v8 still misfiring

shawser · Post by **shawser** » Mon May 16, 2011 9:28 pm

think i may have found the problem, took out old dizzy today and the female drive on end of shaft was moving around all over the place, the pin that goes through was only holding on one side and the holes were worn.

DaveEFI · Post by **DaveEFI** » Mon May 16, 2011 11:00 pm

shawser wrote:think i may have found the problem, took out old dizzy today and the female drive on end of shaft was moving around all over the place, the pin that goes through was only holding on one side and the holes were worn.

The important bit for timing is the gear to dizzy shaft. The bit you've described just drives the oil pump. However, you don't want that to break...

SuperV8 · Post by **SuperV8** » Tue May 17, 2011 8:58 am

As said above, the female part only drives the oil pump and won't effect the timing. You don't obviously want it to fall off!!

As long as the small gear on the shaft has no play on the shaft, and the gear isn't too worn should be fine.

How much play is in the rotor arm when the dizzy is in stiu?

Tom.

shawser · Post by **shawser** » Tue May 17, 2011 7:23 pm

the dizzy is out now so cant check, got a new ignition system ordered, so should arrive next couple of days, will let you know how i get on.

shawser · Post by **shawser** » Tue May 17, 2011 8:03 pm

i put old dizzy back in, i guess you mean play as in pulling upwards on shaft where rotor arm sits, about 3 mm of play

shawser · Post by **shawser** » Wed May 18, 2011 10:04 am

put in new dizzy and coil, sparking fine, getting gas, but still spitting through carb, checked timing, again it seems fine, double checked leads all present and correct. straight jacket almost out of its box now, doing my head in this.

Ian Anderson · Post by **Ian Anderson** » Wed May 18, 2011 11:29 am

Take both rocker covers off and crank it over without the spark wire connected

Are all the valves moving? or has an inlet valve "got stuck / sticky"
If so the "fire" stroke from the engine will blow back through the carb

Could also be faulty valve train holding the valve open

Ian

shawser · Post by **shawser** » Wed May 18, 2011 1:19 pm

cheers mate, was thinking maybe my timing is 180 out, but ill try the valves and see

stevieturbo · Post by **stevieturbo** » Wed May 18, 2011 6:32 pm

Spitting through the carb is either sparking at the wrong time ( unlikely though, unless leads are mixed up ) or weak mixture.

shawser · Post by **shawser** » Wed May 18, 2011 8:10 pm

well well well its now running, it was timing being 180 degrees out, cant understand how it happened as i said before dizzy was never touched, but today i took out dizzy when rotor was oppsite no1 and turned it 180 and away she went. so thanks for all your input guys.

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