My 53 TD has the alluminum pistons without the springs. A early 52 (11,000
something) I worked on also did not have the springs. I have several sets
of 1 1/4 H2's with alluminum suction disks and no springs. The 1 1/2" SUs used
the springs so the TF would have them.
As definitive proof I have an original SU spec sheet "REf. No NEL. 191/16" for
"M.G. Midget (Series 'ED') (H.2. Type. Specification No. 549 Commencing
Engine No. XPAG/TD501" and it lists NO Spring.
I also have the same type of sheet for the Mark II spec H4 AUC578. These HAVE
the spring.
1) The ORIGINAL SU manual I have from "12/59" states that up to 1939 the
suction disks were zinc die cast but the die cast had a tendency to distort
or grow.
2) "The brass piston replaced the zinc tyype and ran in general production to
1950."
3) Current production (1959) uses a THIN wall piston which needs a spring
selected on the basis of the weight of the old suction disk.
4) The old pre-war THICK-walled aluminuium piston used without a spring ...
was used generally on twin- and triple carburetter layouts and is now
practically out of production. It can be replaced by the current thin-walled
type plus a piston spring..."
Regards,
Blake
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive/mg-t
|