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Discussion Starter #1
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...:rolleyes:)

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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Discussion Starter #3
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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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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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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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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Discussion Starter #8
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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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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Discussion Starter #10
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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Discussion Starter #11
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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Discussion Starter #12
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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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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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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Discussion Starter #16
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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Discussion Starter #17
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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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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Discussion Starter #20
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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