[TR] Moss TR6 spin on oil filter conversion

[Michael Porter]

On 6/15/2013 2:18 AM, Alex Cherington wrote:
> Hi,
>
> Has anybody else fitted one of these????
>
> I purchased one a long time
> ago but it leaked on installation and was replaced. I didn't get round to a
> second attempt but my garage attempted to fit the second one and it leaked
> too.
>
>

Note that the original canister will slide on the center stud until it 
contacts the square-section o-ring, and the internal spring keeps the 
filter element pressed against the land which has the output from the 
oil pump. That the canister and element can move independently pretty 
much eliminates the chances of leakage with proper installation.

Now, with the one-piece casting of the adapter, those two different 
lands (for the center stop and the o-ring) have to be accommodated at 
once.  The annoyance--and leakage--occurs because the lands were not 
uniformly machined together at the factory, because there was no need 
for their relationship to be consistent, with the original design.  In 
relation to the adapter casting, if the center land of the block is too 
deep, the outer o-ring flange will seal, but the internal land will not, 
and the adaptor will allow oil to bypass the filter (and the adapter 
will wiggle on the outer o-ring and the center bolt will eventually work 
loose).  If the center land of the block stands too tall, the adapter 
will seal properly internally, but the o-ring flange will not apply 
enough pressure to the outer o-ring, and that will leak.

Essentially, this means the adapter has to be fitted to the individual 
block.  If the o-ring land in the block is too shallow, the o-ring 
flange on the adapter has to be machined down slightly. If the o-ring 
land in the block is too deep, some of the center land of the adapter 
has to removed.  Mocal adapters come with instructions for fitting and 
include a little modeling clay to help with determining the fit at the 
adapter center.   I've written about this before, so there should be 
more in the archives.


Cheers.

-- 


Michael Porter
Roswell, NM


Never let anyone drive you crazy when you know it's within walking distance....