7 replies to this topic

[Ouster]

Apologies for the crappy thread title!

I'm renewing the points, condenser, distributor cap and rotor arm today. Just fitted it all and the engine turns over but doesnt start

I know the firing order is 1-3-4-2 when looking at the car and the radiator is on the right. I've connected the HT leads accordingly on the distributor cap (going anti-clockwise).
My question is: Does it matter what way the distributor cap is put back onto the distributor? i.e. does, say, number 1 connection have to be top right, or can it be (e.g.) bottom left?

I think that makes sense


If not, then what could be the problem?

[Big_Adam]

Dizzy cap will only fit on one way. Well it will only fit on one way on mine.

[Ouster]

Maybe I wasn't clear what I meant. The cap only goes on one way, but it shouldn't matter about the orientation of the HT wires as long as they are in the correct order should it?

[rasher]

thay have to be in the right order and they have to be in the right place, if you put them on in the right order but in the wrong place the wrong plug will fire.

[Ouster]

Ok.
Can somebody explain why this is? The engine doesn't know the position of the rotor arm when it is started |
Apologies if it's a stupid question but I like to know these things!

[langers2k]

The engine doesn't *know* anything, its not intelligent

Four stages to any 4 stroke engine (such as the mini), suck, squeeze, bang, blow. On each cylinder there are valves to let gasses in and out.

Suck
Inlet open, exhast shut
Fuel/air (mixture) entering the cylinder

Squeeze
Both valves closed
Compresses the mixture

Bang
Both valves closed
Ignites the mixture - the power stroke

Blow
Inlet shut, exhaust open
Pushes the wastes gasses out the exhaust

The spark needs to enter the cylinder between the squeeze and the bang stroke to ignite the mixture.

The crank shaft, cam shaft and dizzy are all linked in the engine so that they are all in tune with each other, so the valves are opening and closing at the right times and the spark is arriving when its needed. So although the engine *doesn't know* where the dizzy arm is, due to the linkage it can only be in the right place (unless your engine is badly tuned).

By moving the leads around the dizzy 180 degrees the spark will be enter the cylinder between the blow and suck stages, so there will be nothing to ignite and the engine won't work!

Make any sense to you?

[Ouster]

Yes, that's a lot clearer thanks!
*files in head*

[dklawson]

It sounds like you may have made a mistake by removing all the wires from the cap instead of replacing them one at a time to maintain their prior positions. This is NOT the end of the world but I would not not try and sort it out by guessing and arbitrarily moving wires around until it runs.

Please download the following PDF:
http://home.mindspri...taticTiming.pdf
As the title suggests, I wrote this document to walk people through static timing. HOWEVER, towards the end of the document, several paragraphs are devoted to determining which cylinder is on which of the four cycle steps AND then using that information to put the spark plug wires back on in their correct order.