3.2L Cam Timming

[scarceller]

I just purchased a 84 911 Carrera with modified 3.2L. This engine has Web Cams grind 20/21 and the spec says Intake opens 6deg before TDC it further states 'Valve timing is to be done with zero valve lash @.050 inches of valve lift', does this mean that at 6deg before TDC the intake valve (cyl #1) should be opened .050" if the valve lash has been set to 0?

I am trying to confirm from the specs for grind 20/21 that these are the cams in the engine. The prior owner refered to these cams as Web Cam 'Sport Cams' but this means nothing other than they are non stock web cams.

Any tips on howto verify these cams with a dial indicator would be helpfull.

[2.7RACER]

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"I just purchased a 84 911 Carrera with modified 3.2L. This engine has Web Cams grind 20/21 and the spec says Intake opens 6deg before TDC it further states 'Valve timing is to be done with zero valve lash @.050 inches of valve lift', does this mean that at 6deg before TDC the intake valve (cyl #1) should be opened .050" if the valve lash has been set to 0?"
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Answer: Yes

American cam makers differ from European makers in that American cams are specified at 0.050" initial lift, whereas European cams, (Porsche), are specified at 1.0mm lift (0.03937").

Using the opening degree numbers and closing numbers for the intake, just check the cam with a degree wheel.

Search "degree wheel" for a printable usable wheel.

[scarceller]

Originally posted by 2.7RACER
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"I just purchased a 84 911 Carrera with modified 3.2L. This engine has Web Cams grind 20/21 and the spec says Intake opens 6deg before TDC it further states 'Valve timing is to be done with zero valve lash @.050 inches of valve lift', does this mean that at 6deg before TDC the intake valve (cyl #1) should be opened .050" if the valve lash has been set to 0?"
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Answer: Yes

American cam makers differ from European makers in that American cams are specified at 0.050" initial lift, whereas European cams, (Porsche), are specified at 1.0mm lift (0.03937").

Using the opening degree numbers and closing numbers for the intake, just check the cam with a degree wheel.

Search "degree wheel" for a printable usable wheel.

Doug,

Thanks for the tips, I have verified that the cams are Web Cam grind # 20/21. Here is how I did it: From the 20/21 cam specs it states that initial valve lash must be set to .000" (no lash) then at 6deg before TDC the valve should be opened .050" and normally you should check this with a degree wheel on the crank and a dial indicator on cyl #1 intake valve. But as you know it's nearly impossible to put a dial indicator on this valve with the engine in the car. Since I'm only looking to verify that these are the cams in the motor I really don't need to be as accurate as if I were timing the cams, so what I did is set the valve lash to .050" (set the lash equal to the lift I'm looking for) then start turning the crank till it starts to approach 6deg before TDC on of intake stroke for #1 cyl, as I approach the 6deg mark the rocker starts to move and picks up the .050" lash gap and right at the 6deg mark the rocker's elephant foot made contact with the valve, this confirms the cam profile is 20/21. Also the specs state the cam should close the valve back to the .050" at 52deg after BDC (or 132deg mark on the degree wheel) so I continued through the intake valve stroke and at 130deg mark the the elephant foot starts to lift away from the valve stem.

So if you don't have or can't get a dial indicator on your valve this procedure seems to work for quickly testing cam timming and cam profile in an engine that you may have very little to NO history on. I would NOT use this procedure for setting cam timing but for ball parking settings and cam profiles it seems to work.

Thanks for your help.

[2.7RACER]

Great thinking. You have demonstrated a simple method to evaluate a cam.
It is very easy to get lost in the American vs European cam specs.
Your method goes past all that in it's simlicity.