Adaptor plate thickness...

[El_Freddo]

Hey all,

I've got my EJ, now I'm trying to source some steel to make an adaptor plate on the cheap - When I get the funds sometime I'll drop the EJ gearbox in after the initial conversion is done and running well.

The question I have for you is: What's the minimum thickness of steel I'd need to make an adaptor plate?

I can get some 9mm from my uncle but that seems a little thin - I'm sure it'd be strong enough for the job but my understanding is that the head of the bolts needs to be recessed into the adaptor plate to clear the engine or the gearbox.

Am I on the right track here?

Any experiences/knowledge shared will be greatly appreciated.

Cheers

Bennie

[D3V1L]

13mm

recesss bolts?? what are u on about...the threads u tap into the plate need to be enough to grab on, andimpretty sure it needed to be 13mm thick for some other important reason too


dave

[SuBaRiNo]

It was once explained to me by someone with a lot more knowledge than myself, that 12mm is the exact difference in bell housing size between EJ and EA. To get the perfect alignment and throw or your Starter motor 12mm is what you should aim for.

I have seen people go as thick as 16mm but never higher than that and never lower than 12mm.

Dave

[D3V1L]

sorry..12mm..... lol...made me look bad dave

[SuBaRiNo]

LOL... i was trying to work out where you pulled that number from. Poor guy is probably trying to find a 13mm bit now... would guess that would be kinda difficult to find.

Dave

[AndrewT]

I can confirm, 12mm is the thickness of Aluminium all us who have made them over here recently have used. but 1 or 2 mm thicker or thinner probably won't make a huge difference but might make the clutch feel different.
12mm works.

I've found the best method of making them is NOT via getting a template of the shape from somebody and trying to make another one. This just doesn't work. Even the ready made lazer cut ones you buy form BYB are way off, the bolts just don't line up and people have to elongate the shit out of their gearbox holes.

It's pretty easy to just make them yourself using the actual engine and gearbox as a guide - this way there is no chance of it not lining up!

I made this up as I went along and it worked out okay....I'll try to remember the steps off the top of my head;

- Put your EJ engine and EA gearbox on the floor, you may need to prop them up slightly on some wood etc as you will need to test fit them together lots of times.
- Work with the clutch/flywheel removed from the engine
- The EJ engine has two threaded holes at the top, and two long threads at the bottom.
- Drill out the threads in the top two holes of the engine - that's right, we just need holes there, not threads. Be very careful of the black plastic breather lines behind them, it's easy to hit them with the drill.
- Get a square of aluminum (or steel) 12mm thick
- Hold the ally against the engine and mark where the two bottom bolts touch the ally
- Drill two holes in the ally at the right position for those two long bolts
- Slide the ally onto the motor on the bottom two bolts
- Use a texta and mark out the outline of the outer edge of the engine on the ally
- Take the ally off and cut that shape out of it
- Put the ally back onto the engine
- Slide the gearbox onto the engine's bottom two bolts....you won't get far before the input shaft of the gearbox hits tihe middle of the ally - mark where it does
- Take the ally off and cut out a rough hole for the input shaft to poke through
- Slide the gearbox on and put the bottom two nuts on the long bolts and do it up tight - look's good doesn't it!
- Get bolt bolts the right length to pass through the holes you drilled out in the top of the motor and grab most of the 12mm of adaptor plate
- Put a dob of black paint on the end of them and pass them through, this puts a mark on the adaptor plate
- Take it all apart again and drill these holes into the adaptor plate, you will need the correct size drill bit and tapping set so you can tap out a thread in the adaptor plate here
- Re-fit and test the bolts to make sure they go through and do up properly
- While it's together again do the same but this time with another two new bolts to pass through the top two holes in the gearbox and into the adaptor plate - mark the holes with a dob of paint, take it all apart, drill and tap them. Note that they are slightly off-set to the other holes you drilled and tapped, be very careful as they are very close.
- Now fit the flywheel (obviously this requires that you've already modified your EA flywheel to suit the EJ engine)
- Slide the adaptor plate on and roughly mark out a circle big enough to clear the flywheel - take the adaptor plate off and cut this out. This does NOT have to be accurate at all, solong as nothing is in the way of the flywheel it's fine. Be careful you don't cut too close to the top holes you drilled and tapped, you will have to get fairly close though.
- Reassemble everything and now grab your starter motor, try to put it in, it will hit the adaptor plate, roughly mark out where you need to cut to provide clearance for the starter motor, take it apart again and roughly cut this out.
- Reassemble everything and you are done.

Note that some EJ engines have little locater things sticking out and some don't, you just need to drill little holes or cut little divits in the adaptor plate to clear these.

Here's some random photos from when I made WackyBug's one;
http://members.iinet.net.au/~carine3/IMAGE_4.jpg (metric tap inserted)

http://members.iinet.net.au/~carine3/IMAGE_2.jpg
(Bolted to the motor - note the two sets of two offset holes at the top which have been tapped. This also shows the locater things this motor had, just had to drill some holes for them to poke through)

Now there's bound to be a few more things I've forgotten in between, that's just a rough guide, but it's not too hard to do, that's the gist of it.

[Subafury]

wow great description andyt. u remember all that from thee top of your head? follow that benny and you'll be fine. once you start doing it its easy to work out what needs to be cut/drilled. just be careful of the clearance between the top 4 holes u have to drill n tap.

also my ej thread has a fair few adp plate pix. use ally instead of steel benny because itd be really hard to jigsaw out a plate of steel! the ally takes long enough as is.

btw ive still got enough adaptor plate ally for anyone in wa that needs to make one.

