Valve adjustment interval?

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jlhollowx13

jlhollowx13

10 Year
Joined
Dec 6, 2012
Threads
66
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541
Location
Gunnison, Colorado
so my fj60 and fj40 have always had a valve tick, I thought it was just a cruiser/ 2f thing as it's not something I've noticed as much as in toyotas, but I've been doing a bit of research on it and have come up with a question I haven't been able to find an answer to. How often do they need to be adjusted? I've found a wide range of mileages, but is there a good way to determine when they need done by something else, maybe the sound, rough idling not remedied by a tune, hard starting when there are no apparent issues, etc? My 60 is getting close to 170k miles and the 40 should be approaching 90-100k now according to what the guy I bought the engine from told me. My fj60 seems to have a louder tick than the 40, even with the extra sound dampening in the 60.

I've only had experience with this on an older suburban, but I just observed and didn't pay a huge amount of attention to the procedure. It was done with the engine running, but the fsm says to do it with the engine hot but off on the 2f. Is it advisable to do it with the engine running?

Lastly, what are the negative affects of not adjusting your valves/ not doing them at X interval?
 
The 2F valve train can not be compared to most cars or recent Toyotas. It uses hard lifters with an under-head cam. Old technology.
The factory recommended service interval to check the valves is every 15,000 miles, though few people adhere to that schedule. With experience, you learn to feel and hear when the valves should be adjusted by noticing how smooth the engine is at idle and higher RPMs and how much clicking noise you hear coming from it.

Typically, the valves tend to get tight over time as parts wear, especially the exhaust valves. Intake valves can sometimes get looser over time for some reason...maybe because of inadequately tightened adjusting screws.

Tight valves can cause rougher idling and harder starting.
Looser valve lash will cause ticking noises from the rocker arms. The looser the valve, the louder the ticking.

When the valves are adjusted correctly you can definitely feel the difference. The car will idle smoother and rev up much easier compared to tight valves. The engine won't feel like it is fighting itself at higher RPMs like it does when the valves are tight.

Very tight exhaust valves may not seat fully on the valve seat in in the combustion chamber, which can cause them to overheat and warp. This in turn will cause low compression as the valve no longer will seal correctly. Tight exhaust valves are bad. Avoid tight exhaust valves!

Loose valve lash can easily be heard by the ticking noises the rocker arms make. The 2F will always make some ticking noises from the valve train, but when a valve is too loose you will hear it right away. A little loose is better than a little tight.

The FSM recommends to adjust the valves with the engine hot and running at idle, but some members here on MUD prefer to do it when the engine is cold and off. Use Search for instructions how to do that.

IMO, one of the most important things to be aware of on the 2F is that the valve lash is within spec. Overly tight exhaust valves that have been neglected for a very long time can lead to big expensive repairs if they get burnt and warp.
 
once a year, loose better than tight, cold will give a more consistent lash than hot/off, as it will cool down working from front to back; best is hot/on, but who the hell wants to do that. Cold valve lash with one thousandths less clearance...
 
Valve clearance check with warm engine and engine OFF (not running) from the FSM ! @ 15,000 Mile intervals . I would like to know how to get your wrench , flat screwdriver and the feeler gauge orchestrated together on the rocker arm while the engine is running. I have been a professional mechanic all my adult life and have never even attempted this. On the early GM v8s adjusting the hyd lifters was done this way ... but never on a solid lifter style engine.
 
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I had read here on the forum that the fsm says to do it warm with engine off. I haven't actually looked it up in my fsm. If that is the case, I may wait until summer to do it as it's VERY cold where I live in the winter and I can definitely see the engine cooling enough to make a difference especially with it being my first time doing it, it will probably take longer and id like to take my time the first round. Still wishing for a heated shop!

Is doing it cold ok then? Why wouldn't the fsm just say to do it cold and give the clearances for that as it seems easier/quicker/more accurate (less variation) between valves to do it with a cold engine rather than allowing cooling time and the possibility of different readings?
 
