Dan Baldwin

technicalninja offers the most useful response. But I think the stock CR is closer to 8.5:1, not 9:1. But of course it can be bumped up... Lockjaw, you still haven't presented any evidence whatsoever. I'm running 11:1 on pump fuel now, at 34 degrees total advance, with N42 chambers that are essentially unmodified. I ran the motor for years with the stock cam and ~10.4:1 CR, in Georgia and Alabama (quite a few hot days at Little Talledega), with way too much advance, well over 40 degrees, and no perceptible detonation (I was even dumber then than I am now, and set the stock dist to 15-20 deg. initial advance). At the dyno I have found max power with between ~34 and ~38 degrees, so I keep it set it to 34. Again, I'm not saying the N42 is better, but according to MY experience and others, it does a fair enough job.

I have but one thing to say: Holy CRAP! Looks like there's a lot more potential once the A/F is straightened out. I LOVE IT! Now do mine.

Pretty funny! Actually, why NOT only overbore the cylinder that needs it if cost is an object? So if you do a 1mm overbore on all 6, won't you still have one that is .5mm bigger (1.5mm over total)? j.k.

Hmm, conspiracy theorist?! I got the "euro" pulley, whether it's from European models or not, it has one groove and weighs quite a bit less than the 240Z damper, like ~2.5 lb. vs. ~4 lb. IIRC. Anyway, it doesn't cost any more so I don't see a scam. Still, some prefer using a heavier damper and lightweight flywheel for crank longevity/durability, but I'd suspect that's for 7500+ rpm motors. Or maybe I'm living on borrowed time...

Not this again... You can make VERY good power with a 280Z N42 head. Some are more concerned with what the chamber looks like, though;) I've seen ZERO evidence that the P90/P79 cc design offers *any* performance advantage. Where are the 255rwhp or 12.8x sec @ 107.x mph P90-headed, pump-fuelled, NA cars?! Back to original question: I don't know if I'd let a guy who does cylinder heads for cheap cut any metal on MY cylinder head. As has been said, you can make your own stroker kit with an early 80s Maxima diesel crank, 240 rods, and KA24E pistons. BUT, as has also been said, you shouldn't bore the 260 motor out .120. Only the 2.8 motors can be bored that much. But you should be able to find a L28 block for cheap. Your stock E88 head gives the 2.6 liter pretty low compression unshaved, and it has smaller intake valves than the 2.8 liter heads. On a 3.1 liter bottom end, with your E88 you'd be making ~9.6:1 CR, which ain't too bad, really. N42 would have you at just over 10:1. Or you could shave a P90 (or P79) .080", shim the cam towers, and use the longer N42/N47 valves to get about the same CR. Whatever you do, to get it done *right*, it's gonna cost MONEY.

I don't know all the ins and outs of piston-head clearance, but I believe you want to be closer than 2.37mm for better "squish" (if I may talk out of my behind for a moment). But you know more about engine-building than I do!

You sure it needs to be bored out? Would save a few $$ just to install new flat-tops. It now occurs to me you won't likely want 10.5:1 CR in the wife's street car, so with the KA options you'd use the 2mm gasket, right? You can remove sheaves from it to tailor the CR to what you want, BTW. The one in my car is actually a 1.17mm gasket (two thin + one thick layer from the 2mm gasket).

Pete, I think with KA24 pistons and L28 crank, you'd have to use L20 rods, as with L24 rods you'd have low compression with the pistons 1.37mm below the deck (using the ol' Lengine calculator). You'd also want to shave off the raised .5mm ring so you could use the 1mm HKS gasket. That'd give you maybe 10.6:1 CR (Lengine calculator screws up when shaving dished pistons, it wouldnt be as low as the 10.26:1 it calculates). You could just throw in the diesel crank and use L24 rods, of course! I got my KA24 pistons for $240 from Riley at Lynchburg Nissan. Not too shabby. I still wouldn't think $300 to be too much for Nissan L-series flat-tops. My engine was originally built in North Carolina, orchestrated by Riley (then at Tarheel Nissan). Recent rebuild was done at Abacus Racing in Newport Beach, VA, where they took it to 89.5mm. Min wall thickness is down to a pretty uniform .100" (yikes!), apparently the bores are pretty well-centered.

