Use of rotor during valve adj

moosthuizen · moosthuizen's Garage

Hallo,

I'm planning ahead to my 1st valve adjustment. So I did a lot of searching and a lot of reading.

As one begin with cylinder #1 and the puley at TDC (Z1), I realized that the rotar would at that point, be pointing at #1 on the distr cap. Am I correct?

Assuming I am correct, I thought of looking at the rotar for the remaining cylinders as well. Once finished with #1, one need to rotate the engine 120*(if I recall correctly), in order to work on #6 cylinder, and so forth.

Wouldn't the rotar then also be pointing at #6 on the distr cap? Thereby making it easy to know if you've turned the engine far enough.

My Q is thus whether the position of the rotar is any help while adjusting the valves?

Marius
'80 911sc

qikcpa · qikcpa's Garage

i just use the marks on the pulley. They are at 0/360, 120 and 240. the only time i look at the rotor is to confirm at tdc for #1.

john_colasante · 06-02-2004, 05:15 AM

For each full rotation of the distributor there are two rotations of the crankshaft. You must adjust the valves for a specific cylinder only when the distributor is "pointing at it". This is when TDC indicates both valves fully closed. So yes, it is a useful thing to know.

Rot 911 · 06-02-2004, 05:23 AM

I use the rotor to confirm that I am indeed at the right cylinder for adjusting, but that is only after I make sure I have the correct mark lined up on the pulley.

gerard vaglio · 06-02-2004, 06:59 AM

One little trick that makes things easier is to paint the three marks on the pully with nail polish ahead of time. This makes the marks much eisier to find and prevents confusion with the marks that are intended for vacume advance ( the 2 marks that follow TDC).

I paint Z1 white and the other two marks red but there are so many delicious colors to choose from that can really flatter the pully and make it appear much younger.

Hugh R · 06-02-2004, 09:06 AM

Take your time, you can do it, you'll be adjusting them by feel only on the top. Do the bottom one first, so you can see what's going on. Its very difficult to reinsert the feeler gauge after they're adjusted. Heck, its difficult to insert the feeler without loosening the nut first. If its your only car, start on Saturday. Give each tappet a calibrated "shake" afterwards to double check that you don't have any tight ones. Its a right-of-passage, good luck.

911pcars · 09:14 AM

Checking the rotor relationship with the cap is one way to verify the cylinder to adjust is at TDC-ready to fire; so is marking the crank pulley.

You can also observe when the heel of the cam (the low point of the eccentric lobe) contacts the rocker arm which indicates the valve is completely closed and ready to adjust (cylinder does not necessarily have to be in the firing position). This is easily accomplished by connecting a remote starter switch to the starter solenoid. "Bump" the engine around with the switch until the desired rocker/heel is in the correct position, then adjust it. You can do this while under the car WITHOUT rotating the crank by hand, knowing where the rotor is pointing or matching marks on the crank pulley - adjust all the left bank valves, then adjust the other bank (you don't have to adjust valves in firing sequence).

Hope this helps,
Sherwood

gerard vaglio · 06-02-2004, 10:30 PM

Zen and the art of valve adjustment!

I view valve adjustment as a series of adjustments. Here is how I look at it.

The first time I adjust my valves I sometimes still have tapping. First valve adjustments usually result in adjustments that are a little too loose, which is much better then too tight by the way. Too tight can burn a valve.

First, do your valve adjustment to the best of your ability. When your satisfied button everything up and start the car. If your not happy with the sounds see if you can identify which side of the engine is noisy. To readjust the top left or right simply take off the valve cover and adjust three intake valves at a time. You'll need to rotate the pully accordingly. Be sure to grab the rocker arm and move it up and down to simulate how they would move if the engine were running. You will slowly get a feel for how much movment creates a tapping sound. You want movment - but very, very little.

To do the exhaust valves, the ones on the bottom, jack up the side of the engine you'll be working on to keep the oil from running out of the engine. This saves you the trouble of draining the oil all over again.

After I adjust my valves the following weekend I will readjust three more untill I get the sound I want. This process allows you to really learn how to adjust valves rather then just going through the motions.

If you decide to take this unusual approach I must warn you to save your new gaskets for what you think will be the last time your going to open the valve cover to keep things from leaking.

This approach also takes the stress out of the proceedure because you don't have to be perfect the very first time. It also allows a novice to get very good results.

moosthuizen · moosthuizen's Garage

Thank you all.

Not only do you respond with such great knowledge, but as much enthusiasm. I admit to being cautious, but with all the info and your help at my disposal, I am looking forward to next weekend when I will be doing the adjustment.

Marius
'80 911sc