Perkins 203ci diesel Setting valve lash

[Mean Jean]

Adjusted cold to .012 as per book.
Problem is I measured lash at the valve spring side.
I found a Perkins manual which shows adjustment done on the other side as shown in the picture below.
The arms are different length as measured from the shaft assembly.
Can anyone confirm the proper side which to measure for valve lash?

UPDATE:
The Perkins workshop manual shows measurement at the adjusting nut side as in the picture below.
I found another site which states to measure on the valve stem side.
Unlikely that both sides will have the same lash as the rocker arm is a tad bit longer on the one side.
This will change the angle and therefore the lash.

Hmm.

 

[lescarpentier]

Both sides should measure the same.
I don't see why it wouldn't.
GL!

 

[Mean Jean]

Both sides should measure the same.
I don't see why it wouldn't.
GL!

One side of the arm is longer than the other.
This means the angle will be greater/lesser than its counterpart therefore providing a different gap.
If both arms are the same length then yes, the gap should be the same.

Read something which states the gap should be measured on the valve stem side which is what I did.

 

[Quebecguy]

Adjusted cold to .012 as per book.
Problem is I measured lash at the valve spring side.

When you had .012 clearance on the valve spring side what was the clearance on the adjusting nut side?

 

[Mean Jean]

I don't know that we measured the gap at adjustment nut side.
We did however try the 12 thou feeler gauge and if I recall correctly it was too tight.
We didn't rock the tappet all the way to the other side of its movement though so of course it would be tight.
To accurately measure at the adjustment side we would need to check the valve closed and not open.....I think.

 

[Quebecguy]

I don't know that we measured the gap at adjustment nut side.
We did however try the 12 thou feeler gauge and if I recall correctly it was too tight.
We didn't rock the tappet all the way to the other side of its movement though so of course it would be tight.
To accurately measure at the adjustment side we would need to check the valve closed and not open.....I think.

Sorry, I'm getting confused here. I don't know what you mean by rocking the tappet all the way to the other side of its movement. It should be simple to move the rocker arm up and down. If you get 12 thou of movement on the valve side what movement do you get on the adjusting nut side? I would think there shouldn't be much of a difference at all. Whichever end of the rocker arm is to be checked the valve has to be closed. If the valve is at all open you will have no gap in the valve train hardware.

 

[Mean Jean]

Sorry, I'm getting confused here. I don't know what you mean by rocking the tappet all the way to the other side of its movement. It should be simple to move the rocker arm up and down. If you get 12 thou of movement on the valve side what movement do you get on the adjusting nut side? I would think there shouldn't be much of a difference at all. Whichever end of the rocker arm is to be checked the valve has to be closed. If the valve is at all open you will have no gap in the valve train hardware.

I started by calling it a rocker arm and should have stayed with that term, for some reason I changed to "tappet." It's the same thing but bad form on my part.

When I say rocking the rocker back I mean turning the engine over in order to either open or close the valve.
Here's the process I followed for adjustment:

INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUST VALVE ---OPENING ----- ADJUST INTAKE VALVE

We never did officially measure the gap on the adjustment side.
We did try sliding the 12 thou feeler in there but it did not fit.

Remember that the rocker is actually longer on one side than the other. Perhaps this is why the gaps appear to be different?

 

[shona13]

G'day Mean Jean.
As it suggests you are setting or adjusting the valve clearance not the tappet clearance the 012"measurement is between the valve and the rocker, just a note on that ,after a few thousand hours of operation the hard face of the rocker arm,the area that operates the valve, starts to wear a round mark that the valve creates, meaning that when you slide a 012 feeler gauge in there you will get an inaccurate reading because the feeler gauge cannot bend inside the worn part, if you loosen a tappet adjuster and look between the valve and the tappet you will see the wear I am talking about, if they are indeed worn the best thing to do is remove the rocker shaft assembly and have the worn faces reground this will guarantee a true valve clearance.

The proper procedure to adjust the valve clearance is :
Numbered from the front. Number one valve Open that is the valve is ALL the way down (spring compressed) adjust number Eight valve.
number Two valve open adjust number Seven valve and so on you will notice that they add up to NINE use this formula to do all valves, I mark each rocker with a piece of chalk when it has been adjusted.
My old dad always said If you can hear the tappets they are not to tight,do not be tempted to adjust them to tight.
Regards.
Hutch.

 

[rrrkkk]

At 75 years of age I have never heard of adjusting the valves but on the spring side. Your manual shows the correct way use it!

 

[shona13]

75 years !!!.
Thats a long time ,in my 52 years of working on all types of engines I always set the Valve clearance between the valve tip and the rocker that way you know what the clearance is , How do you adjust an overhead Cam engine or a hydraulic lift type cam engine or a Briggs and Stratton engine or a honda engine or a villiers engine etc etc."

The perkins engines are over head valve and have an adjustable tappet that runs in direct contact with the camshaft and operates the valve via a valve rocker in this instance there will be none or very little difference a difference non the less and from experience there are engines that would make a difference ,what about a pushrod engine with a ball and socket type pushrod would you use a special curved feeler gauge that fits between the push rod and the Adjustable tappet ball !!!! this is the reason I always set valve clearance at the Valve TIP, in this case .012.
Happy days .
Hutch.