Hiya Pete! Why besides Nissan?

You have maximum torque of ~219 lb-ft at ~2900 rpm. 122 hp (@ 2925rpm torque peak) * 5252/2925 = 219 lb-ft.

If you don't see any sense in 30 lb-ft of torque (realistically, more like 25 lb-ft over a similar 2.8 liter), then obviously you shouldn't go to the trouble! Seriously, if you're doing a rebuild anyway, it's well worth the few hundred extra bucks to do the 3mm overbore/4mm stroker 3.1 build. IF a competent machine shop and engine builder are doing the work. It's well worth it especially for a high-performance street car. Note that you can tune a higher-displacement motor more for high-end power while still maintaining decent low-end torque. i.e., for a given level of low-end torque, you could have a 2.8 liter built to peak at maybe 5500 rpm, or a 3.1 that peaks at more like 6200rpm and makes gobs more power. To me, and most people who are of a mind to mod for more power, it makes PERFECT sense!

It's a bit of a reach to say the calipers are inherently "no good" based on one failure. I've had the '82-'83 rear calipers on my Z for the past three years, no problems. Of course my experience doesn't prove them "good", either. One bad seal or one botched build (or rebuild) doesn't make the ZX rear calipers "bad". FWIW, I don't have the parking brake hooked up, the rear brakes do stay in adjustment anyway. Dan

It may SEEM like heavier wheels are helping, but it's the entire vehicle weight that you're talking about here, the total normal force at the tire. And total vehicle weight can't have changed much. Heavier wheels/tires will always result in less grip under dynamic conditions, as the suspension won't be able to control the unsprung mass as well. Lighter wheels/tires will always have better contact with the road in real-world conditions (i.e., bumps, undulations, etc in the road surface). The suction cup feel you describe is likely 100% due to better tires.

Funny that you've decided on either a 280Z or 280ZX, as the 280Z is almost the same car as a 240Z, while the ZX is a totally different chassis. My opinion: If you're serious about performance, get a 240Z. The large majority of the ~400lb additional weight of the 280Z is NOT in chassis stiffness, and it's a lot easier to stiffen a 240Z, while adding only a few pounds, than it is to excorsize 400 lb. from a 280Z. I wouldn't consider the 280ZX because of the inferior semi-trailing arm rear suspension design, not to mention the styling (subjective).

FWIW, those Honda horses are a lot smaller than the Camaro's horses. 2750 lb. S2000 does ~100mph in the 1/4, while a 3400 lb. LS1 Z28 does ~106 (friend o' mine does 107s in the 13.4s, all stock on all-season tires, actually). Assuming a 175 lb. driver, I calculate ~332 net hp for the Z28, and 228 net hp for the S2000. GM was WAY conservative in rating the F-body's LS1 power output. As for high tech vs. low tech, it's a moot point when you get to the track (1/4 mile, roadrace or other). I am not prejudiced at all, I just want as much power as I can get, and as little weight as possible. Nothing wrong with either method. Let it be known, however, that in the power to engine weight, "old-tech" pushrod V8s can do very well indeed. More cams and valves isn't necessarily better than more displacement. I'd rather have the Saleen S7's (2750 lb. supercar) 7-liter NA motor than the Ford GT's (3400 lb. supercar) overwrought supercharged DOHC V8 in my 240z. The OHC 6 will have to do for now, though...

If you're not planning on going over ~7500 rpm, stock Nissan pistons should be adequate. KA24E pistons come in 89mm, 89.5mm, and 90mm. In my recent 3.1 rebuild, it was overbored another .5mm with the 89.5mm pistons. 89mm w/ diesel crank = 3098cc, 89.5mm=>3133cc, 90mm=>3168cc. FWIW, when I had the block ultrasonically checked before the rebuild, min wall thicknesses were around 0.110", with the bores well-centered in the block. With the additional overbore, I'm at ~0.100" wall thickness now. I don't know if I'd want to go any further. Torque will pretty much increase linearly with displacement, so more is always better in that regard. Just a question of risk vs. reward. As far as cam duration, this is totally dependent on your application. How will the car be actually used? A street motor will have far less cam duration and lift than a drag or track car. It's best to be honest about what you want the car for, mine is a dog from a stop unless you really give it a dragstrip launch, which you don't want to have to do to beat the ricer/musclecar/eurotrash next to you at a traffic light.

