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RB25 flywheel to L series Question


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I still haven't put the box in, Had to go to hospital for back injections but will post soon.

New 2 z, I'm surprised the flywheel fitted . The rb20 must have the smaller crank hub or the L flywheel would not have gone on. Good to know though as I searched and got the impression all the twincams and the rb30 were the same.

If anyone knows the rear crank boss dia for all the motors for sure, the info would be appreciated

 

I will go out later today and measure mine and I'll post up the info. If it works for a RB20 it will work for a 25/26/30/24/ whatever RB you want.

 

I'll measure the small boss and then the large boss as well. My L28 flywheel has a large circle ring on it to sit on the crank and a small hole for the pilot bushing, but it works nicely like this.

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I received my starter today and it cranks the motor over fine, don't know whats all this mish mash of 6mm out, MAYBE 1.1mm but the flywheel and starter are NOT a high precision part like a crank and bearings or cam and cam cap placement. The only reason one exist is to start the car that is all.

 

I need to pull it all apart as i have a sleight rubbing on my transmission flywheel dust cover but that will be sorted and fixed.

 

I have a RB20, L28 flywheel, L28 clutch kit and a RB20 starter.

 

I need to measure the bosses on the flywheel and RB20 I will do that later this week, my hand was badly injured after slipping off a ratchet and hitting a rb20 cam sensor open plug NOT A FUN EXPERIENCE! (I was turning the crank to make sure no rubbing went on).

Edited by New 2 z
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For some reason the vidio dosen't work.

I put my box back in and the pressure plate just touches the bellhousing above the starter hole. 

Will post when fixed, just a small grind on the corner back to 45 deg and should be fine.

Could just be the clutch I got , as others don't have this problem.

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The box is in again, the chamfer fixed the clearance issue.

I put the slave cyl on and found the bolts a bit long , so they clipped the pressure plate. Found some the right length ,  problem solved.

Clutch travel looks good and has a bit of free play, looking good so far..

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Starter works well, quiet, enguages nicely, I don't forsee any problems.

I will post again after some racing.

If anyone has the flywheel hub sizes for RB20, RB26, RB30 , Please post them up.

L series 80mm

RB25 81mm

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New 2 z ,

In all my searching so far the RB 20 should have the 81mm crank.

They do have the same bolt pattern , so it's possible you are just pulling the flywheel up against the step.

I strongly recomend you check , as it will cause big problems if i'm right.

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I will go and pull it apart again, I do remember the bolt holes sitting flush when I bolted it on but I will go and double check!!! Thank you for bringing this up! I'm not sure if the RB's have the crank seal ring to mount I know the VG30E's dont but they have a hub ring to mount on, maybe it was the other way around, been so long since I've done a clutch on a VG30.

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This is a fairly easy mod.  But like others have said, you must cut a sleeve (ring) to center the crankshaft in the flywheel ring.  In addition to the sleeve (ring), I also pinned the crankshaft.  The mod gives you a greater selection for flywheels.  Works great!

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New 2 z ,

In all my searching so far the RB 20 should have the 81mm crank.

They do have the same bolt pattern , so it's possible you are just pulling the flywheel up against the step.

I strongly recomend you check , as it will cause big problems if i'm right.

I checked this out yesterday the lip that you are talking about its OVER the lip of the RB crank. I had red paint to confirm this and make sure it was sitting flush with the mating flange. need to upload that video when i have a chance, im sure the RB crank is 79 or at most 80mm (the lip where the rear main slides on) .

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The flywheel is now 6mm away from the stock position , the rb crank is shorter than  the a L motor  crank by 6mm so the off set in the flywheel is made to sit 6mm away to make up for it , why not run a stock flywheel , saves heeps off problems

I would like to see side by side photos for comparasion. I have a hard time believing this as i see their the same bore and cylinder spacing looks the same as well as the same number of mains.

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Good it all fits up for you.

All I can think of is your crank been machined or the plastic calipers aren't accurate. I haven't seen the back of a 2 plus 2 flywheel but it looks like the cast recess is the same as the rb ones. Are you sure it's a 2 plus 2 and not rb? 

If it were an rb fwheel it could just be the plastic calipers are just measuring 1mm out.

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