The Mafia

Thanks for your reply - This is really good to know. As for the gap questions - I have no idea. I had a workshop assemble the engine. I will remove the pistons and rings and get some pictures of what they look like. Its a time thing so I will organise it ASAP and get back to you. Thanks again for all of your replies. Also interested to know what the proper Piston to bore clearance is supposed to be.

no worries mate, thanks very much for your effort. Here is my checklist so far: Piston to Bore Clearance Ring Gaps Crank Thrust If bores are round (Should be, was bored 20thou over)

ok no worries, I will look into this on the rebuild. Just wanted to thank you guys for all of the input so far. I really do appreciate it.

No detonation worth worrying about. I logged diligently and had the timing wound right out for run in. 3 or so times it might have hit 40-50 according to the powerfc while tuning, but that is very minimal.

Can you get good assembly lube that won't run away for this in case you don't start the motor for a week or two? The AFRs were in the mid 14s. Was never left idling for more than about 5 mins. Always up and down on the throttle, and no constant revs. It had Fuchs 20w50 (recommended by the builder) full mineral oil. You can't feel the scores, except the one I have circled in red. Thanks heaps for your help mate.

Oil pump is a standard RB25 pump, with standard springs, with a 2mm shim. Plenty of pressure. Cold the needle was about a width from the top of the gauge. Warm, its always about half way under 3000rpm. Over, was 3\4 to nearly top of the gauge. Engine never lost oil pressure.

1. Not really sure - Engine builder did this. 2. Probably about 2 months. 3. No, I wasn't advised to. 4. Yes, for a little while until I got oil pressure. 5. No idea - When we disassemble we are going to check. Will definitely post results.

To add to this, I just took some advice from another thread, and slipped a feeler guage between the piston and the bore. I'm able to get 0.279mm - 0.255mm feeler guages on either side of the piston without force or pushing the piston to one side. Thats 10.98thou to 10.03 thou roughly (I understand that this is a crude way of measuring) Anyway, thanks again everyone.

Hi Everyone My Specs: RB25 Head Shaved 20 thou, 8.45:1 Precision Pistons (Cast replacements) Hastings Rings Standard Rods King Bearings ARP main and Rod bolts ARP Head studs Cometic Head Gasket Bores 20thou over Engine has done 1000kms, 800kms on 10psi, and 200kms on 16psi. Tune was 14.2:1 cruise, 11.5:1 load. We removed the head to install oil restrictors (coughed about 1L into the catch can overall, oil was always topped up, ran 5L in the sump). This is what we saw: Cylinder 1: Cylinder 2: 5 and 6 look ok. Haven't turned the engine over enough to see 3 and 4. Any idea on what could have caused this? Here are the specs: RB25 Head Precision Pistons (Cast replacements) Hastings Rings Standard Rods King Bearings ARP main and Rod bolts ARP Head studs Cometic Head Gasket 20thou over Engine has done 1000kms, 800kms on 10psi, and 200kms on 16psi. Tune was 14.2:1 cruise, 11.5:1 load. Had a word to the engine builder, and he immediately went onto the defensive. Was quite rude actually. Says he's going to drag me through all the bullshit (sending parts to some forensic mob etc) and I can take him to court and he'll fight it etc. Funny thing is, I never mentioned court, I asked him what he thought was the failure, and that I would like to know how we can fix it. (Was pretty good when speaking to him actually) Anyway, let me know your thoughts. Probably won't bother taking this further, because there are too many variables and he'll just cost me no motor for another 12 months. Plus it seems like he's good at worming out of it (due to experience in these matters) if it was his fault. Just want to know so this mistake isn't made again. Bottom end hasn't yet been disassembled. Thanks guys Jono

NEO's are top feed? Goes to show how much I know, lol. Sorry about the misinformation.

They look like top feed injectors to me, so no, not drop in to a RB25 Neo. I could be wrong, but thats what they look like.

Sounds great. I made 314rwkw on Shell 98, Nismo 555cc injectors, Water Meth Injection, 18psi on a 0.63 rear housing. Standard motor. Injectors where at about 80%. Car was an animal. nice work Joey, now WMI and you made the same\more power. The rear housing and boost is what was holding me back. Can't wait to put E85 through the RB30det Yeap. This is what you need to look at.

Disconnected mine because I was having issues with something, and yeah, a 300rwkw car turned into a 80rwkw car. Wouldn't go over 10psi and stalled, and ran like shit. It is there for a reason. So no flutterz fully sic bro.

Thats a myth. I've run 20% Toluene, many other additives. Not a single problem. As for the OP, Id find a service station with BP98, Shell 98, or Caltex 98. They may cost you a few dollars more, but I bet you go more kms too.

You might want to learn a little more about turbos also, before asking such a broad question like that. Google is your friend.

also, what kind of tester are you using? My first tester said 120psi across all 6. My Second Tester said 220psi across all 6. My Third said 160psi across all 6. As long as they are all within 5-8psi of each other. If not, turn the boost down and wait for it to blow up gracefully.

I'm in the same boat mate, I have a powerfc and Q45 and I am maxing the AFM. Hits the bottom row and stays there, lights are flashing like a disco on the dash, and power is all over the shop. I am going to install a Vipec, and I think that you should look at the Vipec V88. They are PACKED with features, like all sorts of inputs and outputs, launch control, limiters, antilag, engine protections, multiple maps, etc etc. There is a massive list. These things are so easy to use too.

My little instruction sheet says 87ft/lbs, tightened up a third of the torque at a time. I'm not sure if they used lube or engine oil though. They are coming out, as the head has the come off because the builders were dicks.

mate, the R34 will have a RB25NEO motor in it, meaning its a 2.5l crank.

nah mate, I need a driver. If you're game.

Hey boys. I've been watching your chat. Good to hear people are still driving these things. I just dropped a RB25\30DET into mine. Its done 700kms. Cranked the powerfc right up, she's making good power now. Been spending a bit of time tuning it, but getting there, Hard to tune when driving on your own haha. I'll be keen to race a few of you too. Good to hear from you all. Jono

Personally, I'd get new rings and bearings, hone it and re-assemble. Everything else should be fine. This way you have piece of mind.

This is EXACTLY what it looks like. Cheers

For the exhaust manifold Mate.

The Vipec can also switch maps very easily, and by that, I mean switch maps that a tuned specific to Nitrous. Just like if you install Dip switches on your dash to some inputs. This is to allow you to switch to other maps (for different fuel, rookie driver etc), and in the N02 case, the Vipec "knows" when these special maps are needed and will switch to them. (ie, When the nitrous is activated).