Almost useless reply here, but I did use 2" SUs for a while. Tuned them per directions given in an old ZCar Magazine. IOW, didn't really tune them. Never measured A/F. Must've been running pretty lean, because the car used to start to run hot after a couple of laps at the track on warm days, and I'd have to start feathering the throttle. After installing 3x2 carbs, with the A/F in the right ballpark, the car has never run hot since. With the Jag carbs (HS8s), I just ran with the needles that were in them.

Let us know what you make on the rear-wheel dyno, if/when you dyno it. For reference, I know of a 3.1 that did 305 on the Rebello engine dyno and then made 235 rwhp on a dynojet dyno. But of course who knows if the owner/installer had it properly tuned... FWIW, my car only did 106.5 in the quarter, which would seem to indicate a lot less than 255rwhp. I was having some fuel pressure issues that evening (clogged filter), though, and my subsequent runs were at 103, 100, and 99. But I also wonder if the dyno I go to might inflate the numbers a bit to keep the customers happy. Anywho, 347 is the biggest NA L6 number I've heard, should make for one fast Z! What organization/class are you running with it?

Here's what mine did (rwhp) this past June, after being rebuilt: That's with 11:1 CR, on 93 octane pump, btw. It broke up above 6200 because I had to use the stock points, as my 280Z ignition failed the day before (durn). With a new Pertronix Ignitor installed, it now pulls cleanly up to my self-imposed 7000rpm MSD 6AL rev limit.

This wouldn't seem to offer enough of a performance advantage over a mildly built-up 3+ liter L-series motor to be worth the effort, IMO. I had an '85 535i for years. Great car, great motor. Only ~175hp stock, though. Why bother? If I were going to go to the effort of swapping in a BMW 6-cyl, it would have to be the E46 M3 motor. Now THAT would offer some seriously improved performance over the L-motor!

To check advance at higher rpm, you rev the engine while checking the timing, and either mark the pulley up to 35 degrees (mine is marked at 0, 5, 10, 15, and 20), use an adjustable timing light, or just approximate. It's really more important to know what it's doing at higher rpm, as that's where detonation is less likely to be noticed, and more likely to do damage. Also, higher rpm is more likely where you really want to optimize it anyway. Much better to be running at 10idle/35max than 18idle/43max. Better for longevity AND power production. Knowing what the advance is at idle but not at elevated rpm is better than not knowing the advance anywhere, but perhaps not by all that much!

240Z distributor, with a Pertronix pickup. Definitely check your advance at elevated rpm. I drove around for quite a while, on and off the track, with ~18 idle/43 max total advance. WAY too much. Aim for 34-36 max total and you should be in the ballpark. I've checked out the jason510 site, that's what I sorta went by in modding my distributor. Pretty good reference.

Yes, best timing for my engine was ~34 degrees at full mechanical advance (+/-2 accuracy on my reading, at best). You may as well get rid of the vac. advance, as it's probably not doing anything with the 3x2s anyway. Mine is still on the dist, there's just not a vac line going to it. Vac advance is just for part-throttle cruise mpg, anyway. A stock 240Z distributor will give ~35 deg at rpm with only 10 deg. at idle. Like Jon said, I filled in the inside of the slots in the mech adv. to run more initial advance. Running about 15 at idle now, I think. Some like to run more like 20 at idle with triples. I didn't change the springs. I believe all my mechanical advance is in by maybe 3200. Dan

This is a poor method to set timing. Twice I've been to the dyno and gained power by backing off the timing, though it hadn't been pinging. Each time I've wound up at around 34 degrees max timing with mechanical advance fully in.

Reading your last post, I say go with the 44s/45s. They can be made to run just fine on the street. Z vs. 911 is FUN at the track! Saturday and Sunday I had a GREAT time with an '85 911 with a 3.6 and HUGE tires (huge brakes, too). I had way more power to weight, and would really pull him towards the end of the straight (NHIS road course, South Oval configuration), but he could REALLY pull away going up the hill out of turn 3, where I was wheelspin-limited. I wound up beating him in time trials by hundredths!