Only fires when over advanced

[jimthesail]

Ahoy ! Have put together SD1 with SU HIF6's and ballast resistor ignition (in which I have no faith !) in my kit car.

Find that it only tries to catch when the ignition is retarded by about 45 degrees.
(i.e. the dizzy is rotated clockwise) Have checked set up, tdc/oil pump spigot/rotor angle. Engine was assembled by a professional so assume timing marks on chainwheels OK. When I say catches it is probably only 4 plugs. Have set float levels as per an American web expert (discounting needle valve spring travel) as had fuel spouts coming past needles and fitted new plugs and cap but not leads. Any help etc. etc.

[GDCobra]

Think I’d be checking the timing marks and firing order against plug lead location first on the ignition side. Can’t help with carb’s as they’re the devil’s invention!

[ChrisJC]

Gotta check the basics. Is there a regular spark from the king lead?
Check the order of the plug leads - 18436572, and check that no.1 lead goes to no.1 cylinder.

I generally turn the engine until no.1 is at TDC at the top of the compression stroke. Then I put in the distributor with the rotor arm pointing at the pickup point for no.1 lead, and with a good amount of adjustment either way. This bit can be a nuisance as the spindle turns as you insert it, and has to engage with the oil pump as well, so it takes a few attempts to get it right.

Then it should be pretty close.

Chris.

[stevieturbo]

Do a basic check on the dizzy to ensure rotor arm is close to No1 at No 1 TDC compression, and likewise any triggers inside the dizzy for the ignition are sensible placed too.

And check plug leads/firing order

[Ian Anderson]

Is your coil designed to work with the resistor? Some are rated to run on the full 12 volts and others in the resistor system around 8 to9 volts. If you have a 12 volt one in your system you get a much poorer spark.

Ian

[jimthesail]

Thanks for help, useful points made but as the thing is trying to fire and it has improved by retarding by a substantial amount and would appear to need more retardation, I am perturbed that something is basically wrong with set up ? The rotor slid in and ended up at 7.00 o'clock, pointing at No.1 with 6 degrees on crank BTC. 45 degrees is one cylinder so will move leads clockwise one step returning dizzy anti clockwise and try again ! Watch this space !

[harvey]

The only time I've had this exact scenario, I concluded that the timing chain had jumped, because when you can get it to run by moving the distributor that far it's because the timing is then working correctly(ish) in relation to the camshaft, not the crankshaft, which is how you are (correctly) setting things up initially. I'd look at what the pushrods are doing, and when they are doing it in relation to the crankshaft position.

[jimthesail]

Good point Harvey as although the engine was reassembled by a professional it had been standing a long time and the owner......?
However I think I may have an answer and it is something I have done before, (Ancient Arab proverb, 'Man who is kicked by same donkey twice, never learn') I had put No. 1 lead into the distributor cap to the left of the securing clip and it should be on the right which means the advance/retard is limited severely in one direction but it is possible to catch a spark off the next reluctor which will enable it to attempt to run. However having put things as they should be I have found a very weak spark which I think is the root cause. So, for the princely sum of £120 I have invested in a new dizzy and leads ! If it works I'll let you know !