Hi all, I know this has been covered on numerous occasions, I have been reading the old posts through the search. but I haven't found the exact things i am pondering.
I have a misfire underload from about 2500 rpm (no tacho as yet), the engine stops revving and the power goes away and starts to flutter and jerk around a bit (not just me being a jerk behind the wheel)

I have a 1098, new valves, guides, springs all standard, timing is set 5degrees BTDC@500rpm, plugs are gapped to 0.25, the distributor is a new 45D with new points (swapped to my old 29D and still had the same issue, so i put the new one back in), condensor etc. new coil has been fitted. All these were fitted as the mechanic who did my roadworthy told me the old dissy was worn and the dwell was all over the place (hence my fascination with dwell angles)
I have found, their is a vac leak on the throttle shaft of the carb (1.5" su), which will need to be sorted, but it was running perfectly like this before (has been misfiring and carrying on for quite a while now), I had a vac leak in the mounting of the carb, but new gaskets have fixed that up. The fuel mixture is correct according to my gunsons colourtune.
Apart from that, the only other issue I may have found, is with the points setting, If I set them to the book, the dwell is 42 degrees, to get the dwell to 60 degrees, i have had to set the points to 0.010" gap. Does anyone know what is more important? Dwell or gap?
I have the dwell set to 60 degrees at the moment, so the points gap is quite small, will this contribute to the lack of power and revs problem? I will reset the points tomorrow to the gap in the book, which will make the dwell shorter which I assume leaves less time for the coil to charge.
Just wondering if anybody knows, since its getting dark and I don't want to be doing laps of the town until midnight LOL

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Current 1970 Mini K - full resto happening - finished and on the road since 10/2020
2001 Falcon AUII XL 1 Tonne styleside ute

Mini History
1963 - 850 - wish I still had it
1965 - 850 - was an unfinished project, gone
1972 - Clubbie

Point gap determines dwell, so maybe a problem with your distributor.

A worn dizzy shaft or its bushes affects dwell.

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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.

You also have to ensure enough time for the coil/condensor tuned circuit to discharge properly to give a good spark.

RonR

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68 build Mk1 Cooper S
72 Clubman GT project. Total restoration required

You can get the jerking from lack of fuel supply. Sometimes accompanied with backfiring out the carby. Check for a blocked fuel filter and correct float level.

gap = dwell = spark = timing
set the points gap via dwell and the coil build up time will be right and you won’t melt the points
as will happen with high dwell
recheck timing as as the 60 degrees you had will retard the timing shedloads
recheck dwell when running and check stability as said above worn shaft varies dwell
make sure you lube the cam lobe on distributor

Thanks for the replies all, It seems it was nothing to do with points, ignition or fuel, I had a thought this afternoon while chatting to a mate about it that it was starving of air and changed the air filter to a standard one I have, and what do you know, all fixed. It seems the pancake air filter that looks pretty cool in the engine bay, was way too restrictive and small. Never fit one, keep the stockie

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Current 1970 Mini K - full resto happening - finished and on the road since 10/2020
2001 Falcon AUII XL 1 Tonne styleside ute

Mini History
1963 - 850 - wish I still had it
1965 - 850 - was an unfinished project, gone
1972 - Clubbie