Ulster Crankcases

[Tony Griffiths]

Can anyone enlighten me as to the (very) detailed differences between an unsupercharged Ulster crankcase and an ordinary one?

[Chris Garner]

Oil jet holes not present as crankshaft is pressure lubricated.
Front and centre camshaft bearings are larger to allow high lift cam to be fitted.
Crankcase feet repositioned vertically to allow a deeper starting handle housing.
Rear of engine raised to align starting handle and transmission line.

Why? Have you discovered one ?

[Robert Foreman]

Plus the magic 9E number.

[Henry Harris]

There seem to have been at least two rather different types of unsupercharged crankcases. The first type was 8 stud, 1 5/16” crank and the last type was 10 stud, 1 1/2” crank. There were possibly variations between.

[Erich]

In addition to what Chris has said, the front feet of the crankcase were also slightly(less than the rear) thicker as part of the design to line up the starting handle through the shroud.

I've also heard it speculated that after the 10 stud was introduced, the 8 stud may continued to have been supplied. Both to use up remaining stocks and to supply owners who may not have specified the 10 stud.

Erich in Mukilteo

[Chris Garner]

There seem to have been at least two rather different types of unsupercharged crankcases. The first type was 8 stud, 1 5/16” crank and the last type was 10 stud, 1 1/2” crank. There were possibly variations between.

Henry. 
Other than the number of stud holes, the position of the dip stick hole was re-sited. I believe this is the only difference between the two.

[Henry Harris]

The first crankcases were 8 stud, standard depth casting and non adjustable oil pressure relief valve under the ns. rear engine mount.
The last type were 10 stud, extended depth casting and adjustable oil pressure relief valve above the engine mount.
Completely different and I expect that there were development variations between the two.

[Tony Griffiths]

Thank you all very much for all the many details. I don't have one but was "asking for a friend" in the VSCC. I understood the nose piece was, of course, different to take the pressure oil feed and the camshaft rev counter drive.