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Crank Collar

carl h

By carl h,
in Engines & Forced Induction

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Abo Bob Grand Master

Abo Bob

Posted
Posted

degeko - I can't see the RB20 having these issues so go for it.

dave - my oil pump was the same in the sense that it had room for the longer driver on the crank but the crank was a short drive. Perhaps all the oil pumps are like this and the RB26 cranks with the longer drive are just modified due to the discovery of this issue.

I can't see that they found this out on the street. Somebody must have been racing the R32 GTR's and found this to be a problem, communicated it back to Nissan who made the change just in case.

Cubes Grand Master

Cubes

Posted
Posted

There has been issues with rb20det's in the past breaking oil pumps.

I sold my old RB20DET oil pump to a dude that had broke his oil pump. So it definitely does happen, all depends on how the car is driven and the rev's.

I wish I had done this with my rb30det. :)

ProEngines,

Have you came across any issues with the rb30's and harmonics breaking oil pumps at certian rpms?

Sydneykid Grand Master

Sydneykid

Posted
Posted
Mmm, but what part of the pump is breaking?  In theory the crank should be stuffed around the drive as well as the pump if this issue was the one at fault.

The crank is less brittle than the oil pump rotor, plus the crank is much thicker at the drive flange than the rotor. When you have the narrow crank flange driving the wide oil pump flange it applies uneven loads. This may be what contributes to the cracking. It may be the early cranks have slighty rounded drive flanges from the K' travelled, and that is the route cause.

The difficulty is there are plenty of very happy RB20/25/30 engines out there with narrow drive oil pumps. It may well be that the extra oil pressure (say from an N1 pump or higher relief spring pressure) and hard launches (where the rpm and G forces climb rapidly) is what causes the oil pump rotors to crack. Or it may have nothing to do with either of those and simply be a vibration/crank whip problem. Or a loose harmonic balancer, too tight belts or oil surge.

Most likley it is a combination of all/some of the above. Personally I am going with wide crank flange with wide oil pump, or narrow with narrow, never narrow with wide. Plus I am not going to get carried away with increasing oil pressure and all of our engines are very carefully balanced to avoid vibration. They also all have winged sumps with baffles and one way doors to avoid the oil surge problem. We regularly check the harmonic balancer tighhtness (it has been a problem in the past) and don't overtighten the belts.

:) cheers :)

Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted (edited)
Should make up a kit for people doing rebuilds, N1 oil pump with spline drive and sump baffles... get all the oil system sorted in one easy go, and the spline drive will never have any of the problems the RB normal drive has :)

Yeah the rods will be interesting... talked to a couple of people about it (who are in the know, will fill you in later) and they have all said if I keep a sane rev limit the rods should hold it, its the rod bolts that are the weakest link... (from memory you put the ARP 2000's in mine?). Either way, I know the gearbox isnt going to last a week :)

Amaru...our engine is using std rods (although heavily prepped) with arp bolts. Only three items in the engine are not Nissan...pistons, camshafts and sump baffles (four if you count the rod bolts). Around 450awkw and a 9250rpm rev limit and still no problems. The engine has its second birthday on Saturday and its copped a flogging from Stacey and I. Dont let it worry you, as GTR's fail more from oiling and piston issues than bent/snapped conrods.

Edited by DiRTgarage
Sydneykid Grand Master

Sydneykid

Posted
Posted
Amaru...our engine is using std rods (although heavily prepped) with arp bolts. Only three items in the engine are not Nissan...pistons, camshafts and sump baffles (four if you count the rod bolts). Around 450awkw and a 9250rpm rev limit and still no problems. The engine has its second birthday on Saturday and its copped a flogging from Stacey and I. Dont let it worry you, as GTR's fail more from oiling and piston issues than bent/snapped conrods.

Does it have a narrow oil pump flange drive crank or a wide one?

:) cheers :)

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