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Discussion Starter · #1 ·
Right, So far in my search I have not found anyone discussing crank/ oil pump gear clearance on this forum, most of this has been taking place in Canada on their forum: See below:

REIMAX (Collar clearances, pics) - Page 7

I have found this rather interesting and the variations between collars, cranks and drive gears with varying levels of clearances.

I measured mine today (just the reimax gear) on a brand new crank. Clearance was 0.17 one side and 0.16 the other.

So a question for the experts on this forum, should there is a loose or a tight clearance between the drive gear and the crank? What is an acceptable clearance?



 

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I guess if it's not something you can change there is little info on it.

Shame, I was looking forward to see that info was about.
 

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Discussion Starter · #4 ·
Easier option is to get a crank collar made up with a tighter clearance. But the question remains, Why did Nissan design this with such a clearance? To compensate for crank deflection?

People over in Canada are convinced that this is what causes gear to shatter as people bounce of limiters. They also talk about 3/16 of an inch contact as per my second picture/
 

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Yeah I got a custom crank collar made to suit my Nitto oil pump for my RB30 crank. Not sure what the Engine builder used as a clearance amount, but he didn't like the off the shelf ones, he wanted to make sure it was a better fit
 

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Discussion Starter · #6 ·
A crank collar car still be fitted to the wider drive R34 crank right? I would guess the machine shop would have to grind away the normal drive portion on the crank and press for the collar right?
 

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You turn off the original feature and make it parallel. You then heat the drive coller and slide it over. It shrinks on and you grub screw it in place.
 

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What do the oil pump manufacturer recommend?
 

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I think Nissan would have splined it if they could have made it cheap enough back in '89. Flat drive is a cheap design and always creates massive contact stresses at only 2 points. A spline distributes the load around the circumference and lowers the stresses in the pump gear.

Clearance makes little difference to the poor contact areas with flat drives and I guess Nissan left a little to help with tolerance buiild up with block, pump and crank
The bigger issue is the hammering between crank acceleration and deceleration if the clearance is too large. I would think that a thicker viscosity oil would reduce hammering.
 

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Discussion Starter · #11 ·
A spline setup can be designed but would be expensive. I believe the supra has the spline setup and you never hear about pumps breaking.
 

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Discussion Starter · #14 · (Edited)
Just remembered Arnout's pump.

http://www.gtr.co.uk/forum/220193-made-my-own-oil-pump-3.html#post2290305

Easier solution would be to make a spline fit version of the Reimax inner gear coupled with a Brian Crower Supra oil pump drive and shrink fit to the RB crank.

Brian Crower Oil Pump Drive Gear 93 98 Supra 2jz 2JZGTE | eBay

These guys in Russia have done the same but with a Tomei pump and credit to them for doing it!

http://www.nismo-club.ru/forum/index.php?showtopic=102389&view=findpost&p=1062255108
 

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Discussion Starter · #16 ·
There does need to be some play to take into consideration of harmonics and flex of the crank, but overall is a better solution no? would prevent the gear from breaking .
 

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its alright messing with it as long as it doesn't end up less reliable than it was to start with, it is always better imo to have a little more tolerance than not enough which will end in catastrophic failure.
 

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I am installing a custom crank collar as I do the single turbo build.

Not really sure, but I think its bigger or wider. Ill have to ask the seller who customized this.

So any further information gathered?
 
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