1957 distributor cap #1 position

[Ward 57]

I was having all kinds of ignition issues. Replaced everything but the plug wires. I finally did but when done it wouldn't start. $300 later after the tow and figuring out what was wrong. I assumed that a makers mark on the top signified #1. Plugged in the leads in proper order from that point. But it turns out that was 180 deg. off. When cranking the TDC mark lined up and the rotor was pointing at a contact in the cap with the maker's mark above it.. I forgot my old knowledge that the crankshaft turns twice for one revolution of the distributor.
Back in the 70' the caps came with a mark signifying #1 I was assuming such. Somebody else here ran into the same issue. Why don't they identify #1 on top of the cap?

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[jimntempe]

I was having all kinds of ignition issues. Replaced everything but the plug wires. I finally did but when done it wouldn't start. $300 later after the tow and figuring out what was wrong. I assumed that a makers mark on the top signified #1. Plugged in the leads in proper order from that point. But it turns out that was 180 deg. off. When cranking the TDC mark lined up and the rotor was pointing at a contact in the cap with the maker's mark above it.. I forgot my old knowledge that the crankshaft turns twice for one revolution of the distributor.
Back in the 70' the caps came with a mark signifying #1 I was assuming such. Somebody else here ran into the same issue. Why don't they identify #1 on top of the cap?

Because there is no guarantee that is the #1 plug position., It's only positioned there if the last guy who put the distributor in made sure to line it up. There is nothing special about that spot, you can install the distributor so the number 1 plug is at any of the eight positions. The only thing that is mandatory is that where ever plug 1 is, the rest have to follow in the designated firing order.

 

[biddle]

Since your post is about the #1 position on the Distributor cap, I have added this to your subject.

 

[55blacktie]

First of all, the distributor cap can only go one one way. Looking at the installed cap from the top, #1 is at 1 o'clock. Going clockwise, starting with 1, the order is 1, 2, 7, 3, 6, 8, 4, and 5 is at 12 o'clock. Looking at the engine from front to rear, the left bank cylinders are 1, 2, 3, and 4. Again, looking from front to rear, the right bank cylinders are 5, 6, 7, and 8.

 

[55blacktie]

If you look at the bottom edge of the cap, you will find a notch; that notch allows the cap to clear the left retaining screw for the vacuum advance pot. My cap also has "1" cast into it.

 

[Ward 57]

First of all, the distributor cap can only go one one way. Looking at the installed cap from the top, #1 is at 1 o'clock. Going clockwise, starting with 1, the order is 1, 2, 7, 3, 6, 8, 4, and 5 is at 12 o'clock. Looking at the engine from front to rear, the left bank cylinders are 1, 2, 3, and 4. Again, looking from front to rear, the right bank cylinders are 5, 6, 7, and 8.

That is what I assumed as the maker's mark was at 1 o'clock right by the vacuum advance and just to the right of the clamp. I had read that #1 is next to 'A' clamp Everything seemed to line up. When I pulled the old wires out of the cap I didn't pay any attention.
I used pre-cut and assembled correct wires labeled 1-8 and wondered why the #1 wire was kinda short and stretched tightly over the cap. I just thought maybe they were wrongly assembled. After re-clocking the wires they all laid out properly with #1 shortest wire next to the clamp closest to the firewall and back of the block which tells me the dist. shaft is properly clocked.

 

[Critterpainer]

When it comes to tailored (fully finished plug wires) if the distributor is not clocked correctly to the engine then often times the result is that the wires don't fit correctly and cannot be properly routed. This is especially true on many V8's. Some higher quality shop manuals will show the proper position of the distributor in relation to the engine.
Ward I know that your distributor is clocked correctly to the engine so this should not pertain to you.

 

[Ward 57]

When it comes to tailored (fully finished plug wires) if the distributor is not clocked correctly to the engine then often times the result is that the wires don't fit correctly and cannot be properly routed. This is especially true on many V8's. Some higher quality shop manuals will show the proper position of the distributor in relation to the engine.
Ward I know that your distributor is clocked correctly to the engine so this should not pertain to you.

My problem was that I miss identified the #1 position in the cap. My assumption was 180 deg. off and I didn't look around enough to verify the #1 position. it's not well documented, just the firing order.

 

[jimntempe]

Hard to tell from the comments if people are agreeing with any particular other comment. As far as the #1 position, it can be anywhere if whoever installs the distributor pays no attention to where the rotor is pointing when they slide the distributor into the block and hence the lower gear into it's mating gear. That is because the rotor it attacked to the shaft which is attached to the lower gear and that gear can engage with it's mating gear no matter what direction the rotor is pointing. As Ward and Critter pointed out, if you don't line it up when dropping it in you wind up with the "wrong" wires having to go into the "wrong" holes and then what was a bunch of properly set up wires are no longer properly set up, one that was supposed to be able to plug in on the passenger side might have to be stretched over to the drivers side and winds up 3 or 4 inches short.

 

[Critterpainer]

On the Ford Y block the vacuum advance fitting should point to the left side of the engine parallel to the back of the left valve cover

 

[Ward 57]

Well after having my car as long as I have I thought I could plug & play. I never did the mechanical determination of TDC. Just visual, forgetting the dist. turns 1/2 the rotations of the crank.
I apparently was with my remote switch was looking at the top of the exhaust stroke and not TDC. 180Deg off.

 

[paul5456]

Having both valves loose on # 1 cylinder is a good way to tell that the engine is in the proper position for the initial setting of the distributor timing (the # 1cylinder is on the compression stroke and the pointer is at TDC ) . Usually, the #1 hole in a cap is where the lower clip goes. However, as stated above, as long as the wires are in the correct sequence it does not matter where the #1 wire goes as long as the rotor is in the correct position

 

[55blacktie]

Install the wires between the plugs and the cap in the order I provided. The cap, with wires attached, doesn't need to be installed until after the distributor is installed. Looking at the installed distributor from the front of the car, the vacuum advance should be on the right of the distributor and close to the intake manifold. The rotor turns in a counterclockwise direction. If the distributor is properly installed, the rotor should be lined up with #1 on the cap when #1 piston is at top dead center. Make sure the distributor is fully seated.
To find #1 TDC on the compression stroke, pull the valve covers. When both valves for #1 have lash, and both valves are tight (no lash) on #6, you have found #1 TDC on the compression stroke.

 

[doug7740]

I think these two articles will help.







doug7740
1955 Thunderbird Blue

 

[zeroroadkill]

Having been fooled before now I install the cap first then remove & replace the wires one at a time

 

[Ward 57]

Having been fooled before now I install the cap first then remove & replace the wires one at a time

The way the wiring harness is routed around the block it's almost impossible to trace the wire around the block and I thought I had #1 located. After the fact I could have just put a multi meter on the known #1 and traced it to the cap before pulling all the wires out at once and all would be fine. But I didn't and ended up 180 Deg. off.