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High Compression L20b


Nelsontr

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Hello,

I am building a high compression L20b that i intend to make my daily driver and have a question about purchasing new head springs. I have Bored the block out to fit 280z flat tops and purchased a W58 Peanut head (Closed Chamber). Just looking into buying a Racer Brown Cam to put into this head and I was wondering if anyone knows the part number for the aluminum springs that would work best. Racer Brown 325-R Specs: 275 degrees @ 0.025" lift, 250 degrees @ 0.050" lift, 0.475 lift at zero lash. If any other specs are needed, please let me know.

 

-Tim

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W58 is a round port head

Most people use the square port heads.

 

Flattops and closed chamber on street gas??????????. You must be RICH. This isnt going to be a daily driver

I say run stock dish pistons or maybe L18 4cc dished piston but even then the octane has to be high.

I think your waisting your money

 

Racer Brown far as I know is out of bussiness But Isky has a 475/275 and a 480/280,490/290

Webcamshafts.com has a 488/252

 

ck out olddatsuns.com for part numbers on lash pads.retainers ect.....

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W58 is a round port head

Most people use the square port heads.

 

Flattops and closed chamber on street gas??????????. You must be RICH. This isnt going to be a daily driver

I say run stock dish pistons or maybe L18 4cc dished piston but even then the octane has to be high.

I think your waisting your money

 

Racer Brown far as I know is out of bussiness But Isky has a 475/275 and a 480/280,490/290

Webcamshafts.com has a 488/252

 

ck out olddatsuns.com for part numbers on lash pads.retainers ect.....

 

not exactly... the w58 came in both round/open, and peanut .... only tidbit i had to add biggrin.gif for example - http://community.ratsun.net/topic/25336-w58-peanut-head/

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no the w53 is square port w58 is round ;)

 

 

fk sry... reread the post... i was talking about the actual head not the port lol...normally people think the w58 only comes as an open head...

 

but yes the round port does suck, for the most part... its the "smog head" and you cant really do to much to make it flow much better

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Its not a big deal to pull out the liners.

I had a round port short tube header that would fit but sold it.

All my stuff is early square port exhaust manifold.

 

Nelson can run the L20 exhaust manifold if he likes to make use of that head, but i hate them as its hard to get the lower intkae/exhaust bolts up in there.

Plus if this is a truck you need to watch out for the torsion bar routing, So most headers are nmade for cars.

THus a short tube square port is still being made.

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I was wondering if anyone knows the part number for the aluminum springs that would work best.

 

Do you mean valve spring retainers? Because aluminum valve springs are just about the worst idea I've ever heard. Aluminum will ALWAYS fail from fatigue eventually. So an aluminum spring would eventually fail, and given that it's a valve spring, and is going to go though a massive number of cycles, it will fail sooner, rather than later. If you want lightweight valve springs, Titanium is the way to go (not sure if anybody even makes Ti valve springs for Dattos).

 

 

Nismo Retainers:

99996-M1050 ALL 8 Competition steel spring retainer for use with lash pads .150-.180.

99996-M1051 ALL 8 Competition steel spring retainer for use with lash pads .250-.340.

99996-M1052 ALL 8 Competition steel spring retainer for use with lash pads .190-.240.

99996-M1150 ALL 8 Competition aluminum spring retainer for use with lash pads .250-.340.

99996-M1151 ALL 8 Competition aluminum spring retainer for use with lash pads .190-.240.

99996-M1152 ALL 8 Competition aluminum spring retainer for use with lash pads .150-.180

 

Nismo Valvesprings:

 

99996-M1046 ALL 8 Competition valve spring, 280 lb/in, OD 1.34"; coil bind at .970"; assembled

height is 1.720" with a seat pressure of 120lb. Must use competition

retainers below [above].

