Engine only runs on cylinders 2&3

[AndyB72]

I've been trying to get my freshly rebuilt 1100 engine up and running for the first time. Its an over bored 1100 with a modified 295 head and height torque cam. At the moment its fitted with standard exhaust/inlet and single inch and quarter SU. Standard coil with an electronic ignition kit and the dizzy has had the curve modified to match the engine spec.

The engine is only running on cylinders 2&3, even though cylinders 1&4 have a strong spark. The plugs are clean and when you pull the plug leads off the engine running doesn't change, where as the center two plugs are black and the engine slows when the leads are removed. Revving the engine makes no difference.

The plan is to take it to the local rolling road but at the moment I need to get it running something like, any ideas please.

[davidnutland]

Might seem simple but have you the leads in the correct order?

[GraemeC]

I'd suspect the firing order is wrong. If the leads are where you'd normally expect (1-3-4-2 anticlockwise around dizzy with plug 1 (rad end) connected to dizzy at top right) then possibly the dizzy drive is 180 degrees out. Try swapping the leads round on 1 & 4 and 2 & 3.

[ianh1968]

AndyB72

As GraemeC says -

Did you do this bit correctly:

DizzyDrive.jpg

If not, take great care not to drop the spindle in the gearbox
when you are sorting it out...


Ian

[AndyB72]

Thanks guys, I checked the firing order as per the recent thread, but it sounds like I need to check and double check again. Will have a go in the morning before work.

[AndyB72]

I quickly tried swapping the leads round on 1 & 4 and 2 & 3 this morning but the engine wouldn't start, swopped them back and it ran on two cylinders. Will have another go after the weekend.

[graham in aus]

Swap the plugs around / try alternatives,, I've had brand new plugs not fire!

[mk1]

Andy, do you want me to drop round & we can have a go together.

[AndyB72]

That would be great Mark, maybe one evening next week, I'll drop you an email.

[Richspec]

I've had this before, the dizzy leads were all mixed up or the dizzy drive was 180 degrees out, I can't remember which it was. Follow the procedure in the haynes manual to establish tdc on no1 on firing stroke and see where your rotor arm is pointing.
If its in the correct place refit the plug leads to the dizzy cap, check the rotation direction of the rotor arm and refit the leads to suit.

[ianh1968]

see where your rotor arm is pointing.
If its in the correct place...

If I remember correctly, if you have the driveshaft in the correct position,
the rotor arm will pretty much point to the No1 sparkplug...

The rotor runs anti-clockwise.

Recently I looked at Morris Minor that had the shaft in the incorrect position.
The "qualified" engine builder had provided a set of longer HT leads as
following his work, the originals were too short!

The cam wasn't for an 8-port, was it?

Ian

[Frogeye61]

I quickly tried swapping the leads round on 1 & 4 and 2 & 3 this morning but the engine wouldn't start, swopped them back and it ran on two cylinders. Will have another go after the weekend.

Since 2 & 3 were working fine, why exchange them. I was hoping to see that you swapped only 1 & 4.

[boxofbits]

The position of the rotor will not necessarily make any difference.

You are better to give it a compression check, change the distributor cap (it may be cracked), and make sure you have 1-3-4-2 firing order. You can't just change the leads round like a Tommy Cooper trick, you have to make sure the firing order is correct.

[ianh1968]

The position of the rotor will not necessarily make any difference.

OK, you can make it work if it's wrong, maybe with longer leads. But you
still need to know where the rotor is pointing in order to put the first lead on.

If the dizzy spindle was installed incorrectly, or differently to where it was before,
the rotor will now be pointing at the wrong lead's contact point in the cap. It needs
to be checked.

Top Tip:
Get 10 4" (100mm) cable ties.
They don't need to be this long, but they'll be 2.5mm wide...
On No1 lead put 1
On No2 lead put 2
On No3 lead put 3
On No4 lead put 4

Cut the tails off nice and short, and if you are really picky, like me, get a soldering
iron and melt off the short spiky bit that still sticks out.

You now have a braille set of markings that you would be able to use, even in the
dark, if necessary. They will also not wear off, like paint marks do...

With this system, it's virtually impossible to mis-fit the leads once the first post-build
configuration has been done.

Hope it gets sorted out soon...

Ian

[miniminor]

The position of the rotor will not necessarily make any difference.

OK, you can make it work if it's wrong, maybe with longer leads. But you
still need to know where the rotor is pointing in order to put the first lead on.

If the dizzy spindle was installed incorrectly, or differently to where it was before,
the rotor will now be pointing at the wrong lead's contact point in the cap. It needs
to be checked.

Top Tip:
Get 10 4" (100mm) cable ties.
They don't need to be this long, but they'll be 2.5mm wide...
On No1 lead put 1
On No2 lead put 2
On No3 lead put 3
On No4 lead put 4

Cut the tails off nice and short, and if you are really picky, like me, get a soldering
iron and melt off the short spiky bit that still sticks out.

You now have a braille set of markings that you would be able to use, even in the
dark, if necessary. They will also not wear off, like paint marks do...

With this system, it's virtually impossible to mis-fit the leads once the first post-build
configuration has been done.

Hope it gets sorted out soon...

Ian

Got mine done just like that.

[AndyB72]

I quickly tried swapping the leads round on 1 & 4 and 2 & 3 this morning but the engine wouldn't start, swopped them back and it ran on two cylinders. Will have another go after the weekend.

Since 2 & 3 were working fine, why exchange them. I was hoping to see that you swapped only 1 & 4.

Sorry I should have put I tried just swopping 1&4 but it didn't make any difference. Then swopped them all as suggested in another post but the engine wouldn't start.

[AndyB72]

Thanks guys, rotated the dizzy drive 180deg this morning and it fired up a treat... onto the next job...