The Elusive O-Ring - First Oil Change pt. 2

Besides the oil spill from our last installment things went pretty well getting the oil out of the car. Now to change that filter. The filter is held on with one bolt that has to be removed from underneath the car, and an oil pipe connection has to be undone. The big bolt at the pipe connection is bigger than my adjustable wrench, so I had to buy a bigger one of those. Also, I had convinced my 11 year old son to help get the filter off with me and unfortunately got his head in the way of the final thin stream of dirty oil coming down from the oil pan and decided he'd had enough of car maintenance for a few months. Other than that, not too hard to get the filter cannister off. Surprisingly, the pint or so of oil in it didn't leak out as long as I kept the thing fairly upright after getting it loose.  It's probably a little messier than a normal oil change, but not bad at all.

Fitting the new felt filter insert. It's fleece is white as snow.
Notice the nice oil stained fingers.

There are three types of filters that were fitted to the MGA over the years that all look the same to the casual observer. I discovered that mine is the earliest type. This shouldn't make sense for a 1958, but things do tend to get swapped around over 50 years. The filters are the same for each, so no big deal. When I opened the filter box I found it came with a set of replacement o-rings, which I didn't think to order. When you change the filter insert, it's a good idea to change out the o-rings that keep a good seal to keep the pressurized oil from leaking or spurting out. One of mine had hardened and cracked  and the net effect is that a little unfiltered oil would slip past it - not good for the engine long term. If a bad o-ring can bring down a space shuttle, I'm certainly not going to tangle with them.

Unfortunately, none of the o-rings in the box seemed to fit the spot I needed (and they felt more like plastic than rubber). Turning to the parts catalogs, I saw that the later two types of filters used one size of ring, but my older and rarer (it seems) filter uses another. The kind I need was marked "NLA" or "No Longer Available" - the phrase that strikes fear into the hearts of old car owners. A guy from the online MG forum sent me one from an older MG that might have worked, but it was the wrong size too. I hunted around a little and found some in stock with a different parts supplier in Rhode Island. Scarborough Faire - talk to Cecilia. If she's not there, she's down with Julio in the schoolyard. OK, I'm kidding about the last one but the first two are for real. When they arrive, they are round cross section and seem too tight to fit - the originals had a rectangular cross section.

Complicating things is that I've noticed with the parts out of the car for a week or so figuring this all out that the internal part this o-ring fits in is bent a bit, as is the external metal canister.  After searching unsuccessfully for a perfect fit from other suppliers, I decide to try to persuade this one with a hammer since I'm losing good driving weather during the search. Sure enough, with a little light tapping I'm able to get the whole thing back together. I filled up with fresh oil, started it up and anxiously watched for drips under the car and proper oil pressure on the gauge. Success - everything seems fine.

This pressure relief valve fits inside the canister on the early type.
The elusive o-ring fits in the second groove from the bottom.
This metal piece is somehow twisted out of shape and the top
bar is bent in. Can it be trusted for another 50 years?

I got to thinking, though. It seems like not many people can be running this type of filter. If the parts in mine have suffered some abuse over the years causing them to lose shape, maybe I can't rely on them. Rather than buying replacements I really should consider switching to a different filter canister that is more common and easier to source parts. While I'm at it, maybe I should consider switching to an adapter that was used for a while in the later MGs that allow you to use modern spin-on oil filters. If I can find one, there was one that held the filter upside down. This makes it really easy to get to from up top and if you poke air holes in it before removing during a filter change, you can avoid a lot of mess. I decided to hunt EBay and other old parts sources for an adapter - we'll see how that turns out.

Amazingly, according to Wikipedia, the permanent cannister type filter is making a come back in modern car design. Oh well, "Plus ça change, plus c'est la même chose".