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MKI / MKII S type 240 340 & Daimler 1955 - 1967

240 engines - various compression rates?

Old 11-19-2018, 08:01 AM
Lambretta's Avatar
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Default 240 engines - various compression rates?

Hi all
On the engine numbers I read: "Note: Suffix of /7 or /8 to the engine number denotes compression ratio."
So, all the 240s came with an "8" compression rate on their engines or there have been also some cars with "7"?
What's the difference in practice between 7 and 8?
Old 11-19-2018, 08:20 AM
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It's all in the pistons on a Jag & fuel availability in different markets. The higher the compression ratio the higher the performance but also the higher the propensity for knock, pre ignition, detonation, pinging by whatever term you know it. Jaguar built 7 to 1 CR engines for poor fuel markets where only low octane fuel was available. 8 to 1 CR was the most common. They built engines with all 3 compression ratios.


Last edited by Glyn M Ruck; 11-19-2018 at 08:26 AM.
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