L20b optimum performance

[banzai510(hainz)]

Farmer

Motor looks good.

 

like to see how the L18 pistons work on that motor set up

[Braden]

I guess I'll be the first to show pics of an L20b. There old pics, but havnt really changed since then

 

 

Just your typical rebuilt.'

 

L20b block

bored +1 with l18 pistons

mid cam, 3 angle valve job,new valves

Closed chamber head ported to 1.5

crank balance and polished

cam sprocket on #2 timing

Su's with 1.5 inch ports

L16 exhaust mani

Stage two clutch setup

 

Thinking about going FI.

 

The guy who built my engine is working on a LZ2.3 for his 620. But may sell it. Doesnt have time.

 

Larry

 

 

 

hey farmer thanks for posting the pic, i have a question for you, how did that engine compare to your stocker, can you guestimate the increase in performance for me on a scale form 0 to 100 percent, thanks everybody for posting keep the pics and info coming!!!!

[Farmer]

Im not sure on what the differences are. Still on the engine stand. Been like that for almost two years. On my very first 620, I had to rebuild the engine. Shaved the head and put it on #2 cam sprocket. Whole different engine. Of course that could of been from the rebuild too.

 

Larry

[Farmer]

Farmer

Motor looks good.

 

like to see how the L18 pistons work on that motor set up

Thanks

I hope it even starts,lol.

 

Larry

[Braden]

hey farmer i hope you dont laugh at me but will you explain putting it on cam sprocket 2, maybe not necessarily how to do it but what the effect it has is, i guess im confused because if you wanted to play with the timing couldnt you just play with the distributor, i guess your changing the timing of the valves not the spark

[hang_510]

what the effect it has is

each hole changes the timing 6* (or is it 4* ???)

also used to account for slack in an older chain.

[banzai510(hainz)]

Just to let people know the cam came stock on the #2 position from the factory on L20s. it was to help with meeting emissions standards.

 

Farmer

long as the motor is timmed.distributor is timmed and the valve lash set its moroe or less good. it will be the fuel diliever next. if it sucks gas it will fire.

 

many you heard this before but a guy here had a L20 w/L18 pistons and had detonation proplems. so run good gas.

 

 

make sure to PRIME the oil pump and I always run oil on the cam/rockers and down the from chain before start up. Maybe take fuel pump and pump it up also if you wish but I had no proplems.

[Farmer]

many you heard this before but a guy here had a L20 w/L18 pistons and had dedtonation proplems. so run good gas.

 

I was planning on running prem with some race fuel.

Larry

[Braden]

so if i cut the z22 block by 1 mm what would be the diameter of the bore? would i need standard size or over size z24 or ka24 pistons, also both of those pistons come in dished and flat top with valve releifs, i would like to run forged pistons either way

[Braden]

http://www.wiseco.com/Catalogs/SportCompact/Nissan.pdf

[hang_510]

i would like to run forged pistons either way

then it wont make much diference. the custom pistons will fit whatever size hole you make for them.

 

i kept a small dish in the JE and they still had large reliefs cut into them

[datzenmike]

so if i cut the z22 block by 1 mm what would be the diameter of the bore? would i need standard size or over size z24 or ka24 pistons, also both of those pistons come in dished and flat top with valve releifs, i would like to run forged pistons either way

 

Stock Z22 block runs an 87mm bore/piston. Cutting 1mm off the walls will give it a bore of 89mm. This is the same size as the stock Z24 and KA24E/DE pistons.

 

Naturally you don't bore first and then fit the pistons. Always get the pistons and have the shop bore to match the pistons. No piston is exactly 89mm. They are mass produced and some are very slightly larger or smaller. Same with the block. Ever notice the number stamped in the tops of pistons? This is so a slightly oversize piston can quickly be matched to a slightly over bore cylinder during assembly.

 

KA E pistons aren't flattops, they have a 2.8cc dish in them:

 

 

I have reason to believe that the first 3 months of production saw a 2cc domed KA E piston used in the first year S13. This gave a stock compression of 9:1

 

 

Below L to R, are my Z24 (15cc dish) Z22S (9.32cc dish) Z20E (only small valve reliefs otherwise flattop) and L20B (11.36cc dish)

 

[Braden]

Stock Z22 block runs an 87mm bore/piston. Cutting 1mm off the walls will give it a bore of 89mm. This is the same size as the stock Z24 and KA24E/DE pistons.

 

Naturally you don't bore first and then fit the pistons. Always get the pistons and have the shop bore to match the pistons. No piston is exactly 89mm. They are mass produced and some are very slightly larger or smaller. Same with the block. Ever notice the number stamped in the tops of pistons? This is so a slightly oversize piston can quickly be matched to a slightly over bore cylinder during assembly.

 

KA E pistons aren't flattops, they have a 2.8cc dish in them:

 

 

I have reason to believe that the first 3 months of production saw a 2cc domed KA E piston used in the first year S13. This gave a stock compression of 9:1

 

 

Below L to R, are my Z24 (15cc dish) Z22S (9.32cc dish) Z20E (only small valve reliefs otherwise flattop) and L20B (11.36cc dish)

 

ok heres another question, if boring the z22 1mm over is the same as a standrard size z24 block why not use the z24 block instead of the z22? i could get slightly oversized pistons and not have had to bore as much and i will have even more displacement, closer to a 2.5 liter like the chevrolet 2.5 iron duke, match that up with the 44 mm miukis a nice ported head and fat cam then go play with some honda boys and make them cry

[datzenmike]

True but a Z24 bored 1mm or 0.040" over to 90mm will only increase the size to 2440cc.

