REIMAX (Collar clearances, pics)

[jdms13rhd]

yep. Same could be with the pumps if you think about it.

It is the milling after all that is the problem with the drives.

Tho, If there is that large tolerances, Nissan should shake their heads in shame! haha. But your die wear theory is also inconsistent with the cranks we all have seen (referring to any wide drive R32 and r33). Ive had many many of them in my hands and they all have been the same. Yet to see any used nissan crank without the 3/16" contact wear patch when pulled and over the years I've probably seen most of the crank drive photos on the forums and google pic searches (like most people that have spent any amount of time looking into it).

Its all messed and after 15 years with no definitive anwsers, there is just going to be thread after thread after thread on this issue. :S But at least its now not a (buy a jun collar or wide drive crank) and your set.

[gtrjon]

yea allen ill be swinging by evolution tom afternoon some time prob but feel free any time you get a chance to go in a measure the crank with your oe pumps. my crank is sitting ontop of my gtr still in the box lol i would really like to know what kind of clearences we are going to c

[Black BNR32]

maybe nissan uses a wide tolerance for acceptable crank sizes...causing some to be too loose, and some to be super tight, just a thought.

it appears so, yes.

[Black BNR32]

Nissan should shake their heads in shame! haha...

yes, although there is several mating surfaces on top of each other, causing stacking tolerances - crank/collar to internal gear,internal gear to external gear, and external gear to pump bore. but, imo they should be able to hit a total of 5 thou total between all these mating surfaces.

FWIW, a competent machine shop/machinist will be able to hit a tolerance of +/- .0005 using a cnc lathe or mill. i have to spec this tolerance often at the machine shop i work at.

[jdms13rhd]

it appears so, yes.

If that really were the case tho, we would see differences in wear on all these cranks wouldn't we. Not the exact same 3/16" contact wear on the inner gear and drive. I bet I have seen about a hundred Nissan cranks in person and hundred on the webz, narrow and full drive. All with the same 3/16" wear pattern. So if their tolerances were really that wide, there would be some irregularity in that.

[Black BNR32]

If that really were the case tho, we would see differences in wear on all these cranks wouldn't we. Not the exact same 3/16" contact wear on the inner gear and drive. I bet I have seen about a hundred Nissan cranks in person and hundred on the webz, narrow and full drive. All with the same 3/16" wear pattern. So if their tolerances were really that wide, there would be some irregularity in that.

hmmm, interesting. then i agree. would the tolerance need to be that large to account for runout and or/deflection, i wonder?

[GTRADDICT]

Ok... time for a conclusion. What is the best thing to do? Buy a pump, mesure the ID gear get a collar made?? It's a critical part/problem and they're alot of info going around.

*This post is to help avoid mistakes in reading...

[tryingtobebest]

All right, heated discussion!

Here is an oil pum drive measurments:
But i wouldnt trus muself much, i did couple but still... all in mm - 40.77; 40.72; 40.75

[jdms13rhd]

Ok... time for a conclusion. What is the best thing to do? Buy a pump, mesure the ID gear get a collar made?? It's a critical part/problem and they're alot of info going around.

*This post is to help avoid mistakes in reading...

Its been 22 yrs and there hasnt been a "fix" yet. There wont be a solid conclusion for some time I would think or ever. Its really all food for thought.

[GTRADDICT]

Its been 22 yrs and there hasnt been a "fix" yet. There wont be a solid conclusion for some time I would think or ever. Its really all food for thought.

k k.. Well that sucks... It's the biggest flaw of the RB and it's a really BIG one.
This would be my solution.

1. Buy the pump you want
2. mesure the ID of the inner gear
3. Find a machinist, like yours, that can provide good material and good clearance (0.002") on both sides for the collar

[Black BNR32]

+1....

[jrhdohc]

Sorry I didn’t catch this post earlier.
I talked to the president of the company and showed him your pictures. He stated that will not cause a problem. I spoke with other engineers about this issue. They believe the stock gear when pushed beyond “normal” flexes causing failure. They stated the new gear will not break.
I will ask sometime this week what happens if the crank to gear clearance is super tight. It’s worth testing but it might be difficult to remove during the next rebuild. But anyway I will ask the senior people.

[GTRADDICT]

Sorry I didn’t catch this post earlier.
I talked to the president of the company and showed him your pictures. He stated that will not cause a problem. I spoke with other engineers about this issue. They believe the stock gear when pushed beyond “normal” flexes causing failure. They stated the new gear will not break.
I will ask sometime this week what happens if the crank to gear clearance is super tight. It’s worth testing but it might be difficult to remove during the next rebuild. But anyway I will ask the senior people.

Are you talking about reimax???

[drew6]

Thought I would throw this in:

About a month ago I purchased a Reimax gear set and sent Reimax an email asking about the extra crank clearance. I just got an email from RHD Japan who was contacted by Reimax about my enquiry (they don't have any English staff) and they were kind enough to get this message to me from Reimax: "'Crank flexes at high rpm. tight clearance causes the gear to contact oil pump housing. tight clearance is only good for low rpm. bigger clearance allows crank to flex without breaking gear or housing'"

It sounds like they purposely built in the extra tolerance.

Food for thought.

[Dragon Humper]

That makes sense, it's a long crank, plus there is the thrust clearance to take into account. I think it's really a very fine ballance of having the clearance a tight as possible without having the drive gear affix itself to the crank during ALL possible heat/flex cycles.

Whenever my motor comes apart I will definately be going this route, best bang for the buck.



Jon.