 

Kameari (stupid expensive):

http://www.zccjdm.co...M_VALVE_SPRINGS

 

 

Other:

http://www.datsunsto...roducts_id/1369

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Do you mean valve spring retainers? Because aluminum valve springs are just about the worst idea I've ever heard. Aluminum will ALWAYS fail from fatigue eventually. So an aluminum spring would eventually fail, and given that it's a valve spring, and is going to go though a massive number of cycles, it will fail sooner, rather than later. If you want lightweight valve springs, Titanium is the way to go (not sure if anybody even makes Ti valve springs for Dattos).

 

 

Nismo Retainers:

99996-M1050 ALL 8 Competition steel spring retainer for use with lash pads .150-.180.

99996-M1051 ALL 8 Competition steel spring retainer for use with lash pads .250-.340.

99996-M1052 ALL 8 Competition steel spring retainer for use with lash pads .190-.240.

99996-M1150 ALL 8 Competition aluminum spring retainer for use with lash pads .250-.340.

99996-M1151 ALL 8 Competition aluminum spring retainer for use with lash pads .190-.240.

99996-M1152 ALL 8 Competition aluminum spring retainer for use with lash pads .150-.180

 

Nismo Valvesprings:

 

99996-M1046 ALL 8 Competition valve spring, 280 lb/in, OD 1.34"; coil bind at .970"; assembled

height is 1.720" with a seat pressure of 120lb. Must use competition

retainers below [above].

 

Kameari (stupid expensive):

http://www.zccjdm.co...M_VALVE_SPRINGS

 

 

Other:

http://www.datsunsto...roducts_id/1369

 

Totally knew what i ment... thank you much xander

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Has anyone had any luck with aluminum retainers? Everyone I have ever known that tried them had the keepers pull through. I have never tried them. I have always run steel.

 

I have been thinking about making some titanium ones at work. I have some on a set of Air cooled VW Super Flows. Seriously light weight. Guess I need to look into pricing a stick of it.(ouch)

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Has anyone had any luck with aluminum retainers?

 

I been running 2 sets of aluminum retainers. my cams are a 460 and a 475 lift

 

as for the light weight who cares we dont have over 7.5K RPM motors anyways. Most distributors go out of time by the time that happens.

 

Isky has steel retainers but I think a Nismo Alum retainer and the Isky the lash pad might not fit in the smae height wise. Ask "Sealick"

 

The Nismo steel retainer might by a Isky as I know the cams are really Isky

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Has anyone had any luck with aluminum retainers?

 

I been running 2 sets of aluminum retainers. my cams are a 460 and a 475 lift

 

as for the light weight who cares we dont have over 7.5K RPM motors anyways. Most distributors go out of time by the time that happens.

 

Isky has steel retainers but I think a Nismo Alum retainer and the Isky the lash pad might not fit in the smae height wise. Ask "Sealick"

 

The Nismo steel retainer might by a Isky as I know the cams are really Isky

 

What springs are you running? Stock keepers? I usualy shift at 7k. Just looking to gain some valvetrain stability.

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I bought the 'shortest' steel valve spring retainers from Isky...PN 1624-ST

They were much too tall/deep to use a 180 lash pad....so I shaved the tops a bit to use 180-190 pads.

 

P5220016.jpg

 

P5220015.jpg

 

Never did use them...eventually got some steel 150-180s from Nissanparts.cc

 

You will notice the 'collar' that holds the inner spring is longer...I assume this is because the Isky inner spring has less coils....needs a little more meat to hold the spring stable

 

P6070002.jpg

They are 4-sale though......cheap... :D

 

Talked to a few people that have split the aluminum retainer at higher RPMs/higher lift cam shafts....they are rather soft compared to the steel.

 

Good luck on finding the appropriate lash pads..(if you don't already have them)..getting few and far between.

Thicker ones can always be ground down though.

Some sites list them, and are back ordered, but are usually NLA

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I need to rockwell a lash pad to see how hard they are. They wouldn't be hard to make. Just need an open machine and the time. How many of you would be interested in a sewing box full of lash pads?

