Why does the orange Volkswagen Official Service Manual Super Beetle, Beetle & Karmann Ghia: 1970-1979 say to adjust the valves by rotating the crank pulley 90 degrees counterclockwise and all of the other manuals that I have read say to rotate the crank pulley 180 degrees?
Is this a misprint?
Thanks In Advance!
Valve Adjustment Manual Misprint - Help Please!
- Jim Ed
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- Marc
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Re: Valve Adjustment Manual Misprint - Help Please!
90° makes sense if they are referring to the orientation of the distributor rotor, not the crankshaft. Since the distributor rotates at one-half crankshaft speed, 90° movement of the rotor equals 180° movement of the crank/pulley.
Personally I don't bother with removing the distributor cap to see where to position the crank for #1 TDC. Simply rotate the crank until the TDC mark is up, then go below and see whether it's "on" #1 or #3 by observing the position of the rocker arms. If you're on #1, #2 exhaust will be the only valve open on the RH side; if on #3, only #4 exhaust will be open on the LH side....whichever one's ready, adjust its valves and then move on following the firing order, rotating the crankshaft 180° clockwise each time as you go from 1 to 4 to 3 to 2 (or 3 to 2 to 1 to 4).
Personally I don't bother with removing the distributor cap to see where to position the crank for #1 TDC. Simply rotate the crank until the TDC mark is up, then go below and see whether it's "on" #1 or #3 by observing the position of the rocker arms. If you're on #1, #2 exhaust will be the only valve open on the RH side; if on #3, only #4 exhaust will be open on the LH side....whichever one's ready, adjust its valves and then move on following the firing order, rotating the crankshaft 180° clockwise each time as you go from 1 to 4 to 3 to 2 (or 3 to 2 to 1 to 4).
- Jim Ed
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Re: Valve Adjustment Manual Misprint - Help Please!
OK. It makes sense now. I must have been not fully focused when I read that.Marc wrote:90° makes sense if they are referring to the orientation of the distributor rotor, not the crankshaft. Since the distributor rotates at one-half crankshaft speed, 90° movement of the rotor equals 180° movement of the crank/pulley.
Adjusting the valves according to the position of the rotor would be quite helpful to those without a degree ring crank pulley.
- Marc
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Re: Valve Adjustment Manual Misprint - Help Please!
It's not particularly precise - you're probably going to be within ±15-20° of the desired crankshaft position, but that's close enough. But if the distributor was installed incorrectly it'll cause all kinds of confusion for someone who isn't savvy.Jim Ed wrote:...Adjusting the valves according to the position of the rotor would be quite helpful to those without a degree ring crank pulley.
Every stock pulley has at least one timing mark (if not a TDC, there's a 5° ATDC and/or a 7½° BTDC at minimum - again, close enough for the task) radial lines and a couple of holes in the face. More than enough reference points IMO to estimate a half-turn without a degree wheel, but some still like to make a paint mark 180° from TDC.