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Nasty ass lz23 v2


scooter

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Well its together now, lol. L20b rods are still 5.744, theyre arp rod bolted and shot peened.. I know the 6 inch rods are alot better, but at the time i didnt wanna order aftermarket custom ones. Maybe ill do the math and see if i Can even go a bit longer, basicaly as long as i can get without cutting into the oil ring with the wrist pin.

 

I gotta get it in the car and then its dyno time ;)

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Thats a bad ass header! My question for you is what did you end up running for lash caps? I ended up with .300's with that isky cam.

With the 45 mil intakes i had to remove alot of material to try and get rid of the valve shrouding. Also if you order 280zx valves from ferrea they are shorter than stock u67 valves, i ended up moving the seats deeper into the head and completely reworking the chambers. Compression wise i ended up at 11.1.

 

I think whatever horsepower i lost in compression i gained in eliminating chamber shrouding. My valve job im keeping secret as ive been using it on oval track motors with great success.

 

Next refresh its getting 6 inch billet rods and a new set of pistons, i feel the rod strength is going to hold me back, along with not getting tool steel dlc coated wrist pins.

 

I was pretty close to .300 as well. A little thicker as I recall. The 44/ 38 valves i got from SI. The seats from Carquest. The header was a cheap Summit V8, U weld kit i just hacked up to what I needed. The collector was the challenge.

Here is my chamber after the unshrouding. I may have got a bit carried away, and I don't have a flow bench. Just guessing really.    

 

photo1_zps7f05ebc3.jpgIMG_2177_zpsc1aceca5.jpg

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I think you'd want to knock down that sharp edge on either side of the spark plug if you're going to run nitrous. Rasius them good.

 

Also, I ran a 2200 for years with 12:1 on the street (pump gas) but I had a monster cam to use up that cylinder pressure. It was a 63D (custom Rebello grind). I still have it (the cam) if anyone is interested. That motor with dual 44's made 205 hp and 190 tq on the dyno.

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Dynamic compression comes in around 8:1, which is okay, it would be better around 9:1.

Any specs on that rebello cam? I may send the core I have to isky to have a z273 ground up. More LIFT lol.

 

Objective now is to get it in the car, and the car on some rollers!

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I don't have any specs on it. It is what Dave calls a "hydraulic" grind, meaning the takeup is gradual but then really fast. It is very hard on valvetrains. But this is probably the most moderns cam profile for a L motor out there. And like I said earlier, made 205 hp 195 tq on a 2200.

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It's dynamic compression, which is different from static. Statically it's 11.1:1, dynamically, which factors in rod length, and camshaft duration is what you get statically. It's on nitrous, no need for the turbo ;)

 

Yes this helps when starting, but at higher revs the volumetric effeciency can excede 100%

 

What were your combustion chamber cc's?

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  • 3 weeks later...

This thing is running, and its NASTY.

 

I have a crappy cell phone vid of it, but ill get a good one when i get it tuned up.

 

Its Pretty healthy sounding, if it had more squeeze i dont think the starter would turn it over. Im going to Buy a start retard box with a step retard for the nitrous. Very revvy with the light flywheel and super damper, smooth, but had a bit of rock from the big cam.

 

The webers ran great right out of the box! Didnt even touch the idle mixture screws! Im pretty happy about that thought.

 

Itll be going on the dyno as soon as i get a manual master cylinder on it, as the stock master and booster hit on the back carb.

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One lower, z-196.

How close were your springs to bottoming out? I put mine on at the recommended height for iskys and it was as tight as I'd wanna go for coil bind. I ended up with. 310 lash pads. This was achieved by using 080 thick Manley lash caps on the valve itself ( they hang down over the tip but don't touch the keepers) and a shnieder 230 lash cap on top of it. A "cleaner" solution compared to putting pieces of cut up feeler Guage in there.

 

 

When does your motor start comming on? Specs? Pics? I wanna see more of these 2.3's to see if we can pool info together to make more awesome. This is my first crack into frankendats, but definitely not my first into custom engine building.

 

 

Datsunmike it cranks over okay, it labour's on compression a lot more than stock. I'll let ya know how it is once I get the start retard on it.

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Does the vid work above?? That's what the engine idles like, it's really smooth. The carbs haven't been jetted yet, they are twin 48 dco/sp webers strait out of the box. It has 65f8 idle jets. 180 main jets, 160 airs and f7 etubes.

I soldered the 180 mains up and re-drilled them to 165 and drilled the airs to 170.

I know it's way out, probably rich, but it's driving ok, so it will do untill I get a wideband.

 

Specs on mine are l20b block, 96mm stroke (z24 crank), 87mm pistons, ported v91 head (same as u67) 39mm intake ports, 44mm intake valves, 36.5mm exhaust valves. Isky valve springs with isky z-273 cam.

No probs with coil bind, I'm using lash pads around the 320" mark(can't remember exactly)

I haven't driven the car in a while but cam pulls from around 3500 rpm I think and seems to run out of puff at 6000rpm, although as I said its way out of tune and I expect this to vastly improve.

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Does the vid work above?? That's what the engine idles like, it's really smooth. The carbs haven't been jetted yet, they are twin 48 dco/sp webers strait out of the box. It has 65f8 idle jets. 180 main jets, 160 airs and f7 etubes.

I soldered the 180 mains up and re-drilled them to 165 and drilled the airs to 170.

I know it's way out, probably rich, but it's driving ok, so it will do untill I get a wideband.

 

Specs on mine are l20b block, 96mm stroke (z24 crank), 87mm pistons, ported v91 head (same as u67) 39mm intake ports, 44mm intake valves, 36.5mm exhaust valves. Isky valve springs with isky z-273 cam.

No probs with coil bind, I'm using lash pads around the 320" mark(can't remember exactly)

I haven't driven the car in a while but cam pulls from around 3500 rpm I think and seems to run out of puff at 6000rpm, although as I said its way out of tune and I expect this to vastly improve.

Z24 crank with a l20 block? Your rods must be super short. I always thought the V91 head was the same as the 219 head (SSS). That also seems to be a really small power band. Im guessing you have a super light flywheel and clutch to get it up to those 3500 rpm quickly?
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