Ignition Question

First, 10-1/4:1 with iron heads is too much compression for todays so-called 91 octane "premium fuel. Indeed, 9-1/2:1 is pushing it unless you use avgas. Second, all the advance totaled up should not exceed about 36 degreees: initial setting plus mechanical plus vacuum, even though they occur at different times. There should be a rubber bumper on a post in the distributor that is supposed to limit centrifugal advance; if it fell off or split, the mechanical advvance will be far in excess of what the engine needs. Finally, I think it would be a real good idea to pull your distributor and check the drive-gear roll pin. This pin tends to shear a little at a time in some engines. When it does, the timing retards as much as 15 degrees, which also affects engine temp. Don't just look at it; look THROUGH it to see if the pin is bent. The fix is to replace the pin with a real roll pin, not a spring-pin, then add a second smaller roll pin inside the first one to reinforce it. Your roller cam probably requires a bronze distributor gear that often wears out in 2000 miles, retarding the ignition on acceleration and advancing it during slow-down. These gears are consumable items like cam chains. When you chech the drive pin, also check for a worn-out gear with razor-sharp teeth.

I should have mentioned that I am in Colorado at 5000 ft. above sea level and higher! I have tried octane booster but it didn't make much difference. Dennis and Kip at PPC in Castle Rock told me they would not build an engine for use around these parts with less than 10 to 1 CR. I rebuilt the engine my self about 1000 miles ago based on many of their recommendations. The distributor does have a bronze gear with a new pin. I am tempted to say the hell with it and tune it for best performance pinging be damned!

I run 10.5:1 comp ,iron heads,MSD dist.(36 deg.)MSD 6A-L box,93 octane Sunoco gas and have never had a problem with pinging.Even when the motor is hot and the air is cool.
I would definitely recommend the MSD dist.It works like a champ!

YES! R MCCALL, I REMEMBER THE SUNOCO PREMEIUM GASOLINE WAY BACK IN 1971, WHEN I USE TO DRIVE MY '67 MUSTANG FASTBACK GTA, WITH THE 390 C.I. ENGINE; CROSS COUNTRY FROM OAKLAND TO CHICAGO. GOD! THOSE WERE THE GREATEST DAYS FOR "HOT-RODDING". I BELIEVE IN THOSE DAYS THE OCTANE RATING FOR THE SUnOilCO "HIGH TEST" WAS 103!!! THE DIFFERENCE WAS LIKE A FLY SWATTER TO A SLEDGE HAMMER TO YOUR BACK!! EVEN BACK THEN IT WAS THE VERY BEST YOU COULD GET ANYWHERE, AT ANY PRICE! I DID'NT KNOW YOU COULD STILL GET IT! FINAL NOTE: I WAS FRESH BACK FROM VIET-NAM, AND HAD A GORGEOUS GIRLFRIEND IN CHICAGO, I LIVED IN OAKLAND, CALIF. MY TIME TO "CHI TOWN" (I LOVED "WLS" ON THE AM RADIO); WAS EXACTLY 24 HOURS NON-STOP, AND THAT WAS WITH A 2 HOUR STOP FOR SLEEP. AND THEN I STOPPED ONLY FOR GAS, CHECK OIL, AND TAKE A RELIEF! AT SOME,(IS IT??) 2200 MILES, THAT IS AVERAGING 100 MPH FOR 1 DAY. FOR EVERY MINUTE I SPENT DEAD STOPPED, I HAD TO SPEND 10 MINUTES AT SAY 140-150 MPH! IT WAS KIND OF A "COPS BE DAMNED SORT OF THING", IT'S ONLY A TICKET, AND I CERTAINLY RECEIVED MY SHARE WAY BACK IN THOSE GOOD OLD DAYS! IT WAS "RACING YOURSELF". NOW DAYS THEY WOULD TAKE YOU STRAIGHT TO JAIL!! THATS THE TRUTH AS I REMEMBER IT! "BELIEVE IT OR DON'T" YOURS TRUELY, MARLIN.

[This message has been edited by MARLIN JACK (edited 06-29-2002).]

Sounds bad ass!That's when I was born!(1971)LOL

God Rmccall, I Thought you were closer to my age (1952 vintage). On a regular basis we ran up from Camp Lejeune to the Lehigh Valley in the early 70's in less than 8 hrs(550 mi),. ah they were the days.......
Guy

Oh I Forgot to say, that was in a brand new,
are you ready 2000cc german engined 4sp PINTO!!!!!
Guy!!!!