Figured it was about time I adjusted the valves in my wgn. I thought I had done it when I put the JDM motor in, but the shellac gluing the gasket down proves I haven’t been in there before. I have never, will never, shellac a gasket! As with the wipers, I figured I might as well take the extra time and snap a few pics of the process since there’s been a good bit of talk about valve adjustments lately.

This first pic is what you will typically find under your valve cover. This is the 521’s valve train.



Can you say “low mileage JDM motor?” I haven’t had the synthetic in it long enough to clean it up this well.   Dang shellac! I spent more time cleaning gasket off than I did on the adjustments!



I started with cylinder 3 because as I started to rotate the engine, it was the first set of cam lobes to line up. Take all the spark plugs out and you should be able to rotate the engine over by hand on the cooling fan. As you’re standing at the radiator, facing the engine, you want to turn the motor clockwise.   Turn until the lobes are in the 10 o’clock and 2 o’clock. Keep in mind that the 12 o’clock position will be canted to the left because of the L series tilt. There should be a small amount of “wiggle” on the rocker arms. If there is none, then the adjustment is too tight and you can burn a valve because it may not be seating fully. It needs to seat fully to close the combustion chamber and to transfer heat from the valve to the head. If it’s too loose, then you either won’t get as much air/fuel in as you should, or you won’t expend the exhaust gasses properly.




I typically pull 2 or 3 feeler gauge strips, the target strip and the next one bigger. If you like you’re valves on the tight side, pull out the next smaller one too. This way, I can check that I’m not too loose because the next bigger will not fit. If I think I’m too tight, I put the next smaller in and make sure that it’s real loose. You want a slight amount of drag on the target strip. I use two different feeler gauges, one with the strips for the intake and another with the exhaust sizes pulled out.

When you come across one that is not adjusted correctly, you will want to break the adjuster locknut loose and then change the clearance with the adjuster. You will notice that when you cinch the locknut back down that the adjustment will change slightly. You’ll want to compensate for this. I don’t remember if it gets tight or loose when you crank on the locknut. If it gets tighter, then put your setting a bit loose before you cinch it down. Always recheck it after you have the locknut tight. I’ve never had a problem with the tappet itself coming loose when I break the locknut loose. If you do, you’ll have to put a big wrench on the tappet. I only needed the two wrenches.

Once you have the first set adjusted, crank the engine over until the next set of cam lobes line up correctly. Because the firing order is 1-3-4-2, 4 was the next one that came up. Also remember to pay attention to which lobe is the exhaust and which is the intake. 1 & 3 are oriented the same. 2& 4 are the same, also. But, 1-3 are opposite of 2-4, so don’t just think that all the front lobes are intake. You can see the intake and exhaust manifold runners line up with each of the valves.



Cleaning up the old gasket was a pain because it had been glued down with shellac. I typically use a scotchbrite/roloc pad on a die grinder. Be careful doing it this way because you can easily grind a divot in the aluminum. I try to use the edge of the pad that is throwing the debris away from the head. Make sure you don’t scrap any chunks of junk into the head. They will find their way into your oil passages. Once it’s all clean, use either acetone or brake cleaner to wipe the gasket surface.


It’s your call, but I would advise using anti-seize on the bolts holding the valve cover down since they are steel bolts going into an aluminum head. You’ll need it out anyway for the spark plugs.


I like to use a spray on gasket adhesive. It works like contact cement. You have to spray both surfaces. One side of the gasket and the mating surface of the valve cover. I put the gasket to the valve cover since there are no alignment pins of any kind. I won’t put anything on the head side of the gasket, unless I find it doesn’t seal right for some reason. A new gasket and a nice clean and flat mating surface should seal just fine with out using a sealer. This way you can easily remove the valve cover later without having to scrap gasket off the head again.


I always like to run a compression test afterwards. I didn’t do one prior, but it would have been a good idea to do a compression test both before and after. You may not notice much of a difference, but if your valves were wrong before, you may just see a noticeable change.

