Jazzadub

Just a guess, but maybe the muffler packing got blown out? Does the car run fine apart from the noise? Does it get louder and/or faster with revs?

Is the damage in cylinders 4-6? To me it looks like detonation damage. And the reason it happened in cylinders 4 to 6 is that those cylinders run hotter and leaner than the front three if injector trim is not tuned appropriately. Anyway, I don't think you can or should machine the head that much - but I might be wrong. I had an RB26 head with similar damage and it needed to be repaired by welding over the affecting areas and then correcting the combustion chamber shape. I would check with an engine shop that specialises in head machining and reconditioning. Edit: as GTSBoy said.

So I imagine that the original issue was that the rings were never bedded in correctly? I suppose this is testament which proves the "get load on the engine ASAP" run in method. What run in method was originally used?

Good news! Do you think the tighter ring gaps was the main factor in reducing oil entering the catch can? How about deleting the rear head drain? Do you think that had any bearing?

Sorry to bump this, but I think this is all great info! Regarding no 6 running lean, is there any recommended injector trim values to compensate for this while running a standard intake plenum? I have heard trims of 1% for 4, 2% for 5, and 3% for 6, but maybe someone has tuned with 6 EGT gauges and has some input?

Yep the SN rating is the newest rating (2011) and supposedly has improved resistance to alcohol fuels. It should be OK with normal change intervals (5000k) but I would check the condition of it regularly to make sure it isn't doing anything funky like greasing up. If you can afford it I would also recommend full grade V synthetic such as Redline 15W-50 or Motul 300V as that will also have improved stability compared to a mineral blended oil.

No, the rear oil head "drain" is not required if you vent the sump and valve cover breathers to a vented catch can. I would recommend a 1.2 or 1.25mm restrictor with a Tomei oil pump. Go to a 1mm if the car is a dedicated race car. For E85, just make sure the oil you use is API SN rated, and that you change it regularly.

Engine/Car: 1992 Nissan Skyline R32 GTS-4 RB26DETT with GT2859R-9 turbos. Factory oil pump gear had just failed due to narrow oil pump drive. Was replaced with an N1 oil pump, new bearings and longer crank snout. Had been driven only a few thousand Ks and then I bought the car. Type of failure: Terminal oil pump gear failure (N1 oil pump). Factors influencing the failure: N1 oil pump Either missed 3rd gear or wheelspun and hit rev limiter. Instantly lost oil pressure (idiot light came on, and standard oil pressure gauge dropped to zero) See comments also. State of tune of the engine: Had recently been tuned for the -9s, don't think the tune was a contributing factor in this failure. Suspension and tyres: Not relevant. Oil used and service interval: Oil changed frequently, not sure on type. General comments: Didn't want to skimp out on the rebuild so was taken to RIPS. On inspection there was also evidence of detonation - pitting in head and pistons, scores in cylinders. Also the crank pulley bolt was loose causing the keys and keyways to round off. This could have created a bit of slop that could have been a contributing factor in the oil pump failing. That said I wouldn't put an N1 pump in if someone paid me! Currently being rebuilt with low K R33 shortblock, ACL bearings, ARP rod bolts, new piston rings, Tomei oil pump, enlarged sump, the whole shebang! Fingers crossed there are no issues with this build! I don't have pictures of the damage unfortunately but attached are some pics of the reassembled engine - hope that's OK!

For E85 it is very important that the oil is API SN rated, and ideally a full synthetic. This is the notes from API on the SN rating: "Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons, more stringent sludge control, and seal compatibility. API SN with Resource Conserving matches ILSAC GF-5 by combining API SN performance with improved fuel economy, turbocharger protection, emission control system compatibility, and protection of engines operating on ethanol-containing fuels up to E85." As for viscosity that very much depends on the temperature range. A cold grade of 15W is fine unless it gets below freezing, which I don't think will be a problem. A hot grade of 50 will start being too thin at about 130C+ (ie less than 10cst), but if it is a full synthetic it will not break down until 200C or more (it will just have really low viscosity). So for track use that is good, you just want to make sure you don't beat on it until it's nice and warm. That is because at say 70C a 40 grade might have thinned to the correct viscosity to protect the engine, but a 50 grade might still be too thick. Higher grades also have better film strength, which is why a 50 is good for the track.

Real nice GTR - more pics! Yea don't have a Honda anymore so frequenting skyline forums now haha =]

Great post, I think that sums it up nicely!

Case in point, look how high in the "catch can" or breather tank the lines to the sump are. They are obviously not drains but breathers, looks like a great setup.

If by head you mean catch can then yes. The goal is very simple, relieve pressure in the crankcase. Whether people think what they have installed is a drain or breather is irrelevant, improvements in oil return will be noticed when the pressure in the crankcase is reduced.

Wankers! Best of luck getting it back in one piece!

From your description it sounds like it is crankshaft speed related, so I agree with GTSBoy that it is not related to the transmission or axles. I think you need to urgently check out your harmonic damper and flywheel to see if they are in good condition as if they are not working or out of balance your engine will probably not last much longer. I would also check out all engine mounts, as they may be worn, and not able to dampen the vibrations occurring at 5500RPM.

Right - 45 is huge offset so there shouldn't be much of an issue on the fender. I would be more concerned about inside clearance.

What are you currently running and I'll tell you how much clearance will change on the inside and outside.

If going E85 and 1000cc injectors you may also have to upgrade the fuel pump. I would highly recommend a surge tank, dependant on what the car is to be used for.

No they are not. The treadwear rating of the AD08R is the same, 180. I believe they just improved the compound by using something called "Orange Oil". Don't know all the details of it but they are 1.5s quicker around Tsukuba and only 1s slower than A050s. Pretty crazy for a street tyre!

By AD08 I suppose you mean the new AD08R compound?

Haha thanks mate, I am going for function over form so I want to fit the widest, lightest wheel I can in there, wrapped in the best rubber. Hence why I am looking into Enkei RPF1s (18x9.5 ET15) wrapped in Yokohama Advan AD08R rubber, (265/35R18) Hopefully I can find a place that can widen the rear guards out!

Car is a 4 door R32 GTS4 Would 18x10.5 ET15 wheels fit under R32 GTR front guards? Would they fit under the rear with a 4 door blister kit / widebody? Or is it going to be way too much work and I should just stick with 18x9.5 ET15? I suppose they would still fit nice in the GTR fenders and should be able to get them under the rear with a bit of work? If I went with the 9.5 inch wide, tyres would be 265/35R18

Well if it's cheaper that is a good benefit, but assuming closed loop compensates for the ethanol, you will burn through a tank slightly quicker. So the $/KM won't be much less than with petrol. E85 is the business if you want racecar status, not E10

I didn't say anything that contradicts with your statement? Definitely didn't say it would make less power... Also you say that new cars are designed by the manufacturers to run on it, yes that is true, but the important word in that sentence is "new". On an old car that is not designed to run on E10 any benefits will be negligible, like I said.

E10 will run just fine just a little bit lean =D O2 sensor might be able to compensate on closed loop, but on open loop it would be slightly lean. You won't make a noticeable amount of extra power and it won't have much knock protection, so what's the point?