Hi All
how hot should the ignition coil in a B get when running. Mine seems to be a bit too hot. Not red hot but hot pototo, hot potato hot. This is the third new coil I have fitted so I do not think I have had three bad coils in a row, mind you nothing suprises me these days so who knows?.
There are 20-40,000 volts being sent out of the coil thousands of times per minute. It will definitely get hot! Is there a problem other than the heat being produced?
How are the grounds? With crud/paint and other material between the grounds ( Frame to Ground - Motor to Ground ) the resistance could cause heat. I'd check and clean them, and see if that helps.
Hi All
thanks for the replys. I have worked my way back through the electrics replacing terminals, cleaning grounds and checking continuity. So far so good. I have since found out that a coil will be happy up to 70 deg C (170deg F) so I think I am fine. Will test the car tomorrow on a longer drive to see if it cuts out again.
Hi All
The car seems to be running fine now. The problem seemed to be a combination of three things, a failing coil, a failing ignitor system in the dizzy and a large chunk of glue that migrated from the NEW!!!! fuel filter to partially block the carb. Have done about 100 miles now and it is still running so here's hoping. I will be getting rid of the Weber carb and going back to stock SU's so that should rid me of the niggling little problems I have with the downdraft.
Glad to hear you found your Gremlins Mark. Hey another 100 mile run would almost get you to the San Fernando Valley for The British Car Event at Woodly Park 4/6/08. Seems like a good way to shake out the bugs. Hope to see you at an event soon.
I will give it a few more shakedown runs before going too far. My wife and I are looking foward to a trip in the B wine tasting at Paso Robles so I do not wish to come home on a truck again ( see pic ). Need to get this one sorted as we will probably be buying an MGA coupe very soon, so that will take up a lot of my time getting thsat on the road.
Glad to hear you got it sorted out, Mark! We passed through wine country this afternoon in our MGC on the way to the MGVR event in Monterey. It's incredibly green up here and flowers are blooming everywhere. Go for it!
Was that tow truck photo from your recent breakdown? Bummer!
Few people know the basics of ignition coils and so have common troubles .
The ignition coil should be fairly hot but not hot enough to scald your hand .
Coils do not need grounding ! .
The primary resistance is the critical thing and should always be checked and matched to the voltage source ~ some LBC's have only 8 or 9 volts at the coil's power source and so should be using a 1.6 Ohm primary resistance coil .
if , OTOH , you find a full 12volts on the power lead , you must use a 3 Ohm primary resistance coil else it'll get blistering hot and burn out points rapidly ,cause repeated condenser failures and so on .
Epoxy filler coils are the best at resisting vibration and heat , you can remove the stickers and invert it in the plastic cap from any Foo-Foo can and paint it silver , slap a " LUCAS " sticker on it and few will ever notice you've trashed the wretched , unreliable Lucas aluminum cased crappo ' sport' coil .
NAPA sells very good epoxy filled coils , I've never seen one fail .
FWIW , when your oldie begins to spotter from vagrant sparks out on the road , most of the time this is the condenser , if you keep the old set of points & condenser in the boot , you can change it , in dire cases you can usually squeeze the condenser's case with the tool kit pliers to get a few more weeks out of it and get you home .
Lastly , Accell yellow coils , while ugly and occasionally too large to fit the stock bracket , will throw HUGE white sparks and not chew up the points doing so when used in otherwise stock ignition systems~ I am using one in my Russian Moto and it's great if ugly .
Interesting reading, Nate. I will differ to your expertise, as ignition components are not my strongest point. I will add though, that I have never had a Lucas Sport coil go bad on me in any of the M.G.s I've run them in. Perhaps I've been lucky but I've had them in at least three cars over the past 20 years and so far so good!
I always say , use what works for you and what you like .
having worked on these cars (and many others) since they were new , and run a field service truck , worked in a Service Station back when that actually meant something , and done salvage re-construct ,I have perhaps a slightly jaded view of how these things work .
OTOH , I usually buy a vehicle just before it gets crushed for scrap or I find it tits up in a ditch and bring it back to life on a serious budget (I no longer do restorations) , I have an insiders view of what makes things tick .
I used to take any in service training I could get , the ' mechanics ' these days just want to throw parts at problems , I prefer to diagnose things first .
I find it difficult to break my love of LBC's no matter how wretched they are .
I'm really sick : I offed the MG TD , MGB GT Et Al , I only have the Metropolitan Nash's now......
Yeah , I know , it's not a REAL car , they were made for housfraus , circus clowns etcetera....
I can't help it , I wanted one when they were new and never really got over that .
The first year I was with SWMBO , I bundled her into my nasty old primer (shoulda been crushed) DHC Met and we drove to Victoria Island in Canada , the generator blew the first day out and I just bought a $7.00 battery charger & brought the battery into the Motel room every night , it was fine and we had a great trip , as you can clearly see , I have a most wonderful lady and , I'm nuttier than a batch of almond cookies .
I've always wanted one too, but no more room! (or time, money, etc) A couple years ago I spent a weekend swapping batteries back and forth with another guy so I could drain one battery while he charged the other. Worked just fine! Oh, the things we do for the "pleasure" of driving these old relics...
