OldIHC

I have two favored ways of finding TDC. Both require using a compression gauge with a flex hose and plug-hole adapter. Both ways need to have the Schrader valve removed from the spark plug hole adapter.
1) Adapt a vacuum/pressure gauge to the modified compression gauge flex hose. rotate the engine, with a socket and flex/breaker bar at the front crank pulley until the gauge shows pressure. Now reverse the rotation of the engine until the gauge shows vacuum. Once again rotate the engine slowly until maximum pressure is showing on the gauge. This is TDC.
2) I like to adapt a clear plastic hose to the compression test hose. Put one end of the hose into a bucket of water that is set on the floor. Rotate the engine CW until the water rises to the maximum height in the clear hose and just starts to fall. This is TDC.
The timing sequence does not have to be off TDC on number one cylinder. Rather than wrestling the engine around, I like to start with the cylinder the distributor rotor points toward. Use the same method to find TDC on the alternate cylinder. From there a person can break into the Zundfolge (firing order) Standard 1-5-3-6-2-4 or 6-2-4-1-5-3 as the alternate starting point. Or 4-1-5-3-6-2 etc.
Sometimes it is necessary to place the distributor into a different orientation because of a conflict with an external vacuum advance. This could place number one position of the distributor rotor in a different position. Work with what you have and know.

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but as CB posted it could be anywhere now since oil pump was R/R,

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Thus, the reason to "time" the oil pump when reinstalling: So the next guy to work on the ignition system finds the "No1 position on cap" where it's supposed to be.

I've been rebuilding engines for a very very long time and have run into distributors "set at any position", this goes against the Laws of Nature in my opinion!

M

I wouldn't pull the pan to "fix" what isn't broken, just move on from there. If I had the engine on a stand and building I would make every attempt to get it "right" on the build.
It makes no difference to the engine, it is only aesthetics.

GRD oil pump is exterior mounted, don't have to pull the pan on a GRD

2 bolts, slide it out of side of block,

Dumb me I should know that on a flathead, wasn't thinking.

Don't feel "dumb".

I have had to remove an oil pan to reset the oil pump drive correctly after I had an engine (not IHC) in the chassis!


I did another one but that one was the customer's fault. He wanted to assemble the engine we machined. That one wasn't in the chassis.
It cost him a lot, he insisted it was our fault! Until I showed him how.

That's the ONLY mistake I ever made!

Ordered a portable video inspection camera to look into the No.1 cylinder and watch the intake valve position and set my No1 position on the distributor cap using that method - seems simplest. Just got to wait for it to come in, then I will give it a try.

Remember, my distributor is frozen stuck and I cannot move it, so no pulling it out and rotating it to any new position at this time.

Well, you are going to have to get it unstuck or you will have no vacuum advance at all, on these the whole distributor turns with the vacuum, not the breakerplate.

CB was talking about the engine not caring about rotor placement, it being aesthetics...
There ARE some exceptions...I'm being smartass, again..
"Odd-fire" Buick V-6 is one. Number one has to be number one on the cap. The reason being is that the firing sequences are not evenly spread out. It has to do with shared crankpins on the crankshaft...and the angle of the V.
Later, "Even-fire" V-6s have evenly-spaced distributor towers, odd-fire does not.
For a time "odd-fire" Buick V-6s were transplanted into everything, they were the "flavor of the moment" forty years ago or more. My point is that you still run into them in the weirdest places.
Another case (supposedly) is air-cooled VW. Number four (?) cylinder is slightly retarded. Gotta install dist correctly.
HEI "big cap" w/coil in cap is an instance where distributor orientation is irksome unless the distributor is installed correctly. The cap should be more or less "parallel" to the firewall.

mrjim2017
When doing timing work on engines a hand held remote starter switch is a good tool to have. You can bump the starter around from where you need to.
one can be made from two pieces of wire and a 20 amp horn button.

https://www.harborfreight.com/12-volt-r ... 35448.html

Harbor freight not recomended its just an example.