30-03-2018, 11:12 PM
(This post was last modified: 30-03-2018, 11:17 PM by Tony Press.)
(30-03-2018, 01:41 PM)Thowdfella Wrote: Must admit I too have been very sceptical about stale fuel but this exercise has proved it to me except for the compression issue. I have just done a compression test with a hot engine and throttle wide open and it's giving around from 80 to a max of almost 90. As I have previously said Ibelieve that maximum compression is the cars compression ratio times atmospheric pressure so the maximum I can expect with 6/1 ratio which my big seven is is 6x14.7 equals 88.7. Is their correct or not? If it is then no way can you get any higher readings than this so I am either wrong or there are some incorrect testers out there.
I recently bought a brand new compression tester and that gives a reading of 50 ish but an old one I borrowed gives my the 85 ish. Interesting!
From my notes -"Compression pressure checked with a Compression Tester will as a rule will be 17 to 20 times the
compression ratios with a street cam according to Stuart Bonney in his 2006 paper 'Compression Ratios and Cylinder Compression Testing in Ford N Series Tractors ' -
Taking an average of 18.5 for a 6.2 to one CR you get a rounded 115 PSI at a cranking speed of 120 rpm .
Cheers, Tony.