djr81

The leakdown numbers are large - too large to believe that any amount of catch can/breather set up will help the issues and too large for me to want to wind any more hp into the thing - which was the whole point of getting a built motor. The comment was simply that I didnt think it was worth pulling the motor apart to diagnose the problem. There is too much blowby is the core of the issue. Dont need the motor in a bazillion bits to know that. I dont want to trouble shoot the breather system. When first built it had the same breather system as the stock motor - basically a Nismo catch can and that was all.This set up was fine with the tired original motor. With the built motor it puked litres of oil into the I/C and fouled the AFM's so much that the thing would lay smoke screens down the straights. Every change to the breather/catch can system has been after establishing there was a fundamental issue. It was simply an attempt to find a bandaid fix for a motor with too much blowby. To an extent that has worked. But it wont ever be enough. I need to build a motor with good blowby numbers in the first place. When you talk to builders over here they get all nervous and will only ever volunteer 15 - 20% leakdowns. So I have no real confidence that just doing what everyone else does is going to work well enough. Hence the 1.5mm rings which I would have been happy with. Unfortunately the ACL rings didnt fit and I cant find a piston with a similarly thick ring. Hope that is clear?

And there I was thinking I had done an awesome job of disguising just how monumentally frustrated I am. Other than referring to the car as the Exxon Valdez and carrying on like a pork chop about it all the time, obviously. Yeah it looks like an octopus orgy. But please understand it started with a couple of vent lines from the breathers in the rocker covers to the catch can and grew from there. To be fair it works at Wanneroo. Just not Collie because there are too many left handers for the content of the catch can to drain back into the sump. The take off for the vent to the can is well above the oil level so I dont believe it is coming out there. It puked oil before I fitted the vent - at Collie and Wroo. Stopped at Wroo afterwards. In any case it fills the 2 litre or thereabouts can in two to three warm up laps of a track that is a mile long. The last time there was oil all over the engine bay, on the quarter panel, the side skrits, all over the front suspension, wheel, windscreen and the puddle under the thing was the size of a family pizza. So not a small amount. Catching it with anything smaller than a 44 gallon drum wont work. Sump capacity is only 9 litres so even the P76 boot mod has its limitations. Anyway none of this is getting me closer to a piston with a 1.5mm top ring. Or a suggestion (Other than somethng with total seal rings) for a piston otherwise.

5W50 which I have always used. Never had a problem with it.

Well its going to get honed - just to 86.0mm not out 86.5mm. Not going to chuck it together with the finish it has straight from Nissan. Pistons wouldnt fit down the bores anyway.

I have bought a new N1 block for the new engine build so I am starting fresh. It has bores less than 86mm. So why not use 86mm pistons?

So JE won't do you a 1.5mm top ring your saying? I asked them for a ring with the same dimensions as the ACL one. They said no. The next step may have to be asking them for a custom piston for a 1.5mm ring of their own dimensions. Is $$$'s, I would guess. They don't do an 86.0mm piston and like alot of people start at 86.5mm. With everything you've done it shouldn't be a problem even with a 1.2mm top ring. It sounds like it was possibly screwed together poorly? Slap happy job? Ring gaps all probably not measured or done or who knows? I dont believe it was a slap happy job. In fact quite the opposite given the circumstances I beleive the shop in question tried bloody hard to get it right. Which is perhaps even more of a concern. Was the block torque plate honed do you know? Yes, believe so. Also what oil are you using? Mineral oil for run in and then Mobil 1.

Well listening to the race commentary & interviews last night (yeah I know I cbf'd watching it Sunday) Webber basically said Marko placed the Porsche story in the media. So I would suggest Marko is worse in that he appears to be actively trying to undermine one of the teams drivers. Why do they employ that clown?

Yes that is why I want the thick top ring. I had a standard motor running 450 horsepowers and it didnt have any issues. After the rebuild it has more issues than Readers Digest. The fundamental difference between a tired stock motor (With no head drain, standard restrictor,no big catch can) and a brand new build forged motor (which over time collected all of the stuff listed below) is in the pistons and more particularly the ring thickness. I tried JE who do custom rings - just not custom enough. I have fitted: A drain from the back of the head. A small restrictor. Mines baffles (Which I dont think help anyway). A Nismo catch can. Another big catch can with a return to the sump. A dash fitting in the sump to help vent blowby straight to the catch can. In getting to that point I have been through umpteen iterations.

Here: http://www.aclperfor...rgedPistons.htm

Nah NSW is a bit of a drive from WA. I have the original pistons/rings from my motor so could check those. But like I said stock rings with forged pistons?

