Re: New 454 pinging
Your timing is right on with 17 base/37 total @ 3k rpm with the cam your running.
I am not surprised at all that it pings under load with only 223 deg dur @ .05 cam in a 468 with 9.6 comp.
The comp could be even a little higher if you didnt take into consideration a decked block and heads when you figured compression. In that case the compression could be closer to 9:8- to maybe even 10:0 comp if a thin head gasket was used and alot of material was removed from block/heads when decked for flatness.
If it doesnt ping when at part throttle cruise or when accell from a start it's not too much timing comming from the vac adv .
You say it pings under hard acelloration so the vac adv drops out when the intake vac goes away when throttle is opened hard so you only have a few choices without going into the motor to lower compression assuming your already running highest oct fuel avial which is 91 octain in CA.
You can retard the timing untill it stops the ping and loose power & use more fuel or you can buy some real lead kemco booster ,1qt kemco per 28-20 gals 93 fuel increases oct to 97-98 and that will stop the ping and give you some more power.
If the car is not a daily driver it will only cost you approx $100 yrly to retain the full power/perf of your 468 which is what i do with my mild 396 insted of retartding the timing loosing power/perf.
For a wk end cruiser only the kemco is the way to go in your case where the timing is dead on correct and all you need is a hit of kemco to boost the octane.
Search the Kemco site to find the "kemco supreme 130 octane booster" .
Other then doing the above you would have to install more cam to bleed of more cyl pressure,install thicker head gaskets, replace the pistons with lower comp units,or install heads with larger comb chambers to lower comp.
And for all you guys that are going to chime in (like last time ans a post like this one) to say my 540 run's on 91 or 87 fuel with a huge 260 deg @.05 cam & 10-11:0 comp thats compairing apples to oranges in this case,end of story.
I say this because large duration cams bleed off a lot of compression/cyl pressure allowing the use of lower octane fuel in thoses cases even with high comp ratio's which is not his case here. His motor has a farily short dur cam in almost 470 cubes with compression likely above 9:6 closer to 9:8 + on crappy 91 oct fuel used in CA . Keep in mind this is in a 35-40 yr old design motor not desinged to run on low oct fuel and or not built specifically to run on 91 fuel with larger cam to bleed of comp or using flatop pistons for lower comp or larger chambered heads. There motors were designed to run on 98+ oct fuel back in the day which = roughly 96 oct for todays fuel which is still 5 points short for his motor that is running on 91 fuel in CA.
It just confuses the issue in cases like this with a mild perf motor with ping issues being compaired to larger motors with tons of cam duration or even same size motor with a much larger cam bleeding of comp.
I recently ran a post asking for what motor setups were running on what oct fuels and not detonating and in most every case there were large 255-260 deg + deg dur @.05 dur cams being run in 454-540s bbc with the higher comp ratios that were not detonating on 91 or 93 fuel which was no surprise to me.
But when someone has an older gen sbc/bbc built with stock type heads and higher comp above approx 9:5 & up with a short dur cam in his case here that's often a rcp for ping on todays fuels.
Running the kemco to avoid having to break a new engine appart to lower comp is a good solution to his problem not to mention the additonal octane will likely give the motor more power esp when retaining the full perf ign timing curve your currently running which is riught where it belongs.
1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
Last edited by SWHEATON; Dec 31st, 07 at 8:07 PM.