# CanEV Adaptor plates for Honda B series



## jonescg (Nov 3, 2010)

Does anyone here have experience with the CanEV adaptor plates for Honda B series engines? I'm converting a 1988 Honda Prelude and the adaptor plate is a major hold-up. Two firms who promised they could fabricate it for me have let me down, so I wonder if I can just buy one from CanEV.

https://canev.com/product/honda-4-cylinder/

I have two problems - one, the motor I will be using is a Greatland 30 kW cont, 60 kW peak motor which has a different bolt-hole PCD than the standard Warp-9 / AC50 motor pattern. 222 mm versus 213.36 or something. So if I did get one it would need an adaptor plate (for the adaptor plate...)

The other problem is more serious - take a look at the bolt hole and dowell pattern for the Prelude gearbox, and then look at the bolt hole pattern for the CanEV adaptor plate. Does this look like it's not quite right to you?

I think they have it back to front...?


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## x.l.r.8 (Oct 20, 2018)

I'm not sure the importance CANev puts on correct shape, as long as the holes line up,
https://www.diyelectriccar.com/forums/showthread.php/96-del-sol-build-thread-barbie-67510.html
if you rotate the plate 15-20 degrees to the right it looks right to the untrained eye.


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## jonescg (Nov 3, 2010)

Thanks - yeah I just found that thread  The search feature can be a bit like a needle in a haystack, but this reassures me.

So I have just one problem to solve now - the mismatch of the motor PCD and the adaptor plate PCD. I'm sure we can machine 20 mm from it and put a piece of ally plate in there. 

No problems with the flywheel hub to report? I think I might just buy one. Hope they have shipments go out ASAP...


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## x.l.r.8 (Oct 20, 2018)

I see it now the dowel on the left should be inside the center line of the two bolts and the plate its outside and again opposite on the other side


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## x.l.r.8 (Oct 20, 2018)

Also it does say 
"Some adapter plates may have more or less bolt holes than your make and model of vehicle requires.
As some adapters span a broad range of model years the adapter is designed to have enough bolt holes to be compatible with all model designs."


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## jonescg (Nov 3, 2010)

So long as the dowels are in the right location you can always drill a new hole.


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## Tremelune (Dec 8, 2009)

I'm interested in the final results...If my Leaf-into-Mini plan goes south, my plan B is to use a Honda B transmission mated to a Hyper9 or some such.


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## jonescg (Nov 3, 2010)

Well, might have saved myself some time and money - turns out the 1988 Honda Prelude (BA4 engine) has dowel pins at about 12" apart whereas this plate has them at 13.48" apart.

So I have to get them fabricated from scratch anyway...


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## Tremelune (Dec 8, 2009)

If you would be so kind as to record the measurements or CAD drawings (if possible), I'm certain it will help others in the future...


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## jonescg (Nov 3, 2010)

Tremelune said:


> If you would be so kind as to record the measurements or CAD drawings (if possible), I'm certain it will help others in the future...


Yeah I will - I don't have any of the parts in front of me though. Still with the guy who was too busy...


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## jonescg (Nov 3, 2010)

So the Prelude has a B20A6 engine, which appears to have a different dowel spacing to the CanEV plate. Looks like we'll be getting it made locally in the end.


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## jonescg (Nov 3, 2010)

OK just to bring my thread back into line...

It appears the measurements we took were off by about a Vernier caliper's 20 mm inside measure.

I took a bunch of measurements from the engine block and found it to be 343.8 mm centre to centre.

This is still different to the CanEV plate's 342.4 mm, but gee it's close.


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## x.l.r.8 (Oct 20, 2018)

I don’t know why but I was under the impression after messing briefly with D16 and B16 that all engines and transmissions bolt together. Like a CRV trans bolts to a D16 and B16. The B16 even bolts up to a 2.0 crv block, so it’s strange there’s a discrepancy, maybe I just got lucky. But I can’t think why the plate would be different.


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## x.l.r.8 (Oct 20, 2018)

I did a quick search through my rough notes.

“However, the B20A manual transmission is unique and doesn't have any match on other Honda products.”
http://www.b20a.org/gearbox-part-numbers


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## brian_ (Feb 7, 2017)

x.l.r.8 said:


> I did a quick search through my rough notes.
> 
> “However, the B20A manual transmission is unique and doesn't have any match on other Honda products.”
> http://www.b20a.org/gearbox-part-numbers


More specific to this issue, from another page of the same site:


> There was Another B20A made for the 1987-1991 3rd Generation Prelude, It came out SOHC Twin Carb (B20A3) and DOHC PGM-FI (B20A5) and leans back towards the firewall. It shares the same Bore and Stroke as the B20A and the rocker cover is simular, But the Head Gasket layout and intake manifold Bolt patterns are different and not compatible. *Bell housing bolt up pattern is also different again so gearboxes will not swap.*


This is bizarre. I wouldn't be surprised if the engine in the S2000 has a different bellhousing bolt pattern (because the S2000 had a completely different drivetrain layout), but to have one oddball transverse-engine four-cylinder seems pointless.


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## jonescg (Nov 3, 2010)

Hmmm, well it's certainly a head-scratcher.

The 1988 Prelude manual gearbox has the starter motor towards the front of the car, which changes the hole alignment markedly. However, if the dowel pins and the crank are in the same locations, I can still make it work (although it won't be as pretty). 

I'm keen to order one from CanEV regardless - the conversion is well overdue.


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## jonescg (Nov 3, 2010)

Well it's officially official.

The 1988 Honda Prelude with the B20A6 engine has a completely different dowel spacing and gearbox layout to other Honda B series engines. 

