I was hoping that since I'm using a Mocal thermostatic sandwich plate, rather than the original 2.1 interwarmer, I might be able to squeeze the proper oil filter in, but it's still too tight:
There's only a few mm in it though. In fact, if I could get the filter square onto the spigot it would fit, with 6-8mm spare between the exhaust and the end of the filter:
It's tempting to cut a few mm off the end of the spigot, as it's more than long enough to hold the filter. I know I'd always have problems starting the filter after cutting the end of the thread off though.
The alternative is the Polo filter, which is much shorter, and as noted, has a different bypass pressure.