[Ben]

Here is the series of photos I took when I made my plate from 16mm Aluminium.


Make sure the gearbox is actually going to fit

Rough cut some 3 or 6mm ply to shape

use the ply as a template

cut that out and drill bottom two holes and trial fit


I had a dummy box to use in fitting so could trial the box too

Cut the inside bit out

Drill holes

Tap holes where necessary - a 10mm x 1.25 thread tap will cost you about $18 and is necessary...

My adaptor is for sale though now. Any one who wants it just make me a reasonable offer. Yes it works, and has been used in an actual converted car.

[El_Freddo]

Okay, so let me get this straight - the bottom studs on the engine bolt up to the gearbox and not the adaptor plate right?

I thought all four holes needed to be re-drilled to fit. I'm not real keen on those top 4 holes being so close together, but I guess that it works after seeing how many people are using them.

I'll start hunting for some 12mm steel or alloy, this could take a while due to $$ factor and uni time, its the "business" end of the year now. Fun fun.

Thanks everyone. Andrew T - that write up is great, I can picture how you do it.

Just one question - do you not make up a block plate to space the flywheel out with the gearbox? I thought this would be a must for the starter to line up and the clutch to work properly... Is it not recommended to do this?

Cheers

Bennie

[D3V1L]

nobody has ever mentioned this block u speak of benny

the whole reason the gearbox adaptor plate is that thickness is so that the flywheel is in the good spot with the starter motor etc


dave

[AndrewT]

yeah, not required. the 12mm plate amazingly takes care of a few things. The flywheel is in the right place, and the engine is also in the right place so the engine mounts just fit into the standard places.

The bottom studs come out of the engine, they pass through the adaptor plate (no threads need to be tapped into those hole) and out the other side of the gearbox - nuts go there - just like normal.

[El_Freddo]

the whole reason the gearbox adaptor plate is that thickness is so that the flywheel is in the good spot with the starter motor etc

Right o. So the EJ has a different bolt up point to the EA in reference to the flywheel... Makes sense.

The 9mm plate I can get - I'm guessing that will be a little thin for the likes of drilling and tapping threads on the top four holes? I could space the starter motor back with some washers like you do with the 5spd in the MY...

Hang in there guys, I'm just trying to nut this thing out - the budget is rather tight and I've still got all the wiring to get yet...

On the note of wiring - I'm looking at replacing all the wiring in my L with that of a touring wagons. Is it easier to get a carbie loom than the MPFI's to splice the EJ wiring into?
Any takers on that one ^ ?

Cheers

Bennie

[D3V1L]

shouldnt make a difference in reality, as long as the engine loom is cut down to minimum.

only a few wires required to be spliced ie: ignition, on, starter, oil pressure, temp, tacho, fuel pump, earths.. and prolly couple i missed

the same wires would need to be spliced into regardless of which loom u use:P

dave

[AndrewT]

yeah definitely get 12mm.

on the other subject of wiring, yeah, doesn't make too much difference really. if converting an MPFI car it's slightly more convinient because you can splice in those connections Dave mentioned at the point where the old EA ECU sits because they all go there anyway. With carby you have to trace the wires from the dash lights and gauges, but once it's done it's done. Not much of a drama at all.

Methinks you should start a thread for "Benny's Conversion" to fill it with all the many questions and answers

[El_Freddo]

Methinks you should start a thread for "Benny's Conversion" to fill it with all the many questions and answers

Hehehe... I should be marking assignments but I'll get that started

Bennie

[El_Freddo]

Okay, that conversion thread is here.

I hope that'll explain where I'm coming from with some of my "ideas".

Cheers

Bennie

[AlpineRaven]

make this sticky....
Cheers
AP

[AndrewT]

Regarding the metric taps, I think it's worth spending a little extra and getting a set of three - I got one which comes with 3 bits, a starter, an intermediate and a finisher. Taps the thread out in 3 stages which gives a much cleaner finish, less chance of stuffing it up.
I rekon if 16mm ally works then use that thickness, the more thread on those top bolts the better. Some people get scared using ally cause it's abit soft, but amazingly the threads hold up very very well. I know Alex's plate has been in and out a few times due to engine and gearbox swaps....Subarino's must be getting to at least 10 times plus now hey Dave? Threads still fine.

[AlpineRaven]

Regarding the metric taps, I think it's worth spending a little extra and getting a set of three - I got one which comes with 3 bits, a starter, an intermediate and a finisher. Taps the thread out in 3 stages which gives a much cleaner finish, less chance of stuffing it up.
I rekon if 16mm ally works then use that thickness, the more thread on those top bolts the better. Some people get scared using ally cause it's abit soft, but amazingly the threads hold up very very well. I know Alex's plate has been in and out a few times due to engine and gearbox swaps....Subarino's must be getting to at least 10 times plus now hey Dave? Threads still fine.

Yeah I agree about the taps, I have one as well from M3 right thru to M16, bought it about 4 months ago for $50 reduced at TotalTools and its worth it (commonly use M6 & M8) and yes it comes with starter to finish in 3 different types but 1 size. Otherwise you can buy single set but costs more than a set for what its worth.
Cheers
AP

[Matatak]

i didnt tap any threads into my adapter plate.

works perfect