Jump to content
SAU Community

Rb30 Oil Pump Dilemma

PSI086

By PSI086,
in Engines & Forced Induction

 Share

Recommended Posts

PSI086 Community Regular

PSI086

Posted
Posted (edited)

I've put together a new single cam RB30 and fitted an RB25DET oil pump as the VLT pump was worn on the drive flats. I fitted the spring from the VLT pump to the RB25 pump and used the existing RB25 piston. After finding the oil pressure a bit too low I've done a bit of measuring after pulling 3 pumps apart (RB30ET, RB25DET and RB26DETT) and also found a few differences between all the pumps. So I'm now scratching my head with what do do.

I know the RB30 pump has around 65psi when the engine is first started (cold) so I'd like to try and keep it as close to that as possible. I presume the RB25 pump will have sky high pressure if I reinstall the stock spring into that as its a much higher pressure spring. In saying that the relief hole in the cylinder where the piston is fitted is 5mm closer to the bottom than the RB30 pump, so the piston doesn't have to travel as far to let pressure out. As you can see from the pictures the piston is also totally different in design to the other pumps even though all 3 measure up identically in size. The threaded section on the actual pump also protrudes further than the other 2 pumps which would have been easily overcome if the relief holes were the same height in the bore. RB30 - 10mm from bottom of the bore, RB25 - 5mm and RB26 - 7mm.

I'm after feedback from anyone who has either fitted the RB25 pump as it is and had normal operating pressure for the single cam motor or has fitted different springs, pistons, shims, etc so that the pressure will be spot on.

At the moment I'm thinking of running the RB30 spring and piston with a 5mm shim in it which will bring the spring up so it protrudes the same distance from the bore therefore spring pressure will be correct once the retaining bolt is screwed in. But then theres the difference in relief hole height (5mm) so I'm not sure how well that will work as the piston will only move 5mm instead of 10mm to let pressure out. Will this affect my oil pressure much? The design of the piston from the RB25 pump also looks as though it will let pressure out without moving due to the holes and groove in it

Heres a few photos of what I've found

springsandpistons.jpg

The RB26 retaining bolt also has a deeper hole inside of it

bolts.jpg

RB30ET.jpg

RB25DET.jpg

RB26DETT.jpg

Edited by PSI086
Link to comment
https://www.sau.com.au/forums/topic/286637-rb30-oil-pump-dilemma/
Share on other sites
psi Experienced

psi

Posted
Posted

...OR,

be a little out there and weld a large bung fitting into the bottom of the sump (where the oil pump releif vavle is).

Just unscrew the bung and you can get at the vavle!

we did this on an old (R31) Race engine that gave us oiling hell...

I will be doing it to my 25/30 as well (bit over the top, but i HATE taking the sump off!)

does that help ya?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      RB20 in need of modest love injection

      By GTSBoy · Posted

      As you're looking at using a Link ECU, then large injectors are not a problem. But there's not really any need to go 1000s on an RB20 unless you're planning >>600HP on E85, which would seem unlikely. There are other options for injectors. The Xspurt ones are available from a number of places and you can get them in the mid 600s and 725cc, which is probably a sensible place to be. These are all EV14 based. If you are not using the stock AFM (at all, which would be the case with a Link) then a large turbo intake pipe to suit the ATR turbos is not an obstacle, so you should use one instead of a highflow. Results will be better.
    • QB6SAGR
      RB20 in need of modest love injection

      By QB6SAGR · Posted

      Hey guys,  I'm after some advice and this here is the best place to get it imo. I was a member a looong time ago under another account, with a lost email address. Its nice to jump back on and see some of the same names still giving good advice.  I mothballed my car when i moved to perth in 2013, and after getting towed across the nullabor a few times it has officially done more km's on a trailer than under its own power. Now that i have started the process of tidying up and modifying it, i see the fruit available (and the fruiterers selling the produce) is different than back in the day. hence my questions, as i used to 'know' what to get and now, i'm not so sure. Engine wise the car (92 gtst) has a walbro 255, k+n, fmic, cam gears and and turbo back 3"exhaust. Wish list is a Hypergear high flow or ATR43G1, Link G4x and some newer injectors before a tune up. My goals are modest, only low 200's power wise. i know i could achieve this with less, but i've been swapping out old for new where i can. Every cooling hose has been replaced, along with mani gaskets, WP, thermostat and radiator, fuel pump and timing belt, tensioner and idler, and i rebuilt the steering rack. Regarding the injectors, the fruiterers all seem to sell what used to be considered quite large injectors. There are a lot of options for bosch 1000cc EV14's, and i would like to know if that is a suitable choice for my build. Is modern injector design good enough to run these at the low duty cycles that i likely would be? is there a downside to running a too large injector these days? or, would there be an upside to running a smaller injector at higher duty cycle? I can see that there are smaller injectors still available, but the ones i have seen specifically marketed for RB's are pretty large (see: https://golebysparts.au/collections/fuel-rail-injector-kits/products/nissan-rb20-fuel-rail-bosch-980cc-1150cc-injectors-turbosmart-fpr800-regulator-kit), and i dont know enough about them to say one not marketed for RB's would fit or not. I have searched the forums, and amongst all the posts on older tech, I did see gtsboy recommend EV14's, but no size was mentioned... again, i'm not clear on if the smaller size bosch injectors are also EV14's as they do look similar.  also, if someone can recommend a tuner familiar with RB's in the Geelong or West Melbourne area i'd appreciate it. Thanks in advance guys. Cheers, Rowdy  
    • Duncan
      R33 GTR lift points for hoist

      By Duncan · Posted

      FWIW the depth of the groove in the rubber pad is not super essential, the blocks are rubber and squish a bit. If you are worried an angle grinder will make a deeper groove quick smart
    • GTSBoy
      R33 GTR lift points for hoist

      By GTSBoy · Posted

      I mean, if you were to move the jacking points away from the original location, that is, away from the wheels and closer to the centreline of the car, then it will be more likely to overbalance and tip off the supports. Same as we talked about before. I was talking about moving for-aft. If the sill is bent outward or inward, then the car would obviously look unstraight from the outside. Hopefully that hasn't happened either. Again, you can do comparative measurements from the chassis rails to see if there is much deflection.
    • sunsetR33
      R33 GTR lift points for hoist

      By sunsetR33 · Posted

      Can you elaborate what you mean with your first sentence? I meant move as in the bulge kinda seemed like it got pulled "outward" meaning it got pulled down and to the side with the jacking rail itself, so the load bearing bulge now sits lower than usual and is not level with the sill on the other side of the jack point. Either that or the jacking rail just got pushed in a good bit.
×
×
  • Create New...