MGA rotor pointing north

[Sopwith_Camel]

ok I bought a MGA 1500 over the winter and have been swaping it to neg earth.
now its time to get it to run. I have a new optical dissy but when i put the car to Top Dead Center the Rotor points North or 12:00 insted of at cylender one.

i static timed it to about 8 degrees of advaced but no luck, the timing lightt was saying it was past TDC. I have tryed advanicing it but no luck. I have spark.

do i need to pull the cam shaft and make sure the rotor points at cycinder one? and why would it matter?

steve

 

[YakkoWarner]

With most distributors you can set it into the engine pointing in a wide variety of directions - lift it out, move the rotor (slightly past) where you want it to point and set it back in, the rotor willl probably move slightly as the angle-cut gears mesh...if it doesn't point where you want - lift, change, repeat.

In reality it is not a requirement for the rotor to be pointing at #1 cylinder - just common practice. As long as whichever connector on the distributor cap the rotor is pointing at has its wire going to the #1 cylinder it should work, and of course the others following the firing order as the rotor moves.

Also make sure you are at TopDeadCenter of the compression stroke - TDC occurs twice for each cylinder (during compression and on the changeover from exhaust to intake). If you are 180 degrees off it will never run.

 

[Joe Reed]

The MG distributor will only go in one way. You can't install it 180 out. in order to reorient the distributor the drive gear must be removed and reinstalled in a different orientation. Maybe the manufacturer of your new distributor didn't match the configuration of the original...

 

[DrEntropy]

Before you go tearing into the engine: With the dizzy out and the engine static set to TDC #1 firing position (both valves totally closed), you should see the offset slot as shown in this illustration. That would indicate the dizzy jack-shaft & likely the camshaft are in proper orientation.

 

[Sopwith_Camel]

ok ill recheck the values to make sure im on the right stroke.

 

[Sopwith_Camel]

It Runs!!!
ok so i popped off the valve cover and slowly watched the valves go through their sequence.
so with the Rotor point due south at top dead center it started making the right noises, and slowly i advanced it till it ran.

steve

 

[YakkoWarner]

That'll do it!! Glad you got it straight.....

 

[DrEntropy]

It Runs!!!
ok so i popped off the valve cover and slowly watched the valves go through their sequence.
so with the Rotor point due south at top dead center it started making the right noises, and slowly i advanced it till it ran.

steve

Good to learn you have a running engine, but apparently someone was into it before you got it. "traditionally" the rotor in BMC engines would be at about the 1 o'clock position to fire the #1 cylinder.

But as YakkoW said: as long as #1 wire is where the rotor points to fire #1 at TDC compression stroke (plus whatever timing advance), it'll run.