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Discussion Starter #1 (Edited)
Updated 11/12/16

OK, this all started almost 4 months ago, when out of the blue I started getting e-mails about an oil-pump overdrive set that I was making years ago.
People also mentioned the stock pulley failures that have popped up over the years.

I didn't really want to get back into the ones that I had made back then, as it was a lot of work, and still used the inner hub & spokes of a stock pulley.

So I took a look at just addressing the failure problem.
The plan was to machine a disk to go into the front of the stock pulley, to help support the spokes.
Little did I know what a bag of worms that was going to be......

Found that neither the back surface of the pulley, nore the spacer behind it ran true to their bores.
On the first assembly I grabbed off the shelf, the pulley had .030" wobble.

After a bunch of time, I managed to get the surfaces true by machining as follows:

The pulley




A junk spacer (pitted) I started off with



Hardest part was getting the outer diameter of both parts dialed in to under .001" total run out.
Not something that can just be thrown in a chuck. Probably the reason these oem powdered metal parts have so much run out.

It improved pulley wobble to just .005". Better, but about all that can be expected from a powdered metal pulley riding on a 'D' shaped shaft.
And it didn't address the poor flow capacity of the stock pump.

So I set out to do away with the 'D' shaft set up, and at the same time move to an after market dry sump pump pulley.
By doing that, an improved drive ratio could be incorporated. My favorite is +15%.
 

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that's awesome sixpack. nice find! some times the small things have the biggest results! i have many friends who have worked for the big motor companies and aftermarket supply side IE federal mogul and some of their biggest problems with belt misalignment, harmonic vibration, and pulley failure were +80% caused by some sort of manufacturing flaw like you have just found. ive wanted to make a new pulley for awhile now but don't have a indexing wheel on my rotary table for the bridge port to do so. it would also give you the opportunity to under/overdrive if need be. and for the " damned D shaped hole" have you thought about grinding a tapered broach to do that? my Current project (just on paper at this point) is to machine a smaller pulley for the water pump to aid in flow, but not to the point of becoming inefficient due to cavitation... and unfortunately i dont know where that line gets crossed. ive read some people duing this with decent results
 

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I've broken 2 of these so far. 1st was a stock motor with OEM timing belt and tensioner with ~15k miles and the 2nd was OEM timing belt with GSC valve springs (70lb seat pressure). Both pulleys did have a little bit of wobble to them when running. Based on the way the spokes broke on the first I'd wager it had to do with the wobble. The looked as if they had broken in an inward motion if that makes sense.

The 2nd one pretty well grenaded its self so I have no idea what to think about that one.

I am currently running a cam gear off a 95 ish Toyota Tercel (3FE I believe) with 42 teeth vs the OEM 46 teeth. The gear design its self is significantly sturdier and the belt pitch is the same, just a smaller overall OD. I had someone with a far more extensive background in welding the I weld the pulley to the "damned D shape" hub with the hopes that it'll hold. I don't know a lot about the welding process but he said it was a pulsed GTAW process and I don't remember what filler he used but it's supposed to be specific to powdered metal parts. It's held up to 5K miles so far.
 

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Sixpack: as you progress with the electric water pump keep me updated. something i have wanted to do but really haven't acted on it. ive seen some nice products just cant commit to the prices right now. i modify my blocks on the deck to open and match the coolent ports that get cut off with the head gasket and i add holes between the cylinders on the side they are absent(intake) it works great for cooling. better flow through out, i had a friend from federal mogal help me out on doing calculations to justify said modifications. but we figured we would need more flow from the water pump to really see a significant difference.... so far on 2 engines it has been working okay https://www.facebook.com/photo.php?fbid=10210876553334406&set=pcb.1243057165714104&type=3&theater.
 

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Also interested in your feedback on the electric water pump. I really like potential of running the pump after shutting off the car and controlling the speed via standalone but the last time I researched them the consensus online was that they do not provide as much flow as a mechanical pump would in the upper RPMs and are more suited for Drag racing then Street or Roadcourse with extended high heat cycles.
 

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Hi there this coolant mod is what I plan on also doing. Your FB link didn't work? I'm hoping you have pics of what has been done? Also where can I get an electric pump for the 7m? Thanks
 

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Discussion Starter #12 (Edited)
That pump is twice the price of the CSR, that are on eBay for $200.
Have no idea if the meziere is adaptable to the 7M.
And seeing the price, if I had a 2J, I would still make my own plate for the CSR.

And I don't do facebook any more.

There should be a thread around here showing how I adapted the 240Z CSR pump, to the 7M.

If you do have Seth make the 7M plate, it would be great, as he can run a batch of them.
Tell him he will owe me $1 for everyone he makes, that way I'll get something out of my idea......
 

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That pump is twice the price of the CSR, that are on eBay for $200.
Have no idea if the meziere is adaptable to the 7M.
And seeing the price, if I had a 2J, I would still make my own plate for the CSR.

And I don't do facebook any more.

There should be a thread around here showing how I adapted the 240Z CSR pump, to the 7M.

If you do have Seth make the 7M plate, it would be great, as he can run a batch of them.
Tell him he will owe me $1 for everyone he makes, that way I'll get something out of my idea......
Hehe the eletric pump was out for a while on the JZ that were I got the idea and wanted to have a plate made that converts the jz to 7m. Now after this thread not sure which is the best way.

The stock oil pump shaft seems scary to keep if reliability is priory? I don't see it working safely at 8400 rpm and 1000+whp?

IS dry sump the oil way?
 

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Discussion Starter #14 (Edited)
I turn my 7M 8500 every time it goes out of the driveway, and engine power really has nothing to do with that part of the system.
The shaft isn't really the issue, but the pulley seems to be.
I haven't broke one yet, but since that possibility exists, I want to eliminate it.

