[FRRACER]

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?

 

[FRRACER]

Seems like no one is bothered here in the UK about clearances then? :nervous:

 

[R32 Combat]

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.

 

[FRRACER]

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/

 

[Sub Boy]

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

 

[FRRACER]

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?

 

[R32 Combat]

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.

 

[FRRACER]

Still trying to find the answer to what is acceptable and what is not...

 

[R32 Combat]

What do the oil pump manufacturer recommend?

 

[lightspeed]

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.

 

[FRRACER]

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.

 

[AlexJ]

Did NITTO ever release the spline drive they were testing?

From what I've read the clearance you've measured there may change with the crank in the block and the oil pump mounted as the centrelines may be off by a small amount.

 

[FRRACER]

I will have to search for Nitto's solution and the spline drive fitting.

 

[FRRACER]

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

 

[AlexJ]

I've seen it suggested the tomei innergear is the same as the supra, with spline drive and to fit the rb they add a collar to convert the "two flats" RB drive into a supra sized spline, i think their collar still has fair amount of clearance.

 

[FRRACER]

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 .

 

[AlexJ]

Yeah and i guess with spline drive you can have that bit of radial clearance to take account of centre line and harmonics but the splines stay more engaged than the two flats would as they slop around every time the thing loads up.

 

[scoooby slayer]

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.

 

[FRRACER]

Are we talking about flat drive or spline drive clearances?

 

[camlob]

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?