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I want bigger valves for this setup, right?


sneax

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hey 

after my first topic here was answered fast and satisfying... I shoot my 2. question right away!  :P 

 

 

for a rally race L20B engine - I want to put big valvein it, right? at least I got thiimpression, reading through the ratsun forum!

I have no experience with building L enginewhat so ever. And the first reaction of my machine shop here in Mexico City was: "42mm intake valves? ...that should be big enough!" 
I am a
ssuming they don't have a ton of experience with Datun L engines either! 
I am looking more for torque than high rev
...but 150 / 160 hp at the wheels would be great!

I could use the 1000++ dollar for bigger valves very good on other partfor the racecar... but if that's what it takes to get sufficient power out off my engine.... I will spent them! 

 

280z valves with 44mm\35mm in good quality?
or can\
should I go 1mm bigger to 45mm\36mm ???
(price i
s the same for the 8 valves and for the job a well!!)

Ferrea Competition Plus or any other recommendations?

 

 

specs:
L20B in an 1960 MGA for La Carrera Panamericana.
W53 peanut head
forged h beam rod
s
forged flat top pi
stons
2x 45 weber
maybe 270 or 280 cam
shaft for rally use.

 

thanks guys :D 

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What size valves are in the W53 head? Don't forget that larger valves will need the intake ports opened up to make use of them. Strength is built into the block, HP is made by the head... cam, valves, porting and polishing. More air flowing through the head, the more power made. Lots of things can be done to the head to improve the flow. 

 

The stock rods and pistons are good enough to 7K. Maybe add some ARP rod bolts. Keep it simple.

 

To realize 150 hp you will need to really rev a 2 liter engine. I would shoot for 115/120.

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I dont have the head here yet ... it is this one if that helps ?
was advertised reasonly on the ratsun FB page! 

 

18740755_10209598576788844_6356991991398

 

 

The H beam rods are 150mm long and give therefore a better rod\piston ratio as well... 

Intake and Ex port will be opened for sure!
A bit revy is fine with me... the car is a pure street rally car!

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ok thank you - wayno!

 

that would be great, if I have allready big valves in my head!

here is a pic of the intakes:

18765757_10209598577268856_5408320955069

 

 

guess I will have to wait until I have the head in my fingers for more questions...  :D

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I dont have the head here yet ... it is this one if that helps ?

was advertised reasonly on the ratsun FB page! 

 

18740755_10209598576788844_6356991991398

 

 

The H beam rods are 150mm long and give therefore a better rod\piston ratio as well... 

Intake and Ex port will be opened for sure!

A bit revy is fine with me... the car is a pure street rally car!

 

Grey Info lists L20B rods as 145.9mm. Which pistons are you using?

 

Are you making a Z22 out of this?

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As I said, they look fairly big, but it is a photo, you will have to measure them when you get the head.

The intake ports are small, you need to open them up so it can breathe, but it really depends on what intake system you are using.

Ok ... will have to wait until I got it here!  

It will get fully ported - Intake and exhaust!

 

Do you think 44mm 35mm is big enough for a rally engine? 

 

 

Grey Info lists L20B rods as 145.9mm. Which pistons are you using?

 

Are you making a Z22 out of this?

 

I searched and found H beam rods off the shelf!!!  

they have 150mm and match at the crank side 100%!

will use custom flat top pistons!

 

crank and stroke will be original L20B - I have to stay under 2000cc for the Carrera Panamericana! B)

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The Z20E used fattop pistons and 152.5" (6") rods and relatively cheap from a wrecker engine. Nothing custom needed, but maybe forged already exist for the Z20E? Look for '80-'82 HL510 or '80-'81 S110 200sx engines for them.

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The stock Z20E pistons have too high a compression ratio, when used with an L series head. And cutting them down enough to get anything around 10:1 results in cracked pistons. I built a few this way many years ago and all of the motors ended up with cracked pistons.

 

But...

 

Forged pistons aren't exactly expensive anymore. You can get a custom set now days for about $400, with pins and rings. And they will need to be custom to get the CR correct. If this is a race motor, I would run forged pistons anyway.

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The stock Z20E pistons have too high a compression ratio, when used with an L series head. And cutting them down enough to get anything around 10:1 results in cracked pistons. I built a few this way many years ago and all of the motors ended up with cracked pistons.

 

But...

 

Forged pistons aren't exactly expensive anymore. You can get a custom set now days for about $400, with pins and rings. And they will need to be custom to get the CR correct. If this is a race motor, I would run forged pistons anyway.

 

So even a open U67 L head will not work, too high CR?

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But...

 

Forged pistons aren't exactly expensive anymore. You can get a custom set now days for about $400, with pins and rings. And they will need to be custom to get the CR correct. If this is a race motor, I would run forged pistons anyway.

 

I would like to know where?

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Ok ... will have to wait until I got it here!  

It will get fully ported - Intake and exhaust!

Do you think 44mm 35mm is big enough for a rally engine? 

 

 

 

 

I searched and found H beam rods off the shelf!!!  

they have 150mm and match at the crank side 100%!

will use custom flat top pistons!

 

crank and stroke will be original L20B - I have to stay under 2000cc for the Carrera Panamericana! B)

 

Stroke is not original by using rods 5mm longer than original.

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Sneax how strict are the race rules... I came across this in my how to mod an lseries book....

20170603_113805_zps0roscfnl.jpg

 

Says an l20b with 86mm bore will be 2005cc displacement... I would hate to see them give you shit over 5cc....

 

And this is just my personal opinion... the w53 has 42mm and 35mm valves...

I would think your money would be better spent porting and polishing and doing a cam upgrade over trying to get slightly bigger valves in there....

 

I hope you have a good budget.. I did alot of the same stuff on my l16 with a w53 head, and in the end it wasn't cheap....

I learned the hard way but very happy with the end result.....

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Good Idea!!!

 

 

I get 499.303cc per cylinder. This would make 1997.212cc total engine size with 86 bore and 86 stroke. This is the swept volume of the piston from BDC to TDC.... so I don't know what they are measuring.

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 Stroke is not affected by rod length. The Z20E has 152.5mm rods while the L20B has 145.9mm. Both run the came crank. Think about it.

 

Not totally buying your theory. But...

 

 

And...now the piston pin moves up...seems way too close to the top of the piston.

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