Can't get a spark

Post by **MorrisMartin** » Tue Mar 30, 2004 5:55 pm

I cant get a spark at the plugs. I have changed the points and condencer but it hasent helped. I got a weak spark at the plugs once but that was it.

Post by **Alec** » Tue Mar 30, 2004 6:31 pm

hello MM,
I take it that you had a problem before changing the points and the condensor?
A couple of quick checks:-
take the distributor cap off and remove the rotor arm. Turn the engine so the points are closed. Switch the ignition on ond disconnect one coil low tension wire. You should see a small spark at the terminal you disconnect. Replace that wire. Now turn the engine to open the points and repeat the test and you should not see a spark. This proves that your coil is live and the points are working. With the points closed again, and ignition on, disconnect the coil HT lead from the distributor cap and hold that end close to the block, flick the points open with a small screwdriver to check if you get a spark. If the first couple of test were OK you should. If you don't get a good spark possibly the hT lead is US or the coil is.
See how you get on so far.

Alec

Post by **Scott** » Wed Mar 31, 2004 4:34 am

If Alec's tests show a spark at the coil HT lead, but still not at the plugs then there is a possibilty the rotor button has a short to earth. I had one like this a few years ago & I've seen this mentioned recently in Practical Classics where there has been a run of bad ones. If the coil HT lead sparks OK to earth, then hold it near the top of the rotor button. If it sparks to the rotor button, then it's shorted to earth.

Contact points sometimes have a film of wax (or similar) on the two faces which needs to be cleaned off with solvent (petrol usually).

Post by **MorrisMartin** » Wed Mar 31, 2004 8:40 am

Ok, thanks. I will try those tests. I do get a spark at the points, as I have tried flicking them open with a screwdriver. When I dissconnect the HT lead and put it near the block I don't get a spark when I crank the engine over.

Post by **catsoup** » Wed Mar 31, 2004 11:12 am

sounds very coily to me. If you have one try losely wiring up another coil (just three connections.)

If you dont have another coil, put a volt meter across the low tension terminals of the coil. With the ignition on, and the points open you should see more or less 12 volts. With the points closed you should see very nearly zero. If you dont get this, or no spark I would suspect the coil. (Or the king lead!).

To check for a spark, I usualy remove the king lead from the distributor cap (centre one), put a spark plug on it, and rest the metal part of the plug on the rocker cover bolts. This way I dont get too many shocks, and the spark is easy to see.

Post by **Kevin** » Wed Mar 31, 2004 11:55 am

This way I dont get too many shocks,

Rubber handled pliers help as well

Post by **catsoup** » Wed Mar 31, 2004 12:02 pm

True. I once had a shock when I was holding screwdriver. Completely involuntarily the muscles in my arm contracted and the screwdriver landed some distance behind me. Luckily no one was hurt, and nothing was damaged. I felt a prat tho....