Gearbox 1.8

[MM3]

Afternoon,

Hopefully someone on the forum can provide some advice.

I am in the process of replacing my clutch on a 1800 Marina engine.

I have read that there is a choice of spigot bush or roller bearing for the 1300 models. However my
1800 engine has a roller bearing. Is a roller bearing also sometimes used on the 1800?
The input shaft measures .500 thou and the external bearing diameter is .750 thou. Or is it the case
the input shaft /spigot bearing is the same for 1300 and 1800 models? Therefore, the only difference
between the input shafts are the gear ratios and number of splines for the clutch? Is the roller or
bush a better option for the 1800?

Also, the attached photos show the crankshaft oil seal. There has not been any oil leaking from the
hole in the gearbox bell housing, however there is some slight evidence of oil on the lower section
of the oil seal. (see Photos) Is this normal? Is it a matter of course to change the oil seal every time, or is it
best left alone if all seems okay?
Thanks

[MarinaCoupe]

All spigot bearings (1.3, 1.8, 1.7) have the same ID (0.50”) & OD (0.75”). Early cars Mk1s and some Mk2s had Oilite sintered bronze bearings. Later cars used a the needle roller bearing.

The Oilite and needle roller bearings are inter-changeable and it looks like a previous owner has retro fitted a needle bearing to yours at some point in the past.

As far as the gearboxes are concerned, the 1.3 & 1.8/1.7 have different diameter input shafts. The 1.3 has 7/8” (22.22mm), the 1.8/1.7 has 1” (25.4mm). The spigot tips are both 0.5” to match the spigot bearings.

The crankshaft rear oil seal in your pictures looks to be in good condition, unless that is you wiped it clean before taking the picture?