Valve Adjustment

[greytandy]

I know you're supposed to adjust the valves every 5-10K miles, but how can you tell when it's needed? What are the symptoms of poorly (or not optimally) adjusted valves? This is the one routine maintenance thing that seems a bit involved (to me anyway). Also, do you need to replace the gasket every time you adjust the valves? Thanks.

 

[kulangot]

Do at every oil change. Takes a bit of a feel to get it right, it amazes me how often I hear that the valves were just adjusted and they are all off. I like to use the feeler guages from Wurth, you get just the two you need, they are color coded and a good length for doing a cruiser. Make sure it's hot when you do it and work fast or the motor cools. I was taught to do the adjustment, run the motor back to temperature and then double check them.

There is a bit of a trick to get the adjuster right where you want them, you have to kind of sneak up the tightening of the nut or you will over tighten. Make sure you rattle the rockers with your finger and then double check.

Not hard, just takes some time.

It's amazing how well these motors can run if you take your time and get all of the adjustments spot on.

-Stumbaugh

 

[Rocky_LC]

Good Link on how it's done.

I just did mine last weekend. I kept the same gasket.

http://www.birfield.com/~morgan/tech/valves.html

Rocky

 

[RHINO]

you know your valves are properly adjusted when your engine sounds like a fine singer sewing machine

 

[Pin_Head]

but how can you tell when it's needed? What are the symptoms of poorly (or not optimally) adjusted valves? .

If a valve is too loose, it makes noise and there is a slight (or unnoticable) loss of performance.

If it is too tight, the valve burns (especially exhaust) and there is a slight (or unnoticable) loss of performance.

 

[BC Cruiser]

Listen closely near the valve cover and if it sounds noicey kind of like a raddle then it needs adj.

 

[Rocky_LC]

If a valve is too loose, it makes noise and there is a slight (or unnoticable) loss of performance.

If it is too tight, the valve burns (especially exhaust) and there is a slight (or unnoticable) loss of performance.

or you will notice it when you try to pass smog, and can't get the HC's down enough because a burned exhaust valve is squirting gas fumes into the exhaust....

Don't ask me how I know - but the truck runs just fine...

Rocky

 

[65swb45]

Do at every oil change. Takes a bit of a feel to get it right, it amazes me how often I hear that the valves were just adjusted and they are all off. I like to use the feeler guages from Wurth, you get just the two you need, they are color coded and a good length for doing a cruiser. Make sure it's hot when you do it and work fast or the motor cools. I was taught to do the adjustment, run the motor back to temperature and then double check them.

There is a bit of a trick to get the adjuster right where you want them, you have to kind of sneak up the tightening of the nut or you will over tighten. Make sure you rattle the rockers with your finger and then double check.

Not hard, just takes some time.

It's amazing how well these motors can run if you take your time and get all of the adjustments spot on.

-Stumbaugh

That's a good call John. On all counts.

I have installed a vacuum guage on my 40 and 45. When the needle flickers, that usually means a valve is too tight [seat migrated further into the head] If it flickers long enough, it WILL BURN THE VALVE. Further, as Pin_Head wrote, the overly tight valve will cause a loss in performance even before the needle starts to flicker. In that respect, the flickering vacuum guage is more of a 'red light' warning than a true barometer of valve adjustment.

Hth

Mark A.

 

[honk]

someone ought to take the time to try and figure out how much change (and which way they change) in valve clearance occurs as the engine warms.

Would it be useful to have both a hot and a cold tolerance for setting?

How much difference could 100-150 degrees make? The difference between ambient temperature and normal running temperatures? Not a big change for steel. I'd wonder if the dimensional change wouldn't be well within the usual range of error that occurs during the adjustment process.

 

[ecodan]

I do my valve adjustments while the engine is running -as directed by my manual and mechanic. Is a bit tricky to start with, but not dangerous, and no danger of engine cooling off.

 

[F-junker]

I would think that 100-150 degrees would change things a bit, the reason I say this is from experience from old school surveyors. Back before laser transits with common, things were measured with optics for angles and azimuths (north-south etc and up and down in elevation) the other critical measurement STEEL TAPE measures.

Tapes were pulled and stretched with a pliers tyoe tool. I did this type of surveying in college as a practical application for a base knowledge for understanding how all of the individual measurements come into play.
One CRITICAL calculation was TEMPERATURE and the proper temperature correction factor for the steel tape.

Now we are talking about ambient temps here. That steel will stretch more in higher temps than in cold temps. This was a required calculation for that type of surveying, if it was not done properly then the survey plat etc. would be incorrect.

I think temperature makes a big difference, I also think our engines have a fair amount of forgiveness in that the tolerances are not of a racing specification.

I am very happy to have read this and other threads on valve adjustment and have added this to my current list of things to do soon.

