SLVRBLLT40

Now, when they say negative deck height on the calculator, do they mean that the piston is recessed into the cylinder at top dead center or above it, because, at least in 1983 for certain, on a non-turbo L28, the stock piston is most certainly above the deck at top dead center.

I gots a question for ya'll. Maybe I'm totally overlooking something, so hopefully someone can help. The P90 has a 53.6 cc chamber (blueprint OE specs), a Fel-Pro replacement 1mm (0.40) headgasket has a 3.47 bore. L28 flat top pistons pop up above the deck .020 I believe. Engine bore is 3.39, stroke is 3.11. This yields a 9.09:1 compression ratio. That's a decent amount above what Nissan claimed. What am I missing here?

I am paying for now for the fun times of the past haha. I'm 24, 6 points, assigned risk insurance, liability only on my Zed is $86 a month.

I just built myself an L28 N42 for my 240. I'm using the stock '83 280 rods and pistons (which pop up above the deck .020). I found out too late the head was chopped .030 and with a stock headgasket, it ended up yielding me about 11.6:1 compression. Obviously check your specific head and don't take my word for it on any modification. There are some pretty spiffy compression calculators out there to help ya out.

The myth with the Hot Rod guys in general is that modern day, California gas (all gas here is 10% ethenol) is total junk. They base this on the fact that it doesn't contain lead (even though lead hasn't been in gas since 1973) and since all muscle cars died in 1973, that must mean the quality of gas died too. Total bologna. The main problemos with ethenol is gas is that A.) There's a pretty major hit in gas mileage. I think from 100% gasoline to 100% ethenol, it's a 30% drop or something like that. B.) Ethenol eats old cars. The fuel lines, the carbs, the fuel pumps, the tanks, pretty much everything in the fuel system. If you've ever opened up your carb and saw little white crystal babies in there, that's from the alky in the gas. Everything else about ethenol is good. Without ethenol, 11.5:1 on street car would be impossible, since the alky content does lower the combustion temperature.

Yeah, your are deffinately running a very quick 60', but by your 1/4 mile time, I'd say your car has some horsepower hehe. On a car that sees mostly street use, more times than not, your 60' will suffer, since the car will usually bog off the line or just totally annihilate the tires if it's got enough power to break them radials loose.

Outlaw Star, Cowboy Bebop, Hellsing and the OVA, and Wangan Midnight, of course. Also glad to see I'm not the only one that watches FLCL. If Vespa's were A.) EVER ridden by a pink haired broad carrying a two-stroke powered Rickenbacker bass around and B.) Did fuel altered burnouts, I'd actually have a tinsy, tiny bit of respect for them.

PowerSlide: Slow 60ft (depending on converter used) Good mid track One less shift the trans has to make If the tires spin off the line, you pretty much have to completely let out to control wheel spin Much lighter than the TH400 The preffered tranny for high HP cars TH400: Faster 60ft Can take more HP Easier to modulate wheel spin Weighs more Has that extra gear to shift Preferred trans for street driving and moderate HP

I can tell you that when you autocross, do not go from a worn out, 2.4 Zed into a new 2007 350 Zed and forget that you now have 100% more horsepower under your right foot. They get all mamsy pamsy when you dump the clutch and annihilate the the rear tires for the first three turns but then decide it's fun and do it the rest of the track. But that's just an example situation.

I just finished my 280 F54 engine, so I still have all the head gasket specs for a 1mm FelPro saved in my compression calulator Anywho, with said head gasket, if you're running the flat top 280 pistons, which actually pop up above the deck .020, and an uncut E88 head at 44.7 CC combustion chambers, you will be running at about 10.6:1 compression. If you use the dished turbo pistons, you'll be at aroun 8.4:1 or in that neighborhood.

Yeah, I know what you mean. I have my timing at 31 and it was pinging, but I put some 110 in it today and hazaah, it now hauls major ass. So I'm really really happy with it and I think I'm gonna keep running the non-sense money juice. Tomorrow I'm gonna try to advance the ignition to 34 or so and see how it does.

Do you run them on race gas or what's your secret?

It's an L28, in which the pistons are flat tops that pop up .020 above the deck. I'm running a .040 (1mm) head gasket, and the N42 head that's been chopped .030. I typed in said specs to my compression calulator, with a 44.6 CC chamber, and then subtracted .030 from the head-gasket thickness to simulate a chopped head. I know it's not the proper way to do it, but I don't want to take th head off and CC the combustion chamber. Ah, and my cranking compression with all plugs out of the cylinders is 240 PSI across the board.

