JMortensen

Perfect description of the present situation.

The most advance I've heard anyone run on an L on purpose was 38*, all in by 2000 rpm. I think you have too much advance, but if you did it on the dyno and that's where it made the most power, then maybe I'm wrong.

Did you measure from the bottom of the head to the top of the intake port? Cause I wasn't talking about the relation of the intake and the exhaust. Theoretically you'd want both higher, and that's what I thought you got (kinda misspoke about intake without also saying exhaust). This port thing I'm really not sure of, so I don't really want to argue it too much, but a friend of mine told me that as a reason why he used a P90, and he had about 20 L series heads. I **assume** that he measured and I think he said he did, but I'm not absolutely sure. I thought I was pretty much the only one arguing. Dan and I are both stubborn, so it might still be a few more posts. If you can't deal, don't read it. I can say that there have been a few interesting posts on the IZCC list about this... Because it has the L24 bore it has the smaller valves. So in order to take full advantage you'd need to install the bigger valves and unshroud just like the E31. Don't know that I've heard of anyone going that far with the Max N47.

They just stopped manufacturing them. Still totally legal to own, buy or sell as far as I know.

I bought a muffler and a couple of 180* bends from JC Whitney. The straight tube I just got from a local shop because I figured it would be expensive to ship. Took me and a friend a solid afternoon. Just kept cutting pieces and tacking them together. We worked from the front to the back. Cheap and easy.

Well according to http://geocities.com/zgarage2001/head.html the volume of the P79 chamber after the shave is 46cc. The volume of an N42 chamber is 44.6 (Lengine.exe). I would think that you could get damn near the same compression out of either one. Also, the valves in the P90 are .100 shorter (from How to Mod). So you could theoretically mill the P90 .100 instead of .080, and get a little more that way and still be right where you need to be with the rocker geometry.

Thanks, I knew I had that wrong. How do you think these 14:1 guys do it? They don't just mill 1/4" off the head you know. Every forged piston that I've seen for an L series was forged with big pop ups for 12:1 or better compression (actually I think they were all ~14:1) and all of them REQUIRED that the piston be machined. I'm sure that is how John Coffey got his quench area. Just machine the piston to match the combustion chamber. Granted, every forged piston I've seen was for a high compression NA L series motor, and I haven't seen that many (only 2 different race engines). I'm sure you can get flat tops or dished pistons too, but it is definitely not unusual or hard to come by domed pistons that are meant to be machined. Maybe you can't easily quantify it or maybe we're just ignorant of the Q scale or something, but it's easy to find engine builders of all types of gas engines using it to their advantage, and they can tell you why it is advantageous. Actually they use the piston shape to their advantage. Some really funky piston and chamber shapes come out of this. Check out some of the full billet Harley heads. Crazy computer generated CNC milled chambers and pistons designed to optimize the suction on the intake, burn, and the exhaust efficiency.

If Russia were to start wiping out terrorist bases in Chechnya, I would have to herald that event as the world being safer.

OK, so the L28 has a positive deck height of .030mm. The LD28 crank has an increased stroke of 4mm. Norm cut his pistons down 2mm. He could be using 2 Failure Prone gaskets at 1mm each or 2 regular gaskets at 1.2mm each.. That means that he should be at .4mm clearance (.016") with the head, or the pistons should just touch the head. I had this wrong before. Please help me figure out if I've screwed it up a second time. Regardless, doesn't seem right... So we actually agree... man if I ever meet you in person we gotta go for a beer and talk about the time we agreed. Come on man! If YOU'RE going to determine the parameters of what is acceptable proof, at least let me gloat over my ONE instance of "proving you possibly wrong" or at least "less right". The original r/s ratio of the 240 was 1.8. An L28 with 140mm rods = 1.77. Clearly not going beyond the original very successful design. Compression is a known and well proven power-builder in JUST THE SAME WAY that quench is. That's my only point. It's used pretty much universally in pretty much all heads on gasoline engines that I've seen. Don't let the bed bugs bite...

