When the MGB was fitted with the larger pre-engaged type starter motor in 1968, the straight hanging oil filter would no longer fit. The immediate change at that time was an inverted canister type oil filter, which met with many complaints about oil drain back when parked, and spillage when changing the filter element. This then was changed to an offset hanging canister type filter, which of course continued all of the inconveniences of the replaceable filter element, but did seem to quell the complaints about drain back. Each of these offset canister filters, inverted and hanging type, were eventually replaced with a respective spin on adapter. The inverted spin on type is shown in the picture below.

Inverted spin on oil filter adapter.

I used this one on my MGA for a number of years, and I had grown rather fond of it. The filter was easy to change. If you punch a couple of holes in the top end of the filter to let some air in, one in the center and one near the outside edge, and give it a few minutes to drain before removing it, there can be very little oil left inside when removed. This then can be one of the cleanest oil filters to change, much nicer than having oil running down your arm below. I used a felt tip marker to write the oil change mileage and date on the top end of the filter. In a time when it mattered a lot to me (having the engine out a lot to change a clutch or gearbox), I could R&R the engine without removing the oil filter, where the hanging filters would hit the engine mount pedestal on the frame and had to be removed to pull the engine.

This is the same style adapter shown with the steel connector pipe as used on the MGB when fitted with alternator and no oil cooler. The steel pipe will not fit when used with a generator, but I have used this spin-on adapter with a generator and oil cooler with hoses (no steel pipe).

Filters which can be used with the inverted spin on adapter:

AC - PF13, PF-20, PF53 Amsoil - SDF-42 Amsoil - SDF-96 Baldwin - B163 Beck/Arnley - 041-8889 BOSCH - 3402, 3422 BOSCH - 72-137, A600043375 CarQuest - R85348 CarQuest - 85085 (Wix) Cooper - Z27A Crosland - 306

Deutsch - D406 Driveworks - DW-241 Ford - D4ZZ-6731A Fram - HP3, PH16, PH43 K&N - HP-1002, HP-2004 K&N - PS-1002 Luberfiner - PH2835 Mann - W917 Mobil - M1-102, M1-204 Moss - 235-960 Motorcraft - FL-300

NAPA Gold - 1068 (Wix) Promotive - PH195 Purolator - L20081 Purolator - PL-20195 Purolator - PL14670 Royal Purple - 10-2835 STP - S-0228, S3614 STP - S16XL Unipart - GFE 121 or GFE 114 Wix - 51068, 51362

There will be other filters that will work with this adapter, likely any filter with the same thread and seal. Internal pressure relief valve is required, as this spin-on adapter does not have a relief valve.

For the inverted filter, the shape is usually fatter and a little shorter. There is a standpipe on the adapter (at least the one supplied by Moss Motors). The filter then has to be long enough inside to clear the standpipe, but even the tiny little "Toyota" filter would probably fit. Narrower filter leaves more access space for service of distributor, dipstick, generator connections. Fatter and taller have more filter media (and a tad more cooling area). Some filters are reported to have a bypass relief valve positioned just inside the center outlet port, which would interfere with the adapter standpipe, but I haven't seen a filter like this (yet).

On the contrary side, the inverted filter occupies some space between the generator and the distributor, slightly obstructing service access to both (but not much of a problem). If the inverted spin-on filter does not have a properly functioning anti-drain back check valve, it could leave the engine with low oil pressure for a few seconds longer on initial start up, but with a quality filter (hint: avoid Fram) of the correct part number this should not be a problem. Notice the hose adapter fitting on this one is pointed toward the front of the car, suitable for installation of oil cooler lines. But in the absence of an oil cooler, there is a hose available for the connection from rear of engine block to the adapter. See Moss Motors part 435-585.

Here is another solution devised to use a metal pipe rather than a hose. This is strictly non-standard, so if you like it, make your own pipe assembly.

Some people say the standpipe is to aid with the anti-drain back function. I have a different take on this issue, and a different purpose for the standpipe. I also have a report of a similar inverted spin-on filter mount available in Australia which does not have the standpipe, and which seems to work equally well.

