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spark plug leads

Posted: Sat Feb 13, 2010 5:47 pm
by cadetchris
finished rebuilding my engine, but i have forgotten which lead goes from the dizzy to which plug.

anyone care to enlighten me?

Re: spark plug leads

Posted: Sat Feb 13, 2010 5:50 pm
by aupickup
firing order is 1 3 4 2 it is stamped on the manifold

Re: spark plug leads

Posted: Sat Feb 13, 2010 5:56 pm
by cadetchris
that i know, but which lead goes to which plug? do i go clockwise or anticlockwise around the dizzy cap? and which lead is one?

Re: spark plug leads

Posted: Sat Feb 13, 2010 5:58 pm
by aupickup
ah ok sorry

you go anti clockwise

Re: spark plug leads

Posted: Sat Feb 13, 2010 6:13 pm
by mike.perry
You just have to work out which one is No1. Take the distributor cap and rocker box off and turn the engine over until no 1 piston is at the top with both valves closed, the rotor arm will point to no1 HT lead position. If you get it wrong you will be 180 deg. out

Re: spark plug leads

Posted: Sat Feb 13, 2010 6:21 pm
by aupickup
make sure no 1 is on the firing stroke as well

Re: spark plug leads

Posted: Sat Feb 13, 2010 6:49 pm
by dalebrignall
with the number 1 piston at tdc the rotor arm ahould be pointing to about 7 o clock

Re: spark plug leads

Posted: Sat Feb 13, 2010 7:47 pm
by bmcecosse
Can be pointing anyhwere! It is - as said - essential the cylinder is on it's firing stroke! But - not to panic - just stick the leads on - if it doesn't start - move them all round one - and again until it starts!

Re: spark plug leads

Posted: Sat Feb 13, 2010 7:49 pm
by simmitc
The position of the distributor will depend on how the drive gear was replaced in the engine. Easiest way to find position of number 1 is:
(a) Set points gap.
(b) Remove all spark plugs.
(c) Put your thumb over the number 1 spark plug hole.
(d) Slowly turn the engine over with the handle until you feel number 1 coming up to compression.
(e) Continue turning the engine until the timing marks show that No 1 is at approx 4 degrees BTDC.
(f) Set the timing by moving distributor / vacuum advance/retard settings.
(g) Check position of rotar arm, which will be pointing at No 1 plug.
This avoids the need to remove the rocker cover to check that valves are closed, and allows for any add assembly positions.
Good luck.

Re: spark plug leads

Posted: Sat Feb 13, 2010 11:25 pm
by cadetchris
ok,

in order for this to make a little more sense to my brain. let me put this down on "paper" so it makes sense.

engine partially rebuilt, main crank bearings not touched and timing chain replaced after reassembling engine.

however, dizzy removed and cleaned, thus timing should be still intact.

looking at the dizzy cap, going in an anticlockwise direction, top left cable to number one pot, bottom left to number 3 pot, bottom right to number 4 pot and top right to number 2 pot. currently rotor arm is pointing at about 11 o'clock, with number 1 pot tdc. (set up according to manual)

Re: spark plug leads

Posted: Sun Feb 14, 2010 10:47 am
by bmcecosse
Aye - but is it on the firing stroke ?

Re: spark plug leads

Posted: Thu Feb 18, 2010 6:06 pm
by cadetchris
right, so just a wee update.

to quote from the morris minor bible (workshop manual)

"section CC.7

static ignition timing

1. turn the engine until n o. 1 piston is at t.d.c on its compression stroke. this can be effected by turning the engine and observing the valves.
when the valves are *rocking* (i.e. exhaust just closing and inlet just opening) on no.4 cylinder.
no.1 piston is approximately at t.d.c. on its compression stroke. if the engine is now rotated until the groove in the crankshaft pulley is in line with the pointer on the timing cover or the dimples on the crankshaft and camshaft gears are in line the piston is exactly t.d.c

2. set the contact breaker points to 0.14 to 0.16 in, (0.36 to 0.40mm) when fully open

3. insert the distributor into its housing, and engage the drive dog with the drive shafts slots (both of which are offset) by slowly rotating the rotor arm

4. fit but do not tighten the two bolts securing the distributor clamp plate to the distributor housing.

5. position the distributor so that the vacuum control unit is to the rear and the unit is vertical.

6. rotate the distributor body antic-clockwise until the points are fully closed. then slowly rotate it in a clockwise direction till tje points just commence to open. tighten up the clamp plate pinch-bolt and check the the rotor arm is opposite to the correct segment for the cylinder which is at the top of its compression stroke.

7. tighten the two bolts securing the distributor clamp plate to the distributor housing"


this i have all done, EXCEPT, how do i "check the the rotor arm is opposite to the correct segment for the cylinder which is at the top of its compression stroke"

looking at the picture below, you can see that i have done as described above, yet i am still unsure which lead from the dizzy cap goes to which plug.

anyone care to enlighten me?

Re: spark plug leads

Posted: Thu Feb 18, 2010 6:10 pm
by cadetchris
ok, it wont upload the picture, but the vacuum unit is rotated over to about 2 o'clock and the rotor arm is point straight up.

Re: spark plug leads

Posted: Thu Feb 18, 2010 8:15 pm
by bmcecosse
So - you just make that #1 plug - and attach a lead of suitable length and run it to #1 plug! You are making far too much of this - I just stick the dizzy in and turn it till the engine starts! I don't worry about where the slots are etc It's a good sign if you get 'kicking back' - see another thread - which means it's too advanced, then you just retard and start it!