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I've searched a ton and can't find any answers, so I'm hoping someone can help. 

I have an early RB26DETT with the short collar crank and I'm about to fit a Tomei oil pump to it. 

The instructions for the oil pump read that the pump is only compatible with the 'late model Kouki crankshaft, made after August 1991." ( http://www.tomeiusa.com/manuals/TB203.pdf )
...but I haven't seen that anywhere else, not in product descriptions, or anyone who has had issues online. 

have read that people can't use a Tomei oil pump on cranks that have been fitted with an aftermarket collar. 

So, I'm wondering what the best solution is. 
a) is it okay to use the Tomei pump with the early crank, even though the contact point is smaller on the early crank?
b) is there a specific aftermarket crank collar that would work with the Tomei?
c) do I have to upgrade the crank to use the Tomei pump (might as well rebuild the entire engine at that point!!! ugh)

Thanks for any help!

What’s the reason behind changing the pump only on what looks like a factory engine? Going to upgrade the sump too? Going to rip the head off and play with restrictors?

Leave it alone until you build it would be my advice. It’s been doing it’s job quite nicely for 30 odd years, leave it alone.

2 minutes ago, Piggaz said:

What’s the reason behind changing the pump only on what looks like a factory engine? Going to upgrade the sump too? Going to rip the head off and play with restrictors?

Leave it alone until you build it would be my advice. It’s been doing it’s job quite nicely for 30 odd years, leave it alone.

Not at all what I'm asking, but I appreciate the concern. 
- yes, I've already installed a restrictor in the head when I upgraded the headgasket and studs
- I've a head drain kit already
- I have an extended sump kit, yes, of course

The stock oil pump will not be doing its job nicely with my upgraded turbos, track time, and intention to bounce this off rev limiter and anti-lag when drag racing. 
 

22 minutes ago, r32-25t said:

You’ll break any pump with the wrong drive on it 

Thanks. Are you saying that this won't work, or that it will break? Or that there's no collar extension or modification that will work? 

He's saying basically if you want to use the Tomei pump use the longer crank drive. What do you think will happen with your "limiter bashing" as you say driving less than half of the oil pump drive contact area ? - It'll wear the oil pump drive and it will break.

So the options are to get an extended crank drive collar fitted (Nitto or whatever) to your existing crankshaft or get get a long nose crank.

51 minutes ago, BK said:

He's saying basically if you want to use the Tomei pump use the longer crank drive. What do you think will happen with your "limiter bashing" as you say driving less than half of the oil pump drive contact area ? - It'll wear the oil pump drive and it will break.

So the options are to get an extended crank drive collar fitted (Nitto or whatever) to your existing crankshaft or get get a long nose crank.

Sure. Thanks for that. 
I'm trying to get some specific information on a solution to fit the Tomei pump to a short collar crank, hopefully from someone with actual experience of having done it (and succeeded or failed). 
Can you confirm that a Nitto crank collar is compatible with the Tomei pump? (because I've seen other forum posts that said their aftermarket collar was not compatible with their Tomei oil pump)

I don't know where that came from. The Tomei pump is compatible with a late long pump drive crank right ? So all the crank collar is doing is simulating it being a long nose crank at the oil pump drive on the contact area for the pump.

Yes a Nitto or Spool RB crank drive collar will work.

Fitting a better pump to the short crank drive is just stupid really.

  • Like 1
1 hour ago, BK said:

I don't know where that came from. The Tomei pump is compatible with a late long pump drive crank right ? So all the crank collar is doing is simulating it being a long nose crank at the oil pump drive on the contact area for the pump.

Yes a Nitto or Spool RB crank drive collar will work.

Fitting a better pump to the short crank drive is just stupid really.

Excellent. Thanks for that. 
Totally makes sense, but I've seen that people have problems. See here:

I suppose I should simply write Nitto to confirm. 

As for it being stupid: I had sourced the Tomei pump because its description stated that it would solve the issue with the fragile factory pump. Before I fit the pump, I measured the contact area and it seemed small. 
So that's why I'm searching and asking around... I don't think there's anything stupid about interrogating solutions and learning, eh?

Again, I appreciate the help. 

Nitto says all aftermarket pumps for their collar.

44 minutes ago, r32-25t said:

Or buy the tomei collar 

Or just do this if worried about it not fitting. I personally would buy a Lewis engines one as they definitely fit a Tomei.

22 minutes ago, Piggaz said:

Crank has to come out to fit the collar doesn’t it? You’d be silly to do that and then put it all back together.

I haven't used a crank collar in over 10 years, but yes it does have to come out. You are supposed to grind the area on the crank where the collar is fitted to be about the same finish as a crank bearing journal - you don't just fit them to an unprepped crank. Then the collar is just heated up and quickly driven on and held in place purely from an interference fit.

7 hours ago, groovezog said:

I am unable to find anything about a Tomei collar existing. Do you happen to have a link to one?

I've got a feeling they are discontinued, but any collar may or may not cause an issue. Read the thread again regarding collars not fitting with a Tomei pump and why they had problems. All of the issues of a collar fouling the Tomei pump is purely because of machining or installation error due to the very tight tolerances of the Tomei pump and drive collar - the standard pumps have a lot more room for error on the drive area. The collars were sitting up too high or they didn't return back to their original clearance once heated - all caused by preparation or installation error.

Any of the collars should fit any of the aftermarket pumps and if they don't you machine to suit. Remember you have to machine / grind to crank before fitting so any error here couldl make it foul.

42 minutes ago, Nocsyn said:

I have a dumb sort of related question. If the crank needs to come out and be machined to fit the collar...why not upgrade the crank as well to be safe?

Why ‘build’ an engine with a stock crank? 73.7 mm sucks.

No point pulling the crank out to fit an oil pump to try and save an engine when how you’re going to treat it, it’s going to break regardless. Leave it alone or DO IT!

6 hours ago, Nocsyn said:

I have a dumb sort of related question. If the crank needs to come out and be machined to fit the collar...why not upgrade the crank as well to be safe?

Because they cost around $1600-$1800 USD. Plus new bearings, and you might as well do seals too. But then at that point, you might as well put in upgraded pistons and rods, which means you'll need the block apart and machined... That's several thousand dollars at that point.
So that spirals out of control pretty easily. 

6 hours ago, Piggaz said:

Why ‘build’ an engine with a stock crank? 73.7 mm sucks.

No point pulling the crank out to fit an oil pump to try and save an engine when how you’re going to treat it, it’s going to break regardless. Leave it alone or DO IT!

Chill, dude. You seem to make a lot of false assumptions about my build and have some idea that I'm only going to hold the engine at redline and hit anti-lag in a parking lot with the sole intention of shooting flames, while doing no maintenance to the car or something.

I've built this car ground-up, from a shell, for racing and it's held up incredibly well. I'd like to setup anti-lag (as I've already done with my two other cars), and know that on instances where I hit redline that the oil pump isn't going to shatter. I think that's a pretty reasonable idea to upgrade the oil pump before doing that, no? 

Anyway, I got in touch with someone at Nitto and they confirmed that their crank collar will work just fine with the Tomei oil pump. I just have to make sure that the backplate opening is large enough. 

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