Ok, heres my problem, my car wont start unless i have atleast 25 degrees of base timing... but if i leave it at 25 degrees it'll ping at half throttle so i have to knock it back to 10-12 degrees.... and i run 93 octane....is there something wrong with this lol.... having to open the hood before i start it everyday have become more than a lil anoying.... Any one ever have this problem...?


Will

 

run higher octane?

 

Geez, how much compression are you running?

 

my first thought, or two, how much compression, outter ring slipped on dampner, is the cam straight up?

 

My compression is listed in my info.. lol 10.5:1 and the cam was degreed. I asked some other people and they said vortec heads dont like alot of timing.... so who knows.





Will

 

Are you saying we're seeing things or something?

 

huh? no i just said the compression ratio is in my info on the left side of the screen..

Engine:388 stroker 10.5:1

 

that really is kinda alot for a iron headed motor on pump gas, maybe running some octane booster in it just to see if it fixes the problem is in order.

 

how about some air plane fuel? that crap's around 112 octane over here... ran it in my car, no probs

 

i wouldn't run more then sunoco racing fuel or some vp.

 

Wow, that is to high of cr for iron heads. Knock it down with a thicker head gasket, remove a lot of the timing advance and set initial timing to where it's needed, or plan on running $$$ high octane. 10:1 is pretty much the limit on iron heads and 93-94 octane with minimal timing advance, especially on hot days.

You can minimize the iron head/high CR ping with reverse cooling, or an extreemly cold stat, but that's a whole new can of worms...

 

What is the dynamic compression ratio of the engine?

Edit: And other specs...? (intake, exhaust, gears, weight of vehicle, camshaft details, head mods, block mods, etc.) Any information that might help.

10.5:1 compression can be run with 93 pump octane. Some argue that 10:1 to 10.4:1 is the limit area, however...

 

uh.... whats a dynamic comp ratio? and i run 94 octan normally.. im gettin aluminum heads this winter, im saving the $$ as we speak. i was just curious, but now that i think of what you guys have said it kinda makes more sense.

but hey w/ the setup i got goin i make 350lbs/ft of torque at 2500RPM and 300hp @ 5500rpm... these specs are at the wheels i dont know what it does at the crank. i kinda wish it was more... but i suppose with some aluminum heads that can be achieved.

 

10:5 is fine with iron heads and with it properly tuned. My motor doesn't ping at all, 10:25 with iron heads and NO tuning whatsoever. I run 93 octane.

Did you line up your distributor correctly when you installed it? Also as previously said, I wonder if the outer ring on the balancer slipped.

 

Get the #1 piston at TDC & make sure it agrees with your timing mark. You should not experience pinging if everything is set correctly.

 

http://cochise.uia.net/pkelley2/DynamicCR.html

Edit: Check out the Nov. issue of Popular Hot Rodding on the stands. Nice article written by David Vizard..."The Power Squeeze: Maximizing the compression ratio delivers more bang for the buck than you can imagine."

Should clear up a lot of misinformation that you sometimes get from people on these boards, as well as others.