Valve Rocker Adjustment.

[64beam]

Hi Forum,

I have seen this topic discussed many times in different posts. I have never attempted a valve adjustment before and I was wondering if this something that should be left to a professional or something that anyone could handle? I have looked in the WSM and it all looks straight forward (or is it). Any tips or problems to watch out for.

Thank you for your assistance,

Regards, Robin.

 

[Series3Scott]

Robin - it's so easy, even I've performed it! Just make sure you follow the procedure in the manual and you'll be fine.

 

[RootesRacer]

I ignore the procedure in WSM on this in that I adjust the compliment valve when a given valve is at full open.

For instance, when #4 intake is fully open, I adjust the #1 intake.
1 and 4 are compliments, 2 and 3 are too.

After each adjustment, I mark the spring keeper with a white crayon (it will melt into solution in the oil).

If you do it right and pay close attention to which valves are opening first, you can adjust the whole set in 2 turns of the motor.

Dont even consider using the starter to bump the motor, put a socket on the crank pulley bolt to make the engine turn.

Procedure should take about 10 minutes if you are fast, which is handy when attempting the "hot" adjustment.

Also since my cams tend to be very "lashy", I set my final hot clearances closer than stock, one becuase the lash noise is quieter that way, and two becuase I am accurate enough in setting the lash that the finer tolerance doesnt result in burned valves since I set them good and hot.

 

[sunbby]

Isn't that the same as the WSM procedure? Do you mean you basically do the WSM procedure but start at whichever valve opens next instead of specifically finding #4EX open?

I haven't done my Alpine yet, but on my motorcycles I always did one "whole" cylinder at a time. For example, get cylinder #1 to the compression TDC and adjust both exhaust and intake as they should both be fully closed at the time. Is there some reason the Alpine manual has you do 1 valve at a time instead of 2?

I ignore the procedure in WSM on this in that I adjust the compliment valve when a given valve is at full open.

For instance, when #4 intake is fully open, I adjust the #1 intake.
1 and 4 are compliments, 2 and 3 are too.

After each adjustment, I mark the spring keeper with a white crayon (it will melt into solution in the oil).

If you do it right and pay close attention to which valves are opening first, you can adjust the whole set in 2 turns of the motor.

Dont even consider using the starter to bump the motor, put a socket on the crank pulley bolt to make the engine turn.

Procedure should take about 10 minutes if you are fast, which is handy when attempting the "hot" adjustment.

Also since my cams tend to be very "lashy", I set my final hot clearances closer than stock, one becuase the lash noise is quieter that way, and two becuase I am accurate enough in setting the lash that the finer tolerance doesnt result in burned valves since I set them good and hot.

 

[Series3Scott]

There's an even simpler way to make the engine turn - learned it from Jim Ellis - make sure your car is on a nice flat smooth surface and simply grasp the front wheel with your hands and move the car forward until the next valve opens. You can rock the car back and forth this way very easily to adjust the valves.

 

[RootesRacer]

Isn't that the same as the WSM procedure? Do you mean you basically do the WSM procedure but start at whichever valve opens next instead of specifically finding #4EX open?

I haven't done my Alpine yet, but on my motorcycles I always did one "whole" cylinder at a time. For example, get cylinder #1 to the compression TDC and adjust both exhaust and intake as they should both be fully closed at the time. Is there some reason the Alpine manual has you do 1 valve at a time instead of 2?

In a nutshell the basics are the same but if you follow WSM and do one valve at a time followed by the the other valve in the same cyl, you will rotate past other valves that could have been adjusted, which IIRC results in 6 or 8 full engine revs to adjust them all instead of two revs done my way. Time counts when doing a hot adjustment as far as accuracy goes.

An as far as adjusting 2 valves on the same cyl at the same time, this is NOT the same as WSM or my procedure and this doesnt work on many engines becuase this point in the engine cycle is where the quieting ramps are in play and the lash is changing on both the intake and exhaust. Adjusting one valve when its compliment is at or very near full lift results in adjusting the valve on the backside or base circle of the cam lobe, which is nearly ALWAYS the safest location since this is the point of lowest lift (none).

 

[sunbby]

In a nutshell the basics are the same but if you follow WSM and do one valve at a time followed by the the other valve in the same cyl, you will rotate past other valves that could have been adjusted, which IIRC results in 6 or 8 full engine revs to adjust them all instead of two revs done my way. Time counts when doing a hot adjustment as far as accuracy goes.

I think the Series V WSM describes your method, not sure about the earlier ones.

An as far as adjusting 2 valves on the same cyl at the same time, this is NOT the same as WSM or my procedure and this doesnt work on many engines becuase this point in the engine cycle is where the quieting ramps are in play and the lash is changing on both the intake and exhaust. Adjusting one valve when its compliment is at or very near full lift results in adjusting the valve on the backside or base circle of the cam lobe, which is nearly ALWAYS the safest location since this is the point of lowest lift (none).

Yes, thanks for the insight, I guess it would depend on the cam timing to allow 2 adjustments at once. So it's best to stick with the method you describe.

 

[sunbby]

Also since my cams tend to be very "lashy", I set my final hot clearances closer than stock, one becuase the lash noise is quieter that way, and two becuase I am accurate enough in setting the lash that the finer tolerance doesnt result in burned valves since I set them good and hot.

RootesRacer, I forgot to ask my most important question. Do you have any tips on setting the lash accurately? Do you use one of those special tools, sort of a screw driver and box wrench combined? I inevitably end up having to readjust sometimes after I tighten the locknut, even though I try to hold the screwdriver stationary. Do you leave the feeler gauge in the gap while tightening?