You know what you're right Dan. My theories about rod ratio and quench are just theories. There's a hell of a lot of support to back them up in general terms, but they can never be absolutely proven as fact in every possible circumstance. Kinda like these theories: theory of evolution, gravitational theory, atomic theory, germ theory, quantum theory, etc. None of those are absolutely proven either. I never worry about gravity either. I always "know" it will be there for me.

I don't know much about Norm's setup. I certainly haven't paid as much attention to what he's doing as I have to what you've been doing. I ***thought*** he was running 280 rods and pistons on a stroker crank. That would leave you with a LOT of positive deck height, and I ***thought*** he had to mill down the pistons and run the 2mm gasket to get to the point where he would have quench. I could be wrong. I'll take the wrath I suppose. I don't know how you figure out what to do on your Z. Maybe you just ask someone who knows better than you do, and do exactly what they tell you. Nothing wrong with that other than you're limited by the person you're asking. It sounds to me like DAW has access to all kinds of L parts. When I built my current engine I could have used any block, any crank, any L24/L26/L28 rods, and any head except the Max N47. I chose what I chose because I listened to an "expert" and dumped a pile of money into an E31. If I had it to do over again, I wouldn't have anything like the build that I've got now, and I'm as sure as I can be without spending another $1500 to prove my point that I would be pumping out more hp. Maybe I'm some kind of psychic or something, but I can see a head and a block and rods and crank and I can get an idea of what it's going to do BEFORE I actually build it. Similarly, when I go to the fridge I seem to "know" what I want to put on a sandwich, and when I make it: BLAMMO!!! Good sandwich!!! And I knew it was going to be good BEFORE I bit into it I'll re-read the post in question, but I don't remember it being stated that emphatically. I recall it provided the LD block as a relatively easy way to get past the deck height limitation. You know that you don't know. That is true. But the part you don't say is that you write off anything that hasn't been on a dyno chart that YOU'VE seen. You also fail to note that you BROWBEAT anyone who tries to disagree with you. On the other hand I can apply reasoning to the questions that I seek answers to. Unlike an engineer, I can speculate and USUALLY come out right. I know that other similar situations have borne out the benefits of quench and rod ratio, and that those things should translate on an L series being that it is a gasoline powered piston engine. Nissan made their only aftermarket L-series performance head (non-crossflow anyway) with quench in mind. I have the ability to relate that knowledge to my own build. But I had a good idea that the quench area was going to matter even before realizing that about the FIA head. How did I know this? You hit the nail on the head before. Because I understand the theory behind quench, I could tell just by looking at them. I thought the rod ratio thing might also play out. I had been given the advice to fit the longest rod I could into my engine when I built it by my engine builder, but due to financial constraints was unable to use anything other than the L28 rods. When I found out Devendorf used them, I felt that the point was "proven". Why would a nationally competitive racer use them if there wasn't anything to it? BTW, the book says nothing about him using an LD28 block. I think he used an L28 block and crank, 140mm rods and custom pistons. And I think that would be a badass setup despite the fact that I've never tried it and haven't seen his dyno chart. Did you see that Kameari chain tensioner setup? I had a hard on for that thing 5 seconds after seeing it the first time. I am SURE that it would make a dyno recognizable difference in power, even though I haven't tried it. I'm not claiming omniscience. I'm claiming the ability to see a good idea somewhere else and apply it to what I'm doing. And so far I've been fairly successful with that. From the Gtech comparison I'm fairing pretty well with my budget build vs your high dollar build. EDIT-- I upped my compression ratio even though I have never seen a dyno sheet with the same L series engine with dished then flat top pistons. I just "knew" it would work!

Doh... that's gotta be hard to say, even for McAuliffe...

