RB20DE Neo teardown, does this N1 pump and rod look alright?

[Neostead2000]

Hey, and sorry for this generic question, but as usual, I'm your average "just got into the RB/Skyline scene" guy trying to make sense of it all.

In the process of tearing down this 20, I saw it had an N1 oil pump and it has the extra 8th screw in the backing plate. The crank unfortunately is the short snout version and at first glance, the drive gear engagement flat spot looks ever so slightly marked but no noticeable deformation, likewise on the crank's snout. I have yet to pull the pump apart (will do that tomorrow since I got an impact screwdriver today). I believe I have the right tolerance specs from the manual so I will be using feeler gauges on the pump teeth.

Additionally, I noticed all rods aside from #3 had the stamps on the end caps facing one way, but only #3 rod's stamping faced the other. In other words, #3 conrod has the nissan logo facing down, while all other 5 rods have the nissan logo facing up. Yet, on one end of the rods there is a "0-0" marking and they all follow it. On the opposite end, each # rod is marked 1-1, 2-2, 3-3 and so on, and they all were aligned with no mismatch. Am I just paranoid and nitpicking, or is the casting random?

Also, here are some more pictures I took of the conrod/piston assembly with a ruler for rough scale. Could anyone confirm if these would be the same as regular 20DET rods? 2cm thick and 1.2cm wide give or take.

 

P.S It appears to be a low mileage motor off an R34 coupe however the #3 conrod bearing has weird delamination yet the crank journal is spotless. I am anxious to see what condition the pump internals are in.

Edited February 10, 2022 by Neostead2000

[GTSBoy]

Neos have N1 pumps from the factory. They also don't get any special treatment wrt the pump drive though, so the drive is just as troublesome as on any earlier RB without a proper drive. If you're going to thrash this engine, you should probably upgrade the drive.

I wouldn't worry about the rod cap.

[Neostead2000]

Thanks. I completely disassembled the pump today and did all the measurements as per the service manual. She is well within the tighter-end of spec, very little scarring or pitting. Also I measured the snout engagement (40.7mm) versus the drive gear engagement (40.65mm) so that gives me 0.025mm of tolerance on each side. It feels fairly tight when pressed against the snout and coupled with the actual centering ring rotating snugly inside the oil pump inlow, I don't think this pump is going anywhere.... famous last words? 😅

Also, I did a light port/smoothing on the pump inlet and outlet as to ease the oil flow, however I will not be shimming the relief valve at this point.

 

Edited February 11, 2022 by Neostead2000

[Duncan]

I've never noticed a cap with the logo cast different to the others (but then I've also never dealt with rb20 rods). In any case the numbering on the rod end and cap show what is was machined for and you said yours was correct. Suspicious that the rod with the bearing problem had this but co-incidence is still an option.

For the oil pump, I think you were putting this in a street car, right? Nissan engineers knew there were issues with the oil pump engagement from a short crank since at least 1992, so their decision to keep them for another 10 years shows they were not causing trouble in regular engines for road use. Unless you are building this for big turbo power, stick with the short crank nose and just put it back together (and don't drive around on the rev limiter!)

Re that bearing, if you are disassembling the whole engine clean out the crank oil galleries thoroughly, there could be an oil feed issue to that journal