Stroker L23B using Z22 crank

[bludestiny]

So I tore apart the free L20 b I finalyl got and found the source of locking up. rod #4 decided to eat a bearing, not that the other main and rod bearings were much better off. 

 

[

 

So I've been doing a lot of reading on possibly options for this, and I think what I want to do is go with a L23 stroker using a z22 crank, some forged L20b rods and forged KA24e pistons. 

 

I will be bring the block to a machine shop soon to have them clean and check for cracks to make sure the block is useable. 

 

I'm using this thread for reference: http://community.ratsun.net/topic/28820-l20b-23-stroker-maybe/

 

Along with datzenmikes knowledge. 

 

I want to go with CP pistons, although I need to do a lot more research to get stock sized pistons. I belive Rebello might  be selling those. Here is the one link I found for some CP, but I need to cross reference the specs: http://realstreetperformance.com/Products/CP-Pistons/CP-Forged-Pistons-Nissan-KA24E-KA24DE-240sx-89mm-8-0-9-01.html

 

As for rods, I've seen carillo makes L20b rods, but hey so does CX racing: http://www.ebay.com/itm/CXRacing-H-Beam-Connecting-Rods-Bolts-For-DATSUN-L-Engine-L16-L18-L20-510-/140800855736?hash=item20c8628eb8:g:btwAAOxyOMdS4K4x&vxp=mtr

 

Although I know I probably shouldn't trust those rods, but maybe they really use scat blanks or something. 

[bludestiny]

So apparently those aren't L20b rods. They have to be L18 rods with that length of 133mm. 

 

Post 56 says the stock L20b rods are 145.9 mm. 

 

http://community.ratsun.net/topic/15556-l18-long-rod-or-l20b-motor/page-3

[flatcat19]

Where's the Z22 block? That would be a better start than the L20B block.

 

Bigger bore already, better cooling jackets.

[Stoffregen Motorsports]

Z22 block has potential for problems when boring to 89mm. Steam ports between the 1-2 and 3-4 cylinders can be bored in to by accident.

 

Try searching for LZ23 or 2200 long rod or 2300 here on Ratsun. This topic has been discussed in great detail in the past few months, a few times over. I think all the info you need, you will find there.

 

Yes, Rebello is the best source of parts and knowledge. He won't steer you wrong.

[bludestiny]

Yeah I'm going through a lot of threads, from Wayno, LZ franken-motor builds and a lot from both you (stoffregan) and datzenmike. The topic of which block to use has been brought up many times and it seems there are pros and cons to both a Z22 and an L20b. I'm willing to take my chances with the L20b since it was free. 

 

It seems the 4 banger datsun/nissan engines are much more interchangeable than the straight 6 flavor. 

[datzenmike]

Why forged pistons and different rods? Unless turbo-ing or an SC that's a lot of money. You want L20B or early Z22 rods. 145.9mm long

[scooter]

You can use the stock l20b rods or z22 ones. I have a heavily built lz23 but still using l20b rods with arp bolts. I spray a 75 shot at it so far and its gone though 4 10 pound bottles with no issues. Forged pistons is a good idea though, if you look at a stock piston vs a cp one the differences is obvious. If you get a set from cp, get them to cut a d-cup dish in it and run a closed chamber head, and make sure they center the valve reliefs on the pistons.

 

If using the l20b block, dont go more than 88mm. With z22's your milage may vary, mine had lots of meat

[Stoffregen Motorsports]

Forged pistons usually have more differences than meet the eye. The ring lands are usually stronger with less likelihood of cracking. The rings themselves can be custom spec'd. Skirts and pics are also much better in design and metallurgy.

 

And the best part about forged pistons is that you can have them built to any pin height (within reason) so you can run the 6" rods in that L20B block and not have to worry that the cast pistons have been machined too thin on top.

[datzenmike]

You can use the stock l20b rods or z22 ones. I have a heavily built lz23 but still using l20b rods with arp bolts. I spray a 75 shot at it so far and its gone though 4 10 pound bottles with no issues. Forged pistons is a good idea though, if you look at a stock piston vs a cp one the differences is obvious. If you get a set from cp, get them to cut a d-cup dish in it and run a closed chamber head, and make sure they center the valve reliefs on the pistons.

 

If using the l20b block, dont go more than 88mm. With z22's your milage may vary, mine had lots of meat

 

He plans a 2.3 which will require 98mm KA-E pistons. That's a 3mm over size or 1.5mm cut all the way round. With open chamber L head 9.78 compression, 10.39 with a closed.

 

I've already asked why forged and the expense. Forged are also noisy on start up because they are loose fit allowing for the aluminum to expand with the heat. Hyper-eutectic and 20% glass and aluminum and allow closer tolerances and expand very little with heat. Hyper eutectic won't take lots of nitrous or boost.

[scooter]

Forged pistons rattling only happens sometimes on subarus now.

[scooter]

 

Heres your flat top lz23 piston. 89mm bore, clips for floating pins, comp height for l20b rods on z22 crank. valve reliefs. I cant remember is the piston weight was with the pins but id say they are definitely lighter than stock..

 

 

I ended up doing some extra milling to the valve reliefs as they wernt cut centered in the piston for some reason. I wouldof sent them back but i didnt want to wait. Still lots of meat and lots of piston to valve clearance so its good to go!

