bus has started playing up. I’ve a jolting ride especially when holding gas pedal at constant speed. Deceleration ok, acceleration is slow but not as jolting. The fault is pretty dramatic not really drivable far. Came on pretty sudden. So far I’ve; changed dizzy cap (electronic ignition), changed coil, cleaned out the two jets in the Weber ICT bowls and the bowls, checked the timing, reseated all plug leads. This had zero effect. Wonder if electric fuel pump is the cause. Anyone any ideas?
Look also to a leak of petrol one side through the carburettor fuel metering valve. While you accelerate the engine uses a lot of petrol so it works OK. Drop back to cruise and it starts dripping petrol down one side, killing two cylinders for a moment. A Weber problem brought on by use, vibration and maybe too high fuel pressure. Also fouled plugs make for.problems, if its just running rich.
Cheers, probably not. It’s started playing rough even on idle now. I’ve got a horrid feeling the new top end is playing up. Going back in Tuesday. I’ve done all the obvious things around spark and fuel, it getting worse like is mechanical. Hope I’m wrong
This sounds interesting and would explain all. I thought unlikely as I think of electronic ignition as rock hard, didn’t realise it could play up. I guess there’s no way to test this other than new module? Plus could be expensive if it’s not thx issue
Actually not as expensive as I thought for the basic one. It’s just those turbo nutter flamethrower jobbies. Probably expensive for a good reason though
A better cheaper test is points and a condenser which could also prove handy as a back up. The cheaper ( i.e. not Pertronix) ignition modules seem to be prone to breaking down. My own experience of somebody elses was it ran for a few minutes then started misfiring more and more. Waiting a few minutes improved things, but only for a few minutes. Initially it appeared that flooring it got it running better but that proved to be a red herring. It's a more common problem than it should be.
This is what I’ve got. Like the points idea also. Guess the ignition modules for 009 distributors are interchangeable as long as coil can handle it. I presume I’ve got the £40 ish one rather than the £130
I think that might actually be a Pertronix. You'd have to internet search for pictures. One thing I do see in your picture, well two things. First - is there a gap between your magnetic collar and the pick up? Hard to tell on your photo. But the main thing - look at the witness marks on top of your rotor arm. Those are from the plastic inside the cap around the centre sprung electrode. The rotor is not meant to be rammed into the cap obviously. I've found with all of these modules the magnetic collar doesn't allow the rotor arm to fit far enough onto the shaft. This allows a fair bit of slop and in conjunction with being pressed against the cap can really mess with the stability of the timing. Check if the carbon contact in the cap is still springing out or jammed in permanently. Cut 1-2mm off the bottom of your rotor arm and it will solve both problems. Not saying this is your only cause but it could be and it does need addressing.
A lot of people would say that...but I've checked it out with a depth vernier to see my collar was fully seated. Makes me wonder if the rotor would normally overhang the lobed part but as I've cut mine off...the top of the collar is only 1mm or so thick so it shouldn't make such a difference.
On one particular bus, the rotor arm sat so high on the shaft, the web inside the rotor arm barely located in the slot in the shaft and had rattled about and almost worn through the web...as well as being rammed into the cap. Have a look up inside your rotor arm for possible similar evidence.
As we've got on to ignition modules, I'd not seen this before... Test the charging system's maximum voltage: Charging system voltage, measured at the coil’s + terminal, must never exceed 13.7 volts, at any RPM level. You can reduce over-amperage surges/voltage spikes to the ignition module by wiring a 1.4 Ohm ballast resistor between the coil's + terminal and the red HotSpark ignition module's red wire. www.Hot-Spark.com/1-HS14BR.htm From this advert. https://www.hot-spark.com/Hot-Spark...USA-Spark-Plug-Wires-Beru-Z68-Plugs-Combo.htm
The carbon contact in the cap is springing in and out freely. Oddly I’ve tried to remove my rotor in the recent past and found it was stuck on so tight I couldn’t budge it. I guess it would free with some mechanical force, at the time I didn’t really need it off so didn’t persist.
As it’s so close to top end rebuild I think it’s sensible for my engine rebuilder the check this out. She’s booked in tomorrow. I’d love to have the satisfaction of sorting this one as I think it may be the ignition module, but for the these reasons I’ve got to take her back
