ignition

Check the class rules, some places do not allow electronic setups

With the capacitive discharge ignitions like msd .I have started engines just by turning on the ignition and never turning the engine over with the starter. ofcoarse it was oxygenated fuel and the cylinder was aligned to fire on compression . Sometimes all the stars align like that.  So i tend to think they have some hotter better fire. jmho

If you really want to spend time and money on your engine put a ground cam in it and degree it in correctly. If you just want to spend time with your engine degree your stock cam in correctly to about 104* ATDC intake centerline.

You'll notice the advantage from the above. You won't notice any advantage weather you have a good set of points or an electronic with an MSD. Nothing beats a good mag though.

leave the coil loose the points....pertronics it the only way to go with a hot coil

I know of some running nothing more than a petronix electronic ignition and a good coil running RPM's over 5000 with no problems.   

Take WI's advice and change the cam timeing or get a ground cam.  The most important thing for engine performance is the closing point of the intake valve.  By altering the cam timeing of  your stock cam you are changeing the point of closure to allow maximum cylinder filling.  Low RPM engines need to be closed sooner than higher RPM engines.  As the intake valve starts to close the pressure begins to rise in the intake port, the mass of air and fuel rushing into the cylinder slows down and pressure rises.  When the piston comes around BDC or bottom dead center and starts to rise on compression, pressure begins to build in the cylinder. Pressure in the intake must rise high enough to overcome the cylinder pressure in order to continue to fill the cylinder.  When you change your cam timeing the position of the piston to intake valve cycle change helping to ram more air/fuel into the cylinder. 

 

Cranking compression pressure has little to do with how the engine will respond to these modifications when running.  It will indicate changes but the highest compression will come after the cam is to far retarded.  Read some old threads on cam timeing and have a good laugh at the armchair expert. 

You're ignorance is forgiven, when you get some experience you will understand what I posted. As in Larry's sig line "I can explain it to you but I can't understand it for you". So true here.


We all know that advanceing the cam raises cylinder pressure. But peak pressure will come when the cam is to far retarded. Try it sometime and see where peak pressure is and how it runs at that point.   Sounds like a good homework assignment for pank. He still hasn't done the last ones I gave him.

I'm sorry, I forgot. Pank has no clue how to degree a cam, or where to set it at or how it works. Past threads have shown that. I wouldn't take any camshaft advece from pank, he still thinks that no matter where you place an 8 degree chevy bushing the cam timeing will change 8 degrees no matter what. No consideration to basic geometry. Pank realized his invalid attempts at understanding camshafts upon unable to move the pulling sled so he bought one from someone who had it figured out.

Edited by Rod B - 30 Oct 2012 at 7:16am

rod wrote the highest  compresion reading will come after cams to far retarded . and that is wrong read again .  the highest compression reading will come when cam is advanced to correct degree If you add another degree or two compression will start to fall off but the cam is still being moved in the advanced direction . Retarding a cam always reduces cylinder pressure . ford did it alot on detonation prone engines.  here is rods statement cut and pasted so you can see his error."It will indicate changes but the highest compression will come after the cam is to far retarded"   . engines that run under 6000 rpms and need to lug see benefits from advancing and checking for the highest cylinder pressure reading at starter cranking speeds . it really increases the torque and power due to the effects on "effective stroke".

Edited by mlpankey - 30 Oct 2012 at 7:33am

Rod B wrote: Why don't you take some time and play with the allis and tell us at what point peak pressure happens. You'll find that the cam will be to far retarded at 107 degrees. Trust me, you'll want it more advanced. It's because of the inline 4 cyl design with siamesed intake port. 3 valves in the paired cylinders have activity to close to each other. This isn't about a ford or 6000 rpm.   When the engine is running up to speed things happen that don't show at cranking speed.

The more you advance a cam the higher the cylinder pressure will go unrtill it falls off  from being  advanced to far . Now depending on how much duration the cam has and how small the engine is in cubic inches will depend on at what degree the cam will be advanced to when  the compression reading will be the highest.   There is no such thing as to big a cam due to duration. There is such a thing as to small cubic inches and to low of static compresion ratio  for big duration camshaft and when that happens you will see helpful gains in advancing a camshaft to large amounts of degree change to the advanced postition as long as you are looking for the highest cylinder pressure reading. A cam thats correct shouldnt need advanced at all unless your attempting to make a flatter torque to power curve. If you use the highest cylinder pressure method and you find the highest cylinder pressure at cranking speed is with the cam 15 degrees advanced then you know you have the wrong cam in your engine build.  Using the longest effective stroke will show up at cranking speeds and will stil be a benefit when the engine is at running speeds below 6000 rpms. if your wanting to run 7000 rpms or higher do not use this method for your engine will like the cam straight up for the most part some may even like it retarded a few degrees.

Edited by mlpankey - 30 Oct 2012 at 8:20am

Go read my original post in which I say "by altering the timeing of your stock cam".

Sure a custom ground has different charistics. That's not up for debate. You can stop your teenage girl cat and mouse games by simply learning to read.

mlpankey wrote: I do read and simply posted your inaccuracy . quote rod ,"It will indicate changes but the highest compression will come after the cam is to far retarded"   admitt this statement is wrong and my engine intellegence caught your mistake and move on.

I posted where peak pressure is and 107 is retarded further than 104. You have no intellegance if you can't figure that out.

We are not dealing with custom cam. Peak pressure is at 107 which is retarded compared to 104. So you can play around all you want but this still means the same thing as in my original post.

Are your failed attempts at building a competitive pulling engine a result of your fake engine intelligence or yout real engine ignorance?

   Getting back on track with your ignition question.   I have been very satisfied with pertronix systems and also use their stealthy stock looking black coil.  There are two more things to do that are cheap upgrades for your ignition. First is to index your plugs to each cylinder. , when that is done trim the outer electrode on your plugs to  a sharp square  that just ends  at the outer edge of the center electrode, This opens up the spark to face the piston top, and you can open the gap then to as much as 45 thou.  This is  a worthwhile mod......   for not a lot of money.

On the ignition when you find the brown residue inside the black distributor cap then you will need to drill holes between the post to let the plasma ions out. If your worried about moisture then you will need to go to the hei cap with wider posts.

I love how a simple question becomes a pissing contest lol

every distributor cap wouldnt have the brown residue from plasma in it just the ones  sending several joules to the plug and you dont need that unless your running high compression ratios.

Edited by mlpankey - 31 Oct 2012 at 4:00pm