Valve adjusting problem on U20

[svwilbur]

Yup it is Stacey with some dumb problems again.......

Ok so I am trying to adjust my valves for the first time. I wanted to do this since they need adjusting based on mileage and I want to do a compression check prior to changing my timing chains as if the compression looks bad I may pull the head and do some head and valve work or pull engine. But I wanted the valves set properly first for the compression check and possible leak down test. Yup one thing leads to another.

On to the valve adjustment...

All was going well doing a cold adjustment using .006 intake and .008 exhaust like Greg Burrows does. Some do .006 and .010 for cold settings.
Hot adjustment is .008 and .012

But I did intake and exhaust for #1, #3 and #4 and they all needed a little adjustment. #4 was worse on the exhaust than the others and #4 is the one that had shown lower compression at one time many years ago after a rebuild.

I was finishing up on #2. I did the exhaust and had progressed to the intake (literally the last one to do!!!)
I was doing them in the firing order starting with #1. Getting each one to TDC and going past a 1/4 crank turn like the wiki says, maybe less.

My issue. The #2 Intake locker nut was really on tight. It took all I could push on a 19mm crescent wrench to get it to loosen.
But after that I could not get the adjuster nut to budge. normally once the lock nut is a bit loose the adjuster is free to move.
You do not have to break it loose. But this one does not want to move.

Then I noticed the spring was moving with the lock nut, what?

Then I noticed the large 27MM nut below them was also moving. It seems to be a long threaded piece in the carpartsmanual section but no name for it.
http://www.carpartsmanual.com/datsun/sp ... alve-train
See part #58

Anyways, I need to go to a store and get a 27mm crescent wrench I guess to try to tighten that unlabeled part #58 up with and break loose the 19mm lock nut (#52 lock nut pivot). Then I am hoping the adjuster nut (pivot rocker #51) might go loose.


So my question is.....Is this a somewhat normal thing to happen?
To have the large 27mm nut at the very base against the head come loose?
Can I just snug that up or did something bad just happen?

If I can not get the 27mm to break loose from the 19mm what are my options?
I suppose I could remove the rocker (I have never done that before) and replace that assembly with a working one????
I have a couple spare heads I could salvage parts from.

If I get the 27mm to break loose from the 19mm does the 27mm need some special preparation to snug it back in?
Or just some blue or red locktite and go as hard as I can get it?


Any knowledgeable help would be appreciated as I do not know much about the rockers and adjustment setup.

I included two pictures. You can look at the large 27mm nut/flange/bushing? thing and see that it moves now with the 19mm lock nut and that the adjuster nut has been rounded off some by a Previous Owner.

IDEAS?????

[svwilbur]

basically my lock nut is still locked but the 27mm came loose instead so the adjuster is still all tight.
How do I resolve this and get them back to normal and get the 27mm to be fixed hard into the head again?

[bakerjf]

image.jpeg

[svwilbur]

HA HA, yup what I thought Joe when I noticed it!

any thoughts?

[Linda]

Can't you use 2 box end wrenches , 1 to hold the 27 and the other to loosen the 19?
Perhaps vice grips if one of them is rounded off.

Linda
Edit: Open end is what I meant to say.
Harbor Freight has what you need for the occasional job

[svwilbur]

14mm adjuster is the rounded off one and should not be a problem after the 18 and 27m have broken apart. thise two are not rounded off.

I need to get a 27mm wrench first so I have not tried to break them appart. adjustables don't have clearance. my largest crescent is 19mm.

but I was worried/wondering if that 27mm thing needs any special treatment when I try to tighten it back in???

[nismou20]

You probably can't get a box 27 over it with spring in the way so get a open end 27 and lock it against the adjacent 27mm nut then try undoing the 19mm. If that doesn't work I might try like Linda suggested a Vicegrip to the 27. I think the spring is just held in between the 19/27.
I don't think there is anything special to the 27, it just holds the entire unit 19/14 above it to the head below.

[svwilbur]

that is the plan. I am hoping nothing special on the 27mm, just tighten it up as tight as I can go by hand with the crescent wrench I need to find and buy.

anyone have a something else to be concerned with about it?

[bakerjf]

I own some vicegrips, but I treat them as a last-resort tool - I don't think you're there yet. Borrow/beg/steal a 27mm wrench and see what the limitations are, if any. Sometimes it's best just to let these kind of issues simmer between the ears for a couple of days. A simple solution might unexpectedly pop up.

[jrusso07]

Had the same thing a few weeks ago. Take the 27mm base out. Put it in a vise and remove the locking nut. Get a bolt with the same thread as the adjuster. Double nut it and lock it to the 27mm. Drive it back into the head. Remove bolt. Reassemble. The thread is a fine pitch and loctite tends to be forced out of the threads. So I did not use loctite but I did try it.

[svwilbur]

Had the same thing a few weeks ago. Take the 27mm base out. Put it in a vise and remove the locking nut. Get a bolt with the same thread as the adjuster. Double nut it and lock it to the 27mm. Drive it back into the head. Remove bolt. Reassemble. The thread is a fine pitch and loctite tends to be forced out of the threads. So I did not use loctite but I did try it.

why did you use another bolt and double nut to drive the 27mm back in?
why cant you just use a 27mm wrench on the 27mm "nut" and tighten it back in?

what am I missing?

[jrusso07]

I could not fit a wrench.

[Gregs672000]

I just did this last week. remove the beehive spring, remove the clip it attaches to on the bolt, find a way (vise grip, screw driver wedged, etc) to loosen the locking nut, back the adjuster nut all the way off, remove the rocker, remove the entire mounting unit, get a 27mm socket, locktite the mount and reassemble. I did two in about 10 minutes.

[Gregs672000]

You noted that you have a couple spare heads... check them for better units that are without rounded off heads. The threads on the adjusting parts may be messed up making them hard to turn. The critical part of this is keeping the rocker arm on your engine on the same cam lobe so don't change those out. This is not hard. Also, make sure your cam lobes are pointing up when removing things or you won't be able to remove the rocker. You will have to have the adjuster bolt all the way down to get the rocker out, and may have to push down some on the spring using a screw driver and leveraging it against the cam shaft to get the rocker to slide off the spring. It will come.

[svwilbur]

I went to purchase a 27mm crescent but they did not have one. they did have a 1 and 1/16 wrench which I mic'ed at the shop and it was just a tad over 27mm like 27.15 or something. so I got that.

with the spring and clip removed I was able to separate the 27mm base and the lock nut without issue on the vehicle without removing the rocker. I then tightened down the 27mm the best I could but the other adusters and bolts from other cylinders get in the way to really snug it down.

I then put the springs back on it and adjusted the valve several times, locking it down to check the gap. sometimes the 27mm would back out again.

I got it adjusted and locked it down good and tried the 27mm wrench on it vertically or at angles but could not budge it.

I did not use licktite. I think it might be worth a try to put some on it but it is in there tight from the lock nut cranking down on it.

I will keep an eye on it. I may need to remove the rockers during the chain install. I will look at getting a socket on it then and locktite it.

WHAT TORQUE AMOUNT DO YOU USE ON THE 27mm??

I just need to adjust them, start it, warm it up, turn it around in the driveway and back it into the garage, do the compression check and hopefully be satisfied to not do any engine or head work now and get on with changing out my other timing sprockets and chains.

I needed it turned around so I have more room in case when I get it all apart I decide I need to pull the head or engine and need to use the portable hoist.