Time to start taking down measurements and getting a unique one fabricated.


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## Tremelune (Dec 8, 2009)

Is there any chance that swapping in different Honda components _first_ would simplify the EV coupling...?


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## brian_ (Feb 7, 2017)

Tremelune said:


> Is there any chance that swapping in different Honda components _first_ would simplify the EV coupling...?


That's good thinking! 

If the transaxle mounts to the vehicle structure match up (a big "if") then using a Honda transaxle which properly fits the available adapter might make life easier. Of course, you would want either the other Honda's half shafts to work in the Prelude, or the Prelude half shafts to work in the other Honda's transaxle.


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## jonescg (Nov 3, 2010)

I will be exploring this option shortly. My hunch is that the transmission mounts won't line up either, and there are a few other quirks like the power steering speed sensor...

I can probably get an adaptor plate made up fairly quickly from a drawing. Making said drawing will be the slow part.


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## jonescg (Nov 3, 2010)

I've opted to make it myself. I have ordered a slab of aluminium and have been taking measurements. Hope to have it finished soon, but the Easter break is going to slow that progress down.


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## jonescg (Nov 3, 2010)

I picked up my slab of aluminium and band-sawed out the shape I want. I then traced out the bolt hole pattern for the Greatland motor (turns out its PCD was 221.5 mm) and drilled the centre through to 19 mm. This is a bit slippy (out by 0.1 mm radius) as the gearbox shaft is more like 18.8 mm. But I shimmed it and we're golden.

Also turns out the flywheel hub won't fit either. The Greatland motor shaft is a metric 28 mm and the keyway is 8 mm, so we're making that too.


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## jonescg (Nov 3, 2010)

I might as well start my own build thread here, particularly the process of getting this unique gearbox adaptor plate made. But I have made progress and can share it for reference.

The 19 mm hole was a little too big for the input shaft, so I added a few rings of packing tape. This held it snug and it didn't budge in any direction. I can consider this as central as I can ever hope to get it.

Several transfer pins were made to mark the centre of the holes for the dowel pins and the other M12 and M10 threaded holes. Took a bit of filing and sanding to get there.

The plate was carefully lowered over the shaft and aligned, and with a single brisk hit with a hammer, the transfer was done. I took the plate off, removed all of the pins and returned the plate so I could centre-punch the remaining 12.7 mm clearance holes around the top.

So it's all ready to take to a machine shop and get the holes drilled on a mill. Then I can turn the centre out to 100.00 mm so the Greatland motor lines up nicely, and finally remove about 20 mm of depth for flywheel clearance.

I'm getting the hub machined using an EDM wire cutter. sure beats broching a keyway.


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## electro wrks (Mar 5, 2012)

If the gear box has a well supported input shaft and the shaft spins close to true as measured with a dial indicator (clock), this alignment system could work. Most front engine, rear wheel drive vehicles have a poorly support gear box input shaft. An alignment system like this may not yield the less than 0.005" (~0.13mm) misalignment typically specified for these vehicles. Exceeding this misalignment could cause excess gear box gear and bearing wear as well as excess side load on the electric motor output shaft, and other problems.


As such, I suspect you will have problems with the dowel pins fitting as well as they did with the per-conversion(ICE) parts. It's just too difficult to locate and size center punched drilled holes to the tolerances needed for dowel pins. That's alright. If the gear box is like the one described in the first sentence of the first paragraph, the well supported and located input shaft can be used to properly center the adapter plate. Tighten the mounting bolts holding the plate to the gear box making sure the bolts don't exert any side load on the plate-pulling it out of alignment. Usually this means the bolt holes in the plate are slightly oversized. It looks like they are sized 0.5mm over in your case.


At this point the dowel pin holes can be drilled and reamed to fit the next over-size dowel pins. In this way the proper alignment can be successfully transferred through the parts of the set-up. Although not ideal, the tape on the input shaft would probably be good enough to take up the gap to transfer the alignment. I've used aluminum ducting tape and stainless steel muffle repair tape to do similar jobs. This is a successful repair on a trunnion on a 1000 USD steering cylinder off of a tractor, using stainless steel tape pieces(with lotsa Locktite) to fill a worn area under repair sleeves:


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## jonescg (Nov 3, 2010)

Yeah fortunately the gearbox is very solid - zero movement of the shaft and it looks like it spins fairly true. The dowels are hollow, so I suspect they are able to accommodate a small amount (0.01 mm) of misalignment. All the other holes are way bigger than the metric bolt designed to go through it - the 12 mm bolts will have almost 0.5 mm around them to get it right.

In the end, this is really the best I can hope for given the circumstances. We'll see how it goes.


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## jonescg (Nov 3, 2010)

So far so good...


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## jonescg (Nov 3, 2010)

Coming together. Just need to fit the clutch tomorrow and put it all together for a spin test.


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## jonescg (Nov 3, 2010)

So far so good. I need to spin it up and listen out for any eccentricity.


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## jonescg (Nov 3, 2010)

Still haven't had a chance to spin it up, but everything seems right, and it's not like I can do much about it if it's not.

Midshaft support plate is done and lines up well. Hope to position it in the car this weekend and get the final chassis mounts built.


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## Tremelune (Dec 8, 2009)

What is a "midshaft"? I might be trying to use a CRV transmission in my project...


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## jonescg (Nov 3, 2010)

Tremelune said:


> What is a "midshaft"? I might be trying to use a CRV transmission in my project...


The midshaft is the driveshaft which links the differential to the LHS front wheel. Many vehicles just have a very long shaft, but this particular model links it with an intermediate shaft.


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