REIMAX (Collar clearances, pics)

[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

[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.

[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

[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...

[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?

[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]

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.

[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.

[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

[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.

[archaeic_bloke]

I have an interesting story to tell you about...

This past summer I worked in a machine shop, where a learned quite a bit about machining techniques... we had a batch of 35 brass sleeves which act as bushings around 35 stainless steel rods. They are used for elevation shafts on the machines we were building. Anyways, the machinist who I was watching did the first 3 unites and they came out perfect, the fourth was off by a few thou and then wouldn't fit into the brass sleeve. we were trying to find out why, because the lathe was set perfectly the same! it didn't make sense... until we realized that the hardened steel shafts, had worn down the milling bit and caused the shafts to be off by the amount the bit had worn down.

I wonder if the variance in cranks could be attributed to machining variances... like 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.

anyways, heres some photos I dug up of my own N1 pump

Crank




lastly it may be worth considering the crank ratings as an indicator of this machining tolerance...see the numbers stamped onto the journal....

[jdms13rhd]

the last thing I'm still hanging on to is my own personal expeirence. heres what I know to be true 100%
- I bought a brand new R34 crank
- I bought a brand new N1 oil pump

Sitting at home, i took the crank and put it on my work bench... I then took the oil pump and attempted to slide it onto the crank. at first it did not go on and I freaked out thinking something must be wrong...
So I measured the inner diameter of the oil pump gear flat spot to flat spot (stupidly didn't write it down of course!) and I measured the outer diameter of the crank drive collar, again flat to flat, and it was exactly the same.
So after speaking with my engine builder he said that was normal of a new crank and oil pump, and its almost press-fit. the clearance on it was soo tight that it has to be installed perfectly straight, even the slightest tilt from perfect 90 degree perpendicular will cause it to bind during installation.

You know, im still hung up on that as well. Ive seen only a couple r34 cranks and who really knows if they were r34. Thats just what I was told they were. Maybe I take some gears over to Jon and see how they fit on his R34 crank. Maybe that nissan had only some select cranks that were fixed? Its just weird that Nissan would go from a narrow-loose drive to a wide-loose drive to a wide-tight drive and that the reimax gears have a larger ID than the OEM pumps. Anyone on here know what year/engine the gears were produced?. Any of you guys know if the part numbers on different year R34 cranks are the same? Or if the 34 and 33 are the same number??? I've never looked into that.

Jon, next time your heading to Alans shop, give me a ring. I'll pop by with an oe pump and one of my collars. we can measure and see.

I do know that slipping the pump over the crank can be a little tedious sometimes. Only way to measure is to remove the gears. I usually measures the clearances with Two tools. Thats why my numbers at times are a full tho off of the measurements in this thread because they are not in ten tho intervals. I just wanted a centered measurement. Doesnt really make any difference tho.

[GTRADDICT]

we're all on the same page, just that 'deformation' isn't quite the right term me thinks

hey josh, a near press fit is what i would expect, so i agree with your builder.

most will already know, but you can (should) heat your pump gear and/or cool your collar/shaft to make installation easier. you will gain a couple thou of clearance easilly. at least that's how press fit bearings are installed.

+1 same a sleeving.

[Black BNR32]

we're all on the same page, just that 'deformation' isn't quite the right term me thinks

hey josh, a near press fit is what i would expect, so i agree with your builder.

most will already know, but you can (should) heat your pump gear and/or cool your collar/shaft to make installation easier. you will gain a couple thou of clearance easilly. at least that's how press fit bearings are installed.

[gtrjon]

i hope so lol josh i followed you exactly and bought a brand new r34 crank. i am going to measure it with my n1 pump i have already talked to allen and we are going to see the clearences if they are too large i will be getting a collar off him