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MG MGB GT V8 Factory Originals Technical - Ignition wires question

I am asking for some help from those of you knowledge able with the Buick 215 engine. I performed a tune up and installed new ignition wires, now having trouble starting the engine. The car has a Mallory dual point distributor. It acts like the ignition wires are on the wrong plugs, however I need more information to be sure. Fire order is imbedded into the intake manifold. 1 8 4 3 6 5 7 2 Can I trust this?
Where is the #1 plug on the ignition cap? Mine is not marked.
Where is the #1 cylinder? Right front side of engine? #2 Left front, #3 second cylinder on right side ect.
It appears the distributor rotates clockwise when engine turns over.

Proceedure should be to locate the #1 position on the cap. Run wire to #1 cylinder. Move clockwise to next position, #8 per fire order, run wire to #8 Cylinder. and so on until finished. Would this be a fare assumption? Any comments would be welcome to get this car running again.
Bill R

This might help:

http://www.zaks.com/mgb/leonsmgb/images/215-2.jpg

rick
rick ingram


The firing order cast into the intake manifold is correct, and if it's a Buick manifold, I think the cylinder numbers should also be cast into the 8 respective intake runners. As a general rule, all engine makers number cylinders from front to back... as the rods are sequenced on the crankshaft. (If you look closely at the block, you'll also note that the left-side head is closer to the bumper than the rightside...)

Rick's link graphically shows cylinders and firing order and the factory's preferred location for wires on the distributor cap (relative to the little access door, if your distributor has one.) Yes, the distributor turns clockwise!

However, it's technically possible that the distributor wires could've been mis-indexed previously (and that this error was accomodated by rotating the whole deal when setting timing). All of the plug wires may need to be shifted by a position or two... but you can easily verify this one way or the other! If you're not sure, just remove the number one spark plug and rotate the engine until the number one piston reaches the top of its stroke. (You don't have to be very precise for this quick check.) When the piston is at "top dead center", look at the distributor's rotor - it should be pointing to whichever lug corresponds to the "number one" plug wire.
Curtis

Another way is to remove the right valve cover, and when the rockers on number 6 (next to the last on right side) are rocking number 1 should be on it's compression stroke and the mark on the damper pulley should line up with the mark on the timing cover.
On the stock distributer tne rotor points between 10 and 11 oclock.

Al
Al Wulf

Firing order for the factory V8 is also 1 8 4 3 6 5 7 2 FWIW. Because the distributor engages with the camshaft with a spiral gear there are as many ways of engaging the two as there are teeth on the gear, unlike the 4-cylinder where the distributor can only engage with the drive gear, at least, in one position (however the drive gear on that can also engage in as many positions as it has teeth).

On the factory V8 No.1 (left bank facing forwards front) distributor contact is the 2nd one anti-clockwise counting from the bottom cap clip. However the leads are counted *clockwise* from there, unlike the 4-cylinder which is anti-clockwise. An additional thing to note is that when placing the leads in the combs that the factory V8 has, Nos. 3 and 5 must be reversed i.e. 5 adjacent to 1 and 3 adjacent to 7. This is because 5 and 7 are adacent in the firing order and the spark to 5 can trigger a parasitic firing of 7 way too much BTDC.

A 4-stroke piston has two TDCs of course, but only one is correct for firing and hence the position of the rotor. This is when both valves are closed for the majority of the up-stroke (compression) and the majority of the down-stroke (expansion), or where compression pressure lifts off your thumb placed over the spark plug hole on the up-stroke. So turn the engine to BTDC in this position, and experiment with removing the distributor and seeing how far the rotor turns, to set its position so that when inserted it turns to the correct position. If this puts the oil pump drive dog off you will have to turn the engine and hence distributor until the distributor fully engages with it and drops fully into place.
Paul Hunt 2

This thread was discussed on 16/12/2007

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