The first pic is the remote start switch. You can do it by the ignition key, but this way is easier if you have one. Don’t forget to disconnect the positive (or negative) wire from the coil if you use the ignition switch to crank the engine over. You don’t want any kind of sparks in the eng compartment while you’re blowing fuel charged air out of the spark plug holes. Don’t forget to prop open the throttle to allow air into the cylinder to be compressed.

On a cold engine, I tend to crank mine over until the needle on the tester peaks. On a hot engine, I think it should hit that in about 4 revs. It should get close to your max on the first two pulses. Maybe someone has some input on exactly how many times it should be cranked. This is just what I’m used to doing.



I suggest writing down what you get in each cylinder. Add which vehicle/eng the readings are from and the date and mileage you took them. You’ll be glad you did later down the road.

Put the plugs back in. Reconnect all the wires. Don’t forget to remove your throttle prop or you’ll pee your pants when the motor starts and revs to the moon!! Anyway…start it up and see how it runs. If you had a couple of valves that were a good bit out of adjustment, you’ll want to check the carb adjustment and the timing. I’ve been running mine for about two weeks after the adjustment without doing that…oh well!!!

This isn’t necessarily the best or fastest method to use. It’s just my way.   If you can keep track of the valves you adjust, you can actually adjust a couple of others at the same time. When one cylinder is on the compression stroke, another will be on the intake stroke, so it’s exhaust valve will be close and you could adjust that one at the same time. I just find it easier to adjust them one cylinder at a time. If I was getting paid for it or did it everyday, I’d do it differently.

I guess you spent a good bit of time cranking the motor over extra times! :)

Trying to help you over the phone with it was a big reason I did this thread. I just couldn't seem to find the right words. Got a bit frustrated. I appologize for that! Any luck yet?

I just checked about 6 different manuals....I don't think it matters, so let me know what you find. One book said to have them straight up like you said. Two had pictures only and they were set like mine. Two others said to have both lobes up(like mine) and adjust intake/exhaust at the same time. One manual didn't have anything about the adjustment.

Maybe Hainz or Datsunaholic will have an opinion. I'm pretty sure the clearance should be the same, but I haven't tried it your way.....check both positions please and let me know.

Bleach and RIS seem to have a good bit of knowledge on the cams too....and RIS has probably checked his a few times during his build up.

I always adjusted them with the lobes up and in no particular order. But maybe i'll try it the other way and see if it works mo betta. 

Mike, my next step is to spray some starter fluid down the carb then crank again then see if it fires. Ive still got that intake valve #2 cylinder that I cant get a good gap on but as you said it should still fire & run rough. If it wont start I plan on replacing the Hitachi with a weber 32/36 down the road.

Mike, i cant get it to open at all. I cant even get the feeler gauge inbetween the cam lobe & the rocker arm. I loosened the 17mm bolt, then loosened & adjusted the 14mm [adjuster]nut all the way down and i still cant get the gauge in there.

Ill have a look tomorrow to see if the bottom bolt is seated all the way down. If the arm has slipped its position is it hard to fix? And if it ends up the valve is broke then its gonna be rebuild time. I know I can probably just replace the valve but after all ive done so far with minor progress Ill want it all new. There goes my tax return, maybe...

I've always adjusted them in the 10/2 positions. (less cranking time) But my truck does have a longer duration cam. I wouldn't call it radical, but maybe I'll take a close look at the back of the cam lobe to see if I should be taking more time with that one and pointing the lobes straight up. My truck cam does tick a bit more than then stock cam in the Z. I always figured it was because it is a higher lift/longer duration...

So Mike, can I copy this article to my website? I'll give you credit for it and 1% commission.

Yes its good to have photos.
I took photos of my engine asemble but wish I took more in step procudures of it.
Photos help when also reasding the book. But notice some people dont read the book and just want photos. If they didnt read the book most time they are not going to read my/your post in great detail which is very critical. But these are EZ motors to work on(well at least the non emission L series motors)

The next motor I will take lots more photos

J1500 is a pushrod engine but the technique works for them to, just have to watch when the valves close.