Datsun L-Series Engine Testing and Tuning Ep.5 Adjusting Valve Lash

[@veraciousreasoning863]

I have look high I have looked low I have looked far and I have looked wide I finally came across your channel and I also have a L series engine (1980 datsun 720 4x4 l20b) and not a single video on youtube was that clear and consise on how to do it.

[@alienpoker]

On your chart it should clearly show Cold E = .01 in (not 0.1 which it kinda looks like) and I = .008 in (the mm you gave are about correct). Hot you would add +.002in so: E = .012 in and I= .010 (E= 0.30mm I=0.25mm) It’s worth saying that if it’s not a stock cam, then these numbers could be different. As you said, the preference is to set them cold to be about right and then dial them in exactly when hot to the figures above for hot lash.

[@alienpoker]

Oh... and you can lock down the rocker locknut as you say to “very snug” by hand. The FSM spec is actually: Rocker pivot locknuts 40 lb-ft (FSM says 5 to 6 kg-m) you can use a “crow-foot” wrench on a torque wrench if you are as OCD as me.

[@kaibiagi5602]

Very helpful video, thanks for taking the time to make it.

[@oldscholz7395]

Keep up the good work bud thanks for all the great info I'm working on my 75 280z.

[@RestorationForBeginners]

You got it!

[@dillonnash9435]

excellent way of explaining...very help full... keep up the good work bud

[@LuisGonzalez-pj1pt]

Really enjoy you’re videos. They’re really helpful and good video quality 👌🏻

[@RestorationForBeginners]

+Luis Gonzalez you got it brother, wrench on!

[@LuisGonzalez-pj1pt]

So I have a question, I have a 77 280z the car cranks and at times it stays on for like 30 seconds but runs real rough, other times it stays on for as long as you want as long as you keep foot on gas. Idk if you can probably give me any tips on that or ideas on what it can be. Thanks in advance

[@RestorationForBeginners]

I'm going to guess that it's either a vacuum leak or a fuel delivery issue. When the car has a vacuum leak, it tends to idle real rough and can die at low rpms. Other thing I would suggest is to install a fuel pressure gauge (check out episode 29 if you haven't already) and check the fuel pressure. You should have 30+ PSI at idle.

[@LuisGonzalez-pj1pt]

I will definitely do that, thanks for your time and keep up the good videos.

[@darrylleigh7514]

I adjust them hot 10 &12. I use a starter button, Matco "go no go" feeler gauges and can do this in about 20minutes. You can determine whether it is an intake or exhaust valve by simply looking at where the cam lobe is as opposed to where the intake or exhaust runners are. Always recheck the lash after locking them down, it can change. The valve lash should be adjusted every 15k miles.

[@herrcrazyme8713]

What are your plans for the car after you're done with the engine? Will you try inrcreasing the horsepower once the engine is running perfectly? Or do you want to focus on bodywork/rustrepair/paint? or even on the interior? Great video as always! They will be very helpful once I get and start restoring my Z this summer ^^

[@RestorationForBeginners]

Do burnouts and road trips, what else?!! I will most likely focus on the frame rails, total rebuild of the suspension, and brake work. But there's no shortage of work that needs to be done! Seats need reupholstering, half the lights are dead (including the cute little inspection light under the hood), door doesn't close, rear view mirrors keep flopping around, carpet needs replacing, dash crack needs to get fixed...

[@herrcrazyme8713]

That sounds like enough work for hours of content ^^ What is the frame rails' condition ? Worthy to replace or still reparabel? (The small inspectionlight is the cars lucky charm)

[@RestorationForBeginners]

Haha one on the passenger is in bad shape. I'll need to get it professionally re-strengthened. I'll probably buy a custom-fabbed frame rail that fits over the existing rail and have a shop weld it on.

[@joseaguirre9389]

@@RestorationForBeginners hey ive tried looking up the floppy mirrors issue, and i havent found anything online about it AT ALL, do you have any info on how to repair them? or would i just have to buy new ones?

[@myjrny2]

You say this is for the Datsun L-Series so the chart that you made on the card board . . . My 82 280zx would have the very same sequence and valve lash adjustments correct? I'm about to attempt to do what you've shown here on my 82 zx because the rebuilt engine that I had just put in is making that "ticking" sound. Let me know asap. My car engine seems to run and idles fine, just have that more than suttle ticking sound! Thank you in advance.

[@tycityci228]

Hi Tell me please if changing valve clearance can cause rpm waving when engine is cold. I adjust my according datsun manual and have problem with cold engine rpm is going very low and then jumping up to 1000rpm and down again but after 15 min of runing is completly perfect and she keeps 900rpm. I have to say that before adjustment when valves gaps were biger then should be engine didn't have this problem.

[@gav240z]

Is your car fuel injected? Sounds like an idle air control valve is behaving badly.

[@brauliolopehandia8451]

It is possible change the valves seals without removing head in this engine? I want to try to change them in my car but I don't know how to take out the camshaft. Very nice videos!

[@ChicagoSkyliners]

Normally the hot spec is smaller since hot engine parts expand and eliminate the lash. I assume that your specs are directly from Datsun. Good video.

[@hectorromero3536]

You have a lot of great info on maintaining your vehicle but by any chance would you be able to recommend someone that can modify an L series engine pretty well or do you??

[@RestorationForBeginners]

Only datsun specialist I personally know is in the DC area called Datsun spirit. He's expensive but he's highly regarded.

