OK this is just from my experiences and my friends experiences with buick engines especially the 350. Whats the deal with buick engines and SPARK KNOCKING? I feel I need to bring this topic up, anyone that has a buick engine and the spark knocks knows that t can be a real pain to fix and believe me I've tried everything I can think of. If anyone is in or has been in the same boat that Im in and has a solution to this problem that seems to happen to most guys I know with buick engines please, any tricks to fix would be greatly appreciated. Thank you
Good gas..... If I buy gas anywhere other than Amoco (now BP) I will get spark knock in my 350. As long as I stay with the Amoco, non-oxygenated 92 octane it runs SWEEEEET :TU:
Sounds like you may need some 'tweaking' of the ignition to some degree. I would suggest using the search function on this board and type in both 'ping' and 'vacuum'. There's some very good info to be had there. IgnitionMan Dave and others have spelled out in detail, ways to check and modify your current ignition setup.
Adam, How much timing are you running? When is your mechanical advance all in? Are you running a vacuum advance, and is it limited? Have you checked to see if you have an advance stop bushing? How many miles on the engine? Compression ratio? What plugs are you running? What's your engine temperatures? What timing light are you using? Give us some more details, and we'll try to help.
WARNING!!! Before attempting anything I'm about to suggest here, think very VERY carefully about the possible damage it could cause.... CONSIDER YOURSELF WARNED! I solved my knock problem by pouring a large sized bottle of brake fluid down the carburetor of my engine while it was running. Just DUMP the whole thing down there, untill the engine stalls. Do this while the engine is warm. Once it stalls, turn off the key, and walk away from it for 24 hours. The idea is that the brake fluid permiates into and brakes down the built up carbon in the combustion chambers. 24 hours later, re-start the engine, and using a garden hose turned way down low, to just a small stream, and let the water run into the carb of the running [idling] engine. Keep the water running for 10 minutes or so, untill the engine is up to full temp. The water turns to super heated steam, and blasts off the carbon deposits that the brake fluid has "loosened" up. I know this all sounds totally crazy, but it really does work. The chunks of black crap blasting out of the tail pipe will attest to it's affectiveness. One more thing..... And this is kinda important.... While the motor is burning off the brake fluid, it's gonna smoke like you would not believe..... So dont attempt this in a closed garage, or parked next to your neighbors open bedroom windowou:
I've never used brake fluid, just the "urine stream" of water from a garden hose with the engine at (very) fast idle. Make sure you do both sides of the carb on a dual plane manifold. About 5-10 minutes. Works GREAT! Change oil afterwards, (Lots of moisture in it) and you're good to go. If you have spark knock on an engine at PART THROTTLE, install (or repair) the EGR system! EGR works like magic to kill spark knock at part throttle. Since there's no vacuum at full throttle, the valve is not active then, therefore no power loss, but also no spark knock protection. Beyond that, yes, play with ignition timing, advance curves, etc. Verify proper engine operating temp, and verify proper fuel mixture. Are you feeding the carb overheated air with a stuck air cleaner heated air door, or ripped/missing cold air induction air hose? How about one side of a dual exhaust restricted, or a stuck heat riser valve forcing exhaust thru the intake crossover? When the heat riser valve is closed, the intake crossover should be SCREAMING hot! If your skin is instantly destroyed before you can register pain, the crossover is oK. When the heat riser valve opens, the crossover will cool down somewhat. it'll still be plenty warm, though. Sorry, you need to have some experience here. I don't have temp measurements! If the crossover is plugged with carbon (REALLY COMMON) your EGR will not function. (but the cooler manifold is good for performance. Many people deliberatlely plug the crossover!) When it comes time for a rebuild, verify your quench distance, and verify the dynamic compression using Pat Kelly's calculator http://members.uia.net/pkelley2/DynamicCR.html
I never got rid of the spark knock in my cars until I put in a larger radiator. These cars were designed to run on 100 octane fuel, which actually has less energy in it. With the high compression and the lower octane fuel (more energy), more heat is produced and the radiator sized with the car when new won't keep it at the temp it was designed to run. This is especially true on non-AC cars with the 2-core radiators. It doesn't take but a 15 or 20 deg temp increase in the engine to cause you to run into spark knock. If you can keep the engine at 180 deg., you shouldn't have any spark knock problems when using 93 octane fuel. I put a 3-core radiator out of an AC car on mine and I haven't had a bit of spark knock since.
