Timing mystery

You are to trust the pulley marking, not any of the sharp "v" shaped marks on the inner rim, but the single wider "dimple" on the outer rim. That's your TDC and there's no escaping it. (This is 100% certain with STOCK pulleys. Some aftermarket "degree" pulleys have the degrees etched/painted/whatever WRONG. )

The rotod didn't point exactly to the notch on the distributor body, because the ignition is adjusted to other than TDC as it should be. Like, 7.5 degrees advanced. It's normal. If it DID line up togehter with the TDC mark on the pulley, you'd have ZERO advance. And a lazy angine.

Jan

Thanks for enlightening me Jan. The pulley wheel is quite old and so I can't make out the dimple you mentioned. But I did notice that 180' opposite the TDC I used (the one the rotor arm gave me) a series of markings on the outer edge inner lip of the pulley wheel, a cut and seven smaller ones in a row - the large cut is directly opposite to the mark I used as TDC. Anyway, here's piccy of them: -

But why are these opposite the two v notches on the inner edge? I get the feeling the answer is so simple I'm overloking it! :-/

--Steve

Basically: do not trust the markings on the distributor _at_all. If you = have no clear markings on the crank pulley, it is time to find out where the TDC is exactly.

Approximately you can seek for the TDC by taking #1 cylinder=20 (right side, front cylinder) spark plug out and sticking a pencil=20 inside, then rotating the engine. The TDC is in the middle of section where the piston is in it's topmost position (or one complete rotation off). You can check if it's #1 or #3 TDC by looking/feeling the=20 #1 valves when the #1 piston is most close to the spark plug hole. If both the valves are closed (there is lash), you have #1 TDC.

Repeat: The distributor is no place to look at the TDC. When you have found the correct #1 TDC, you find the place on the pulley. After that you can use the distributor to see, wether you have=20 #1 or #3 TDC when marks on pulley are ok.

Yes, I think I'll check with a pencil down #1 spark plug hole just to confirm I used the right setting and then mark the pulley with paint! All the tappets were tight when I checked them which does not bode well :-(

--Steve

Basically: do not trust the markings on the distributor _at_all. If you have no clear markings on the crank pulley, it is time to find out where the TDC is exactly.

Approximately you can seek for the TDC by taking #1 cylinder (right side, front cylinder) spark plug out and sticking a pencil inside, then rotating the engine. The TDC is in the middle of section where the piston is in it's topmost position (or one complete rotation off). You can check if it's #1 or #3 TDC by looking/feeling the #1 valves when the #1 piston is most close to the spark plug hole. If both the valves are closed (there is lash), you have #1 TDC.

Repeat: The distributor is no place to look at the TDC. When you have found the correct #1 TDC, you find the place on the pulley. After that you can use the distributor to see, wether you have #1 or #3 TDC when marks on pulley are ok.

There at least used to be a weight in the pulley that was crimped in place on the inside of the U shaped channel. The markings you show are result of that crimping, not intentional cuts or timing related marks. Just that the edge was "peened" over the cylindrical, "rod" like balance weight piece.

Jan

Oh ho -- that clears up the ambiguity I had with my pulley. I, too, have a notch on the rear pulley flange and a dimple on the front. The Bentley manual has a pageful of different markings and timings.

Trust the dimple, Luke.

Thanks, Jan.

[snip]

Ok, sorted out the mystery of those markings.

After using a pencil in #1 spark plug hole to find TDC it turns out the left of the two timing marks is 7.5' BTDC and the one on the right is 10' BTDC. I think the pulley wheel is from an earlier F series engine.

--Steve