OK so yesterday I swapped the #6 needles into Barney's twin HS4s and we took him for a run to Pie in the Sky.
Ran better than with the CP4s, but he had a variable misfire under load at about 2500-3000 rpm that cleared if you stayed up it.
Ignition is a Pulsar dizzy with the plugs gapped at .035".
Plugs (NGK BP6ES) were swapped for new Champion N9YC, same symptoms.....
Soooo, this morning I checked the `new looking' Top Gun leads the PO had put on a couple of years ago.
They were all over 12K ohm- one was 17K ohm when straight, open circuit when bent..
So I binned the lot & the coil one- fitted new Bosch ones @ $4.99 ea, he's now running sweet. These new leads only measured around 1.8 K ohm.

So, check your plug leads, people- the suppression ones don't last forever...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I've been wanting to get some Bosch ones leads. Which ones are suitable for a Mini (model number or something)? And what colour are they?

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Jonathan
http://photobucket.com/albums/y64/FatMaserati/

They are black only, hanging in the rack at Supercheap. $4.99 each.

I use the ones with 90* elbow at dizzy end, plug end is straight.

I bought:
3 off B35Ri,
1 off B45Ri,
1 off B30CRi (coil lead)

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Why not 4 of the same, plus coil lead?

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Jonathan
http://photobucket.com/albums/y64/FatMaserati/

Won't reach #1 on mine.. and the longer one is too long for the other 3.
Measure yours...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Would it still not be better to get all 4 the same length? I kinda thought it was like speaker wire in that the lengths to each speaker should be the same length for optimunm performance.

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Jonathan
http://photobucket.com/albums/y64/FatMaserati/

I hate to say it Kev but the PO probably put the other style of Top Guns.

A couple of years ago someone imported some el cheapo asia made Top Gun copies. I bet that is what you got.

Yep they were crap and it was too late for the Feds.

Soooo if you buy Top Guns make sure they're real.

shame they don't have RED, but black would be the next best thing for JAM.

Cheers for the part numbers Kev

I just bought 4 x B35Ri and 1 x B30CRi. Thay are really good. I think my Mini was misfiring or something in the lower range, maybe u pto 1500 revs. When it's idleing at a set of lights, and you plant your foot, it doesn't hesitate anymore, and just shoots off really cleanly. Mighty impressed. Plus, these leads I bought were heaps shorter than the ones I had on my Mini.

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Jonathan
http://photobucket.com/albums/y64/FatMaserati/

Nope it's not that critical. You need some resistance (600 ohm+) to get a spark that doesn't `self quench' but it doesn't matter a rat's if it varies a bit. Look at any 6 or 8 cylinder motor (with dizzy) the leads vary a hell of a lot in length.

Most plug leads these days are not copper wire, they are some carbon impregnated material or Bosch's`inductive core' ( whatever this means).

I usually bin leads if they get to 8K ohm- they are past it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Bosch leads are awesome

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Lillee - 1969 Morris Mini K

I'm going to grab a set of these today

I'll let you know if it makes a difference!

Got some blue leads (look nice too) from AutoPro about 4 months back - don't know the manufacturer but I have some misfiring probs. Think I'll follow your lead Doc and get new Bosch ones from somewhere. Might cure the problem, but at least I'll know if my current ones are crap. Can always put a spare set of leads away in the garage for a rainy day.

Hooroo

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

well I visited Repco where a good mate of mine works nudge nudge, wink wink, half price you say?

I got new leads (red ones too) . The number in the part number Kev noted is the length. Repco sell a different brand, but the same length reference is in their part number. For a Pulsar dizzy they were spot on.

I picked up a new dizzy cap and rotor too......and it made NO DIFFERENCE to the cars perormance bummer.......

Be careful, not all leads are made equal... different brands = different cores...

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Lillee - 1969 Morris Mini K