameter inner CV helped clearance quite a bit in my cg13 conversion. Nissan seem to use the same spline count and driveshaft oil seal between makes, the same could be true of the leaf, a k13 micra driveshaft is relatively small diameter, probably still doesn't make it through the driveshaft hole but I was able to bend 6mm plate and weld it in to widen the hole on the LHS. I don't think the allspeed frame will gain you much room to move it back, the rack is always the limiting factor.

[DomCr250]

Subframes -  I've built 16v conversions before, been running for over 10 years, road and track.

 

If you have the skills to go EV then you can easily modify the standard subframe.  Whatever you buy off the shelf thats aftermarket you are going to cut and weld anyway, so why not do it with the OEM mini one?

 

Before you do anything make a jig for the existing subframe out of decent steel - basically you build a square frame that locates just 8 points on the frame - at the back it picks up on the top of the towers and the rear head board mounts - these you can actually weld to your jig.  Look on the 16v mini forum for examples of jigs, you can use scrap steel.

 

At the front you create a set of upward arms - to these to weld washers which locate with the front subframe mounts and the tie bar locations - they just identify where they are located and are not attached to the frame.

 

Then get your angle grinder out and cut the whole front section of the frame off, plus the sides, take it as close as you can to where it meets the towers.

 

Now lower you lump in, look through the driveshaft holes in the towers and try as basic alignment with your eye of approximately where the drive shafts should run and be in good alignment.

 

Thats your only critical measurement - once you have that you can start hacking off the back of the subframe for clearance - the good thing is you can add extra strength between the towers further up, this also might give you engine mounts.

 

Once you have your driveshafts right and a rear mount just build the sides and the front of the subby back up.  The trend now is for bent round steel tubes, 10 years ago it was just box section.

 

Use rubber engine mounts, either utilise the existing Nissan ones or use early land-rover ones that look a bit like a rubber donuts with a screw each side - they will easily cope with you power and torque and allow easy mounts to be made.

 

Hope this helps - took me a year of looking at it to work it out, but once you start and build forward its easy.

Edited by DomCr250, 04 December 2019 - 12:10 PM.

[fuzzy-hair-man]

I used the landrover cotton reel mounts but it can make it sensitive to alignment, the bolt through round mounts I've seen since would make life easier. The electric motor is far more balanced than a ice so I'd not be too worried about dampening and nvh.

[DomCr250]

I used the landrover cotton reel mounts but it can make it sensitive to alignment, the bolt through round mounts I've seen since would make life easier. The electric motor is far more balanced than a ice so I'd not be too worried about dampening and nvh.

I was thinking more of road noise being transmitted back to the car if the motor was solid mounted?

[DomCr250]

I should never had starting reading this thread - just seen a 2012 Leaf go for £2650 at Co-Part - only had light OSF damage - make a nice donor car.  Probably get £500 back from the left over parts - so say £2500 for all the drivetrain, batteries, loom and dash.

[fuzzy-hair-man]

I used the landrover cotton reel mounts but it can make it sensitive to alignment, the bolt through round mounts I've seen since would make life easier. The electric motor is far more balanced than a ice so I'd not be too worried about dampening and nvh.

I was thinking more of road noise being transmitted back to the car if the motor was solid mounted?

Not solid mounted, but a mount you can rotate which makes fabricating mounts much easier.
Most road noise would come through the suspension I'd think a much more direct solid pathway to transmit vibration.