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Re: Breaking up over 5500rpm

PostPosted: Tue Aug 25, 2009 6:18 pm
by miked

The 23D4 is the stock Dizzy the car came with and has the HT leads going into holes on the side of the cap. As I recall the aftermaket ones have extended collars that the leads enter/exit.

Re; wear.

I was refering to HT breakdown (insulation breakdown). This can not always be seen inside a cap or on an arm. It can show as a thin carbon black track mark. It can be helped form by too much oil put in the dizzy for the counterweights (gets thrown upwards). It manifests itself as a misfire at higher revs and get worse with heat. After cool down it can clear. This gets quite violent in my experinece and the car hunts as the spark goes to ground.

I also had the sh*ts with standard plugs. My Stromberg only ran right with the BP6ES. I know they are hotter and for track use you are meant to use 7's (or even higher) but No 1 plug kept fouling even if I kept reving through. The engine was in good condition!


Re: Breaking up over 5500rpm

PostPosted: Tue Aug 25, 2009 6:32 pm
by bast0n

I have had a similar problem and it was the coil overheating. (Aldon distributor etc). I was advised by someone hugely more knowing than me to reposition the coil in the cockpit as racers do. I have moved mine to above my feet and to the right, (right hand drive). Since doing this no problems even when going a bit mental in plus 35c!

Hope this helps. David.

Don't grow old too quickly!

Re: Breaking up over 5500rpm

PostPosted: Tue Aug 25, 2009 6:59 pm
by pauljones
i had a few problems with my twink,it was and still is running a bit rich.however the point is i had a few misfires every now and then. long story short i replaced the plugs with super 4's (bosch) from halfords, a set of new leads(standard) these will be replaced with performance at a later date. the cap and rotar arm as they were a few pounds were swaped for new ones..

after timing being reset she ran fine and the miss fires had gone. this all cost about ?35. cheep considering the damage a missfire can do.

as far as the coil is concered,mine was an old lucas unit and running fine although a bit hot.i have heard stories that modern and more powerfull units can possibly cause early wear in the rotar arm/cap area due to the charge being stronger.result is to replace these abit sooner than normal.

just a bit of a thought,make sure if you need a coil with a ballast resistor that you use one.

hope that helps solve a problem...