I used my E31 because it has a bunch of quench. Not a perfect correlation, but it was also just a way to show to anyone who reads this that you don't need the dogmatic F54/240/KA24/HKS/N42 to make hp. It was more a response to your BOW DOWN AND WORSHIP ME thing. The BOW DOWN thing is my problem with your argument. It is always "well I made x by following the formula" or "why WASTE time and money on an impractical experiment that will have no real benefit" and you really don't know that these things have no benefit, nor that they are impractical. For instance, how hard would it be to lower an LD block an inch in the chassis. I think I could get that done in fairly short order. This is what I said: Correct me if I'm wrong, but if you shaved an N42 you wouldn't be able to run pump gas. Right? So in order to get a significant amount of quench out of the N42, you'd need to run race gas. The other advantage to the P head that I haven't been able to verify is the height of the intake ports. We didn't even get into this yet, and I almost don't want to, but supposedly the intake ports are located higher on the P90 which makes for a longer short side radius. I'm sure I don't have to explain the benefits of that to you.

Thank you for getting the title right. 'Bout time you showed some respect. Yeah, that is a pretty crappy comparison, but it's all I've got. You missed my point. My point was that I have a grand total of about $1700 in the machine work on my engine. If you include the ancillaries I've probably got $2500 total in mine. I did it because it was fun. You're right, I haven't dynoed, so I can't see where improvements were made. I can only say with some assurance from my ass that there were improvements. Cars on jack stands and will be for a while yet, and even if it wasn't, there are so many other things I want to buy before I spend time on a dyno that I can't see wasting the money on it. I'm spending some real $$$ on my car for the first time in 4 years, and I'm running very overbudget already trying to get a number of projects done. If and when it gets to the dyno, you'll be the first to know. EDIT--Gtech stuff was with the dished .020 over pistons on the first motor.

Now you're talking, except we should keep more than 1/2 and they should leave us alone.

Look at the arguments and decide for yourself. If you can't tell who is right on the argument, then study up until you can. All the info you want is right in front of you.

Public education and the war on drugs are already in the govt's charge, like it or not. Health care is increasingly in the govts charge, but there are those of us who look at the public education and war on drugs and think that the govt shouldn't be in charge of health care. Those are the people who hate Hillary's policies. I am one of them. I'm not accusing you of this Phil, but it always amazes me when people talk about how crappy the govt is then in the same breath tell you how they want to expand its powers. I don't care about Nam either, but forging documents to slander your opponent? That's almost Watergate-ish.

Well I've actually lightened up. Yesterday I was taking it too personally. Today I laughed when Dan said BOW DOWN BEFORE ME. I guess maybe my sarcasm wasn't evident in my last post.

EXACTLY. This is why I said that I thought it was such a huge improvement over the type I. HELP! PLEASE! ANYONE ELSE WHO UNDERSTANDS! Drax? Someone! I'm going to try again. Torsen--Look at the yellow picture that Drax provided before while you go through my expalanation: The invex gears slide on their axles. When the helical side gears turn on the invex gears, they slide until they hit the case. There is your "side gear face to differential housing". The side gear continues drive the invex gears, but now there is added friction. This is the "Side gear to element gear Invex gear meshes." Remember the bushing that Drax mentioned that sits between the side gears? That's there because the pressure of the invex gears pushing against the side of the case makes the side gears inside want to move the opposite direction, together. This is the "Side gear face to side gear face." In order to get a 1.5 way action on the diff, they've put needle bearings (which Drax also mentioned) on the outsides of the side gears, so that it won't make as much friction on decel. And that is the "Side gear face to differential housing." The Truetrac is pretty self explanatory but if you don't get that one, read the pdf I linked to again.

