Oil Filter Mounting block

[rfs1957]

Hello, Not sure what the protocol is for a first post ?
My 3.8 S1 OTS lives in Montpellier, France, and has proved a welcome distraction from 20+ years specialist work with Ducatis, belts and bevels, both as a racer, engine builder and dealer - with cars, at least, I can still believe na?vely what I read in magazines ..........
Does anyone know where I can find a concise drawing/section of the 3.8 oil-filter head block, with the various flows and functions ?
The pressure-release valve seems straightforward enough, but I can't find any post relating to the bypass device with its ball and spring apparently sealed in place ?
I have a spin-on filter adapter from SC parts, supplied with no instructions or drawing unfortunately, and it leaks from the ring-seal that would normally take the original filter-housing edge.
It took me a while to realise there was a centre-core AND an outer block, but upon closer examination it seems that the various steps and heights of the centre core make it quite difficult to ascertain what sort of crunch you're getting on the nose O Ring that presumably separates the Flow-In from the Flow-Out.
I have assumed that the sort of baffle-plate, that is usually captive on the nose and forms the seal against the original filter, can be removed when using a spin-on filter ?
Does anyone else have experience with this area or know where there are some sections showing the critical areas ?

[kingzetts]

Hi, welcome to the forum.

I had a similar problem with a spin-on adapter (supplied by another of the usuals). Although I did not have a drawing I spent some time measuring the block and the adapter and concluded that by the time the adapter had bottomed out against the block there was not enough crush on the big O-ring to be sure of a seal.

It did seal initially, but started to leak presumably as the new ring (which is actually a square section rather than a true o-ring) settled slightly into the groove.

After thinking about it for a while I decided to go back to the original filter housing as on that there is plenty of scope to crush the seal. So far so good.

[rfs1957]

Thanks for your take on this.
I initially assumed that I was facing that problem too, but in fact the SC Parts version has the core separate from the outer sleeve, sealed by an O ring carried in a groove on the core which makes it a tight but sliding fit.
In that way the tightening of the centre bolt brings the core down towards the block, crushing the other O ring until the shoulder on the bolt hits the block.
Tightening the filter is thus a separate operation and the torque on the bolt is quite independant to the torque on the filter, the core sliding within the sleeve as necessary.
I think the system looks good, although it effectively means that every time you change the spin-off filter you are releasing the compression on the main cartridge-edge O ring ; so far I've sealed that sleeve/O-ring/block interface with black Loctite 5910 Quick-Gasket and it remains to be seen if every filter change requires that sleeve/O-ring/block seal to be changed ........ which as you say may be a good reason to keep the original set-up !
I'm still not clear however whether the baffle plate is meant to come out.