UZ oil pump failures (cracked rotors)

[Arnout]

hi guys,

I was playing with a few engines I have disassmbled here in my workshop. I got the RB26 engine, 2JZ engine and the 3UZ engine.
I removed and took apart all the oil pumps. The RB oil pumps are known to crack (the inner rotor) because of the big free play this rotor has on the crank collar. At certain RPM's the pump starts to swing on it's own harmonic frequency and this causes the inner rotor to crack, this is all combination of the frequency, the free play of the rotor on the crank collar and the inner rotor not being very strong.
Looking at the 2jz engine they dont have this problem as the oil pump is driven by a splined collar with no free play.
Then I looked at the 3UZ. Also only 2 flat pieces driving the oil pump. And even worse; the free play is also big. Now these engines tend not to rev that high as the RB and JZ engines can, but still I am worried about the oil pump to explode one day.

Has anyone seen this problem / had this problem?
I can make a few small movies so you can all see the free play on the connection crank -> inner rotor

 

[cribbj]

I was going to suggest contacting Erol, but then remembered he dry sumped his 8500 RPM screamer.

What about Ed from Oz - didn't his 1UZ make it up past 8000 rpm for a short time before it blew? Don't know anything else about his engine - was it dry sumped?

 

[Arnout]

I checked and measured a little bit more. Also took apart a toyota V6 pump, the 1MZ-FE pump. That pump is even worse than the UZ pump.
I think I can fit the JZ rotor inside the UZ pump. Some machining welding and some more machining is required.
However I will have rock solid internals in the oil pump.
Also I need to put the JZ crank collar on the UZ crank, but that's an easy job.

Any thoughts?

 

[ash]

The uz pump is " thinner" than jz pump
The pump housing needs approx 2 mm taken out of it to allow it to fit

The inner jz with the spline can be sized for the tang drive, and be made tighter too..
Get the inner re nitrited to keep hardness on the drive surfaces

 

[JustenGT8]

I have not yet seen a UZ pump fail Arnout? This is after 8 years of track work for me now. Admittedly I have kept the revs below 7500rpm, but not having seen a single failure, it suggests they aren't as bad as they initially look and some rpm headroom still?

The water pump however is a cavitating nightmare. Really needs an under drive pulley for sustained higher revs

 

[Arnout]

justen
the rb also fails after 7500 rpm. I think it has to do mainly with engine harmonics / vibrations. I have made a small movie of the 'free'play the pump rotor has on the crank and it's amazing how much. I'm sure this can cause problems.
I'm redoing the waterpump on my setup as well. I am making a new rotor that allows the water to enter from the back (inside the banks), so I can remove the whole front intake & heatbridge. Gives me enough room to place the supercharger super low and hopefully close the hood without a big hole in it

 

[Arnout]

I hope this link works:

 

[ash]

I hope this link works:

Nothing wrong with that..

 

[youngcnc]

made an oil pump not long ago...

Hi guys
The other reason for failures is the material that the oil pump inner and outer ring are made from powdered metal which is then compressed and heated as opposed to machined from solid. Late last year I made a set for a company that they used in a RB26 drift car used by a guy named Corey ( I don't know him personally)... Hes used and abused it now for about 5 months and is still going well even won some races with it.

The factory oil rings will shatter when hit hard but the rings I cut from 1045 hollow bar just bend...
The other interesting thing about the oil pump is that I made a cover that allows the oil pump gears to be 2mm wider meaning about a 10% increase in oil volume...

For interests sake they sell for $350NZD per set when bought 6 at a time.
inner ring, outer ring and custom cover..

Cheers Craig

 

[Arnout]

I took the following oil pump gears in the vice and hammered them to death:

- RB26
- 6G72
- 1MZFE
- 3UZ
- 2jz

It turns out ALL of them were from sintered metal. None were billet from factory. Obviously the 2jz was the strongest because it's the biggest. Also the connection to the crank is best (splined) instead of only two flat pieces like all the other engines.
I know you can buy billet gears for RB26 and (limited) for 6G72. I think for 3UZ this would be a nice upgrade.

 

[Arnout]

The water pump however is a cavitating nightmare. Really needs an under drive pulley for sustained higher revs

Justen,
Do you think this problem is with the engine being at high RPM or do you think this problem is an acceleration problem? When the pump accelerated too quickly, it will cavitate?
Normal cavitation problems is especially with pump acceleration. When it pumps it pumps. I dont have enough knowledge on pump designs to improve it, but I can look at the 2jz to see if we can copy that design into the UZ pump?

 

[XR8tt]

Hi guys
The other reason for failures is the material that the oil pump inner and outer ring are made from powdered metal which is then compressed and heated as opposed to machined from solid. Late last year I made a set for a company that they used in a RB26 drift car used by a guy named Corey ( I don't know him personally)... Hes used and abused it now for about 5 months and is still going well even won some races with it.

The factory oil rings will shatter when hit hard but the rings I cut from 1045 hollow bar just bend...
The other interesting thing about the oil pump is that I made a cover that allows the oil pump gears to be 2mm wider meaning about a 10% increase in oil volume...

For interests sake they sell for $350NZD per set when bought 6 at a time.
inner ring, outer ring and custom cover..

Cheers Craig

Would any one be interested in group purchase of these pumps ??

 

[JustenGT8]

Hard to say Arnout as I didn't ever test accel versus simply sustained high revs......probably a combination of both. I know RMS was chasing this issue for a while.

Higher pressure, rad cap, bigger rad, water wetter and frequent top ups got it to an acceptable performance, but I couldn't do longer races as 10 laps of my local track was the limit. Adding a good expansion/header tank would have helped.

I bought an external electric water pump that I would have used if I kept the Celica as a track car. No need now it's retired from circuit duties.