The interior is bright blue, in pretty good condition although I am kicking myself for not getting door panels at Carlisle at Al Knock's booth.  They have cracks.  The seats look good and I just sprayed the dash and console, what a taping that off but it looks great.  The carpet is not to bad, next year, new white top, and Mulsanne Blue exterior, my dream car.  I just love that car.  At night I feel like giving her a big kiss.  What a great hobby!!!

 

Also, does anyone know the best brand of Octane boost??? 

     I also could not run more than 28 degrees of total of timing.  I also ran 4 degrees less of initial timing than Comp Cams recommended.

     You have gotten alot of good advise.  Just have someone adjust your timing until the ping is gone and run the best gas you can buy with the best octane booster you can find.  Enjoy your Vette!!

Good Luck,

Steve

 

 

Seems like the machine shop suggested 36 degrees at 3200rpms.  I think that puts it about 12 degrees at idle.  Still trying to tweak it.    Mybe by the end of next summer I'll have it right.  Would that be similar to total timing?  I wish you could remember the brand octane booster you used because it's about $10 a bottle and I know some are not effective.  If it comes to you please let me know.  Thanks!!!!

 

Pinging is from detonation.  Detonation is gas lighting in the cylinder from something other than the spark plug.  The flame lights in the wrong place, and at the spark plug.  When the two flame fronts collide inside the cylinder it creates a pressure impact, which resuslts in the ping noise.

This creates a lot of uneven pressure and impact in the cylinder and can do some damage.  Severe damage in some cases.

 

Ping is caused by a hot spot in the cylinder.  This is a result of heat.  There are several sources.   One is carbon deposits.  The carbon holds heat and lights the fuel.   A warm running engine is also a cause.  If the cooling system is not working properly, for any reason, pinging will occour.

How much heat is too much?  It is not water or oil temperature.  It is the combustion temperature in the cylinder.   The magic number is 2500 degrees.  Above that the engine creates a lot of NOx emissions, and causes the detionation the creates ping.

The key is to cool the combustion temp in the cylinder.   This can be acomplished in several ways.

1. Improve the cooling system, but it can only do so much. Perhaps a good flush with a flush chemical?

2. Retard the timing.

3. Use higher octane fuel (more on this)

4. Add EGR (and more on this)

 

The higher octane fuel actually burns cooler and slower than low octane fuel, which burns hotter.  I know this seem backwards, but it not.   Due to the fact that the high octane burns slower, it transfers more heat into the air in the cylinder, but at a lower temperature.

There is a huge difference between temperature and heat.  Temp is an intensity measured in degrees, and heat is a volume measured in BTUs.  As an example try to cut a hunk of steel with a furnace.  Lots of volume but not intensity.  It won't cut.  But try to heat a room with a cutting torch.  Again not happening.  Very hot, but no heat volume.

With more heat, but less temp, the air in the cylinder expandes more, producing more pressure on the cylinder, and thus more power.

 

So higher octane pings less, but you can go too far and not have any performance benefits.

 

Exhaust gas is now inert gas.  It no longer can burn, the oxygen and fuel are both gone.   EGR is exhaust gas recirculation.  It allow exhaust into the intake, and into the cylinders, to cool the combustion.  If we add air it's too lean which runs hotter, not cooler.  If it runs richer we waste fuel, to a point, and pollute.  But rich mixtures do run cooler.  If the carb is too lean it will ping.   The inert EGR gas mixes with the air fuel mixture in the cylinder without affecting the air fuel ratio.  Bue it does diluter the total mix in the cylinder, seperating the molocules which causes a slower, cooler burn.  This stops ping.

Due to the fact that EGR is closed at idle there is no effect there.  It also closes at Wide open throttle so it will not harm performance there.  Keep in mind at WOT the mixture is rich and stops pinging.  Mid range allows EGR to stop ping.

 

So there are several thing to check out.  All of them related to heat in the cylinder.   Do some more checks and let me know what you find.   And no, I don't have an EGR on mine, but it's not a stock set up.

 

I have solved my problem I believe.  I found a gas station that sells 110 octane racing fuel.  The guy that rebuilt my engine recommended a 2:15 ratio to start then most likely reduce to 1 gallon per tank.  I drove about 25 minutes to the gas station with pinging at anything other than minor acceleration.  Somewhat acceptable until the car got a taste of the high octane fuel.  I put 2 gallons in the car and topped it off with the premium, 93.  Within 5 miles the pinging was all but gone and the car literally took off without my doing.  Rediculous how fantastic the car runs now.  It seemed as though the car taking off like a rocket.  Way to much fun!  I drove around for another hour on back roads just because it was 80 degrees and sunny, a beautiful early fall day.  The difference is phenomenal. 

 

The only down side is the price...$6.70/gal.  But worth every penny!

 

I would still like to know where that valve is so that I can check it.  I have tried to make the car as stock as possible with only a few minor exceptions, tires, stereo, etc.   Thanks!

An EGR valve mounts on the intake manifold.  Most modified engines no longer have one.  The stock ones do.

 

I used to know the formula for blending to create close to a certain octane, but I honestly don't remember.   I suspect a few ounces per gallon.  Wish I could remember the blend.

 

Regards, John