Breakthrough in valve adjustment

[Germain]

Hello everyone. I would like to share with all of you a breakthrough I came across. I just did a complete valve adjustment in under 30 minutes (jacking time not included). Basically its the same procedure as the articals listed, but determining when to measure the valves is differant.

As we all know we have 4 stroke engines. They make a Exhaust-Intake-Compression-Power. Since the Exhaust and Intake valves are closed during the Compression and Power stroke, you can measure the clearance anytime during that cycle. So if you watch the two valves as you rotate the engine you will notice that one acuates (exhaust), then the other (intake) starts to open, then exhaust valve closes and intake one opens fully then closes. When both have closed you can take your measurement.

No needing to know where TDC is, no remembering cyl numbers. Just look and do.

Now the reason I am posting this here is to see what you guys think. Any reason this won't work?

Open for input.

Kevin Germain

[John Rogers]

The main reason not to adjust valves this way is because the cam designer sets the clearances at TDC so that there will be the correct clearance at normal operating temp and at the desired RPM since the lifter may actually be ramping up on the cam lobe. If you adjust the valves as you describe the clearances may be to small and burned valves could result. Since you have already done this, did you notice how quiet the valves seemed to be, I had a neighbor that did the same thing and he immediately said "wow, sure is a quieter engine now...". Good luck.

[Germain]

After I did this, went through and found TDC and remeasured all my gaps. This involved rotating the engine. They were all correct. A cam should be perfectivly round. If its not, it should be very very close.

[Dave at Pelican Parts]

I have tried this several times on my motor. All I can say is DON'T DO IT!

The cam base circle may really be a circle, but there is more going on than just the cam. There is deflection in the rocker stands, and probably more than that.

Every time that I have set my valves correctly (at TDC), then checked the clearance at a valve when its neighbor on the same cylinder was rocking, I have found the clearance to be larger than specified. So, if I had set my valves by using the "intake open, adjust exhaust" method, I would have set the valves to be too tight.

If you don't like trying to find TDC to set the valves, you can try Jim Thorusen's method. What you do is adjust the OPPOSITE valve from one that is rocking. When the front-left exhaust valve is open, you adjust the front-right exhaust valve. This is due to the way the VW cam works.

I still prefer the "stock" method--find TDC for each cylinder and adjust there. I have put paint-marks on my flywheel, so determining TDC can be done from the bottom of the car.

--DD