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I need to rockwell a lash pad to see how hard they are. They wouldn't be hard to make. Just need an open machine and the time. How many of you would be interested in a sewing box full of lash pads?

 

They are very hard.. :blink: ....I used that belt sander in above pic, was a bitch and I only took off ten thousandths

Other problem was holding onto it with the fingers :lol:

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Has anyone had any luck with aluminum retainers? Everyone I have ever known that tried them had the keepers pull through. I have never tried them. I have always run steel.

 

I have been thinking about making some titanium ones at work. I have some on a set of Air cooled VW Super Flows. Seriously light weight. Guess I need to look into pricing a stick of it.(ouch)

 

Never run them, but aluminum should be fine as long as they are properly designed, and not just a copy of the steel part (which you could do probably with Ti but not Al).

 

I need to rockwell a lash pad to see how hard they are. They wouldn't be hard to make. Just need an open machine and the time. How many of you would be interested in a sewing box full of lash pads?

 

I would be.

 

They are very hard. I used that belt sander, was a bitch and I only took off ten thousandths

 

You could always harden them after machining, might lose some dimensional stability or surface finish.

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You could always harden them after machining, might lose some dimensional stability or surface finish.

 

 

Exactly. Just identify the material and mimmick the manufacturing process. I have a buddy working on it right now.His shop has a Rockwell tester and this radar gun lookin thing that identifies material.

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Exactly. Just identify the material and mimmick the manufacturing process. I have a buddy working on it right now.His shop has a Rockwell tester and this radar gun lookin thing that identifies material.

 

Anything that is really hard generally starts out soft then is heat treated to achive the hardness. Machining really hard stuff is not practical in an industrial enviroment.

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IM running Isky springs I believe that are sold thru Nissan Motorsport

 

You might be able to get to 7krpm in first and 2nd but never in 4th or 5th

 

MY 460 Scheider lift cam Im using a inner motorsport spring and stock outer. to keep the pressure down as its a daily driver. dont need to overpound the valve seats

this cam is asymetric meaning it has a slower closing rate to help reduce pounding tha valve float

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The lash pads Rockwell at 50. Pretty damn hard, but not the worst I've dealt with. The material is most likely case hardened 9310. There is a bunch of 8620 available to me, that could be case hardened afterwards. If i'm not mistaken, 8620 is what ARP uses on their head studs kits.

 

That little relief on the sides of the slot would need to be done with a very small ball end mill. Not sure that would last. Might have to think of something else for that. Millions of those things were made, no reason why it couldn't be done again. Apoligies to the OP if I've led your thread down another path.

 

Oh and Hainz, your right. First three gears, and third is stretching it. I'm running Crane springs, that I dont see available anymore.

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The lash pads Rockwell at 50. Pretty damn hard, but not the worst I've dealt with. The material is most likely case hardened 9310. There is a bunch of 8620 available to me, that could be case hardened afterwards. If i'm not mistaken, 8620 is what ARP uses on their head studs kits.

 

That little relief on the sides of the slot would need to be done with a very small ball end mill. Not sure that would last. Might have to think of something else for that. Millions of those things were made, no reason why it couldn't be done again. Apoligies to the OP if I've led your thread down another path.

 

Oh and Hainz, your right. First three gears, and third is stretching it. I'm running Crane springs, that I dont see available anymore.

 

The lash pads might have been made out of powdered metal, then sintered. Don't know if that was a viable manufactering option back in the day?

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What compression are ratio you aiming for -- 11:1, 12:1?

 

How much HP does it add?

 

Not much. OK for racing where every horse counts but paying through the pump every tank full wears thin very quick. A very general rule of thumb is 4% for every point of compression increase. So...

 

10 would be 1.5 X 4 = 6% increase On a 100 hp L20B that's 106hp.

11 would be 10% or 110 hp

12 would be 14% or 114 hp.

 

In a way it's 'free' hp by just making the engine more efficiently extract the power. But it's rough on the motor and parts.

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