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'70 521 a new beginning?


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Finally got me a 521 after 4 years of looking! Has an l20b out of a 79? 620 don't remember haha! Got the truck from my buddy, traded one of my 4runner' for it. Story of the truck is a guy out in Omak had it in his field for a while no engine and stuff and there was a forest fire sweeping through so the guy turned on his sprinklers and watered the field and around his house a few days before the fire came. The fire burned down everything but his house the Datsun and his work truck, killed a lot of livestock and some barns but the 521 survived. My buddy saw it on craigslist and went and grabbed it after a 13ish hour round trip getting it! He put an l20b that I gave to my brother and my brother to sold him in it and used a parts truck for all the chrome pieces and things that got burned off! Has a 4 speed and does way to many rpms on the freeway so I need to put some lower gears and a five speed in. Now for oics cause who doesn't love them? Will get more as I work on it. So far I have replaced the fuel pump and fuel filter. GM 1 wire alternator  and done some cleaning. got 21 mpg on the first tank! Think that sums up the first post!









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Looks great man.  Damn that mouse eating look on that back of the steering wheel is a common Datsun problem??   Had the same problem on mine.  

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Looks great man.  Damn that mouse eating look on that back of the steering wheel is a common Datsun problem??   Had the same problem on mine.  

yeah my 620 is the same way

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And some one told me that it does matter... maybe even mike... I have a filter on both because I haven't dealt with it on my side draft yet but I need to... the crank vent need vacuum to pull the fumes out... I thought I was told the valve cover actually draws the air in....

I'm sure I'll be corrected if I am wrong

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I'll swap it...so it needs to go from the valve cover to the crankcase? 



I'm only into the truck about $1200 he was asking $3600 so I'd say I'm doing fine

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on most weber kits the bottom of the aircleaner will have a hole and you use a 90 deg elbow to hook up the hose from valve cover to under the airbox.



crank case goes to the PCV valve.


really does it matter. Well the overall pressure is the same as its all coveing from the front cover by the timming chain area goes to the oil pan.

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I would try to get it as it should be.


what I did with my L18 as it had the same type of metal pip from crank. is I cut it right when it cam up and out(90deg) then I spliced my L16 spare tube I had to it then used the stock L16 PCV rubber tubing to the PCV va;lve like it was stock.   

Since you most like don't have these parts around its harder for you to visualize.  the rubber part has 2 different sizes on the end ,so a generic setup might not work but you could pc something together and hose clamp it.



olddatsuns.com is your friend. read the tech section.


if this runs fine don't be swapping stuff just to swap. ask us here before doing.



ck all fluids and make sure oil in trans is full and diff. and grease all the kingpin steering joints asap.

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It will work the way it is, but I would pipe it correctly, crank case to the PCV, and the valve cover to the intake filter housing, I believe it will extract the moisture out of the crank case better instead of trying to suck the case fumes thru the little holes the oil is supposed to drain back into the crank case thru.

If piped correctly the valve cover does suck in and blow out, that is why the valve cover needs to be vented, if not vented and the PCV is piped properly, then normally the seals/gaskets in the engine start blowing out and oil starts getting all over everything including the ground, sometimes the oil blows out the dipstick.

The way you have it the case is what sucks in and blows out right now, it's cleaner looking if you pipe it correctly as the hose from the crank case is very short going from the case vent tube to the PCV, and then the valve cover vent goes to the air filter housing so any oil fumes escaping go into the carb, and any air sucked in the valve cover is filtered air.

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sweet wheels! and cool back story too.


sounds like you are on the right track of taking your time and feeling out the truck before you decide to go all out one way or another. enjoy it!


I to have an l20b and thought the rpms were to much, I added a 5spd and kept my tire size as close to stock as I could, and its much better. hwy's are a breeze now..

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