I recently adjusted the valves on my 2F 'cold' using the chart from this thread:
https://forum.ih8mud.com/threads/fj60-valve-adjustment.489587/page-2#post-9466390

The chart calls for using feeler gauges that are 0.002" thicker when adjusting 'cold' than the ones used when adjusting 'hot'...because when metal heats up it expands...

On the intake valves, I erred on the feeler gauge grabbing a little tighter, thinking that the intake valves will loosed up over time.
On the exhaust valves, I erred on the feeler gauge grabbing a little less, thinking that the exhaust valves will tighten up over time.

It's difficult to try to articulate what I mean by the feeler gauge grabbing less/more (but I will try) and just as tricky to know if a valve has been properly adjusted (which would be helpful in building an intuition around what the correct 'grab' on the feeler gauge should be).

So, when setting the intake valves 'cold', for example, I used a 0.010" feeler gauge (instead of the 0.008" specified in the FSM for adjusting intake valves 'hot'), made sure that I was adjusting the correct valve (that it was one that was at TDC compression), slid the feeler gauge in the gap, screwed the screw on the rocker arm in until the feeler gauge was tightly pinched (couldn't move the gauge), then backed the screw out a tad (barely broke it back...could feel the feeler release a little from being pinched) and tightened down the nut to torque (I broke all the nuts loose at the very beginning...helps keep track of which valves have been adjusted...).

Then I measured the resistance on the feeler gauge in the gap by sliding it in and out.
If it was too loose (what my intuition was telling me was too loose), it would slide in and out with little resistance.
If it was too tight, it would barely slide in and out or the gauge would even bend up on itself.
If it was 'just right', the gauge would have some grab to it.

It is difficult to articulate different degrees of 'grab', but I tried to get them all the same for all the intakes and all the same for all the exhaust....because I don't know of another way other than this of determining at the time of adjustment if it is the correct amount of resistance on the feeler gauge (which is why I'm trying to communicate it here, so some MUDer with more intuition on this can set me straight for the next time I have to do this...)

But, I can say that after I painstakingly set all the valves to the best of my ability, when I actuated the rocker arm for a valve (with the engine off of course), there was still a gap (I could here and see the gap close/rocker arm tap)....so they weren't so tight that there was no gap for oil to slide between...

And I know that properly tuned valves will quiet up...so I guess one of the benefits (although I have not tried this) to adjusting valves with the engine running is that you can use the sound of the valves tapping on the feeler gauge to find the right tension.

But other than that, it would be nice to know if there is a better more direct way (other than intuition) for feedback DURING valve adjustment to know that you've got the right tension...

EDIT: here is another thread discussing the hot versus cold valve adjustment:
https://forum.ih8mud.com/threads/2f-3f-hot-cold-valve-set.257668/
 
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It is best not to overthink a procedure and just follow the procedure as it is laid out in the FSM . The FSM says do it while the engine is at operating temp. I still cannot fathom how to do it with the engine running with this style of rocker arm / adjustment style? If you have a noisy (ticking ) valve after you have done a correct adjustment , I would look at the rocker pivot point / shaft for wear or binding . if not there then go in a little deeper and inspect the cam and mechanical lifters/cam followers . There is no reason in my opinion to modify the FSM procedure.
 
augirthedude said:
It is best not to overthink a procedure....
Click to expand...
Ha, ha! Good point...Let me think about that here for a minute or two (thousand)....

Nah, but what I noticed is that I could only convince myself that I had adjusted a valve to the best of my ability (in the absence of any other feedback other than the tension on the feeler gauge) when the retaining nut was to torque...because if I tried to find the right tension on the feeler gauge before I had the retaining nut to torque, inevitably after I torqued the retaining nut the tension on the gauge would either loosen or tighten.

That is how I can up with the system of pinching the feeler gauge, breaking the 'bite' by just breaking the screw loose, torquing the retaining nut to spec, then measuring the tension on the gauge...and if I found the tension too loose or too tight, I would repeat the whole process for that valve until I got it just right...and then since it was to torque, I could move on to the next valve.

