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MG MGB Technical - 1967 spark plug wiring order
|What is the order of the spark plugs on a 1967 MG midget? I don't have a Haynes manual yet. Looking down at the distributor and numbering #1 - 1.5 O'clock, #2 - 4.5 O'clock, #3 - 7.5 O'clock, and #4 - 10.5 O'clock. Looking at the engine from the side of the distributor and numbering the spark plugs #1 in front, #2 next, #3, next and #4 near windshield. How should the wires be connected?|
|Firing order is 1-3-4-2|
as you look at the top of the distributor:
|Thanks Rick. That's exactly what I needed to know.|
|Craig. Actually, Rick has given the proper illustration for a distributor having a clockwise rotation. (Rotor moves clockwise as viewed from the top.) However, the BMC engines use a counter clockwise rotation. The number one spark plug lead should be at about the two O'clock position. To the left, next firing, is the number three lead at about ten O'clock. Below that, at about the eight O'clock position, is the number four spark plug lead. The number two lead is at about the four O'clock position. |
You may also wish to verify exactly which terminal is actually the number one terminal. Over the years, many engines have been rebuilt and the orientation of the distributor may not be correct. To check, set the timing mark on the crankshaft pulley at top dead center on the compression stroke of the number one cylinder. Then, look to see where the rotor end is pointing. Where it is pointing will be the number one terminal. Les
|Les, let me get this straight. I have heard that my engine has counter clockwise rotation. So I should connect like Rick said, but switch #2 with #3?|
Unfortunately, right now, my starter seems to be bad. It dis-engages as soon as the engine turns over and the engine doesn't start.
Les, what is a BMC motor and how did you know that I have one?
|Craig. The British Motor Corporation (BMC) was the one who produced the A series motor (used in Sprites/Midgets), the B series motor (used in MGA/MGB) and the C series motor (A-H 100-6/3000). Hence, if you have an orginal engine, you have a BMC motor in it. |
As you are viewing the engine from the front, the direction of rotation is clockwise. When viewed from the top (looking from the right, passanger side in US, side of the engine), the distributor rotates in a counter clockwise manner. Thus, if your number one terminal is at about the 2 O'clock position, you will have the number three to the left of it, number four to the left of number three, etc. Might be worth having an assistant crank the engine over while you watch what is happening. That may aid in your understanding of what is happening and what will need to be done. Les
|If it's like an MGB you also need to confirm where the rotor is pointing when No.1 piston (nearest the radiator) is at the top of its compression stroke i.e. both valves closed (rockers loose) while it was rising to TDC. It *should* be at about 2 o'clock, and the cap contact nearest that should go to No.1 plug, but if the drive gear has been inserted incorrectly or the distributor dismantled and assembled incorrectly could be pretty-well anywhere.|
|1-3-4-2 worked! Thank you.|
I'm posting in Midget Sprite forum now. Sorry about the confusion.
|re: Sorry about the confusion. |
Not as sorry as I am...I had a COMPLETE brain fart on that one.
|Yes, connecting in that order will work. As to posting Midget items on the B board, most of us have owned a Sprite or Midget sometime over the years. It was the "entry level" sports car in the BMC family. Many of us B driver's also post on the Sprite/Midget boards. Hence, I do not see any problem, especially since the engine is now started. One cannot argue with success. Les|
This thread was discussed between 31/12/2004 and 01/01/2005
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