Miss at 1800rpm

[marc69]

My 1.0 ohv Nova has a miss at approximately 1800 rpm. It is a pain going around town.

If I just touch the pedal and let it accelerate really slowly it is ok but with any pressure on the pedal it just misses/kangaroos for a second. It does it in every gear at the same revs but otherwise it drives fine and I have tested it in 2nd gear up to 6000 rpm.

Is this likely to be carb or ignition?

[thegingerwhinger]

ignition id say mate.

[marc69]

Thanks, any idea which part of the ignition, I have tried finely adjusting the timing and the miss is exactly the same

[thegingerwhinger]

Have you took dizzy cap off and had a good look about? i had this on a stock car engine once and it turned out the centre shaft in the dizzy had play in it.

[marc69]

I've changed the dizzy cap, checked the point gap.

I'll check the shaft, if it does have play it means bye bye dizzy......

[marc69]

I have checked the shaft in the dizzy, there is a little play and you can open the points partialy just by moving it, I have another second hand spare two of these bosch distributors which do exactly the same.

Doesd anyone know if there should be a little play or are all three dizzy's worn out?

[mowgli]

are you timing it by haynes' figures?? have you retarded it a touch for unleaded?

coils, plugs & ht leads can cause trouble like this.

try new plugs first.

[marc69]

Thanks, I've put on new leads, just gone for a lovely drive in the snow to my lock up to removve the dizzy from a complete engine which again has exactly the same amount of movement.

I'll try plugs and coil next, although it's only a small issue it is really frustrating!

The ignition timing is back where I had it before the car started missing, when I do align the marks perfectly the only diference is a tiny bit of pinking....unleaded fuel. Did vauxhall move the timing marks after unleaded fuel became the main stay for uk cars or did they leave it for all the ohv engines?

[mowgli]

i dunno. i've only ever removed ohv engines from novas...lol

[marc69]

Changed heaps of stuff, eventually it turned out to be the coil, totaly wierd as it is only at low revs under load.

Ironically the next day (monday) the carb then got dirt or something in it and went mental, I had to use full choke at every junction/roundabout...slightly stressful. Eventually after loosing my temper, redlining the thing in second gear seemed to create enough vacuum to pull whatever it was out!

[marc69]

Update, the car run ok but had wee misses here and there so.....with much frustration, I removed the carb, points and condenser.

New condenser, new points, ignition timing reset by strobe exactly on the marks (no pinking either).

Carb pulled apart and cleaned again.

Had two weeks without a miss at last, don't know what was at fault but for the price of condenser and points I don't care and I now have a spare coil, consistent smooth running.

Did a 500plus mile round the highlands and seriously got 55mpg, shame i doubt i'll even get 35 here in the city where most of my running is!