Trying to get TDC

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pauly
Posts: 134
Joined: Sat Feb 10, 2007 9:07 pm
State: NSW
Location: Mudgee, NSW

Trying to get TDC

Post by pauly »

I am checking points gap and valve clearance on my grey motor. When getting number 1 cylinder to tdc i line up the mark on the flywheel inside the cover but the rotor arm is not lining up where it should be. I thought the arm should be pointing towards number 1 lead but its pointing more towards number 5. I will post some pics tommorow.
What am i doing wrong ?
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Harv
Posts: 5020
Joined: Mon Oct 08, 2007 2:00 pm
State: NSW
Location: Sydney, Australia

Re: Trying to get TDC

Post by Harv »

Pauly,

It's because the dizzy spins at half crank speed. My guess is that your dizzy is pointing to number 6. Keep turning it around, and you should find a spot where the dizzy points to number 1 with the mark in the window.

The table below may help (ignore the yellow highlight):

Image

If your timing is waaaaaay out (or to double check the process above), You can also verify by popping off the rocker cover and looking at cylinder #6 (the one closest to the firewall). Watch carefully until you can see one of the cylinder #6 rockers rising (and just stopping), and the other cylinder #6 rocker just starting to fall. This is referred to as cylinder #6 “rocking” (i.e. one rocker just finishing and one just starting) and is when cylinder #1 is firing.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
pauly
Posts: 134
Joined: Sat Feb 10, 2007 9:07 pm
State: NSW
Location: Mudgee, NSW

Re: Trying to get TDC

Post by pauly »

I tried harv but no luck, once the mark shows up the rotor is more than halfway along to the next point. Im doing something wrong somewhere.
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Harv
Posts: 5020
Joined: Mon Oct 08, 2007 2:00 pm
State: NSW
Location: Sydney, Australia

Re: Trying to get TDC

Post by Harv »

Have you had the dizzy out? It could be that you have put it back in 1 or 2 teeth out. The can easily jump teeth (when lowered in) if the oil pump tang is not where it needs to be to align with the oil pump.

If the dizzy has always been in, and the car has been running normally, then it is a different story. If it has been running OK, put a timing light on it. See where the dizzy is, then advance or retard it until the mark appears in the window under the timing light (you can always put it back how it was). See how it runs then. It could be that the engine has just been advanced (or retarded) to buggery. Could also be the wrong flywheel for the engine (I suspect this is the case with my FB, that runs just outside the window).

In any case, if all you want to do is find TDC, then use the rocker cover method.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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