Fouling plugs mighty grey

[Quaddy]

Righteo here we go again.
138 grey twin carb extractors fouling plugs.
New reco carbs, new jets to compensate having twin carbs, new throttle linkages so both carbs are doing the same thing at the same time, new air cleaners to suit carbs,new reco distributor with advanced vac working, new points, new rotor button, new dizzy cap, new condenser, new coil, new leads, new spark plugs multiple times now, and running a hotter plug also Ngk4. Have had multiple people look at this car last time it was tuned was with some wiz bang tool/sensor thingy up the exhaust was running sweet. Didn’t drive to far at all and now she’s playing up again running like a pig which I’m guessing is the plugs breaking down/fouling up. When I pull the plugs out it’s kinda like there dry carbon. Where should I start looking next? Maybe compression test and then where? Thanks for any help/suggestions.

[Blacky]

I would take it back to the last bloke mate, and take the plugs with you. Maybe put a new set in , go out and do a plug chop and see what they tell you ????

[Harv]

An exhaust analyser is only good for Strombergs if the mechanic has a tray full of jets and power valves in front of him. There are not too many grease monkeys left that do. Otherwise, all they are doing is playing with idle emissions... smells good in the driveway, makes little difference once the car is moving.

Dry plugs are good... at least it's not oily. Mixture is fixable... oil leaks into the cylinder are a lot harder.

Lots of black, dry soot sounds like an overly rich mixture. The question is, which circuit is it coming from (idle, cruise or power)?

As a start, take the air cleaners off and make sure the choke plates are fully open. Closed choke plates will pull a lot more vacuum, and can cause rich running.

Give the plugs a clean in some petrol with a toothbrush, and put them back in again. Kick it in the guts, and leave it idling in the driveway for five minutes. Avoid the temptation to give it a few revs. Switch it off, and pull the plugs. If they are sooty, then we have an idle problem.

If they are not sooty, put them back in again, kick the old girl over, put the plug socket into the car and go for a ten minute drive on the highway. Avoid stop/start driving, heavy acceleration or hills... just tootle along at 50mph or so. Pull over, shut the old girl down and pull the plugs. Avoid the temptation to get it home through stop/start traffic. If they are sooty, we have a main metering jet problem.

If they are not sooty, put them back in again, fire it up and take it for a hard run. Heavy acceleration, big hills, four fat mates in the back seat, car trailer. Pull the plugs, and check for soot. If they are sooty, we have a power circuit problem. The power circuit can also come into play early if the car has low vacuum (lumpy cam Quaddy?) or the valves are stuck/failed.

Let us know how you go.

Cheers,
Harv

[Quaddy]

Thanks for the replies. The car is pretty much undrivable it farts and carries on.but I’ll do my best to have a look at those things.

[Quaddy]

Also the power valve size is 70 and the main jet is 48 that’s what’s in the twin stromys at the moment. That sounds alright doesn’t it?

[Harv]

Jetting sounds about right... farting may not be rich-mixture related though. More likely an ignition problem.

Cheers,
Harv

[Quaddy]

What else should I be looking for with the ignition Harv? Or what tests should I be doing to try find a ignition fault. I’ve done the test where the cars running in the shed at night and looking for any sparks jumping across anything etc.

[Quaddy]

Also the coil I’m running is a tridon tico33b does this sound like the right coil?

[yaapeet30]

Hi. Have a read of this thread over at FE FC Forum.

http://forum.fefcholden.club/index.php? ... #msg129290

I had similar frustrations after having my carbs refurbed. There are many variables to consider but I think its worth looking at the main metering system. Before my refurb I ran 48s with good milage and then it went south afterwards. Admittedly I also put in restrictors. I also changed the power valves to 70 (i think - definitely changed from stock).

I jetted all the way down to 44s where it leaned off. I am now running 45 and getting 30 and sometimes 30 plus mpg on open road and 23 to 24 around town.

Have a look at the thread and it may have you thinking and asking more questions.

Whatever you do listen carefully to Harv. He was of great help to me at the time.

Happy motoring

Rod

PS: Getting jets may cause some issues locally. I sourced mine from the States.