EK to HR diff conversion driveshaft modifications for M20 fourspeed

Includes clutch, transmission, propeller shaft,
universal joints, differential and rear axle.

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Brett027
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EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

What driveshaft modifications do I need to do to connect between HR diff and M20 four speed gearbox?
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Blacky »

You will need to change the rear uni , not sure about the spline into the box or the length - there is probably an early Holden tailshaft that will go straight in but they are starting to get thin on the ground ..... maybe an EH shaft ?
When you're faced with an unpleasant task that you really don't want to do, sometimes you just have to dig deep down inside and somehow find the patience to wait for someone else to do it for you.


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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by fb delivery »

I use i think is a LH for m20's and i think a LJ for w57's 5 speeds

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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by ardiesse »

If you have an HD or HR, you use a Slide'n'Glide driveshaft and gearbox crossmember with an M20, so I'd guess an EK Hydro driveshaft would be the starting point here.

Rob
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Errol62
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Errol62 »

I used an EK hydramatic tailshaft behind M20 years ago. It worked although on the long side. The motor was well back, with the seam lip shaved. Got an LC one I picked up at a swap meet which is about 1" shorter I intend to use with the 3 speed in the ute. All synchro 3 and 4 speed and Trimatic all seem to be exact same length or near enough.

Wouldn't be dear to get your old shaft shortened and balanced.

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Brett027
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

Many thanks everyone. I have had a look and the black ute that came with 186 and powerglide has a front yoke that fits the M20 as has been suggested. That shaft also has the later ubolt universal joint set up that suits the HR diff so its only the length I guess that needs sorting. Thanks again😀
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by ardiesse »

Powerglide's the same length as an M20, so - you can just bolt everything up.

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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

Surely it won't be that easy???? Thanks Rob. I will start worrying about another problem now😀
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Errol62 »

The LC must be a slightly shorter wheel base than FX HR and hydramatic, Australian manual and auto all about the same. Maybe the hydra a bit longer. I fitted a Borg Warner 5 speed in my hx and got the soft shortened to suit and balanced.

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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by 62ekute »

Brett027 wrote: Tue Jan 25, 2022 7:49 pm Surely it won't be that easy???? Thanks Rob. I will start worrying about another problem now😀

finishing off this thread already Brett? no-one got to talk about beverages yet

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Brett027
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

Great photo Pat. Just as well it wasn't washing day😁
I suspect the thread will spring back to life in a month or so when I attempt to connect the engine to the wheels.
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

New problem. Can I buy a clutch and pressure plate to suit the M20 that will bolt onto a black 202 motor Flywheel ? I think that the black motor clutch is slightly larger diameter than red motor?
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Errol62 »

It all bolts up Brett. Black 202 flywheel is lighter due to the heavier counterbalanced crank, but they are interchangeable with red motor flywheel. The pressure and clutch plate should be interchangeable from FX to VK, subject to bell housing clearance, but that is only an issue on the crash boxes.

Are you using the HK to HJ, LJ LX mechanical clutch type bell housing? There is a Dellow or Hadfield cast bracket that adapts your original slave to the later clutch fork. They work well although I have known the cast brackets to break.


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Brett027
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Re: EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Brett027 »

Thanks Clay. I tried an fb clutch and the input shaft size on the M20 is bigger. It's 28.3mm with 10 splines. I have been told black motor clutch is slightly larger diam than red motor- is this not right?
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EK to HR diff conversion driveshaft modifications for M20 fourspeed

Post by Errol62 »

Now I recall that I used red motor flywheel and clutch bolted up to blue 202 crank. This was only a temporary fit to ensure the motor was a good runner. I haven’t used the blue black 202 flywheel, but research tells me they have a larger diameter bolt spacing for pressure plate, and that fouling on the rat trap bell housing can be an issue.

The later cable clutch bell housing ought to work with the black flywheel but then you need to convert your pedal, which isn’t that hard. Also may help with booster clearance.

If you needed to use a red clutch you could easily get the black flywheel redrilled. You’ll want to get it machined and balanced in any case. If you used a red flywheel you would need to use a lightened one.

I’ve generally run trimatic behind blue motor.


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