Help with distributor for 998cc
Hi Jamie, Here's some things to check inside the dizzie.
1. clean the aluminium terminals inside the cap - use sandpaper or small file to remove grey dust oxides.
2. check the cap doesn't have a hairline crack as this causes shorting between leads and misfires or weak spark.
3. Clean the rotor arm so the spark jumps easily - use fine sandpaper or emery paper on the brass
4. There is a wire from the baseplate to the body of the distributor - this gets flexed a lot during use and can break internally - it presents as an intermittent fault depending on the vacuum advance unit position under acceleration
5. the condensor itself - I've been through 4 in the past year and the quality of modern parts is sheer rubbish - even the lucas branded items. (I had such a problem with a my triumph that i fitted Accuspark electronic ignition - it all fits inside the dizzie cap and I'm so impressed I will be buying one for my son's mini as the performance is as good as new again)
6. set the points so that with a 16thou (.0016") feeler gauge you can just pinches it - this will give you a nice fit for 15thou which is the optimum gap.
Outside the dizzy
7. are the new leads a good fit into the cap? if not then open up the blades of the connector and push them back on - they should be a tight fit into the top of the cap.
8. check the tops of the spark plugs - make sure those little aluminium tops are screwed on tight - do them finger tight then with a pair of pliers give them about 15 to 20degrees more twist. do the spark plug end of the leads fit snugly onto the plugs? if not, adjust them.
9. make sure the spark plug gaps are 25thou (.0028")
10. the last check is the vacuum advance unit. connect a thin piece of rubber hose (or use the existing one if you don't mind petrol fumes) and suck hard on the tube. you should see the vacuum advance mechanism move a little bit and then be able to suck no more. If nothing moves and you are sucking air then the vacuum unit is shagged.
If you've got all these things right and the timing is set correctly then you need to start looking at the breather hoses, inlet manifold gaskets and air filter mounting gaskets. also check the tappet chest covers at the back of the block under the exhaust manifold. the geskets dry out and shrink so sometimes nipping them back up with a spanner prevents air being sucked through these gaskets and up the block into the carb thereby weakening the mixture. you'll need a small 1/2" ring spanner and a box of plasters :)
good luck
Posted: Mar 02, 2012 10:17 PM