Valve adjustment sequence

[Synchro909]

I am adjusting the valve clearances on one of my motors and vaguely recall something about the sequence and the "rule of 9" but I can't remember the details. I think Vince Falter had details on his website but I can't find them.
Is anybody able to help me please.

[PalAl]

Model A & B
Valve Tappet Adjustment
Rule of Nine
Described below is a timesaving method for adjusting or checking the adjustable valve tappet clearances when the engine is in the car and you have to hand crank it. Original Ford valve tappets (push rods in Ford nomenclature) were solid and non-adjustable, but all modern replacements are adjustable.
First of all, it is not necessary to know where the pistons are positioned. The tappets (push rods as Ford called them) must be adjusted with thin wrenches when they are on the peak of the cam lobe, and the clearance must be measured when they are on the heel of the lobe (lowest point). Hand crank the engine a few times and watch the valve stems and you will see this.
The Issue:
Ideally, you would want to adjust the gap when the valve tappet was on the heel of the lobe and the gap could be measured with a feeler gauge. Unfortunately, the tappet adjustments are not accessible at that position, and the cam must be rotated and the tappet raised to make an adjustment. At that point the tappet can be adjusted, but the gap cannot be measured. Thus a lot of cranking is typically required, alternating between measuring and adjusting.
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Here's the Trick:
Valves are numbered 1 through 8, from front to back. Regardless of which valve tappet is on a cam lobe peak (and can be adjusted) at a given instance, there is another corresponding valve tappet that is on its lobe's heel (and whose gap can be measured).
By understanding the relationship between the valves, (Rule of Nine), you can do two things at once and adjust and measure multiple valves in steady progression (if you keep track of your actions). This will greatly minimize the amount of time spent cranking, measuring, and adjusting.

The Rule of Nine relationship works like this:
If for instance the #6 valve is full open, then it can be adjusted with wrenches. Also at the same time the #3 valve tappet ("9" minus "6" equals "3") is on the heel of its cam lobe and its gap can be measured at the same time as #6 is being adjusted.
Now crank a little more until a different valve is full up and adjust it, and/or measure the gap on the other valve tappet whose sum equals "9" (e.g. if #2 is full up, then #7 can be measured, and #2 could also be adjusted if you know how much). Keep cranking until a different valve is up, and adjust it and measure the gap of the one whose sum equals "9".
Do the Math:
Adjustable self-locking valve tappets use a 24 TPI bolt, which equates to a pitch in inches of 0.042" (one revolution of the bolt changes the gap 0.042"). Since the bolt head has six wrench faces, it is fairly easy to estimate rotating the bolt 1/6 of a revolution, which equals one wrench face, which equals a 0.007" change axially at the gap.
Furthermore, with a little eyeball engineering, you can guesstimate 1/3rd of a rev of a hex wrench face with the two wrenches in your hand. This is ~0.002" of valve gap adjustment per 1/3 wrench face rotation.
With a little practice, you can measure and record the gap when the valve tappet is on its cam lobe heel, and can adjust it to within 0.002" of where you want it the very first time that same valve tappet is on its cam lobe peak (and is accessible by wrenches).
This can really minimize the amount of hand cranking necessary when the engine is in the car. If the engine is on a stand, then perhaps a lot of cranking is not such a big deal.
This procedure works very well on Model A camshafts, and quite well on Model B cams, though B cams have a slightly different lobe separation angle and the 'down valve' is not as centered on the heel when the corresponding valve is at its peak.
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Recommended Tappet Clearance (inches)
Camshaft
Design Intake Valve
Clearance (gap) Exhaust Valve
Clearance (gap)
Model A
A-6250 0.015 0.015
Model B
B-6250 0.015 0.022
Stipe
IB330 0.012 0.012
Stipe
IB340 0.012 0.012
Stipe
RR340 0.012 0.014
The table above shows the manufacturer's recommended design tappet (push rod) clearances (cold) for several cam profiles.
A typical clearance setting of 0.013" intake and 0.015" exhaust is also commonly used by many people, and is also used when the cam profile or the cam grinder's recommendation is unknown.
Important Note:
It is best to avoid setting the exhaust gap too small, as this can create insufficient heat transfer time for the valve on the seat, and can ultimately burn the exhaust valve.

The linear thermal expansion of a hot exhaust valve also has the effect of increasing its length and decreasing the clearance gap at a higher rate, compared to the expansion of a cooler intake valve's length.

When in doubt, err on the side of setting the exhaust valve gap larger, rather than smaller.

[PalAl]

Ok figured out how to attach the good part

[Synchro909]

Thanks guys. That's just what I need.

[PalAl]

Glad I could help. What a great place the Ford Barn is for getting and sharing information

[burner31]

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I'm going to be checking/adjusting mine this Winter, thanks to you both for this great information.

[Synchro909]

Reporting back. I decided to adjust them because they were dead silent, even when cold so I couldn't be sure they were n't holding the valves open a bit. I set them at 0.016 and 0.018 - wider then spec, I know. I can now just hear them when I start up.
The car has seemed low on torque (dies on hils, head winds etc) so I'm looking forward to seeing if this makes a difference.

[Werner]

Hallo Synchro,
if you increase the valve clearance, the valves will open slightly later and close a little earlier. As a result, the cylinder filling is a little less and the power drops.

[Synchro909]

Originally Posted by Werner

Hallo Synchro,
if you increase the valve clearance, the valves will open slightly later and close a little earlier. As a result, the cylinder filling is a little less and the power drops.

Yes, Werner, I'm aware of that but power is lost also if the valves are not properly closing.

[Werner]

Good Morning, PalAI wrote:

Originally Posted by PalAl

Model A & B
Valve Tappet Adjustment
...
Adjustable self-locking valve tappets use a 24 TPI bolt, which equates to a pitch in inches of 0.042" (one revolution of the bolt changes the gap 0.042"). Since the bolt head has six wrench faces, it is fairly easy to estimate rotating the bolt 1/6 of a revolution, which equals one wrench face, which equals a 0.007" change axially at the gap. ...

This sequence is an excellent hint! Yesterday I set all exhaust valves just to only 0.3 mm. Tonight I thought about it again and I do not like it anymore, better a bit louder the chattering. I turn for safety 0.4 mm.

With above note I put all open exhaust valves on the plunger by 1/6 turn down (= 0.1 mm lower) and about 6 minutes later I have done it!


P. S.:
Synchro, you are right, of course! Too little valve clearance ruins the surfaces in the cylinder head because the valves burn off. Too much valve clearance has never done any harm.

[richard crow]

a very simple way . remove dist cap crank eng till rotor lines up with number on spark plug wire. adj valves number cylinder crank eng till rotor lines up with next plug wire. you adjust all the valves this way you only turn the eng one reverlution

[Synchro909]

Originally Posted by richard crow

a very simple way . remove dist cap crank eng till rotor lines up with number on spark plug wire. adj valves number cylinder crank eng till rotor lines up with next plug wire. you adjust all the valves this way you only turn the eng one reverlution

I think that would mnean 2 turns of the engine but yes, that would work too.

[Pete]

Originally Posted by Synchro909

I think that would mnean 2 turns of the engine but yes, that would work too.

Nope, not very accurate because of cam overlap. The lobes need to be exactly on the heel for proper adjustment.

[Werner]

Good morning.


Maybe that means adjusting the valves per cylinder?

I find this much clearer: You put some cylinder on overlap of the valves in the TDC. Then in the firing order 2 cylinders back counted shows a cylinder exactly on ignition time TDC and both closed valves can be adjusted.

Then the following cylinder (1/2 turn) is adjustable. a. s. o. ...