l20b performance tips wanted!

[javelin520]

I have a 79 l20b out of a 620. engine has never been apart. i want as much power as i can get out of it without sacrificing drivebility and reliability. i want to run a weber downdraft and tube header.that is where my knowledge of these engines stops. so i will ask the worlds best datsun builders! ok so what cam should i run and where to get it. how oversized can i make the pistons for a healthy streeter,what piston brands are recomended? I dont have an a87 head would love to get one but i have looked. are there any mods that can be done to improve the head i have? any help with this build will be greatly appreciated! i am so excited to start this engine build! (longtime dream being realized)

[MicroMachinery]

i want as much power as i can get out of it without sacrificing drivebility and reliability.

 

-Power

-Economy

-Reliability

 

Pick 2 and go from there.

 

Spend some time reading archived information here in the forum by using the SEARCH function. Everything you've asked or even thought of asking has been covered.

[Ratwagon1600]

I have a 79 l20b out of a 620. engine has never been apart. i want as much power as i can get out of it without sacrificing drivebility and reliability. i want to run a weber downdraft and tube header.that is where my knowledge of these engines stops. so i will ask the worlds best datsun builders! ok so what cam should i run and where to get it. how oversized can i make the pistons for a healthy streeter,what piston brands are recomended? I dont have an a87 head would love to get one but i have looked. are there any mods that can be done to improve the head i have? any help with this build will be greatly appreciated! i am so excited to start this engine build! (longtime dream being realized)

I'm going to be moderately nice here.

 

Your (relatively) new to Ratsun based on your post count, so, despite my desire to smash the 5h1t out of you, here goes.

 

Dude, there are a fucking gazillion threads not only on this forum, but also on the worlds über search engine "Google" where you need to be looking about on the question you have asked!

 

C'mon mate, you may get a gentler answer from other forum members in relation to your question, but, seriously, I think you need to do a little more research first!

[banzai510(hainz)]

bolt a 38/38 weber/w adapter on there and call it good

[datzenmike]

Unlike the '77 and earlier L20Bs, the '78-'80s intakes and exhausts manifolds were not joined together. This means that a much earlier L16 four into two exhaust manifold will fit with ease. Your '79 will have round exhaust ports on the head, but this will still work on a square port manifold.

 

Here's why...

Only thing a bought header does better than an L16 manifold is be lighter. These L16 manifolds are often thrown away and are cheap, never leak, rust out, come loose, fit perfectly and are easy to install. Truth be told there isn't much gain from this or a header but you'll be less pissed off.

 

Get a 32/36 from Redline or whatever on line. For less than $300 you get everything needed, gaskets, adapter plate, air filter etc. to convert it over. Very slight drive ability loss but better mid and top end grunt.

 

Your '79 was the only year where the 620 had 4.11 gears intended to extend mileage on the highway. Find a differential bum from an earlier truck with 4.375 gears.This will increase acceleration through the gears and is probably the best bang for the buck, easy to do and does not mess with the engine.

 

Mild cam increase. Something with more lift but not much duration added will keep it from affecting drive ability but add some breathing mid and top end.



.

[javelin520]

I'm going to be moderately nice here.

 

Your (relatively) new to Ratsun based on your post count, so, despite my desire to smash the 5h1t out of you, here goes.

 

Dude, there are a fucking gazillion threads not only on this forum, but also on the worlds über search engine "Google" where you need to be looking about on the question you have asked!

 

C'mon mate, you may get a gentler answer from other forum members in relation to your question, but, seriously, I think you need to do a little more research first!

[javelin520]

So i have seen this clown being a dick on here before. What is the point of having access to all these people and there info if we cant use it without offending some Australian puddwhacker? I didn't think i had to be as formal as you want me to your honor.eat some Vegemite and a few zanex and leave us alone king troll.why can't i start a new thread? A conversation with online friends? Get a life crocodile dundee

[TENDRIL]

loooolz

[Dawa]

its just such a common occuring question that it gets old and some people

get more tired of it than others. plus australians are known for being... "surly"

in the first place. its nothin personal.

 

its just that if more people searched/researched more than posting up new

threads with all the same questions...

