Pre igntion is flame initiation prior to spark. Causes are from compression heat, Poor octane fuel, a glowing combustion chamber deposit or overheated tip of sparkplug. Spark knock is from advanced timing, or poor octane. It is caused by early plug spark for that gasoline, or correct timing in low octane fuel. If a flame front is initiated too soon, the trapped mixture is still being compressed as the piston approaches TDC. The heat and pressure of the progressing flame super heat the remaining unburnt fuel/air. this allows it to detonate (combust through its volume all at once, not burn with a flame front. Compare a firecracker to lighting a trail of gun powder with a match) This detonation causes Knock/Ping sound. Modern computer controlled systems listen to each cylinder and adjust timing to produce the tinyest knock. This is not harmful as it is just barely present. The timing thus set produces the greatest Peak pressure in the chamber just as the piston goes past TDC (5 degrees or so), and burns more of the remaining fuel that would normally have quenched out. Todays cars' CPUs learn timing from those sensors and adjust to each cylinder to talior combustion efficience, and adjust for differences between each tank of fuel. Jim
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - The 8N and the Fox - by Zane Sherman. Dec. 13 1998, Renfroe, Alabama. Last niht I dreamed about the day that I plowed the field of about 10 acres over on what Jimmy and Dandy called the Ledbetter field. I was driving the 1948 8N Ford tractor that Jimmy bought in 48 new This was prebably in about 1951 and maybe even befor the house was built. This would have made me to be about16 years old and I drove the tractor for nothing and would have paid to drive it if I had had any money which I didn't, but neit
... [Read Article]
Latest Ad:
Sell 1958 Hi-Altitude Massey Fergerson tractor, original condition. three point hitch pto engine, Runs well, photos available upon request
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.