I'm replacing my old electronic ignition distributor with a new one piece, I've already marked "top dead center" and removed old distributor. How accurate must the rotor pointer alignment be for the #1 cylinder/plug, I have it pointed relatively close, but not dead on! Engine: 327cu in
The rotor won't be pointed exactly at the #1 tower, it will lead it a bit because of the timing. "One tooth off" is how some describe the problem when it isn't quite where it needs to be. Moving the distributor body to compensate will work, but only to a point, as often it will start hitting things, or things attached to it will anyway - vacuum advance canister for example. Another alternative often seen is moving the plug wires, making a different cylinder the new #1. At the cap the #1 cylinder is an arbitrary designation, the distributor doesn't care so long as they are all in the correct firing order. It's best though, to keep everything according to Hoyle. It's easier to troubleshoot and less confusion.
There are 2 'Top Dead Centers', I take the valve cover off and watch the intake valve close, bump the motor until you see the timing mark and drop distr in with rotor pointing at #1 (I put a mark on the distr itself where #1 is on the cap), with distr in the hole continue to bump motor until it falls into the oil pump. I then bump it around again when intake closes and the timing marks line up I set the distr so the rotor aligns with #1 on the cap and snug the distr down, install cap and fire it up. Done.
While watching the damper rotate, put a finger over the number one spark plug hole, when the pressure inside the cylinder pushes your finger out and the timing mark comes up you will be where you need to be to fire number one.
Of course, at least when re-installing the same distributor it's wise to simply mark the body of the distributor before removal with a scribe or paint marker or something to indicate the correct rotor positioning. After a while ya get good at it. Thanks to a bazillion web pages on the subject the first time I installed a new distributor it fired right up, and a bunch of times afterwards. Make sure the distributor gear is compatible with the type of cam you're using, btw.
Apparently my first attempt at lining up the rotor to the #1 cylinder was close enough! It fired up on the 1st try! Thanks guys for all your comments and suggestions! It's always appreciated!
Once you have the engine on compression stroke (top dead center )you can actually put number one wire anywhere on the cap with rotor , but make shure have the fireing order corect order, it does not have to be @ 4 or 5 oclock position 18436572 unless 4 7 swap
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