ozconnection

...and you started an engine without checking this??? I'm surprised at you Tony, not up to usual high standards mate

This works!!! Sounds VERY different, tuning going on atm with Megasquirt 2 V3 motherboard. Will be turbocharged soon, too. YAY

Yummy

No, I like this better. Leave the head, the Y70/O5L heads have beaut high velocity ports and small unshrouded valves. The Valve sizes in the L20A are actually the same size as in the low performance E30 heads which were also used on P30 L24 bottom ends. Inlets 1.5 inch. exhaust 1.3 inch. It was the late model L24's that had notched bores for the larger 1.65/1.38 valves. My point is, leave the head and bang a big cam in it. Let the overlap and lift do the breathing, the ports will remain responsive at any engine speed, not just after 4000 rpm when anything below that will be useless for the street. I currently have the 'ultimate' two litre 'street' L series. A Y70 head, stock sized ports and valves but with nearly 10 to one comp and a bigger than stock, stage two MSA turbo grind camshaft. Heck it still pulls 18 inches at idle. Midrange is very good and kickdown is very 'entertaining'. LOL. The sound of those high velocity ports is something else, too. Everything else you mention Tony is spot on. The bigger bores will allow great valve unshrouding at maximum valve lift with the little valves. I love my combination can you tell?

Yep, sorry, I was wrong. I have used a small dab on the ring gear in the past but the risk of using it and causing clutch problems is real. I NEVER run without the lower plate in situ. The bell housing area pretty much sealed up when it's on and dirt ingress is mininal, if at all.

You'll have no problem using the auto backing plate on your manual shift engine. In fact there are advantages in using this combination of parts. You can grease your starter ring gear easily, inspect your rear main oil seal easily (if you suspect an oil leak from here) and even set up a flywheel based ignition timing setup. Easily. I've never had problems with dirt either.

Displacement...? It's the baby six and so the obvious choice would to increase the displacement but I get the idea from the original poster that he doesn't have enough mulla to do it or just doesn't want to. He might have a good reason for not increasing the size of the engine but that question could be asked of anyone who doesn't run an L28 or larger engine in their car. As for the other bits, derr, but power isn't always the answer. Build torque instead and let the power fall where it falls. Big cams with big ports will kill low speed torque bro...derr! Great at 9.2K rpm though! Turbo's are excellent torque generators. Superchargers even better for low down grunt, very linear. Think "street" engine, not "race" engine.

But surprisingly, the idle is very smooth. You really couldn't tell it isn't a stocker by listening to it, even the idle vacuum is up to 17 inches now with a little bit more tuning. In gear, it runs 13.2 to 1 mixtures and idles at 750rpm. At one point during my adjustments, I had a lean 16.5 to 1 mixture and an idle speed of 550 rpm. The valve gear is a bit noisy atm so it'll need a hot lash adjustment soon but that's easy. I bumped up the timing to 20 degrees static, so total will be 32. I haven't connected the vacuum advance up yet and I might not even do it. I want to test it thoroughly with just the mechanical advance and see how that goes. I'm excited by this combination. I will get out the G-Tech, as soon as I'm satisfied I'm getting close to a good tune, I'll compare it to the figures I had with the old N42/N42 L28 combo. Then maybe a run down WSID... A general question "Who else has a Y70/P30 L26 combo?" Probably some dude in Japan and maybe New Zealand but I doubt the US or even Oz. Interesting.

FINALLY... the new engine is in the car and I took it for its maiden voyage today. Problem! The carburetor on this engine is a modified 390cfm Holley mechanical secondary unit. It's waaaaaay too rich at open throttle and I'm seeing 10 to 1 mixtures and even 9.8 on the Innovate WB. Allowing for this, the engine takes snap wot bursts without hesitation or stumbling, just like a vacuum secondary equiped engine. Totally happy with this situation. The same carb on my other engine with the Clifford just totally dies (massive bog) when driven this way. Static timing is 15 degrees ATM, a conservative figure to start with. Total timing is 27 degrees. No vacuum advance just yet (as I want to see how this engine responds first to incremental mechanical increases). Response is excellent but the high stall converter is just killing it (2.5K rpm). Its too loose for efficient street driving. I left it in there because I thought the cam might be too lopy. The Stage two MSA turbo grind is a gem, idled smoothly at 800 rpm and created just over 16 inches of vacuum. The sound this thing makes is unlike any other L Series I've driven...throaty plus. Love it already. Cheers. There's tuning to be done with this engine but I have to say there is potential in it. Can wait to get my hands dirty (again).

