[TR] oil pressure, felt filter?

Randall tr3driver at ca.rr.com
Wed Sep 24 11:32:02 MDT 2008


> Shown below is a message I got from an MG'er, do TR3's have this kind of
> oil filter?

TR2 and early TR3 did use a felt oil filter (like at least early MGAs did).
However, the felt filter can only be used with a "bypass" filter setup,
where the filtered oil is returned to the crankcase and the galleries are
fed with oil direct from the pump.

I don't recall the change point offhand, but the TR3 went to a "full flow"
filter setup well before the introduction of the 3A.  A felt filter should
not be used with the full flow filter head, as it will not pass enough oil
to feed the bearings.  Doing so might make the oil pressure appear higher
(since the gauge measures pressure before the filter), but the actual
pressure to the bearings will be lower.  Plus the bypass valve will likely
open, feeding unfiltered oil to the bearings.

The "bypass" filter head can be recognized because it lacks the blank brass
plug found on the later heads.  Both types are illustrated in the Moss
catalog.

If you do have the early bypass filter head (very unlikely for you, Paul),
my suggestion is to replace the filter head with a full-flow type; rather
than searching for felt filters.  The later filter head just bolts on.
IIRC, the canister is the same, but the center bolt changes.

BTW, the spin-on conversions will not fit the early bypass filter heads
either.

Randall


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