Engine capacity

[swifty]

Hi .can anyone confirm what I'm thinking here. I have a 1300 gt block . It's bored out to 73.5 with omega pistons . The rods are cooper s 521. The crank is a non (s) tufttrided . I've measured the big end journals to 1.625 . So does this mean the stroke would be 84 mm and in effect I have a 1430 engine or to be more precise 1425 . Thanks

[GraemeC]

You won't know until you measure it, it could have had the big ends resized on their original centres or it could've been stroked. I guess it could even be an S crank.

[swifty]

It's not a ( s ) crank . That's for sure . So I'm thinking if it has the same journal size of a (s) rod then it's fair to say the stroke has been increased to 84 mm ? . Can anyone else shed any light on this . Maybe Simon . 251ENG may be able to help

[InimiaD]

My old rally engine used S rods and the 1300 A series crank was offset ground for a stroke of 79. something mm and with + 60 pistons gave a cc of 1297 to keep it within the 1300 class at the time.
Your example has probably been offset ground the other way to gain maximum stroke on the crank.