# homemade transmission adaptor plate questions



## dragonsgate (May 19, 2012)

Sounds like you are not up to snuff on cars in general. I suggest that you get a repair manual for your car. I like the Haynes because they seem to have more pictures. Anyhow get the manual for your car and read the whole thing. Most homes have a special room with a built in chair for such reading. Enjoy


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## few2many (Jun 23, 2009)

You've got a lot of reading to do. Start in the Wiki and search threads for your questions.


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## ruckus (Apr 15, 2009)

Geeze guys, throw the guy a bone.

Yes you can make your own adapter. Do you have a drill press and welder? Aluminum in way easier to drill, but harder to weld.

Youtube "ev adapter" etc. There are some good vids of folks making their own. They are all basically the same with slightly different dimensions and hole locations. You may be able to find another model that is close and just buy one and drill some new holes or do some minor machining.

What is your vehicle?


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## few2many (Jun 23, 2009)

I certainly mean no disrespect. He wants to make an adapter plate, which requires some precision, but has limited knowledge and experience on cars. Properly lining up the motor to trans is difficult and misalignment can be disasterous. The reason why I said to check the wiki, there is a detailed area on clutch, or no clutch, the pros and cons. You could go either way, although I beleive the most popular is without.


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## dman58 (Sep 13, 2012)

thanks for the suggestions. i will definitely read the wiki about the plates. also you are right, this is my first time working on cars in general lol. the car i am working on is a porsche 924 (1980). from the websites ive looked at it seems like the only adaptor plates people are selling pre made are for the porsche 914. also whats the fun in getting a pre made adaptor plate?  

also i am definately looking for a setup that retains the clutch (assuming that you could not shift with a setup that bypasses the clutch).

regarding reading the car manual, i have the original owners manual (with lots of water damage), and i printed a 312 page parts catalogue (on the printer at my school ). im not planning on reading them all at once but rather consult them as necessary. once i take the gas engine out of the car i would probably be able to solve my clutch questions just by looking at it, but i think its good to plan everything out before i just tear into it. unfortunately the schematics in the parts catalogue doesnt include dimensions .

anyways thanks for the help i will definitely read the wiki. ill post in here again after i read it with any more questions. but please, if you have any more suggestions or words of wisdom by all means...


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## few2many (Jun 23, 2009)

You can shift without the clutch. Takes some practice and skill, not too hard at all. Although, it is rough on the synchros! You would likely only shift once or twice anyhow.


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## onegreenev (May 18, 2012)

dman58 said:


> first off i am sorry that i am completely new to electric car conversions and am currently starting my first one.
> 
> i decided since i have a less common model of car, i need to get a custom made transmission adaptor plate. i have some experience with machines so i would like to mill one myself. heres my questions:
> 
> ...



Well, What kind of car DO you have? Maybe someone has done one. Many be, Just maybe there will be someone to help. Maybe you might think of buying one already made? 

Well?


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## dragonsgate (May 19, 2012)

It would be interesting to know what kind of car you are converting. My suggestion of a manual was due to the uncertainty of the location of the clutch. It will also help with many other steps in the conversion. I read and tried to get as much info I could for several years before I started a conversion. I made sketches and drafted out the way it would go together before I did anything in the way of an actual conversion and still wound up making mistakes and changing things. Trying not to sound abstentious but I did my conversion with out any real outside help and managed to muddle through. With the eagerness of everyone on this forum to help (many with hands on experience) you stand a good chance to do a good build.


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## few2many (Jun 23, 2009)

Not to post for the OP, but he said it was a 1980 Porsche 924.


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## dragonsgate (May 19, 2012)

dman58 said:


> thanks for the suggestions. i will definitely read the wiki about the plates. also you are right, this is my first time working on cars in general lol. the car i am working on is a porsche 924 (1980). from the websites ive looked at it seems like the only adaptor plates people are selling pre made are for the porsche 914. also whats the fun in getting a pre made adaptor plate?
> 
> Thats the spirit!
> 
> I completely missed that whole post telling what kind of car. Before you start yanking motors and stuff take pictures of how things are hooked up and measure them for future reference. Also record the position of the engine and transmission so when you replace the electric motor transmission combo you can get them at the same angle. When I did my X19 I just jumped in and started pulling stuff out. Later I sort of regretted my brashness. Luckily I had worked on Fiats long enough to remember how thing went and the big butt saver was the fact that I still had another X19 I was driving at the time to use as a reference.


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## mk4gti (May 6, 2011)

Just to chime in with my experience.

I tried to make my own coupling using the crankshaft end, and drilling it using a drill press and precise digital calipers. Needless to say, it was a disaster! a fraction of a thou will throw the flywheel into a wobble/wabble. 

The plate itself is not too bad, but again you need to be very very precise.

There are a few places that you can "cheat" when building an EV. This is not one of them, unless you have a decent lathe, experience and lots of time to throw at it. my 2 tar sand covered cents.