I just wanted to vent a little and say that I lazily didn't measure the combustion chamber CC's on my junkyard N42 head. Turns out it's been chopped .030 and I used a thin 1mm headgasket. I just built myself a 11.63:1 race gas engine with a stock cam, valves, and ports. D'OH! At least low end torque is super duper.

I just took a dial indicator to my P79 '82 280ZX camshaft and to my N42 camshaft. They ARE NOT the same. The N42 carries a a .433 lift on both intake and exhaust lobes, whereas the P79 carries a .413 intake lift and a .433 exhaust lift. And no, the P79 cam does not have worn out lobes. I am also willing to bet the duration specs differ on both cams as well. Super duper.

Darn, I already have an engine. That lot is right down the street from my house too. Boo. Oh well, maybe someone will want to pay me to trailor the whole car out to them.

And that is the main difference/point of argument between the two types of intakes I'd say.

Think about it for a second. The mikuni's your are talking about flow 211 PER TUBE. A 390 ontop of a common plenum, single plane intake manifold flows 390 PER TUBE. That equates to a total 3120 CFM V.S. the mikuni's 1266 CFM, which doesn't matter anyways, because all we care about here is flow per cylinder. Just take a look at a drag car running I.R. Hilborn versus one running a single quad ontop of a tunnel ram. The total CFM of the Individual Runner is WAY higher than what the single quad flows, due to the fact that each and every intake valve has access to the entire plenum full of air and gas when running a common plenum. So I didn't speculate on this one, I'd say I thought it through pretty well thanks.

Ok, I was being VERY sarcastic, just thought I'd add some humor to the debate, but I keep forgetting, that sarcasm doesn't transfer to the typed text very well. Of course I know that my one time experience means jack. Geezy.

Ah, and a little bit mroe fo my 2 cents, since it is only 2:20 AM and I have an L28 swap to continue on in 5 hours. I will honestly say that the 4 barrel conversion on my Z is the biggest love-hate relationship I've had with any car part. Driving it around, I HATE it. Mostly I believe it's due to the 390 Holleys lack of metering rods, thus making mid-range fuel delivery GARBAGE. But, when I floor it and tack it up, I love it. Also, I do sincerely believe that 390 CFM is WAY too much carb on a single plane/tunnel ram deisgn for a 2.4 Liter engine. I do not believe that I've ever gotten the vacuum secondaries to open up. This is reinforced by the fact that when I had a "500" CFM Holley 2 barrel on it (not really 500 cfm, as 2 barrels are measured at a different vacuum drop), my 1/4 mile and 1/8th mile times were identical. Also, With the single plane design, every single intake valves is getting 390 CFM, assuming the carb is wide-open. If I recall correctly, a Weber 45 flows like 230 CFM, and that's direct runner and easily enough carb for a midly built 2.4 liter. SO, I think my carb setup will work well when I get this mild built L28 swap in, and it sure beats the hell out of that flat top Hitachi's. Even averages about 21 MPG, which I'm ok with, still having the 4 speed and such. All in all, it beats shelling out $600 plus for the round top's or trying to dial on triple webs on what was a mostly worn out engine. Did I mention my cam is retarded about 5 degrees from timing chain slack?

You are correct sir. BUT, and this is surely the science part you were looking for, MY 4 barrel 240Z had it's way with another 240Z on the freeway, and THAT Z was running them funny sideways triple dueces

All the compression math I've done with the N42 head on top of the flat top L28 suggest about 10.1:1 compression with a 1mm head gasket. The N42 is an open chamber design, which I've always understood reduces the chances for pinging. Since the head is also aluminium, you can get away with more compression. Don't turn total advance above 36 or 37 degrees, and don't run static advance above 16 and you'd be fine. If I can run 10.25:1 compression on an ironhead MoPar and be good, you will be too

Lordy, you guys are brave. I'd never be able to bring myself to use a head gasket that's already been ran.

I'm currently rebuilding an '82 280ZX engine to go in my '73 240. I was just curious as to a few things. First off, according to some specs sheets I have, the 280Z ran a slightly wilder cam than the 240. Problemo: 280 uses internal cam oiling, whilst the N42 head I have was set up for the oiling tube. Can I install the 280 cam towers on the N42 head and thus have internal cam oiling? If I can, is there a reason why I shouldn't? Thanks, Mike

When I took the intake manifold off my 240Z, there were alot more than 4 bolts holding it on. The exhaust manifold and intake manifold share several bolts and they are all on the underside of the intake. I had to take my heatshield off to even get to them. So try taking a look at that, if you haven't already.