QuestionMy daughter has a 1973 Spitfire with a 1978 engine. It still has the 1973 transmission. I need to replace a slipping Clutch. Since the 1978 Clutch is larger than the 1973, and the 1973 transmission spline does not match a 1978 clutch disk, what am I likely to find when I get it disasssembled?
AnswerJim,
Well, if it's truly a '78 engine then it should be a 1500cc engine. One simple way to check is to look at the block on the distributor side at the back end near the firewall. If the engine number starts with an "FM" then it's a 1500.
You need to match the clutch disc to the type of transmission that's fitted.
You need to determine if it's a 3 rail trans (proper for the '73 model year) or a single rail trans (fitted starting in 1975).
It'd help to pull the dash support and the carpet from over the transmission cover.
Several simple ways to tell. A three rail trans shift lever is held in place by a bolt at the bottom of the lever. There is also a metal cap that holds the nylon washer/spring assemblies in place.
A single rail transmission gearshift lever is held in place solely by the metal cap.
The three rail gearbox shift lever is held in an aluminum housing that's roughly flat on top and extends forward towards the top of the gearbox with the actuating rod underneath the aluminum housing.
A single rail gearbox shiftlever is held in an alumimun extension that comes up from the back end of the transmission near where the driveshaft bolts up.
The three rail transmission has an input shaft with 10 squarecut splines.
The single rail transmission has an input shaft with 20 triangular cut splines.
The 1973 US 1500 had the large diameter clutch disc with 10 spline center.
I hope I haven't made the situation any more confusing. If so, let me know and I'll try to clear things up.
Cheers,
Jim
'73 Spitfire 1500 with '76 transmission
