Another Tappet Question

[KVH]

Thanks for the help on the jam nuts, and here's another question:

For valves 1 and 2, there's absolutely no doubt that my clearance exceeds .010 if I use the factory recommended method of going one full revolution after the lifter is at its highest point and then turn another 1/4 turn. I actually flop around .011 or more if I go another 1/4 turn.

I assume I should keep the clearance to .010 when it hits that sloppier point and not fret too much about the factory suggestion of going only one full turn after the highest point.

Otherwise, I assume there's too much play.

Any explanation for the discrepancy?

thx

 

[Andrew Mace]

Not sure, but I've long found it easier to use the "Rule of 9" for four-cylinder engines -- set #1 clearance when #8 is open, set #2 clearance when #7 is open, etc. -- or the similar "Rule of 13" for six-cylinder engines -- set #1 clearance when #12 is open, etc. Works out about the same as that "factory recommended method" but is easier to remember for, uh, older minds like mine. :wink:

 

[AweMan]

The way I have always done hydraulic lifters is piston at top dead center for the cylinder you are working on, zero valve lash {finger tight, No play} then tighten to factory recommended specs. Eg. 1/4 turn
Solid lifters basically the same except that I set them cold first, piston @ top dead center, adjust both valves to factory spec. gap {Eg. .010} with a feeler gauge. Then check them again hot {normal operating temp} engine idling to ensure the gap is correct. Too tight or too loose adjust accordingly with hot {normal operating temp} idling engine.
The tricky part is to get the piston exactly at top dead center {compression stroke} for the cylinder you want to adjust.
NOTE:
With this method you can adjust both intake and exhaust valves then move on to the next cylinder.
P.S. There are other methods, Someone will chime in with them i`m sure!
The above methods are the way I was taught by my father.

 

[Geo Hahn]

I too use the rule of 9. Really goes quickly once you have the sequence in mind.

My understanding is that in no case do you want less than the spec gap of .010 and that some set them to .012 just to be on the safe side.

 

[TR3driver]

I'm with Kerry. Since TDC for #2 & #3 cylinders is not marked on the pulley, easiest is to look at the valves. When both valves are open, that cylinder is near TDC (between exhaust and intake), which means the opposite cylinder is at TDC (between compression and power) and can have both valves adjusted. That way you only need turn the engine 3 or 4 times, instead of 7 or 8. And this method works for any even number of cylinders (assuming an even fire engine).

Any explanation for the discrepancy?

That says to me that the base circle on your camshaft is not accurate; which may mean either a poor regrind or a failing camshaft. While I don't believe it makes much difference, I'd go with the reading in the standard position, rather than looking for the low spot.

 

[KVH]

Well, with these suggestions and some literature I found, this seems like the thing to do: When No.1 Intake is beginning to close, set No. 1 Exhaust; When No.1 Exhaust is just beginning to open, set No.1 Intake; So on for all valves. The point of "just beginning" has some allowable lattitude.

That way the cam is rotating at just the right time to set the tappet clearance.

Doing it this way seemed to get all tappets at about .010.

I think my cam, which is new, might not be a perfect grind; otherwise, I wouldn't think I would have found the clearance descrepancies from the Owners Manual.

However, a good "Macy's Garage" article explains why the "just beginning" technique valve by valve works well. I realize I could've used the rules of "9"s.

I'll report back if my engine explodes. (After I return from Bristol with a new one.)

 

[martx-5]

I'm with Kerry. Since TDC for #2 & #3 cylinders is not marked on the pulley,...

Which is why I made a mark 180 deg opposite of the TDC mark on my TR3 pulley. I used to use the "rule of nine", but find having two marks on the pulley much easier when adjusting valves. I suppose you could add two extra marks 120 deg apart for the six cylinder engines.

 

[TR3driver]

To each their own, I guess. I find it easier to watch the valves than the timing mark(s); especially when trying to turn the engine at the same time. And the "both valves open" technique also works for either direction of engine rotation, which is handy because I usually find it easier to turn the engine backwards while adjusting valves. Just stick the gearbox in 4th and push against the rear of the opening with my right hand (stronger than my left).

 

[JFS]

Another method: With no. 1 piston TDC on compression stroke and timing marks alined, adjust both valves on no.1, intake on no. 2 and exhaust on no. 3. Turn crank one complete turn according to timing marks and adjust no. 2 exhaust, no. 3 intake and both valves on no. 4.

 

[Don Elliott]

Kentville Hound - With a new cam, make sure you have added some ZDDP Plus (from Moss) or use an oil which has enough of it to start with - to prevent your new cam from destroying itself in 200 miles or less.