20 replies to this topic

[Kawh1]

Hello,

 

When I replaced the old distributor cap and spark plug leads and plugs on my 96 Rover Mini Cooper, I wanted to make sure that the correct leads went to make the correct firing order so I found the attached photos on the Mini forum and set up the new leads with the new plugs with the firing order of: 4-3-2-1 as shown on the attached photos - plug 4 is the LH plug when looking at the engine and plug 1 is the RH plug when looking at the engine. The Mini has been going really well with this set up, however in checking the 4 plugs after a few months, they looked white as if they are too hot.

 

This week, I managed to get hold of an original copy of the 92-96 Rover Mini SPi Service Manual, and it says that the correct firing order is 1-3-4-2 which is totally different from the above - now I am totally confused.

 

Which firing order is correct?

 

Can anyone help me with this?

 

 

 

 

Attached Files

•  Dist Cap Leads.jpg   12.86K   4 downloads
•  Dist Cap Plug Leads.jpg   13.07K   4 downloads

[Steam]

Yes 1 3 4 2 going anticlockwise is correct.

[Bobbins]

Where did you get your information from about a 4-3-2-1 firing order? Both those diagrams are showing a 1-3-4-2 firing order which has been applicable to every Mini made with the A-Series engine.

[Kawh1]

Thanks Dave.

 

One Carb Or Two, Sorry, don't understand as the diagrams to me seem to show 4-3-2-1, therefore how do you arrive at 1-3-4-2?

[stuart bowes]

if you assume the dizzy rotor is turning constantly in one direction which it obviously does, your diagram would be either

 

clockwise - 1 2 4 3

 

anti clockwise - 1 3 4 2

 

I don't know which way it turns but it definitely can't be 1 2 3 4 or  4 3 2 1

 

also no engine ever fires sequentially as far as I'm aware (could be wrong?) because that would make for weird uneven loading on the crank (or something like that but worded in a more technically correct way)

Edited by stuart bowes, 15 March 2024 - 09:28 AM.

[Kawh1]

To help me, is the distributor cap & lead position drwg correct?

Attached Files

•  Dist Cap Leads.jpg   12.86K   1 downloads

[stuart bowes]

yes now imagine the rotor turning in this way and connecting with each position in turn

 

[Kawh1]

Thanks, however I have attached a copy from the SPi manual specification and it shows the firing order as: 1-3-4-2 "clockwise", so when looking at the attached drwg of the distributor cap, the number 2 lead goes to the RH side plug (next to radiator when looking at the front of the engine) followed by number 4 lead, number 3 lead and then number 1 lead on the LH side plug - is this correct?

 

Also, is the distributor cap drwg correct?

 

Sorry to sound like a stuck record but I just want to make sure that I have nailed this 100% as obviously I had the leads incorrectly fitted before, however surprisingly the Mini did go well

Attached Files

•  SPi Manual.jpg   34.35K   3 downloads
•  Dist Cap Leads.jpg   12.86K   1 downloads

[madalicesdad]

That's engine rotation direction, not the distributor

[brivinci]

Trust EVERYONE on here. Its 1-3-4-2. 10000% The motor is statically setup starting at cylinder 1, always and on every car I have ever worked on. When building, you have cylinder 1 at TDC, the timing, distributor angle, everything is set from that. Please believe everyone here when they tell you, no matter what that one paper you found reads. THE ORDER IS 1-3-4-2!

[Kawh1]

Firstly, I am not questioning the info that's been provided at all and thanks for all the comments so far..

 

I'm just trying to find out if the drwg of the dist cap lead numbers is correct for the firing order of 1-3-4-2 for my Mini. Based on the lead numbers on the dist cap, I have attached the dist cap drwg showing the leads going to the firing order cylinder plugs - Have I understood this correctly?

 

 

Attached Files

•  Dist Cap Leads.jpg   19.06K   1 downloads

[KTS]

Cylinder number 1 is the one closest to the water pump; if you're stood in front of the engine bay it's on the right, with number 4 on the left

 

 

i.e. as depicted in the right hand image in your first post

[nicklouse]

Yes. To the order but the position can be anywhere depending on how the drive was fitted.

 

on the SPi the trigger is on the flywheel. The “dizzy” just needs to point at the correct terminal in the cap at the correct time.

 

the firing order used to be cast in the exhaust manifold. Not sure if it is on the SPi/MPi manifolds but it has not changed ever from the factory.

[Bobbins]

Thanks Dave.

One Carb Or Two, Sorry, don't understand as the diagrams to me seem to show 4-3-2-1, therefore how do you arrive at 1-3-4-2?

I suspect you’re reading the spark plug / cylinder numbers from the diagram which will always be 1-2-3-4 or 4-3-2-1 depending whether you start at the radiator or the clutch end. This is not the “firing order”, I’m sure you’re aware of this and I don’t want to tell you how to suck eggs!

[Designer]

As far as I can see in your drawing above with the green writing stating left and right of engine and looking from the front of the engine you have got the leads in the wrong positions.

 

Number one cylinder is the one to the right of the engine nearest the rad and number four cylinder at the clutch end.

So working from that starting point

The HT lead from distributor contact No 1 should go to cylinder No 1

The HT lead from distributor contact No 2 should go to cylinder No 2

The HT lead from distributor contact No 3 should go to cylinder No 3

The HT lead from distributor contact No 4 should go to cylinder No 4

 

The engine/crankshaft will turn clockwise when looking at it from the fan/radiator end but the distributor rotor will be turning in an anticlockwise direction.

So in your mind's eye picture the rotor arm pointing at cylinder 1 contact (HT Lead for cylinder 1) on the distributor cap, as you turn the engine over clockwise the distributor arm will move anticlockwise from cylinder one contact to cylinder 3 contact  then to cylinder 4 contact and finally to cylinder 2 contact.

Thus your firing order is 1342 on the distributor.

It is not determined by the order you put the HT leads on to the spark plugs. The position of the  cylinders and their respective numbers are fixed for evermore.

The position of each cylinders HT lead in the distributor's contact number is also fixed for evermore.

Therefore you are connecting the HT leads from like number to like number so that the engine fires in the correct order.

 

I to got it wrong reading that clockwise was for the distributor and not realising it was for the engine. I realized my mistake when I had someone turn the engine by hand and I watched the rotor arm and saw it went anticlockwise.

Firing order was soon sorted and engine burst into life immediately.

 

Hope this helps to clarify your confusion.

 

Paddy

Edited by Designer, 16 March 2024 - 06:06 AM.