the compression ratio is not a ratio of pressure. it is a volume ratio;specifically its the cylinder+combustion chamber volume at BDC/combustion chanber+cylinder volume at TDC. The compression gauge pressure for typical gas engines on tractors is ~ C x pambient x[(compression ratio)^1.4-1] wwhere C is between 0.65 and 0.75. ).67 seems to work well on the Ferguson Continentals and the N seried Fords The compression gauge pressure should always be measured with the throttle plate fully open.
So for your 7:1 compression ratio, if the ambient pressure is 14.7 psia , your compression pressure should be ~ 140 psi.
Having said that if the manifold pressure is 20 inches Hg vacuum, that"s about 4.9 psia so the compression pressure at idle would be ~ 48 psi.
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 - Third Brush Generators - by Chris Pratt. While I love straightening sheet metal, cleaning, and painting old tractors, I use every excuse to avoid working on the on the electrics. I find the whole process sheer mystery. I have picked up and attempted to read every auto and farm electrics book with no improvement in the situation. They all seem to start with a chapter entitled "Theory of Electricity". After a few paragraphs I usually close the book and go back to banging out dents. A good friend and I were recently discussing our tractor electrical systems when he stated "I figure it all comes back to applying Ohms Law". At this point
... [Read Article]
Latest Ad:
1945 Farmall wide body gas with pto and front plow. Runs good but needs new points.
[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.
