2.25 petrol - an annoying miss

[series3]

Good afternoon my faithful brains trust,

I have a light, intermittent miss on my 2.25 petrol 2a. I took a short video to show you what I mean..

2a2.25 missing - YouTube

I have recently done the tappets, set the points gap, set timing to a point that it drives really well, replaced all of my HT leads, and pulled apart/cleaned the carby a couple of times. Doing these things hasn't assuaged the problems.

My next thing will be replacing the condenser and maybe the coil, but I thought I would throw it out to the general populace for discussion. Are intermittent misses indicative of something in particular?

It still drives smoothly (other than the odd power-loss fart) and powers along well on the road.

Cheers,

Sam

[Brad110]

I wouldn't think the units themselves would be a problem intermittently if its running so well but certainly a connection or short. You didn't mention fuel.....

[series3]

The fuel is less than 1 week out of the bowser, if that is what you mean.

That's a good idea. the low tension wiring is looking a bit worse for wear these days, I cleaned some of the contacts, but not all. They could do with replacing...


Sam

[Cobber]

Plugs?

[tangus89]

Sam, i had a similar miss in mine, it still revved up alright, and ran ok.

I checked compression, timing, points, I changed the coil and the leads. Finally I changed the plugs and it runs without a miss now.

The last time it had a miss it ended up being the dizzy cap.

[korg20000bc]

It may be worth replacing the rotor button.
Apparently when worn it can slip on the distributor spindle and cause a miss.

[Blknight.aus]

it could also be the condensor fialing

[gromit]

it could also be the condensor fialing

I had a similar problem with a cheap condensor.
Occasional misfire when hot. Then it would run OK, then the car would stop completely. Eventually fitted the old original condensor and fixed the problem.

I'd used a cheap condensor from a Land Rover parts supplier and it karked it after a few days use.
I now use Bosch GL103 from SuperCrap.


Colin

[vnx205]

Maybe a leaking inlet manifold.

Can a valve stick intermittently? Is it worse when cold?

[shorty943]

Sticky valve? That can happen, mostly when the engine is hot.
I had a similar problem come into the shop some years ago with a Harley Sportster, seems it had a tiny bend in one exhaust valve stem from brand new.

Could also be a leak in the inlet manifold, that should make a squeaking noise or a timed hissing sound so pretty easy to hear with the bonnet up.
Found that one on an old Ford V8 with a cracked carby gasket, that would normally stop it from revving to full throttle though.

Or, it could be "D" all of the above suggestions made by all members.

Tricky things to isolate intermittent missing.