Mark, thanks for the tip on the vaccum gauge! That is good information. I 'll see you all on the trail soon. See my thread here shortly with pics of recent fixes and additions. Stay cool and keep the rubber side down.

 

[ranger]

Most engines that I have done valves on had both hot and cold settings. Usually they differ between .001" to .002".
I'm sure if you had a tuned engine and took readings cold and hot the difference wouldn't be too extreme, you could use the differance to get a cold adjustment.

 

[IDave]

Having tried it, I would say it's at least .002". Of course, it also depends on the ambient temp you are starting with. 0 degrees vs. 100 degrees, I'm sayin'.

 

[kulangot]

someone ought to take the time to try and figure out how much change (and which way they change) in valve clearance occurs as the engine warms.

Would it be useful to have both a hot and a cold tolerance for setting?

How much difference could 100-150 degrees make? The difference between ambient temperature and normal running temperatures? Not a big change for steel. I'd wonder if the dimensional change wouldn't be well within the usual range of error that occurs during the adjustment process.

Honk,

I think it makes a big enough difference to matter however small it would be. On a BMW R series air cooled boxer the transmission case is nearly impossible to take apart cold as it has a precise fitiment. If you heat it up to 212C in an oven, it comes apart readily.

Same thing with the timing gears. They will not fit together by hand but if you heat one to 100C (212F) they pop right together with finger pressure.

On a pushrod motor, with a long valve lifter, push rod and rocker assembly (and in a F/2F/3F is pretty darn long) there is a lot to change in size with heat and cooling.

I have noticed cold settings given more with over head cam motors than with push rod motors, perhaps this is because there is significantly less total valve train length? Just an idea, I am no engineer.

-Stumbaugh

 

[kulangot]

That's a good call John. On all counts.

I have installed a vacuum guage on my 40 and 45. When the needle flickers, that usually means a valve is too tight [seat migrated further into the head] If it flickers long enough, it WILL BURN THE VALVE. Further, as Pin_Head wrote, the overly tight valve will cause a loss in performance even before the needle starts to flicker. In that respect, the flickering vacuum guage is more of a 'red light' warning than a true barometer of valve adjustment.

Hth

Mark A.

Thanks for the compliment Mark, I think your right about the vacuum gauge, it's the foundation of Land Cruiser super tuning. Every truck should have one in the dash, makes for better fuel economy as well. If you have a problem, you'll see a corresponding relationship to the problem in the vacuum gauge and this combined with some text book learning of vacuum needle readings and you can get closer to seeing what the source of the problem is.

-Stumbaugh

 

[Pin_Head]

The gap is determined by the relative length of the moving (lifter, pushrod, rocker, valve) and non-moving (block, head) components.

The length is a function of the temperature of the parts and their thermal expansion coefficients. The expansion corefficients of steel and cast iron are nearly equivalent, so only the temperature differential would be significant. I can't envision the temperature of the moving and non-moving components being that different in a water cooled engine, so my guess is that the gap isn't going to change very much in a hot and cold engine.

 

[kulangot]

The gap is determined by the relative length of the moving (lifter, pushrod, rocker, valve) and non-moving (block, head) components.

The length is a function of the temperature of the parts and their thermal expansion coefficients. The expansion corefficients of steel and cast iron are nearly equivalent, so only the temperature differential would be significant. I can't envision the temperature of the moving and non-moving components being that different in a water cooled engine, so my guess is that the gap isn't going to change very much in a hot and cold engine.

It does not change very much, but it does change. In fact, when manufactures give specs for hot and cold adjustments they difference in feeler gauge size is usually the next size up or down.

I see no reason why it can't be done hot or cold if the spec is given. Some cars and motorcycles say must be done cold and some just give hot specs, others give both. I have no idea why, I just do what the manufacturer recommends as I figure that they probably know what is best for their design.

Since when they do list hot and cold numbers for adjustment that are often different, it does in fact change on some motors. So I can't agree.

If the number given is for hot adjustment, I think you need to do it hot.

I guess someone with lots of free time could adjust the valves hot and then check them cold and see what the changes are. I'd want to see more than shade tree measuring though as I think many people don't have the correct feel for a feeler gauge and the amount of pull that it's supposted to have.

-Stumbaugh

 

[IDave]

I can say for sure from first hand experience you won't be able to get the feeler in when it is warm if you set it up cold to the specified gap.

 

[Poser]

I can say for sure from first hand experience you won't be able to get the feeler in when it is warm if you set it up cold to the specified gap.

DING DING DING!

 

[REZARF]

Do you guys use the tool for adjusting the valves or just use the three handed method with two hands of a feeler, screwdriver, and wrench? I was thinking of getting one of those tools for it, but thought I would ask some with experience.

Thanks, hijack over.

rezarf <><