If you think oil will drain out of the engine head and block and backward through the filter, the anti drain back valve would have to fail. That being the case, oil would drain back the same regardless of the standpipe, as oil would rise in the pipe and fall in the outer portion of the filter. If you think it might drain in the other direction, losing oil at the crankshaft and flowing in the forward direction through the filter, the oil still has to rise in the outer part of the filter and fall in the standpipe. In any case the filter could never actually drain empty of oil unless there was some way to allow air to enter the filter. In the reverse flow direction air might enter from the crankshaft journals to rise upward into the oil gallery and ultimately into the filter. This would also require back flow of oil through a failed anti drain back check valve, or gravity flow of oil downward through the oil gallery at the same time that air is percolating upward. This is very unlikely, as the oil passages in the crankshaft bearings are exceedingly small, about 0.001 inch radial space containing the oil film. For air to enter the filter from the supply side as oil drains through the crankshaft, the air would have to be introduced through a pressure relief valve which was stuck partially open. The oil pump pickup is submerged in the sump, so air cannot enter there. Any of these scenarios are unlikely to happen. I would bet good money that any engine with inverted spin-on filter, regardless of condition, could sit through six months of storage and still have no air in the filter.

So what then is the function of the standpipe? I believe the more significant purpose of the standpipe is to direct oil flow more evenly through the entire filter area. Oil enters and exits the filter at the gasket end. If not for the standpipe oil would like to take the shortest route from inlet to outlet (especially with low flow rates), resulting in most of the oil passing through the filter media closest to the gasket end of the filter. The standpipe makes oil exit from a deeper part of the filter, thereby encouraging more oil to flow through the farther reaches of the filter media. This has the potential to prolong the life of the filter before it gets partially clogged, but this would only apply to an engine where the oil and filter were not changed for an excessively long period of time (like at least a few years). It might also be a factor for an engine in badly worn condition which may generate a lot of trash in the oil to clog the oil filter. This same theory of even oil distribution could just as well apply to any oil filter installation, although I have never seen the center pipe in any other oil filter mount. Engines do not fail because of the absence of the standpipe, so I suspect it has no measurable advantage.

On 11 Nov 2015, Neal Roland wrote: "I installed an inverted spin-on oil filter on my 1970 MGB. I purchased it used and it is fine except it does not have a standpipe that goes in the filter head and extends up into the spin-on filter. Should I add a standpipe? If so, do you know the ID of the hole the standpipe fits in"? On 11 Nov 2015, John Twist of University Motors, Ltd wrote: " I assume you have the top loading oil filter housing used from 1970 through 1980 (with the exception of about six months in 1974 when a bottom loading filter from the Morris Marina was fitted). This housing takes a NAPA Gold 1068 Filter The outlet is 1/2" BSP The fitting for the filter is 3/4-16 SAE The pipe is 1/2"� OD and stands 1 1/2"� above the threads or about 2-1/8"� above the filter contact surface. "This is what I would do. Purchase a 1/4" NPT pipe nipple, a 1/4" NPT tap, and two 3/4-16-UNF nuts. Run the nuts down the oil filter threads so they won't distort. Use the 1/4" NPT tap and thread into the inside of the oil filter threads. Fit the pipe nipple and adjust the length so it matches the numbers above. Obviously, clean all the chips and swarf from the housing".

There is also an offset hanging spin-on adapter. Again check the MGB parts catalog. This one can be used with the larger pre-engaged starter motor on the 1968 and later MGB engines. When this adapter is mounted in the proper position, offset slightly forward, the port connection will point latterly toward the inner fender. There is also a steel pipe with a banjo fitting on the front end which was used for the original installations (sans cooler), but this part was moderately rare and is particularly difficult to find now. Otherwise you can use the short connector hose mentioned above. Like any of these filter mounts, this can also be used with hoses for an oil cooler. This configuration points the filter downward where it does not obstruct service access above, but it does obstruct removal of the starter motor, and the spin on canister must be removed to remove the engine.
Adapter with Pipe

Adapter with Hose

Filters which can be used with the offset hanging spin on adapter:

AC - PF-56 Bosch - 72-143 CarQuest - 85516 Fram - PH-3600 Fram - PH-3614 Full - PH-400 K&N - HP-2009 Kralinator - L38

Lee - LF-42 Mann - W719/36 Moss - 235-950 Motorcraft - FL-276 Motorcraft - FL400A NAPA Gold - 1374 NAPA Gold - 1516

Purolator - L20064 Purolator - L20195 Sears - 45197 STP - SO-400 Unipart - GFE443 Wix - 51516 Wix - 51374

There will be other filters that will work with this adapter, likely any filter with the same thread and seal. Internal pressure relief valve is not required, as the (original) spin-on adapter has a relief valve.

Filter descriptions, original MGA type - - Filter Descriptions, original variations
Filter Cartridges - - Filter Seal Rings - - Spin-on adapters, Aftermarket
Spin-on adapters, MGB - - Filter types - - Frequently asked questions
Personal preferences