 

The Z24 is a more crack prone block. It is actually 2cm taller so slapping an L20B timing cover on the front will leave a 2cm gap between it's top and the bottom of any L head you choose to put on it. Also the timing chain will need to be lengthened by 4cm.

 

The Z22 block is sounder and the same height as the L20B so ALL the timing gear and cover stuff will fit with no alterations. With an 89mm bore and Z24 pistons with L head you have a big bore LZ23. Sure you have to bore it but you can build from spare used parts. The Z24 will need new slightly over size pistons, a welded modified timing cover and a lengthened timing chain.

 

The Z24 piston pin height allows a -1.55 deck height which avoids the excessive compression associated with putting a small L chamber head on a Z block. The compression of a Z22 punched to 89mm with Z24 pistons is 8.99 A stock Z24 with an L head is 9.84

[720Joe]

True but a Z24 bored 1mm or 0.040" over to 90mm will only increase the size to 2440cc.

 

The Z24 is a more crack prone block. It is actually 2cm taller so slapping an L20B timing cover on the front will leave a 2cm gap between it's top and the bottom of any L head you choose to put on it. Also the timing chain will need to be lengthened by 4cm.

 

The Z22 block is sounder and the same height as the L20B so ALL the timing gear and cover stuff will fit with no alterations. With an 89mm bore and Z24 pistons with L head you have a big bore LZ23. Sure you have to bore it but you can build from spare used parts. The Z24 will need new slightly over size pistons, a welded modified timing cover and a lengthened timing chain.

 

The Z24 piston pin height allows a -1.55 deck height which avoids the excessive compression associated with putting a small L chamber head on a Z block. The compression of a Z22 punched to 89mm with Z24 pistons is 8.99 A stock Z24 with an L head is 9.84

Not to thread jack, but would you know the compression of a z24 with KA-E pistons? How about the Ka-de ones?

[datzenmike]

Z24 with 2.8cc dish KA24E pistons with Z head is 9.87 if using an open chamber L head (un shaved) it's 11.76

[gary little]

On 2/4/2010 at 1:56 PM, Braden said:

ok so i am getting close to start my engine build and ive searched and searched and with no results i wanna ask this, what have you done and what can you do to you L20 to get more out of it, ok so heres what i know, i have 44phh carbs, gonna run a peanut head, hotter cam, etc, what im curious about is swapping the z22 crank and what is all involved with that, also what about bigger valves? have any of you run big valves? if so what size and where did you get them? how about block boring? 10 20 30 40 50 over???????? please post what you have done to your engine, what you know you can do to your engine etc. i dont wanna go throwing different cranks and heads and shit on and the clearance not be right, that would be one expensive firework, and may be an unnecessary cost, i have a mcahine shop that can do anything i want, thanks guys

so back in the day ive built several l engines. never a crank swap as l series seemed to have tougher cranks, if this is a driver then port and polishing stock head is fine, you can run 194 intake and 202 exhaust, crane offers nice camshaft replacement if you furnish them all info on engine and vehicle including weight and gear ratios. i used nissan comp valve springs and rocker arms but you might wanna stay with whichever camshaft mfg you choose. remember most of your everyday performance upgrades are in top end, its important to not over carb just because they are pretty, it will kill lower rpm performance, I used holley 600cfm and it was plenty and worked all the way to 7000k rpm. You may have to fabtricate manifold and add header, Last l20b i built was .40 over, there is also stock piston trick that raises compression to 9;5 to 1. this motor will pull all way to at least 7000rpm without giving up low end torque. Good luck

 

[Stoffregen Motorsports]

15 hours ago, gary little said:

so back in the day ive built several l engines. never a crank swap as l series seemed to have tougher cranks, if this is a driver then port and polishing stock head is fine, you can run 194 intake and 202 exhaust, crane offers nice camshaft replacement if you furnish them all info on engine and vehicle including weight and gear ratios. i used nissan comp valve springs and rocker arms but you might wanna stay with whichever camshaft mfg you choose. remember most of your everyday performance upgrades are in top end, its important to not over carb just because they are pretty, it will kill lower rpm performance, I used holley 600cfm and it was plenty and worked all the way to 7000k rpm. You may have to fabtricate manifold and add header, Last l20b i built was .40 over, there is also stock piston trick that raises compression to 9;5 to 1. this motor will pull all way to at least 7000rpm without giving up low end torque. Good luck

 

Sounds like a circle track motor. Chevy valves, Holley 4 barrel.

[datzenmike]

16 hours ago, gary little said:

so back in the day ive built several l engines. never a crank swap as l series seemed to have tougher cranks, if this is a driver then port and polishing stock head is fine, you can run 194 intake and 202 exhaust, crane offers nice camshaft replacement if you furnish them all info on engine and vehicle including weight and gear ratios. i used nissan comp valve springs and rocker arms but you might wanna stay with whichever camshaft mfg you choose. remember most of your everyday performance upgrades are in top end, its important to not over carb just because they are pretty, it will kill lower rpm performance, I used holley 600cfm and it was plenty and worked all the way to 7000k rpm. You may have to fabtricate manifold and add header, Last l20b i built was .40 over, there is also stock piston trick that raises compression to 9;5 to 1. this motor will pull all way to at least 7000rpm without giving up low end torque. Good luck

 

 

Braden the original poster was banned after a half dozen warnings. He hasn't been back since Jan 2012.