[DanielC]

You need to first determine the condition of the engine.  Bare minimum, do a compression test.  If the compression is not near the high point of the range for your engine, you need a ring job, a valve job, and while there, probably need to replace the bearings.   You probably think you need to "bling out" the engine, with a bunch of showy stuff, but reality is most of the power is with stuff you never see just by lifting the hood.

[EricJB]

Build the bottom end bone stock. Maybe .040 for cylinder wall clean up. Find an exhaust manifold as DMike suggested and a compatible intake. Spend some time cleaning up the ports on the head. Don't hog them out, just straight and smooth. You can do this by hand. Gasket match the intake/head, and blend the carb adapter to the intake. Find a cam with a advertised duration less than 270-280 degrees, with accompanying springs. Run a 2" exhaust out the back with a good turbo muffler. 

 

 

[DISLEXICDIME]

stroke it to a 2.2 port and polish the head add 44mm intake valves run a 480/280 cam . then get side drafts the choke point is the 2 barrel down draft . lighten the fly wheel then change the rear end to a 390 or 370

[banzai510(hainz)]

I like Austraila and the people. They very funny. Tho he is right but I doint take offense to the question.

Key really is how much time and money you got. Cause there is always More TALK then time and money.

 

 

Ratsun is EZ to get all the awnsers you need in a short time.

 

I have a Jeep CherokeeGet on those Furoms) and if one doenst monitor your question in 1 day its like 5 pages back and then soemone will say why dont use the Search funtion. Forget it!To hard to keep up with the 500 new owners joining everyday.

[EricJB]

stroke it to a 2.2 port and polish the head add 44mm intake valves run a 480/280 cam . then get side drafts the choke point is the 2 barrel down draft . lighten the fly wheel then change the rear end to a 390 or 370

 

We cant keep telling the noobs to find a Z22. There wont be any left for us. 

[datzenmike]

stroke it to a 2.2 port and polish the head add 44mm intake valves run a 480/280 cam . then get side drafts the choke point is the 2 barrel down draft . lighten the fly wheel then change the rear end to a 390 or 370

.

He said L20B so I don't think he wants to build a motor. Cam is ok but side drafts and a manifold ain't cheap. Lighter flywheel is ok if the motor is out but not exactly a bolt on either. Going down to a 3.90 or 3.70 is totally the wrong direction and even worse if the flywheel is lightened don't you think?

 

Or is this a case of...

 

.

[javelin520]

I really appreciate all the tips.i do have the engine disassembled and at the machine shop. I like the cam suggestions piston size info.just wanted to know the good numbers and formulas that the experts use.i wish i could get a sidedraft set up I'm looking though!

[TENDRIL]

i would suggest a single side draft 45 or 50 if you go that route and make sure its complete and jetting is close to what you going to use the motor for .

[Camtron]

This thread is a pretty good representation of Ratsun.

n00b makes a "n00b mistake" and half the responders flame, half are helpful, and half flame AND help. And the other half are bad at math.

:)

[Sealik]

This thread is a pretty good representation of Ratsun.

n00b makes a "n00b mistake"...... and half the responders flame, half are helpful, and half flame AND help. And the other half are bad at math.

:)

 

 

WTF....that's 4 halves...way too much 'info'. 

[metalmonkey47]

Best thing you can do is get a nice 32/36 or a 38/38 with a good intake manifold. NOT a 210 manifold, as their ports (1.1'') are very restricted in comparison to the U67 and other manifolds. You can maybe open up the ports on an L16 intake, but it's easier to find a good one with the larger port size.

 

 

Also, I can vouch for the header being ABSOLUTELY USELESS.

 

 

Reference: 52hp L20 dyno verified. 

[metalmonkey47]

 And the other half are bad at math.

:)

 

 

WTF....that's 4 halves...way too much 'info'. 

 

I think you... hmmm...

 

yeah, you missed it. 

[Camtron]

And the 5th half is bad at seeing what I did there.

:rofl:

[EricJB]

Also, I can vouch for the header being ABSOLUTELY USELESS.

 

 

Reference: 52hp L20 dyno verified. 

 

So bad I cant sell the one I took off my truck without feeling guilty. If I offer it up, I first say what a total POS they are.

[GreaseMonky]

So bad I cant sell the one I took off my truck without feeling guilty. If I offer it up, I first say what a total POS they are.

Is there any good headers out there?

[TENDRIL]

stock manifold is the best IMO