Like Howard, and others here, I have some very expensive, if not impossible to replace cams, and my pistons were none too cheap either.
I don't run deep valve reliefs on the pistons, it's no longer a non-interfearance design.
And if I lose a belt, I'm in big trouble

Dry sump system, with an external pump is great for a race car, but not something that is to be driven on the street.
You have any idea how much work is involved on changing the oil on a dry sump system, and if you don't do a complete drain, how much oil is left in the lines?
A track car's oil doesn't get as dirty as a street car, so oil left in the lines isn't such a big deal.

Also, what do you plan on doing with the cam belt if you eliminate the countershaft pulley ?
Had one newb start talking about a dry sump system on his 7M, and when I asked him about that problem, he just replied that he would just cut the shaft off behind the front bearing.
At that point I dismissed him as a low grade moron.

I haven't put in any time trying to find a shorter belt to run strait from the crank, to the cam. And that is what it would take.
There may be one out there somewhere. Just haven't put time into it.
Since once I have this aftermarket pulley thing in the works, I will have to pull parts off the front of mine. At that pint, I'll take an old belt, cut it, and just see how much shorter it would have to be to bypass the countershaft pulley.
 

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I turn my 7M 8500 every time it goes out of the driveway, and engine power really has nothing to do with that part of the system.
The shaft isn't really the issue, but the pulley seems to be.
I haven't broke one yet, but since that possibility exists, I want to eliminate it.

Like Howard, and others here, I have some very expensive, if not impossible to replace cams, and my pistons were none too cheap either.
I don't run deep valve reliefs on the pistons, it's no longer a non-interfearance design.
And if I lose a belt, I'm in big trouble

Dry sump system, with an external pump is great for a race car, but not something that is to be driven on the street.
You have any idea how much work is involved on changing the oil on a dry sump system, and if you don't do a complete drain, how much oil is left in the lines?
A track car's oil doesn't get as dirty as a street car, so oil left in the lines isn't such a big deal.

Also, what do you plan on doing with the cam belt if you eliminate the countershaft pulley ?
Had one newb start talking about a dry sump system on his 7M, and when I asked him about that problem, he just replied that he would just cut the shaft off behind the front bearing.
At that point I dismissed him as a low grade moron.

I haven't put in any time trying to find a shorter belt to run strait from the crank, to the cam. And that is what it would take.
There may be one out there somewhere. Just haven't put time into it.
Since once I have this aftermarket pulley thing in the works, I will have to pull parts off the front of mine. At that pint, I'll take an old belt, cut it, and just see how much shorter it would have to be to bypass the countershaft pulley.

I'm in the same boat on high end engine part that I don't want to lose. Plus all the time it will take to repair it all.

I do have a dry sump on my jetksi which is not hard to get most of the oil out but there aren't any lines just a tank and sump. I use a air compressor siphon. It has a tube and it's very easy but never done it on a car which has an aftermarket dry sump.

I know it's not easy but don't know how else to make things reliable? Maybe try and do my best on the stock pump setup?

So far these are the only things I know to improve things on oiling system.

- New AZ cross over oil pipe

- New thermostat based oil cooler

- New oil squirters

- New Technico oil shaft bearing retention plate

- New oil pump with coated gears for tighter gears and shimmed oil pump which I will double spring with your recommendation.

This is it so far with all I know? I'm hoping to get an upgraded pulley for the pump as well. You also wrote about mods to the shaft which I would need to read and understand better?
 

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I turn my 7M 8500 every time it goes out of the driveway, and engine power really has nothing to do with that part of the system.
The shaft isn't really the issue, but the pulley seems to be.
I haven't broke one yet, but since that possibility exists, I want to eliminate it.


Power has an affect on the pulley. The more horsepower you have the faster the crank is trying to spin that pulley putting more pressure on the pulley which can cause the metal to fatigue and in time causing failure especially a 20+ year old pulley. Mishandling of the pulley can also be a reason for some failures. In stock form the pulley is more than capable but with more rpm and horsepower it seems like the pulley can't handle the extra stress. If you think about the high horsepower is probably going to cause failure before high rpm do to the stress of the engine increasing rpm so quickly.
 

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Power has an affect on the pulley. The more horsepower you have the faster the crank is trying to spin that pulley putting more pressure on the pulley which can cause the metal to fatigue and in time causing failure especially a 20+ year old pulley. Mishandling of the pulley can also be a reason for some failures. In stock form the pulley is more than capable but with more rpm and horsepower it seems like the pulley can't handle the extra stress. If you think about the high horsepower is probably going to cause failure before high rpm do to the stress of the engine increasing rpm so quickly.

Interesting. All these little things that need to be considered.
 

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Discussion Starter #18 (Edited)
Power has an affect on the pulley. The more horsepower you have the faster the crank is trying to spin that pulley putting more pressure on the pulley which can cause the metal to fatigue and in time causing failure especially a 20+ year old pulley.
Bull shit.....
Engine power is in no way related to stress on the pulley.
There is no difference in power transmitted through that pulley, if everything else is the same.
At the same rpm, same oil pressure, same cams, and same valve springs, a 400 hp engine has the same power being transmitted by the cam belt as one with 30 psi boost (1000 hp).
 

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So pump acceleration rate has no effect on reliability?

So a good true pulley hand having it and the shaft balanced to 9000 rpms might help?
 

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Discussion Starter #20 (Edited)
There is hardly any rotation weight on the oil pump drive, and most of it is at a very small rotational mass.
Maybe if it was going instantly from 500 rpm to 30,000 rpm, but with even a 10k rev limit, which is next to nothing, and isn't even a factor.
 
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