misfire help

[bigdaz]

Ok so my choke works now but unfortunately I still have a misfire it's only very slight and seams to be under light throttle the carb was rebuilt and mixture set up with exhaust gas anilizer so that's ok, ignition side all is new
Apart from the dizzy, I can't remember what plugs I fitted and there motorcraft ones so no identification on them,
I think the plugs look very white what do you lot think about it,

[bigdaz]

[mk2cossie]

Is this a cologne engined Granny?
First thing I'd suggest is valve clearances and then set the timing and CO up on it

[bigdaz]

Yes it is, I set the valve clearances about a month ago, do you think I may of over adjusted them ?

[bigdaz]

Ok today on my way to work the car drove pretty much perfect, but in my way home 3:30 ish this wasn't the case
There was quite heavy traffic and the cars idle jumped around and stalled but restated ok, and there was a slight misfire, all the way home when I got home the car idled a little higher then normal and still the slight misfire I turned the car off left it 5 mins and restarted and the idle was normal and the misfire had pretty much gone, how bloody odd is that,

[ChasR]

What brand of ignition components have you used? Were the plugs new or new old stock?

Also when was the car last running right and what has changed on the car since?

[bigdaz]

I used motor craft plugs, as for the rest I can't remember I rebuilt the carb and serviced it at the same time, was running ok before, I done 600 miles around South Wales just after and never missed a beat, it seams to of got worse over the last few weeks, I got the service parts from the local motor factor, I'm going out of my mind

[bigdaz]

Here's a video 

[mk2cossie]

Sounds quite throaty from the exhaust, and a consistent tapping that sounds like a dicky tappet.
What did you set the valve clearances to and in what sequence? As i seem to recall its an odd layout for checking them
As ChasR says, whats been changed thats possibly caused it?
Also, whats the timing set to and what type of petrol is it running?

[bigdaz]

I used the sequence in the Haynes manual and adjusted them to what it said in the Haynes manual, it was quite tappety before, I always use tesco supper and ignition is set to 9 degrees I'm a little concerned now

[bigdaz]

Ok done a test held a peace of paper over the exhaust results not good :-( either I've over tightened and exhaust valve or I have a burt valve I've probably done best part of a 1000 miles since I adjusted them so I'm guessing the damage is already done :-( I'm off Friday so I'll readjust them then damn I'm curse word off, here's a video if anyone didn't know about this easy test,

[steveg]

Has fixing the choke made it run too weak ?
I would be tempted to make sure the choke is definitely not doing anything and adjust the mixture to the fastest smoothest idle.
Are you running a standard air filter ?

Hope it isn't a valve, I had a burnt one on my Triumph 2000 and did everything I could to make it run better. I only found out what had happened when I decided to change the head for an unleaded one.

Might be worth doing a compression check.

[bigdaz]

I had the mixture checked at a local mot station so I know that's fine, it's not run right since I started working on the engine I think it's just got more noticeable because I've set everything up right, I'm just praying it's only adjustment as don't have the money to get the heads reconditioned at the moment,

[steveg]

Just thinking that as the plugs look a bit white it suggests a problem that is affecting all cylinders although if it's an exhaust valve it probably wont show up anyway.
I've had coils gradually fail but that would show up as sooty plugs.

Another thing I have had trouble with is carb icing and blocked jets.

[mk2cossie]

It may just be the valve clearances then, don't forget they arent all in the same order :S
I always used to use the next thinnest feeler gauge to whats suggested, as the rocker tips wear a groove in them and you cant get a normal feeler gauge in to measure accurately
Only other thing is is that 9degrees with the vacuum pipe disconnected from the dizzy and blocked?

[ChasR]

I'd recheck the clearances but I reckon it is an ignition fault. I attempt not to use cheap ignition parts these days and attempt to stick to Bosch or BERU ; there leads are very good to be fair.

If you were closer I'd lend you a spark tester than tests various parts of the ignition.

[bigdaz]

There's a diagram saying which is in and ex in the Haynes manual I used that before, and yes I did disconnect vacuum from the dizzy and plug the hose, fingers crossed I've just made a stupid mistake then but at lest there's no more head rubbing about what it is, I don't think it's that bad the misfire is only just noticeable

[bigdaz]

When I get home from work I'm going to do a compression test to see if any cylinders are low if one or more is then a wet test to confirm its a valve if it is I'll undo the adjustment a little to see if it brings the compression up, if it does when she's cold ill readjust them all and slap my self,

[bigdaz]

Well all cylinders where just over 180psi
So it's clearly not what I thought I took all the plugs out snd some where a little darker and more the colour I would expect which is odd, so I'm still scratching my head

[bigdaz]