So it was more of repeated guesstimation of how much or little to back the screw out while breaking the initial 'bite' on the feeler gauge until I got the right final measurement...instead of trying to hold the screw at the 'perfect' point while I fumbled around trying to torque the retaining nut.
In other words, I removed the error of the position moving away from spec as a result of the process of tightening the retaining nut...
 
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augirthedude said:
It is best not to overthink a procedure and just follow the procedure as it is laid out in the FSM . The FSM says do it while the engine is at operating temp. I still cannot fathom how to do it with the engine running with this style of rocker arm / adjustment style? If you have a noisy (ticking ) valve after you have done a correct adjustment , I would look at the rocker pivot point / shaft for wear or binding . if not there then go in a little deeper and inspect the cam and mechanical lifters/cam followers . There is no reason in my opinion to modify the FSM procedure.
Click to expand...
I think that the call for the engine to be running isn't for adjusting, but checking the lash...then shut down and adjust the ones that were out, start and check; repeat as needed. It works on the carbed family of f motors, not so well on the FE types...
 
As long as you are close and consistent , is what matters
 
jlhollowx13 said:
Lastly, what are the negative affects of not adjusting your valves/ not doing them at X interval?
Click to expand...
I was wondering the same thing, which ultimately motivated me to go back and readjust them 'cold' as best I could.

I think Output Shaft nailed the implications of tight valves...but I still kinda wonder what is a tight valve? Like I said above, all the rocker arms have some play and the correct slide feeler gauge will slide in the valve gap...if it was a 'tight' valve would that mean that it is 1 thousandth off, 2 thousandths off? So then the only feeler gauge that should fit in the gap is the one to spec down to a thousandth?
Or is a 'tight' valve that leads to the implications above one where the gap is completely closed?

I was more concerned about loose valves and I was attributing poor gas mileage and poor performance (acceleration) to loose valves...but I don't know what the whole cause and effect there looks like...maybe loose valves don't move the full stroke that they are supposed to, so gasses don't move in and out of the cylinder chambers as efficiently (because the gap between the valve and head seats is slightly smaller, etc....)
 
LAMBCRUSHER said:
I think that the call for the engine to be running isn't for adjusting, but checking the lash...then shut down and adjust the ones that were out, start and check; repeat as needed. It works on the carbed family of f motors, not so well on the FE types...
Click to expand...
This makes sense...that is a relatively simple way to add in more feedback as to whether you're getting the correct gap...by the sound of the tapping on the feeler gauge...maybe I'll give this technique a go next time around...
 
Ah I see the issue . in the 1986 land cruiser maintenance procedures there is a discrepancy

Hot Engine Operations
10. ADJUST VALVE CLEARANCE
(a) Warm up the engine to normal operating temperature.
(b) Stop the engine and remove the valve cover.
(c) Adjust the valve clearance.
• Start the engine.
• Use a feeler gauge to measure between the valve
stem and rocker arm. Loosen the lock nut and turn
the adjusting screw to set the proper clearance.
Hold the adjusting screw in position and tighten
the lock nut.
• Recheck the clearance. The feeler gauge should
move with a very slight drag.
Valve clearance: Intake 0.20 mm (0.008 in.)
Exhaust 0.35 mm (O.014 in.)
(d) Reinstall the valve cover.
(e) Reinstall the air cleaner.

IMO the bulleted item " Start the Engine" is a mistake.

If you look in the 2F Manual it does not include this step . It does however include the cyl. head re-torqueing step .
 
I argue the discrepancy is they omitted " If any valves are still out of spec, stop the engine, readjust the lash, and restart the engine to recheck the lash..."...but I digress. and don't forget to remove the rockers and check the head bolt torque before you adjust the valves....
 
Yes, I have those tools for a variety of engines . They are very handy . But I still think trying to get an accurate valve lash setting even with the tools described above with a running engine is ludicrous and would not attempt due to safety reasons.
 
I am thinking I may try the cold way since i doubt I'll get very accurate readings with it being as cold as it is here and it being my first go around with the 2f. This summer when the engine won't be cooling as fast from the ambient temp and I have a round under my belt I'll go the fsm route and see how much of a difference there was doing it cold vs warm.
 
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