I see what you are saying. I could try a set of Nissan rings for an RB26 - not sure what they have available or how they match up with forged pistons. Has anyone tried this?

Nah I was just curious. Obviously a rubber grommet is cheaper than a window, not to mention the drug money Nissan want for the rubber sealing strip that goes around it. Probably why I have seen a few GTR's that have suffered from a broken rear window where the owner has full glass coverage on their insurance. Coincidentally. Allegedly. Apparently. From what I heard. On the internet. From overseas. Hmmm. What I would like is a new windscreen with an antenna in it, rather than the local ones which I understand dont have them.

Havent pulled the motor down I wanted to get the parts I needed for a rebuild before doing so. There didnt appear to be a whole lot of point after the leakdown test was done. The engine isnt burning oil just puking it. As for pistons, the ACL stuff is here: http://www.aclperformance.com.au/NissanRB26DETTForgedPistons.htm Ring part number is C1686 (As per RB30) SR20 is here: http://www.aclperformance.com.au/NissanSR20DETForgedPistons.htm Part number is: C1834 There may be a 1 in a thousand chance that ACL have a couple sets of SR20 rings left. They dont have any C1686 unfortunately. To be clear the rings you have a re ACL items? If so and you could check their end gap that would be awesome.

You need to differentiate between weight distribution and centre of gravity. The heavy wing helps with weight ditribution but not with the c of g. Anyway out of interest are N1 rear windows available at all?

Well the ring gap claimed for my CP piston install is/was 19 thou. And its looser than...... I won't say. But yes the 22 thou number is already larger than what I wanted to run and the bores are in the 85.7 to 85.8mm range. So yeah add about 10 thou to 22 and I dunno you get next weeks winning lotto numbers.

The concern is I had an engine built last time. By a workshop who claimed a reputation for building track motors. (And no I dont want to talk about who it was). Unfortunately things didnt go well and I need to rebuild the rebuilt motor. It has CP pistons and enough blow by that I cannot run it at my local track. Basically I am trying to find a recommendation for a piston that reliably produces single digit blowby numbers and therefore will allow me to do more than one lap at a time without the motor puking its oil out the breather. And yes I read all the threads on the subject and have done the mods listed in there. The difficulty is trying to differentiate the motors used on the road (because mine would be fine if it was just used on the road) and those used on the track. I had hoped the 1.5mm ACL top ring would be a large part of the answer. Unfortunately when we got the top ring and stuffed it into the (unhoned) N1 block the end gap was already 22 thou. Or in other words too big. Sorry if I sound cranky but this is doing my head in.

After a great deal of messing about - the ACL piston is a no go. I actually had the things but for whatever reason the top piston ring came with far too much end gap. ACL no longer make the rings and could not change them. Nor could anyone else supply a ring to fit the piston. So in the absence of a 1.5mm top ring does anyone have an opinion on the 1.25 vs 1.0mm?

Not that I care, but: Telstra was privatised starting in 1997 and the last of it was shoved into the future fund in 2006. So it was not coincidental with anything. The government got the best coin for it in 2009 at $7.40 a share (Now worth 4.76). Bargain. Something somehow related to hype and the internet. Glad that has changed now. It has, hasn't it? Most people dont have multiple users in a house wanting to upload/download HD simulataneously. I certainly dont. I really dont care how long peoples mega uploads of Doctor Who take.

How many of them in the last 15 years? Their 2010 car was such a dog it should have been left chained to a fence somewhere. Actually that is a little harsh. The 2011 car was worse. Maybe this years is too.

Williams, Force India or Sauber. Which of these is a "big name team"?

Like Roy says McLaren have the long/slow strategy covered off with Button. So why sign Perez???? Hulkenburg has shown he has speed over a single lap - claiming pole in a Williams and did well in the Force India last year - particularly late on in the season. Probably too late. Di Resta is no muppet either. Anyway I cant see McLaren winning a race this year. Hope I'm wrong.

Me too but then again I cant figure out how Perez ended up at McLaren. The new Kovaleinan by all accounts. Would have gone for Hulkengurg or Di Resta.

Wow how old is Mal Rose?

What if I already do? What then?

R30. You may get a more helpful response if you tell the people what you want from the car & how much coin you may be willing to spend. You want atmo, GTST/GTT level or a GTR? Two or four doors? Wagon? Stock/modified. What are you going to do with it? Drive it to work. Enter it in Targa Tassie?