Thanks,
Todd

 

[RootesRacer]

RootesRacer, I forgot to ask my most important question. Do you have any tips on setting the lash accurately? Do you use one of those special tools, sort of a screw driver and box wrench combined? I inevitably end up having to readjust sometimes after I tighten the locknut, even though I try to hold the screwdriver stationary. Do you leave the feeler gauge in the gap while tightening?

Thanks,
Todd

They key to my own procedure is loosening the nut, then tightening it back down just enough that it is well under tension, but can still allow the adjuster to turn if you twist it hard enough. I then use the screwdriver to put a consistent force on the rocker which opens the valve to stem up. Insert feeler and adjust till the feeler moves, but is under the slightest amount of valve spring tension. Yes I leave the feeler in place till the nut is fully tight, that way I know the lash is just right.

You get a feel for it after doing it a few times.

Also make sure the rockers arent grooved where they contact the stems, this adds extra lash that is a big unknown.

 

[Nickodell]

Hi, Rootes Racer - or can I call you R-R? Your method is the only one I have used for half a century. The only other thing I was taught by my dad was to rap the top of the rocker above the pushrod smartly, to displace any oil between the pushrod and ball on the rocker, and ditto between cam and follower, that might cause a false reading. It might be no more necessary than knocking wood for luck, but I got into the habit of doing it.

 

[jumpinjan]

Believe it or not, I use to adjust the valves (back in the '70s) while the engine was idling. Try holding a screwdriver & 9/16" wrench on a valve while it going up & down. It worked and I could hear the ticking on the loose ones and get them all in one shot. I don't need a stinking wrench on the crank pulley nut!

 

[Alpine 1789]

Someone told me to do that on the Alpine 25 years ago. I still have the chewed up feeler gauge in my tool box.

 

[64beam]

G'Day Guys,

Thanks for all the replies to my post. Why is it so important that the adjustment is done hot . How much difference is there between the hot and cold clearance? What will happen if the rockers are adjusted when not fully open? I just want to cover all bases when I attempt the adjustment.

Regards, Robin.

 

[alpine_64]

G'Day Guys,

Thanks for all the replies to my post. Why is it so important that the adjustment is done hot . How much difference is there between the hot and cold clearance? What will happen if the rockers are adjusted when not fully open? I just want to cover all bases when I attempt the adjustment.

Regards, Robin.

Rob, when hot the metal will expand, you set your clearence as close as possible to when they are at operating temperature, that way they will be in spec.. adjusting cold will set clearance and once the metal expands the will be to tight and you will have trouble.

 

[64beam]

Hi Michael, I understand that metal expands when hot and that the clearances will change due to this. Under normal conditions (What are "normal" conditions), the amount of expansion should be about the same so in theory, you should be able to set them cold (in theory )?

Regards, Robin.

 

[RootesRacer]

Hi Michael, I understand that metal expands when hot and that the clearances will change due to this. Under normal conditions (What are "normal" conditions), the amount of expansion should be about the same so in theory, you should be able to set them cold (in theory )?

Regards, Robin.

The simple facts are that you have an iron block with a steel cam, steel followers and steel pushrods, pushing on steel rockers and steel valves, connected to an aluminum head. The differential of expansion is super complex and cannot be ignored.

You SET them hot becuase you DRIVE the car when its hot. The bottom line is you want the clearances temp compensated so you know that the valves close with a safety margin when the motor is good and hot. If they dont, you burn valves becuase valves are cooled by thier contact with the valve seat.

Very few motors dont require setting the lash hot, ones that claim to need a cold only setup are usually single metal motors (all iron), or closer tolerance OHC motors where the lash is done by shimming the followers.

 

[Nickodell]

The coefficients of linear expansion of steel, cast iron and alumin(i)um differ widely:

Al..............248

Mild steel....121

Cast Iron....108

With a cast iron block, steel cam, followers, pushrods, rockers and valves, and an aluminum head, lots of differential expansion goes on as the engine heats up, so you need to measure the lash at operating temperature.

Thank your lucky stars that you don't have to adjust clearance on an old Ford flathead V8 as I did once. There are no lifters; the valves operate directly from the cam. To increase clearance you mount the valve stem on a V-block and grind the end, then reassemble and check clearance. To reduce it, you grind the valve head into the seat with grinding paste. The whole operation is a royal pain in the ass, and can take two days for all 16 valves.

The only good thing is that you do it cold!

 

[64beam]

As can be seen from my posts, I have not had much experience with the workings of internal combustion engines. This is why it may seem like a stupid question and/or just being plain ignorant, but if I don't ask I will never know the answer. What it comes down to is that I don't want to stuff it up and cause myself more problems (take my time and do it right the first time). Thank you to those who take the time to explain the issues.

Kind Regards, Robin.

 

[ozzie alpine]

OK, we all agree that valve clearances need to be set hot....

For a freshly assembled engine/head, what clearances should be used as a cold "baseline", ie until the clearances can be re-set when the engine is hot.
Is the usual 12inlet/14exhaust close enough?
cheers
Dave

 

[RootesRacer]

OK, we all agree that valve clearances need to be set hot....

For a freshly assembled engine/head, what clearances should be used as a cold "baseline", ie until the clearances can be re-set when the engine is hot.
Is the usual 12inlet/14exhaust close enough?
cheers
Dave

Those numbers are fine.
Quite often to save time, I dont even use a gapping set to set the cold lash for a first time setup. You just need a little gap, but not so much that the engine sounds like a thrashing machine while it heats up.

Having a consistent lash from valve to valve is important for idle quality while it warms up, but the absolute lash value is not so important (for the base rough adjustment).