[@davewm9589]

have you looked into the best oils to use for this kind of engine? Many opinions out there about use of modern era oils. When the engines were new oils had higher zinc content (per the internet for what that is worth). Modern oils have low zinc content, and supposedly are not good for the wear surfaces of the cam lobes. Not sure why this would not be a problem with modern engines unless they all had roller bearing in the valve train. Anyway again internet info says to use a zinc additive or a high zinc oil to help protect the camshaft. I use Valvoline VR-1 based on various forums. I have no idea if this is correct, just something to consider.

[@RestorationForBeginners]

Haha yes, I also spent some time researching this subject, and the prevailing sentiment seems to be that almost any oil today (as long as it's the right weight) is better than oil that people used 40 years ago, although for some reason some owners swear that using Royal Purple will ruin your engine. While this isn't the most solid logic (we're always looking for the BEST oil to use, not what's satisfactory), many seem to prefer Mobile 1. I use the high mileage synthetic oil, which has higher zinc content. Probably unnecessary but I have a TON of it from impulse purchases whenever they go on sale. This just got me thinking though. I wonder if using a slightly thicker weight oil will help me with the oil burning problem.

[@simonmooncalf3892]

I too did a lot of research and the general consensus is Valvoline VR1 SAE 10W-30 Racing Motor Oil because of the higher zinc content.

[@RestorationForBeginners]

Man it sounds like I need to switch oils.

[@davewm9589]

that's the thing, opinions everywhere on the subject. I just threw it out there for consideration, along with the qualifiers about internet. I hope it does not matter, but I went with the forum consensus. Since I am in the south where it rarely gets below 30f (like maybe a couple days a year and only at night) I run 20-50 VR1I mostly have to deal with 95f and AC running adding more to the temp loads this should not really matter though since the thermostat keeps the temp pretty constant I figure the only real issue with weights has to do with initial start up. I am guessing here that most modern engines have roller bearing in the valve train to reduce friction (gas mileage reasons) so the need for the cushioning of the zinc is not as important. But again I am only parroting what I have read. Also read that zinc was an issue for the cat converter, causing oil blends to reduce it to protect them.

[@davewm9589]

there is another opinion for you.

[@Slyzxx76]

So I have a datsun L16 and tried This today, the number 17 and 14 spanner loosened soo much I still couldn't put the valve feeler in the cam was lobe was facing up and still the feeler could not go in

[@lenwhite9901]

Thanks for the videos. I have a question about a fusible link I think goes to my fuel pump, but I'm not sure. It's a car my son and I are rebuilding together after someone else disassembled. It is an open plug and the Factory Service Manual isn't clear where the other end of the plug should go. Is there a way I can send you a picture of the wire for any advice?

[@RestorationForBeginners]

Sure man send me a pic and I'll see if I can help

[@lenwhite9901]

@@RestorationForBeginners Not sure how to send a pic through KZbin. Are you on Facebook?

[@Schaferizer]

So if I wanted to waste time... I make the first lobe towards the front of the car pointing up check and adjust it. Go to second lobe, point it straight up check and adjust and so on? Am I checking every one when it is straight up? Or am I checking others when one is up

[@Schaferizer]

If I am checking when it is straight up, then is tdc a must or???

[@charlesmiller5078]

I forget what car I owned at the time, but I used to adjust valves while car was running, sounds funny but actually worked great. Got my chain holding tool, thanks for the link, its pretty well built. 30 degrees, well now thats darn near summer temps. I have a P90 head with out a spray bar, wondering if adjustment could be done while running , might just try that out. With a solid lifter car, you will always hear a little clicking from the lifters, esp when cold.

[@RestorationForBeginners]

Haha yeah that chain tool is pretty neat. It does exactly what it's designed to do, nothing more, nothing less. For 12 bucks I'll skip the woodcarving and potentially having splinters in the engine! Oh man, even if it was possible to do, I would not recommend it! Here's just a few reasons: 1) if the oil gets hot enough, it'll burn you; 2) it's hard to access the lash with the feeler gauges with the spray bar on; 3) if you're relying on internally oiled cam to do the lubrication, the camshaft lobes will throw oil; 4) the engine will probably die in 1-2 minutes due to the massive vacuum leak; 5) I assume it'll be very messy!

[@charlesmiller5078]

I believe the engine we adj the valves "very hot", was a 289, no spray-bar, very little oil loss, I think the oil came through the rockers, and cam for lobes only, and not alot, at idle. I do remember we did it quickly. But that was 48 years ago, do remember doing it, but memory is little fuzzy. wonder when Datsun quick with the spray bar, guessing 1980. Didnt know that you have done a compression test since head has been reinstalled.

[@RestorationForBeginners]

Ah. That's fascinating! On the spray bar, I think they actually started installing them around 1977. Oil spray bar, when it works, sounds like the preferred method of lubrication over the internally oiled cams. Most people run both, but I personally do not think that's ideal with the stock oil pump. I have A TON to say in this matter based on my findings with the clear valve cover, look out for the next episode on this. While I wouldn't recommend doing it while the car is running for the L-series engine, if you do attempt it, please film and I'd love to watch!! A cold adjustment and hot check/refinement should be sufficient.

[@rock_and_ink]

Don't do it while running. That's why they give you the clearances for cold. As for doing it while running, I think he's referring to the older American V8s... 289, 302, 350, etc

[@charlesmiller5078]

It was a 289 I used to adjust while running, some 45 years ago, worked good.

[@myjrny2]

You say Intake is 0.008 and Exhaust is 0.10 And another youtuber is also doing an L-series valve lash as well but he says it's .010 Intake and .012 Exhaust. So what is it guys!? Even found a 3rd youtuber doing it 0.028 Intake and 0.030 Exhaust!!!??? So which one is it guys!?

[@عبدوبنجدي-ل8ص]

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