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Need help with valve adjustment


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 Hi to everyone

i recently purchased a 521 with an L18 that has the peanut head, and the weber carb setup, all with essentially zero time on it.  long story.  i was told that the valves need to be adjusted, and i have no idea how to do it.  any help is sincerely appreciated.

thanks in advance.

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Tip buy shorty wrenches (I think 17 and 13mm is what use), otherwise getting them on the lock/adjuster can be a bitch. You can take the battery out to make it easier.


1. Remove valve cover

2. Turn motor to TDC #1

3. Adjust 4 valves ( lob pointing up)

4. Turn motor one full turn

5. Adjust other 4 valves 


Intake......... 0.008"

HOT (warm motor thoroughly)
Intake.......... 0.010"
Exhaust...... 0.012"

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If they haven't been adjusted in a long time, getting the lock nut loose might be a pain. Snap-On sells a special Datsun L series crowfoot style wrench that fits a 1/2" ratchet. I have one and have used it hundreds of times.


Adjusting L series valves requires a bit of nuance and takes a bit of time to learn how to do correctly.

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First, go on you tube and type datsun 510 valve adjust. Seeing it will give you a better idea. You may want to do it cold first, its recommended hot adjust but it takes some getting use to if you do this hot. Also write on a piece of paper, E I I E E I I E, to check of which one you checked a adjusted and also write down measurement for each valve. Someone said 13mm, its 14 mm. The stubby open end wrenchworks better, you may have to take out the battery since it can get in the way. The main thing is that you adjust when #1 piston is at Tdc at compression stroke.

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I'd be interested in hearing that answer too.... I guess the book should say if we dig one out.... sound from the valve train will probably be the indicator that you wanna check them again..

I plan on checking mine every oil change... if not sooner... and then decide how long I go between checks as well as listening... then put together my own maitnentce schedule...

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Every 15K miles or less.


Sound is only an indicator if they get loose. If the get tighter they will be quieter. Tight is very bad. Valves (mostly the exhaust) are cooled by conduction with the valve seat when they are closed. A tight valve may ride on the cam and not quite close. Exhaust will leak out from the poor seal and where it passes will get VERY hot. The valve face will erode and often crack and even pieces can come off.



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Very interesting, thank you for the feedback. I would think that 15k or so would be about right. If you rewind to back in the day when these engines were prevalent, known issues such as valve adjustment at every oil change would be a turn-off to would-be buyers I would think.  The engine in the running 521 I recently bought was supposedly rebuilt with essentially warm-up time on it, so I want to get this right.  Thanks again.

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