Find TDC & adjust valves

[justgimmecoffee]

I re-centered the hyraulic lifters a few weeks ago. Since then, the sound of the engine has changed slightly and now I'm getting The Doubt. Did I do it right or have I doomed my engine? I looked on TS and ratwell but can't find a clear, concise and complete bentley-ish explanation of how to adjust them. Colin explained it to me, but its been a year. Hence the gnawing doubt. Here's my adjustment procedure.. I don't have the bentley handy and may not have the correct terms, but you get the idea.


Its my understanding that the lifters for each cylinder should be adjusted when it's piston is at TDC. Both lifters at the same time? I think so so thats how I did it.
I removed the distributor cap and turned the engine (sans spark plugs) until the rotor was aiming for the #1 plug position. I set it at the closest TDC mark. I"m now at TDC for #1 cylinder, correct?
Removed valve covers. Loosened the appropriate rocker arm nuts and backed off the adjustment screws. Wobbled the rocker arm, got some free play in there, then slowly tightened the adjustment screw til it wouldn't wobble. That's zero adjustment. Next, I tightened the screw, turning it inwards one and one half turns. Now tighten the lockdown nut. On to the other valve, same procedure.

Okay on to cylinder #2. I turned the engine til the rotor was aimed at spark plug wire #2 (or where it would've been had the cap been on) and adjusted both the lifters on that cylinder. And so on to #3 &#4. When finished, make sure everything is tight.

Is that the correct procedure?

'79 VW Campermobile Automatic
Type IV with Stock F.I. system
aftermarket Pertronix ignition

[vwlover77]

That sounds correct to me. (You want the piston at TDC so both valves are closed and the cam is not trying to push them open.)

[Bookwus]

Hiya Barry,

.....I removed the distributor cap and turned the engine (sans spark plugs) until the rotor was aiming for the #1 plug position. I set it at the closest TDC mark. I"m now at TDC for #1 cylinder, correct?

Maybe. I think you also need to check the number one hole to make sure that the piston is all the way out. You could be sitting on number three also.

[vwlover77]

Maybe. I think you also need to check the number one hole to make sure that the piston is all the way out. You could be sitting on number three also.

If he's got the rotor pointing to the cap post for cylinder #1 to adjust cylinder #1, he's gonna have it right. That's a guarantee that
a) The piston is at TDC
AND
b) both valves are closed because the cylinder is set to fire

Remember that the rotor only goes around once for two revs of the crank.

Barry, you did it correctly.

[Gypsie]

I will presume that everything was proper before you started (ie-that the rotor is properly aligned for being at #1 along with the cam lobes being at the right position for #1 valves to be completely closed). This wasn't a tear down, just a resetting of the valves.

The only cautionary I would have is that when you loosen the valve to reset that you be aware how far out you come. If you get too far out you can let the push rod slip out of the center of the lifter cup. then it will be sitting on the lower lip and when you go to adjust you are actually setting it to be 1 1/2 turns in from that position. When you start it up the rod will likely bounce back into the cup and then you will have a setting that is wonky.


If the sound is really concerning and you have reduced performance go and double check.
Check your push rod position by looking into the tube with a flashlight to confirm that is is in the center of the cup. This will test your contortion skills.
Next loosen the lock nut and back out half turn. test for play at the rocker arm. No play (ie gap)? nuther half turn. and so on. If you find that you have gap before you reach 1 1/2 turns out then you know that you likely had a misaligned pushrod when you started your original adjustment.

when I set mine I use finger tightening to get to 'start position'. then the screwdriver for setting. You can also tell because when you start turning the screwdriver to set the lifter, in the cup it is often much easier to turn than when it is sitting down on the lip of the lifter.
2 cents

[Gypsie]

Well?