Building adapter plates... How do they work?

[Kagetsu]

I've never been quite clear on adapter plates for gearbox to engines and was hoping for some clarification on the subject.

From what I've seen (and that's not a lot) I have three idea's on how they work.

The first is where two plates are used, one bolts to the gearbox flange and the other bolts to the engine flange both using recessed bolts (except where bolts correspond) and they're then bolted together using the protruding plates on the outside.

The other is to use a single thicker adapter plate which is bolted to one flange (usually the engine?) that also has threads for the gearbox to be bolted to it afterwards.

The other option is to weld a fitted flange to the bellhousing on gearboxes that don't allow removal of the bell housing.

[CrUZida]

All 3 options are common.

Options a) and b) are usually used when the input shaft protrudes past the edge of the bellhousing (as per the JZ series).

Option c) is usually done as a last resort when options a) and b) are not possible, and where the bellhousing is not removeable.


The most common option of course is the complete new bellhousing. But obviously thats not possible when option c) is used.