SBF Timing Question

TonyMadrid · #1 (**permalink**) 09-01-2003, 06:58 AM

351W with an MSD Ignition System; what is the correct, preferred, or best way to cold time the ignition.

Being an old points guy, used to set #1 at TDC and make sure that the points were open, then where the rotor lined up that became the terminal for the #1 plug and just followed around the firing order.

In an MSD Dist. being there are no points, how do you make sure that the dist is set to fire?

Tony

HighPlainsDrifter · #2 (**permalink**) 09-01-2003, 08:40 PM

Tony,
Hi, I take out # 1 plug and turn engine over with a wrench .place finger over spark plug hole,when air stops coming out you are at top dead center and ready to fire. Check dist to see if rotor is pointing at # 1 plug[dist can be 180 out of phase]
Turn engine back slightly to set timing marks to 12 degrees before top dead center, then set dist so rotor is just touching #1 plug.rotor turns counterclockwise in a ford.This should be close enough to start engine.
Perry.

TonyMadrid · #3 (**permalink**) 09-01-2003, 09:33 PM

Hey Perry,

I have no problem getting #1 to TDC, what's confusing me is that I've always worked on distributors with breaker points. With points you would always want to be sure that the points are on a high spot on the dist cam/lobe so that the points would be open. What gets done with an MSD distributor that has no points?

Also, as far as being 180 degrees out of phase, would it really matter as this is a new build? Or, is there a particular distributor plug wire terminal that I should locate as being plug #1? I looked at the dist. cap and there were no markings to indicate #1. Or, is there a terminal, on SBF's that is commonly used as #1 for ease of routing the rest of the plug wires? Should #1 be to the front side or rear of the distributor, or does it really matter as long as the correct firing order is followed?

Tony

HighPlainsDrifter · #4 (**permalink**) 09-01-2003, 10:29 PM

Hi,
The #1 plug wire is usually on the front pass side of the dist cap as it is usually the shortest wire,but as long as the firing order is right it can go anywhere.
The out of phase I refered to;
The cam turns 2 times or 720 degrees of crank revolution for one complete firing sequence. So you need to check that # 1 cylinder is at TDC on the firing stroke,compression then both valves cosed.
# 1 will then fire ,go down on power stroke, then piston up on exhaust stroke to TDC again[exhaust valve closing and intake opening-this is the cams overlap, both valves open slightly ] If you line up dist and rotor now it will be 180 crank degrees out of phase and engine will backfire into intake and carb.
Now the piston goes down on intake stroke [intake valve open,exhaust closed.] and up on compression stroke[intake valve closed] to TDC and should fire now, both valves closed. This is where the rotor should point to # 1 plug.
The MSD fires multiple sparks for 20 crank degrees, so the timing looks slightly retarded,I think MSD says you can add 4 degrees more advance to the static timing. I run 16 degrees initial advance.
Perry.

Mr.Fixit · #5 (**permalink**) 09-03-2003, 03:31 PM

Make sure #1 piston is at TDC of compression stroke (blows air out sparkplug hole)

Mark base of distributor with a magic marker showing where #1 terminal is located. Line up rotor with mark on dist base.

This should be close enough to get it to fire, then set it correctly with timing light ASAP.