Well I took the old girl for a spin today, and everything was good until I turned the car off. I'm not sure if it was just dieseling, or started to run backwards.! What causes this? Is there anything I can do to fix this little problem? It only happens after i've been driving the car for a good while and it's pretty warm. (the car being warm that is) Could header wrap cause this to happen? I'm currently useing header wrap, but I haven't even wrapped all of the header tubes. The ones I did wrap are only wrapped far enough to keep the sparkplug boots from getting toasted off. Would running high octane gas help at all? I'm currently running 93 octane, and might put a couple gallons of 110 octane in each time I fill up. I'd appreciate any advice you guys could give me.

Thanks
- Ben

What is your timing set at. Advancing the timing will raise the idle speed some. Then you can address the problem of the throttle blades being opened too much (likely the problem) by lowering the idle speed down with the carb idle speed screw.

Chevy engines, in general, like a lot of initial timing. Even a totally stock engine will run much better with 12-14º of initial. The engine will run cooler, too.

Another trick you might try is dribbling a small amount of water into the carb while the engine is running. This will clean off any carbon buildup that might be causing a hot spot.

I don't think header wrap has any effect. Even with the wrap it's no hotter than manifolds.

Thanks for the info. My initial is set at 12 degree's advanced. I may have checked this wrong though. What exactly do I need to do to check initial timing? All I did was start the car and put the timing light on....turned the distributor until it read 12 degrees on the indicator. Did I do this incorrectly? Also, what is generally ideal for initial timing for a modified small block? I'm just curious....

Would running a mixture of 93 octane (12-14 gallons) and 110 octane ( 2-4 gallons) hurt anthing? I mean can you run too high of an octane? Just curious.

Sorry for all the questions....I know they are probably pretty moronic.

Thanks in advance
-Ben

Originally posted by 71chevy0192:
Would running a mixture of 93 octane (12-14 gallons) and 110 octane ( 2-4 gallons) hurt anthing? I mean can you run too high of an octane? Just curious.Ummm...maybe just your wallet? :confused: :D

Well the wallet isn't a concern as far as this car goes. Well.....at least not for gas. That stuff smells AWESOME too!! lol Call me a dork, but I love it. Burning/watering eyes, people looking at you like "what the hell is he running?" it's a beautiful thing *wipes a tear from my eye* :D So lets say I ran straight 110 octane (not that I would) it wouldn't hurt anything right? Would it help in anyway other than leting me safetly advance my timing more? Last question.....how much do you guys think I could advance my timing without pinging if I were running a total mixture of 100 octane? Just curious.

Thanks a bunch guys!
-Ben

I run 18º in my bracket car and 24º (including 10º vacuum advance) in my street car. I wouldn't run race gas unless you have to. In Calif, it's a big fine if they catch it in your tank. You can run too much octane. The engine will be down on power.

Why don't you post the car's specs, engine, gears, stall, ect? You probably don't need more than 91 octane.

I don't believe that I need the high octane fuel (110), but it's just that I love the smell of it. I'm also wondering if I would be able to kick up the timing a decent amount if I were to run a high octane....something higher than 93 that is.

I really need to make this so I can cut and paste this info...given it too many times. lol Anyway the specs are....

Engine 333 cu in... no not 331. it's a .040 327

Accel HEI Ignition
14" K&N air cleaner
1" carb spacer
Edelbrock 600cfm electric choke carb (1406)
Unsure of fuel pump type probably stock 3/8" line
Performer intake ported/polished
Performer RPM heads ported/polished
1.5" roller tip rockers
216/216 .454/.454 110 LSA crane energizer cam
Double roller timing chain
10.35:1 64cc pistons .125 dome forged speed pro
stock rods
forged steel crank
fully balanced
1.75" headers 3" collector
2.5" exhaust w/ flowmasters and turn downs ending before rear axles

Trans
TH350 with B&M shift kit (don't know what stage)
2K stall

Rear end/tires/rims
10bolt open 2.73 or 3.08 (don't know)
225/70/R15 all the way around


Currently running 93 octane (will not run less) with 12 degree initial advance (as long as I set it properly) not sure what the total advance is.

After talking with the guy who built my engine, the summit tech guys, and people on this site, it was unanimously agreed that I shouldn't run less than 93 octane. Basically all i'm wondering is how much more, if any, I could advance my timing, compared to normal while running 93, if I were to put a few gallons of 110 into the tank. Also what is the proper way to check initial advance, and total advance?

Thanks
-Ben

What is your idle speed? If you can drop the idle speed you will problably cure the dieseling issue.....

I have my idle set at 900 - 1000. In gear it idles at 700 - 800. I was told this is pretty much ideal...no?

Try 600 in gear. With the cam you have you shouldn't need 700-800.