Dan--READ the links. They tell you EXACTLY what factors need to be in place to have quench. You DON'T have it. OK Dan, this is all I can do to actively prove my point to you. This is my last shot at delivering you from what I can only describe as beligerent ignorance. My current build: Stock 2.8 bottom end with flat tops no overbore (notched the block, removed the casting, balanced, but that's it) 12 lb flywheel euro damper E31 head, ported and polished by me, 280 valves 490/280 cam 44 mikunis on Cannon manifold MSD running through ZX dizzy The closest I've come to a dyno was a G-Tech test, because I've never had money lying around that I didn't want to use to buy something to make the car faster. The clutch was slipping BAD, as I was still running the stock clutch at the time. I had a buddy in the car, so the weight of the car was 2660 lbs. ET 15.5. Trap speed 108. According to this calculator: http://www.speedworldmotorplex.com/calc.htm I'm putting down 266 hp, 11 MORE horsies than you!!! Now most people say that the Gtech is a little high on its trap speed, couple mph anyway. Lets drop it down to 104. Now I'm putting out 234 at the wheel. Since you have a 10% displacement advantage if you knock your number down it would be 229.5. So I'm STILL putting out more than you per liter. I'm not saying that I totally believe these numbers. If I were to estimate my rwhp I'd say 225. But I've got a total of about $1700 in my motor. How much do you have Dan??? If you want to tell everyone how to build an $8K (guessing) motor that puts out 82hp/liter fine. I'm not telling them not to. I'm just saying that there might be a small advantage in the quenchy head. There might also be a small advantage in the rod ratio. I'm sure I have a small advantage in the way that I notched the block to match the unshrouded head, and the way I blended the seats into the chamber. If I told someone such as yourself about the number of hours I spent doing those things (it was over 40 easy), you'd probably have told me it was a total waste of time. But IMO it is not. Every little bit counts. The only track proof I have is I know that I was within 2 seconds of Mike Eckhaus's best time at Buttonwillow when my motor was in a really bad state of tune and it was 105* on the day I was there, and he's supposed to have crazy hp. More than you. I think you let that one dyno sheet and all the compliments you got from it go to your head. Your motor is impressive. Don't get me wrong. But since you've built it you've become the self appointed authority on rod ratio and quench, NEITHER OF WHICH YOU'VE USED. I didn't want to use my "evidence" because I know it is half-assed. But my 1/2 assed evidence shows that there just might be another way to build an L series engine. EDIT--FORGOT TO MENTION, GTECH AND TRACK RESULTS WERE WITH MY PREVIOUS LOWER COMPRESSION ENGINE. WENT FROM 8.5:1 TO 11:1, I HAVE YET TO GET ANY PROOF OF THE INCREASE IN POWER I CAN FEEL ON THE BUTT DYNO.

I am definitely not an engineer, but I read the info from Tractech and Torsen below and I have good comprehension skills. I just don't think I'm wrong on this one. Especially since the manufacturers themselves seem to agree with me. Or am I missing something? From Trachtech: From Torsen:

Well I'd ditch the flowmaster and get a better flowing muffler like a Super Turbo or even better an UltraFlow. Mandrel bent? I've got a friend with press bent 2 1/4" and I swear it probably flows like mandrel 1 3/4" from the looks of it. I suppose it depends on who does it, but mandrel makes a big difference regardless.

I was trying to figure out your compression ratio, and looking at the How to Modify book. Be CAREFUL when you try to figure this out. It looks like your pistons from the Big Bore kit should have a positive deck height of .025 (the book suggests machining the pistons), where most 3.1 builds have the KA pistons -.37 mm below the deck (from Lengine program). That's a big difference. I suppose that Nissan could have eventually changed the pistons in the kit, but I was surprised when I saw that in the book and I've never heard anyone else mention a positive deck height with the pistons. Did Sunbelt give you a build sheet? You'll need to know how big the chambers are post shave too. I would think you should be able to get more out of it too, I'm wondering how much carbs and possibly exhaust are restricting you. You pretty much have everything else covered by the looks of it. EDIT--You've seen this right? http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=34844

Was looking at How to Modify and I noticed a couple things: The FIA L series heads have a big quench area and a heart shaped chamber. Stupid Nissan. How could they let themselves get sucked into this decades old quench "fad". You'd think they'd know that quench doesn't matter on the L series; everyone knows that's just for V8's. Also, Devendorf's IMSA GTU L28 used, get this, 140mm rods. Looks like he used 133mm rods in his GTO turbo car. Looks like he was going for that bogus rod ratio of 1.8. What a dumbass. Too bad Dan wasn't there to keep him from falling into that whole rod ratio trap. Too bad I can't back up my points with any "proof".

Not really, because for those of us running stock valves we'll still need to get the N heads for the longer valves. We'll just take the valves out and throw the head away...