the standed px200 timming is set at23degres and is a castiron cyilinder dosent dispers heat as well as ali but ail cyiliders are set at 18degres to make the run cooler this is confusing to me any exlanation would be gratefull
[:dance1:] [:dance1:] [:dance1:]

Apologies all, been in a gutter for the weekend. WELL. how to put this. Ozzy is pretty much getting a cigar, but. The actual point of ignition is determined obviously by your timing. In a perfect world it would ignite at top dead centre - the speed of the volume of mixture igniting. This is not, and never will be, a perfect world. If it really happened like that youd melt pistons and horrendous pre-det. So in our real world the ignition is set BEFORE TDC. Otherwise Pre-det occures originating around the squish band in the cylinder head, Hence the importance of having a machined head to suit you preffered piston. So, an ali kit has one major advantage fron our point of veiw. It dissapates HEAT so much quicker, therefore we can set the ignition later due to less pre-det. Even a cast iron barrel that is tuned/ported can run later ignition due to extra piston crown cooling from the bigger flow of cooling gasses. IM not going into exhausts and expansions at this point, its a bigger can of worms.

basically it’s not all directly about cooling…

the idea behind ignition advancing is to get the little explosion in the combustion chamber burning so that it is optimally expanding just as the piston passes TDC. if that optimal point is to early then the piston and explosion will crash into each other and the piston will be trying to compress desperatly expanding gasses. this will result in over heating/detonation/hole pistons and all sorts of baddness. if the ingition is to late the explosion will just blow all its energy out the exhaust resulting in crap performance.

the reason the ali kits require less advance than the standard px200, is because they have better port designs and may be run with bigger transfers and an expansion all things that will aid better breathing. Better breathing = better quality induction charge, which = quicker burning, which requires less ignition advance… you get it??? basically the PX200 barrel was designed in the stone age to be ran with an exhaust which only serves to make things quieter, as a result the induction charge is probably a large part exhaust gasses and burns slowly requireing a large advance…

please correct me if I’m wrong anyone?? BEERACE??

wot a load of old toss acey baby,youve been on the meth’s again havent you!!!.see boys told you he’s the new messiah

No it was the morphine Im on on a daily basis. Just to add to the timing equation, but to confuse things further, timing is dependent ALSO on;- Compression ratio, Exhaust port duration, Transfer port duration, Tuned length of expansion chamber,The anticipated working rev range of the engine, Inlet timing, Configuration of carburettor design, Piston crown profile,Spark plug gap, etc, etc, etc, And not forgetting the partridge in a …

So back back to the morphine and the gutter I go, Such is life. And Ive yet to do the ceiling, but itll have to wait now. Slidy, where you to matey? Email me from profile. Cheers .S.[:roll:]