The man himself in action doing what he does best. Enjoy.

I now use Prad Penn 20w-50 too. I was sold on the higher zinc content, something that's important so I've been told. A close mate of mine who runs an 800hp small block in his race car swears by it too. Good enough for me.

Hi, A quick question; do the exhaust liners of the P79, N47 and Y70 heads alter the air/fuel ratio's seen by an Innovate WBO sensor for example compared to an otherwise 'identically' set up engine with square exhaust ports? I know that here in Australia, when the R30 Skylines were being sold, the L24E engines were equipped with both the E88 late model head with square exhaust ports and the N47 head, identical as far as I know except for the round exhaust ports. Would they have had different tunes in the ECU's to compensate? Can anyone shed some light on the subject?

That's a heck of a lot of oil!! How long do you have to warm up this engine for? PS Keep filling it until its full, pull the sump plug and measure how much oil is in the bucket!

This is a very interesting build with a lot of work being done. Well done mate. A quick question, did you consider using ARP main studs on this engine or did I miss that bit?

Yes, I'm curious to! And running 38-39 degrees total advance...wow. Stock dizzy?

Yeah, the Y70 would be a good head to start with. It depends on what you'd rather; round exhaust ports in the Y70 or square ports like those found on the E30 and O5L heads. I have the Y70 (two in fact) and the O5L head in my shed. I'm about to run one of my 26's with the Y70 head, stock size ports and valves for maximum gas velocity through the head. Valve shrouding is vastly reduced since this head was designed to fit to a block with bores only 78mm in diameter. The 26 it's on is bored 100 thou, now you know what I'm saying here! I concentrated work on the valve seat area and bowl which, I believe, is where significant gains are to be had. I wasn't put off by the liners in the exhaust ports, I've run heads before with them in and never felt like the engine was restricted by them. In fact, the engines with them in always sounded louder (and meaner) than the square ported heads. What does that mean? Dunno. The O5L has dinky little runners at 28mm's, smaller than the other two heads (30mm's). Certainly, this head would be a very interesting base for a 'sik' head buildup. If you ever want either head, Pm me and we can talk. (Need a P65 intake, got that too, LOL) Cheers.

OMG, that's really ugly, but functional, I guess?

Hey Heath! You could try something like this? Or this!

Has the engine overheated once too often in a previous vehicle and the head has gone soft?

I've used foam rubber instead of a rag, a much tighter seal is achieved. A rag will suffice though.

With the very mild lift on a stock turbo cam, there will be no problems running your P90 on that flat top piston F54. Mine is an "A" grind cam in a P90 on an N42 with VG30DETT "flat top" pistons...no problemo!

I've been telling all my friends over the years the virtues of the local brew made from fermented plums. Does a great job of taking away any pain you might be feeling.....lol and doubles as a great octane booster too BTW!! Stocks are low and I need to re-supply!

Hi Tony, going to Serbia.

This is a blast from the past. My N42 bottom end has finally expired. It will be rebuilt but probably not for a while as I need some cash for an O/S trip in June. So what to do? A spare L26 P30 bottom end with 100 thou over slugs is the basis for my new creation. The pistons have a dish on them and are cast. The head I'll be using will be the Y70...still 'wrapped in plastic' from a few years back when this thread began. Compression with a stock Nissan HG will be a touch over ten to one. The cam will be an MSA/Schneider Turbo stage 2. I like the 114 degree lobe separation for the torque it can potentially produce in the lower rpm ranges. The engine is in the build up stage with the block assembled and painted and the head being assembled as we speak. The N42/N42 will probably taken out this weekend and the new engine slotted in very soon. With the L28 out, I can tidy the bay a little too, just for fun. I'll keep you guys posted.....

There looks to be a 'conventional' water pump up front....thank god. May even be a stock L series one? LD28?? Where did they get it from I wonder, if it is???