When Rootes Scotland released the new Imp in May 1963 the car was fitted
with a 5 1/2" clutch plate, I had one of those Mk1 Imps and drove it far and wide for abound 18 months, the size of the clutch was never an issue.
This is a Mk2 and 6.25" clutch plate, its a fair bit larger than that as found on the Mk1 cars. The later clutch had much larger diameter bolts as well.
Note the Laycock spring diaphram plate,this design was first used in 1962 on an F1 car,was it the Cooper Climax? A year later Rootes Scotland had the same design on their new car, how up to date was that.
Rootes manual:
5.5" diaphragm fitted to Mk1 up to B.429
6.25" diaphragm ever after
So why was the change made? The folk law has it that some older drivers were used to starting off in 1st gear in the car they normally drove, the same practice used in the Mk1 Imp just ruined the clutch.
How hard can this be?
Roy
with a 5 1/2" clutch plate, I had one of those Mk1 Imps and drove it far and wide for abound 18 months, the size of the clutch was never an issue.
Note the Laycock spring diaphram plate,this design was first used in 1962 on an F1 car,was it the Cooper Climax? A year later Rootes Scotland had the same design on their new car, how up to date was that.
Rootes manual:
5.5" diaphragm fitted to Mk1 up to B.429
6.25" diaphragm ever after
So why was the change made? The folk law has it that some older drivers were used to starting off in 1st gear in the car they normally drove, the same practice used in the Mk1 Imp just ruined the clutch.
How hard can this be?
Roy
I was working as a graduate engineer at AP Leamington which owned Borg & Beck clutches. They refused to design a 5.5in clutch requested by the Rootes engineers based on the planned power and torque curves of the Imp. As a trainee, I was shown the maths. A clutch should last longer than 18 months! For F1 they weren't bothered - using hard friction material and pretty stiff diaphragm spring. The later migration to 6.25in would cost more, so it would not have been done if it were not necessary.
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