Distributor help

Twinmustangs · Apr 29, 2018

My Son in Law removed my distributor helping me prime my new oil pump on my 66 mustang 289. Problem is he is busy and I am stuck putting it back without him. The rotor is pointing at the spot on the block we marked before we pulled it. when I put the cap on I see some diagrams showing the cap should be put on with #1 at 1pm and I see other diagrams show #1 should be at 12 pm looking straight back at the firewall. Do I need to find TDC and put the rotor on at TDC or put the rotor back where it was when we took it out and place the distributor cap on according to a diagram found online showing the cap order on small block fords?. I have not used the starter to bump over the engine or turned the crank since we pulled the distributor, the engine has not moved.
Thanks

tos · Apr 30, 2018

No it does not have to necessarily point at one or the other as long as you can adjust your timing properely. When re-installing the distributor, you can be off a tooth clockwise or counter clockwise which is no problem if you can rotate the distributor enough to adjust the timing. So if you put it back just like it was when you removed it and its running ok then you're good to go. The thing you want to do is look at the diagram and compare where the clips are positioned that hold your cap on and figure out where your number 1 plug plugs in to the cap in relation to the clip notch on the distributor cap.

Twinmustangs · Apr 30, 2018

Can I just Find TDC and put the cap back on with the #1 on the cap lined up with the rotor, will that get me there?

tos · Apr 30, 2018

Yes, provided you know how to find tdc. Just rotating the engine to line up the marks on the balancer isnt good enough. Your crankshaft makes 2 revolutions to one revolution of the cam so its easy to be 180 degrees off. Pull the number 1 spark plug and feel for pressure as you slowly rotate the engine by hand. Stop when you feel the pressure then start rotating again till the timing marks line up. Then you can set your distributor as you described. This should allow you to fire it up but then you'll need to time it.

Twinmustangs · Apr 30, 2018

I know there are 2 strokes for every 1 stroke of the cam. How will I know the difference between the compression stroke and the other stroke (exhaust? )

tos · Apr 30, 2018

Because of the pressure difference. Put your finger tight against the spark plug hole (#1) and as you rotate and the engine comes up on tdc of the compression stroke is when you will feel that pressure. It will blow air out no matter how tight you hold. You wont feel that pressure on the exhaust stroke because the exhaust valve will be open on that stroke relieving that pressure. During the compression stroke both valves are closed and the only place for the air to go is out the spark plug hole.

Twinmustangs · Apr 30, 2018

Thanks that helps. Using a finger how would you find when the piston is at its highest point? Is the Highest point considered true TDC?

tos · Apr 30, 2018

You are only using your finger to feel when you are on the compression stroke. Then you can take your finger off and rotate to line up tdc.
Yes highest point (true tdc) would be when your marks line up to the tdc hashmark (or zero mark) on your balancer.

rbohm · Apr 30, 2018

Op you are way overthinking thing here. so stop what you are doing and just put the distributor back in where you had it. you have already marked wher the rotor needs to point, and once the distributor goes back in at that point, you are at least close to the proper timing. so put the distributor back in where it needs to be and get the engine running again, no fuss, no muss, no trying to find number one TDC on the compression stroke, and hoping you get it right, only ti find you are 180 degree out and the engine wont run at all, yadda yadda yadda. seen that far too many times over the years. it even happened with a friend of mine, even after i told him what he needed to do when replacing the distributor in a running engine. he choose to ignore my advice, and find TDC on number one, and ended up 180 out.

Twinmustangs · Apr 30, 2018

When my son in law pulled the distributor he only marked where the rotor was pointing. I have put the distributor back in at the same place, I am just not sure where the distributor cap was. He said the small bolts (MGD distributor) were horizontal to the engine, that leaves a great variance I think. The rotor is dead on where it was but guys tell me I need to find TDC to make sure the cap is on correctly????. Another question, If I use a piston stop to find TDC, most are adjustable. Where do I adjust it so that it strikes the piston at the highest point?

tos · Apr 30, 2018

If you haven't rotated the engine any since you pulled the distributor then you wont need to find tdc. Like rbohm said you can put it back in and as long as your cap position is close you should be able to start it. If it doesn't start then rotate it a little in either direction while cranking until it does. I probly should have asked this first. Did you mark the position of your rotor on the engine or the body of the distributor?
You don't need a piston stop. Lining up your marks will get you right where you need to be.

Twinmustangs · Apr 30, 2018

I marked the rotor direction on the exhaust manifold. I have not turned the motor at all, I just primed the oil pump with a drill.

tos · Apr 30, 2018

look on the base of your distributor and see if you can see where the clamp marks are. If so then position it back to that point and you should be good. Otherwise see above.

Twinmustangs · Apr 30, 2018

Thanks guys, it looks like my project continues after work.

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