 

If i was doing this motor again i wouldof went with a d dish style piston and a small chamber head, get the piston tops ceramic coated and have lateral gas ports. Same wrist pin but dlc coated

[Stoffregen Motorsports]

He plans a 2.3 which will require 98mm KA-E pistons. That's a 3mm over size or 1.5mm cut all the way round. With open chamber L head 9.78 compression, 10.39 with a closed.

 

I've already asked why forged and the expense. Forged are also noisy on start up because they are loose fit allowing for the aluminum to expand with the heat. Hyper-eutectic and 20% glass and aluminum and allow closer tolerances and expand very little with heat. Hyper eutectic won't take lots of nitrous or boost.

Piston technology has changed a lot in the past two decades. Sure, 20 years ago, the forged slugs were clunky, but now they don't require tolerance that different from stock. You can still get them tight in the bore if you want to.

[Stoffregen Motorsports]

 

 

 

One commonly overlooked aspect of the piston is the sharp edges on the dome. You should treat the dome as you would the combustion chamber in the head and radius those valve reliefs and any other sharp corners. Not just for detonation, but for flow.

 

I use a combination of tools to smooth out the tops of pistons, anything from a flap wheel on a bench grinder to a carbide burr in a pneumatic die grinder.

[scooter]

One commonly overlooked aspect of the piston is the sharp edges on the dome. You should treat the dome as you would the combustion chamber in the head and radius those valve reliefs and any other sharp corners. Not just for detonation, but for flow.

 

I use a combination of tools to smooth out the tops of pistons, anything from a flap wheel on a bench grinder to a carbide burr in a pneumatic die grinder.

That picture was straight out of the box. They recieved some sanding.

[bludestiny]

He plans a 2.3 which will require 98mm KA-E pistons. That's a 3mm over size or 1.5mm cut all the way round. With open chamber L head 9.78 compression, 10.39 with a closed.

 

I've already asked why forged and the expense. Forged are also noisy on start up because they are loose fit allowing for the aluminum to expand with the heat. Hyper-eutectic and 20% glass and aluminum and allow closer tolerances and expand very little with heat. Hyper eutectic won't take lots of nitrous or boost.

 

Forged only because I can't for the life of me find ITM. I have seen some rock auto pistons for like $12. I don't normally like being spoon fed, but at this point I'm having trouble finding things. I will be taking the rods, crank and block to a shop next week to see if it is salvagable. If I can't find a crank for a reasonable price, and the stock crank is useable then I'll be doing a cheap stock rebuild. 

 

Forged pistons rattling only happens sometimes on subarus now.

 

True, always thought it was weird. My other car (wrx) has some forged, and they rattle on startup. 

 

 

Heres your flat top lz23 piston. 89mm bore, clips for floating pins, comp height for l20b rods on z22 crank. valve reliefs. I cant remember is the piston weight was with the pins but id say they are definitely lighter than stock..

 

 

I ended up doing some extra milling to the valve reliefs as they wernt cut centered in the piston for some reason. I wouldof sent them back but i didnt want to wait. Still lots of meat and lots of piston to valve clearance so its good to go!

 

If i was doing this motor again i wouldof went with a d dish style piston and a small chamber head, get the piston tops ceramic coated and have lateral gas ports. Same wrist pin but dlc coated

 

 

That definitely helps point me in the right direction. 

[flatcat19]

If you're boring things out you can use used pistons, if within tolerance.

 

New hole, sized to provided piston. No fucks.

[bludestiny]

Has anyone used north american autoparts to order a crank? If they have one ready to drop in with bearings, then it might be cheaper to go with this way. 

 

http://www.northernautoparts.com/ProductDetail.cfm?ProductId=3253

[bludestiny]

Other option is going with autozone http://www.autozone.com/parts/internal-engine/crankshaft-kit/nissandatsun/200sx

[scooter]

Dont use used pistons, thats garbage. And you wont find a piston for an lz23 unless its cp custom or je or etc.

With new pistons being 12 bucks on rockauto why the fuck would you use used ones?

 

You could use z24 or ka24 pistons if u desired, i wouldnt stick forged ka pistons in it, if your gonna spend that much money just get cp to build you some.

[datzenmike]

Nothing wrong with used stock pistons as, like gato said, you are over boring to that size anyway.  Don't want $12 Chinese  piston in my build.

[Stoffregen Motorsports]

As long as they fit, and are in good shape, used pistons are totally viable. But sourcing them may be a waste of time.

 

The major benefit to using custom forged pistons is that you can build them to allow for the N85 rods. I wouldn't spend money on custom pistons and still use the short rods.

[G-Duax]

The trouble with using used cast pistons, is that you have no history on them, how hard they were run, or how many times they were subject to detonation.

Cast pistons fitigue over time, and not something that should be used in a performance build.

 

You also have to check ring grove for wear, as there is no such thing as fitting larger rings......

 

Now if I was just trying to get an old farm truck running, to haul chicken feed once a week, then used pistons would be fine.

[Stoffregen Motorsports]

Only an engine building shop would have a good supply of used pistons laying around.

 

When I worked for Rebello, I had a pretty good stash of good used parts on hand. Some of the sweetest little engines I ever built had only new head gaskets in them. Everything else was used. Of course, these were never for customers.

[Dolomite]

^is that where cody's l19 came from? He said something about it being a rebello parts bin build.

[Stoffregen Motorsports]

Yep. That was a spare parts motor. I even used a cracked block that I "Franken-bolted" back together.

 

Still running strong, after all these years.