2 replies to this topic

[Poppet2]

What's the difference?

[Spider]

Bigger question that you might think !

 

Excluding the Cooper S Engines and some stuff that springs to my mind;-

 

The 1275 engine from it's first production up to the introduction of the A+ circa 1979 underwent a few changes on it's own.

 

Initially, they were in in-line engine first produced in 1964.

 

Later from around mid 1967, a Transverse type was introduced and up to mid 1969 had a crank that had 1-5/8" Big Ends. These used the 'Sprite Midget' Con Rods, very similar in spec to Cooper S Con Rods.

 

In Mid 1969, the Crankshafts were changed and now had 1.75" Big Ends and a change in Con Rods. These had a huge lump on the cap of them.

 

Around 1977-ish, the block were changed a little to include a boss for the later Timing Chain set up, which went from Duplex to Simplex at that time, but now included a Timing Chain Tensioner.

 

In the very late days of the 1275 A, the Con Rods were changed to a lighter version that carried over to the A+

 

In 79 the A+ was introduced.

 

The first recognisable item is the external ribbing on the lower part of the block and they had a different casting / machining for the distributor. Consequently, they also had a different Distributor Drive. They also used a different grade of cast iron.

 

Around late 81 or 82 the Crankshaft was changed to the Rolled Fillet type. There was small but important changed to the Main and Big End sizes at this time too.

 

As far as I am aware, they were then largely unchanged until the introduction of the MPI.

 

Throughout this time, the Camshaft profile (excluding MG and Cooper Versions) was largely unchanged, though the Cam Timing was changed.

 

The Cylinder Head did undergo a few but subtle changes but from the earliest to the last was for the most part unchanged. For some models,  bigger Inlet Valves were fitted and the later ones had a different external appearance.

[nicklouse]

I would say what do you want to know?