[Mgs] Oil filter sealing

[mgbob at juno.com]

Paul,
   Though I have seen plenty of retained seals in the cannister filter heads,
this is a challenge I have not seen before.
   Yesterday afternoon was spent by helping a friend remove 1969 MGC engine
from his GT.   He said that engine had been experiencing intermittent
overheating last summer, losing water but neither leaving puddles or making
steam out the exhaust that anyone had reported to him.  His driving season was
concluded when the engine seized.
    Stripped to bare block, the lined cylinders all had visible honing marks,
but two cylinders had a scratch. All top rings were broken. No metal in sump
or oil pump, and all bearings appeared normal.  The cause seems to be that
previous owner had replaced water pump, with a new pump that was not well
cast, and had had to be modified to fit the engine. Not marked with a brand
name, it had large clearance between impellor and housing, and the output
passage appeared restricted.   We are hoping that he finds no further damage.
Bob



---------- Original Message ----------
From: "PaulHunt73" <paulhunt73 at virginmedia.com>
To: <mgs at autox.team.net>, <MG-MGB at yahoogroups.com>
Subject: [Mgs] Oil filter sealing
Date: Mon, 10 Mar 2014 13:09:40 -0000

Anyone seen this before?
http://www.paulhunt73.webspace.virginmedia.com/mgb-stuff/images/fh2.jpg

I've had the roadster (1973 with inverted filter on an adapter) 25 years and
changed oil and filter annually. For years I never had a problem, then
started
getting a spurt of oil from the new filter at first start, about an egg-cup
full, then it sealed itself and no further problem. Then it started getting
worse. A couple of years ago I had to remove and reseat the filter, checking
the seal and the face on the filter head, before it would seal. Then last
year
I had to remove and replace four times, and use a second new filter, before
it
sealed. I thought there must be a problem with the filter head so got a
2nd-hand one.

This year I removed the old filter and looking at the filter head the sealing
face seemed obviously warped, something I had not noticed before. I got a new
filter and smeared copper grease round the seal, and screwed it on till it
just touched. Removed it, and the grease had transferred to just two areas
180
degrees apart, with about as much area again showing no grease. Regreased the
seal and fitted it again, this time tightening it by half a turn after
contact. Removed it again, and this time grease was showing about 3/4 the way
round the sealing face, no grease top right, where it has always spurted
from.

Checked the replacement filter head and that was dead flat, filter sealed all
the way round as soon as it touched. Swapped the filter heads (stressing
about
a seized adapter fixing bolt, but it was barely finger-tight!) and with a new
filter on the old head when the seal was just touching at two opposite sides
there were gaps between them, one of them being 65 thou. You can see daylight
right through as in the attached. Tightened by half a turn it was still 25
thou where it has been spurting from.

New filter head has sealed just fine. The original filter head must have been
warping gradually over the years, as I can't imagine how multiple filter
manufacturers could have contrived to change their seals, gradually and in
unison, such that a fixed warp on my filter head gradually got harder to
seal.
But I guess I'll never know.

PaulH.
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