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## ga2500ev (Apr 20, 2008)

dman58 said:


> first off i am sorry that i am completely new to electric car conversions and am currently starting my first one.


Welcome aboard.


> i decided since i have a less common model of car, i need to get a custom made transmission adaptor plate. i have some experience with machines so i would like to mill one myself. heres my questions:


This is where I currently am in my conversion. I've been stuck here for quote a bit.


> should i use steel or aluminum?


Whichever works for you. Note that steel is heavier.


> how thick should the plate be?


Depends on the material. Most designs I've seen used 1/2 inch plate for steel and 3/4 inch for aluminum.



> where can i find the dimensions to cut for attatching the motor (warp 9)? (obviosly ill measure where to cut and drill for the transmission holes).


Should be a plate pattern in the datasheet for the motor.



> here is the main thing that is confusing me right now.
> 
> sorry again that i am such an amateur, but is the clutch for the stick shifting on a manual transmission in the bell housing?


Yes, it is.


> i would imagine that it is between the motor and the transmission. also once i mount the motor will i be eliminating the clutch functions and only be able to drive in one gear?


It's not as cut and dried as this with an EV. While it is difficult to change gears with an engine engaged, it is a lot easier to do with an electric motor. This type of connection is called clutchless. It facilitates a direct connection between the motor and the trans, which is not nearly as difficult to construct.

The final item is that you can change gears in both modes. But with both electric motor torque and RPM characteristics, there is a lot less need to change gears. One can go from 0-40 MPH in second gear with no problems for example.



> i need to find a way to attatch it so the clutch would work like on a gas car. would i thus need to make multiple plates layered or something to achieve this? please help.
> 
> thank you!


I always planned on clutchless, so I can't really help you there.

ga2500ev


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## few2many (Jun 23, 2009)

1/2" steel plate??? Guess it depends on how large of an adapter you need.


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## skooler (Mar 26, 2011)

Have a look at posts 45, 51 and 52 on my build thread for an idea of how to do it with a clutch.

Mine was a DIY job - admittedly I gave the measurements to a local machinist to actually make it as I don't have the kit. It works absolutely perfectly.

http://www.diyelectriccar.com/forum...onversion-formally-good-motoriii-61556p5.html

Cheers,

Mike


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## Woodsmith (Jun 5, 2008)

To do a DIY adaptor isn't too difficult if done with care. This is the process I have learnt from being on here and looking at youtube videos.

On thing you need to do first is to measure the 'magic number' which is the distance from the back plate of the ICE to the friction face of the flywheel. This will be needed to get the clutch, if you are using one, or the splines of the clutch centre for a solid coupler in the correct location.

Once you have that then an adaptor plate can be made using two aluminum plates.
Aluminium plate is easier to use as it is soft enough to cut but also the surfaces are generally flat and parallel, unlike steel plate which can cup and distort when flame cut to size for you.

With your motor to hand, and the magic number to get the clutch/coupler in position, you can work out the gap between the motor DE (drive end) face and the face of the transmission's bell housing. That will determine the thickness of the adaptor plate.

Make one plate to fit the bell housing mounting bolts and have an over size hole in the centre. Make sure the locating dowels are a good fit to locate the plate.
Make a second plate to fit the motor with enough over size to put a ring of bolt holes around the plate so it looks like a pipe flange.

Bolt the plates to the respective components and for the flywheel and clutch or coupler.
With the transmission up ended on the floor and made secure, lower the motor assembly onto the trans locating the clutch/coupler as you go.

The motor will rest on the trans with the freedom to be moved about a small amount.

Apply 12v to the motor so that it is spinning the trans. Gently nudge the motor about on the adaptor until it runs smoothly and quietly.
That will be the position to bolt the two adaptor plates together.

Carefully scribe a line around the motor plate onto the bell housing plate for the position and also a couple of marks for the orientation.

If that is accurate then the whole lot can be disassembled again.
Place the two plate back together, located by the scribe lines, and secure with G cramps.
Drill some bolt holes, that can be tapped to size, right through both plates.
Tap out the ones on the bell housing plate and drill to a good clearance on the motor plate.

Reassemble the whole lot as before and, with the motor running at 12v and nudged into the smoothest running position, insert the bolts and tighten up.

Remove the trans and the motor from the adaptor plate but leave the two plates assembled.

Drill locating dowel holes through both plates, at least two dowels are needed, and then drill and tap any further bolt holes.


That gives you a two piece adaptor plate that is well located for both the motor and the trans and should be thick enough to get the magic number right.
If the adaptor needs to be thicker then can be achieved with two plates then do it with three, the process is the same.

For the one I make for my aborted MR2 project I used 19mm thick aluminium. For the first motor on my tractor I used 22mm thick.


You can do a search for the adaptor plates made by others.
Here is a good one:
http://www.diyelectriccar.com/forums/showthread.php?t=38895&highlight=adaptor+plate


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