Subaru Starter Motor Selection:
RJES bellhousings take the starters from manual transmission Subaru’s. Some earlier model auto starters also fit. The way to tell is as shown below. Overall, the manual starters are smaller, with a dimension of 48 mm from the mounting face to the end of the pinion (unengaged), and a location spigot diameter of 65 mm. The auto starters which don’t fit are the larger ones shown. They have a dimension of 34 mm from the mounting face to the end of the pinion (unengaged), and a location spigot diameter of 82.5 mm.
Manual Transmission Starter Motors:
There are two types of manual transmission Subaru starters - gear drive and direct drive:
Gear Drive Starters:
Earlier model manual Subaru’s used gear drive starter motors. These fit RJES bellhousings, and work fine. However, they take up a lot of space due to the large offset motor. If you need space in this area for your conversion (such as a late model bay window, or a T25 with two long radiator pipes), you would be better off with a direct drive starter (see below for more details - there is more then one type).
Gear drive Subaru starters need a minor modification to fit RJES bellhousings. Note how the starter is not sitting flat on the bellhousing in the photo below. This is due to the earlier model starters having a large flange around the location spigot - Note how much smaller it is on the late model direct drive starter shown at the top of this page:
...This foul is easily fixed by filing a small chamfer onto the edge of the starter, as shown below:
Direct Drive Starters
The direct drive starters are used on later model Subarus. These are the best ones to use with a VW conversion, as they are very small. There are at least two types - a short one (as shown above - Subaru part number 23300AA380), and a long one (below - Subaru part number 23300AA420). The long and short starters have the solenoids in a slightly different position. Of the two, the long version gives slightly more space around the coolant pipes in a T25 - useful if you have a T25 with two long two long coolant pipes.