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Cam Options?

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I am thinking about getting a cam for my L20B.  I want to know the largest cam I can get without having to change the springs and retainers.  I do plan on doing an engine swap sometime in the future, but for now I want to play with the 4 banger for a while.  The engine is completely stock and mated to a 4 speed manny.  I plan to get a holley 350 2bbl. as well, I have heard good things about them on this engine.  I am not worried about driveability, I just want to play with it for a while.

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One can lower the spring height by machining abit

But my book says around .470 were the springs might bind



How about just buy a weber 38/38 and bolt it on. Thats best bang for the buck and tha fastest to set up.


Doing a cam is more than just putting a cam in. You still need new Roacker arms and still need retainers and lash pads of the correct size. or close to the right size.  all this to get 5 hp.

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Never, never, never over cam your engine. Only runs good above 4,500, shitty idle,



'79 2dr must be an A10. Shitty rear gearing so even more reason to not go crazy with the cam. This is going to spend 80% of it's time climbing out of a bog hole. Find a set of 3.90 H-165 gears, 4'11s even better!! easy to swap in a couple of hours, cheap, good bang for the buck. Doesn't affect engine running or add extra strain on it.

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Better gearing is great advice.  Plus anything over the 270's for duration is going to lose torque, which is what you need in the rpm range you're able to drive 90+% of the time.  More cam will only get you so far, unless the intake, head, and exhaust are modified to work WITH the cam.  To get more air in and out, the WHOLE pump has to be sized for it, not just the cam.  Knock the exhaust restrictors out of the head and put on a better carb along with the gears, then lighten the flywheel.  Maybe even address the distributor so the engine timing is correct all the time, not off by 5-10 degrees in the rpm where you drive most of the time.  

Banzai, you can actually resurface the rocker arms.  They are hard enough they can be reground.  Some valve facing setups have the extra tooling needed to do that.  Mine does, but I haven't made the adapter for the Datsun rockers yet.  

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Both surfaces are hardened. How deep? Who knows? As long as smooth it's up to the oil and the anti scuff additives to prevent wear.


Got an L20B regrind right here. Says  W 91 M Iskenderian 14MS  09  L  .490  1701.  Found the 1701 brings up a 170149...


Lift 0.490............bullshit! rocker ratio on L is 1.48 my lift is 0.458". How they get 0.490???

DATSUN 1600cc L-16 -- 1800cc L-18 and new 2000cc L-20 4 cyl. SOHC engines

Grind No (L-490) Part No. Valve Lash Caps (LC-.175) Type (Stage III) Intake (36-74) Exhaust (74-36) Lift (.490) Valve Lash Cold (.010 .012) Duration (290 deg) .050 Duration (242) Grind Customers Cam (A) - See more at: http://iskycams.com/cart/index.php?main_page=product_info&cPath=12_14&products_id=949#sthash.qXkFlNZk.dpuf
DATSUN 1600cc L-16 -- 1800cc L-18 and new 2000cc L-20 4 cyl. SOHC engines
Taking the lobe vs. the flat diameter the lobe lift is 0.31", times the rocker ratio (1.48) = 0.458 valve lift. As the stock lift is 0.413 I can work out the stock lobe lift as 0.279" (this agrees with 0.276" per my FSM) so the amount ground off the radius is 0.030" or about 0.015" thick. How deep does the hardening go?
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There are several ways to harden a cam.  One that's quenched when cast (refrigerated molds) will generally be hard 30% of the depth.  Stellar.  Typical Datsun cams with oil drillings in the lobes are VERY soft, then surface hardened later - and not very deep so a regrind WILL need to go through another hardening process.  If the color of the cam is not blackened, it has not been hardened after final grind, and is subject to premature failure.  

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