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MG MGB Technical - Replacing the Oil Filter Head

The threads on filter head of my '74B have stripped so I have a slight leak where the inverted spin-on filter should seal. I need to replace the filter head (Moss #460-910)

Has anyone here done that? Any advice before I tackle this project?

Dan in Kentucky.
Dan Hiltz

Yes - 73B. I was finding it increasingly difficult to get a new filter to seal, which turned out to be the filter warped, because the hose adapter had been hitting the inner wing as the engine rocked and dented it - never any rattles from it in decades.

My first concern was getting the old one off - another job that once you have started you have to finish but the centre-bolt was barely tight (and no that wasn't the source of the leaks). Double spanners on the hose adapter if you don't want to mess about taking the hose off the cooler.

Ideally one would change the O-ring in the block groove, but once you start digging that out you have to finish the job, so I decided to try the 2nd-hand adapter with the old seal despite the flange on the adapter not being dead flat, a bit wavy - and it's been fine in the past four years. I didn't go mad tightening it up but did check it after running a few miles and put a little more on it.

Obviously I was careful about the positioning of both the replacement adapter and the angled hose adapter in regards to the inner wing.






paulh4

Thanks Paul. I haven't gotten under the car yet. Do you recall any particular difficulty accessing the center bolt?

Also, I'm not clear on the significance of the picture with the yellow arrow. What am I missing there?

I appreciate your insights!

Dan
Dan Hiltz

No, just straight up.

The yellow arrow shows the dent in the inner wing from the cooler hose adapter, and the paint rubbed back to metal from engine movement. It tips that way under acceleration so wasn't immediately obvious otherwise.
paulh4

Got it. Thanks so much!
Dan Hiltz

Dan. It is most easily accomplished if you have a lift available, as sometimes it is easier to work from the bottom while doing this and a lift is much easier to work with than having the car up on jack stands. But, it is possible to do the job with the car sitting on the ground.

The 18V oil filter adaptor attaches to the block where (and in the same manner) the older, cannister type filter system did. A single square rubber "O" ring and a single bolt holding the cannister, or adaptor, to the block. There is a line, made of either heavy rubber or steel, running from the rear part of the engine block to the oil filter adaptor. Paul seems to believe that there will be an oil cooler as part of the system. While I have sometimes seen an oil cooler installed, most of the 18V engines I have seen (North American specification) do not have an oil cooler. Rather, they have a hard, steel line from the rear of the block to the filter, or a rubber line. The steel line, if used (I believe it is original and the rubber lines a replacement), can be very hard to detach without damaging the steel tubing. I have successfully removed the tube intact once out of three attempts.

The biggest problem is removing the old oil filter adaptor, which has to have a single bolt, on the underside, removed and then replaced. That is when being able to elevate the vehicle so you can either work from below, or better, have an assistant do so, will make the job much easier.

If you have the rubber hose from the block to the adaptor, you only have to detach the front section of the hose when replacing the adaptor. With the steel hose, you need to detach each end (from the block and adaptor).

The oil filter thread is a standard size and, sometimes, the threads can be cleaned up using a rethreading die to chase the threads. But, that can only be done with the adaptor off the engine so you do not get any metal pieces (called "swarf") into the oil system. It is, also, an excellent idea to test fit a new oil filter to the new adaptor before starting work. I have seen some parts that were out of specification and it is best to check them before going through the work of installing them.

Les
Les Bengtson

Thanks Les. Unfortunately for me, a lift is something I can only dream of! I'm OK working under jackstands, but I can imagine it's easier when you're not flat on your back.

My B has an oil cooler and I've started hitting the front hose connection with PB Blaster as a precaution. great suggestion about test fitting a filter to the new head.

I already have the head but I had to order a new O ring, so I want actually start the work for few days.

If you have any other thoughts, please send them my way. Thanks again.
Dan Hiltz

According to Clausager the oil cooler "was fitted as standard on export models from the start of production" and for the home market on all five-bearing engines i.e. from October 1964.

Having worked under my cars both lying on my back and standing under them on a lift the latter for any length of time is really hard work with the head tilted right back.
paulh4

Paul and Les,

Still in the planning process. When you remove the center bold, does the starter present an obstruction?

Thanks,

Dan
Dan Hiltz

Paul. I have observed that Clausager's book is valuable because it is the only book of its type, not because it is particularly well done. When I have had to use it to try and figure out how something should look or be properly mounted, it quickly became clear that it is a rather marginal book and could be expanded to several times the current thickness with benefit to the MG community. It is useful when you cannot find any other reference, but I find that there are some conflicts with other books that cause me to beleive that "Original MGB" should be taken with a large amount of salt. I owned one North American specification MGB, a 79, that we could document the history of since it was new. It did not have an oil cooler installed. It, and two others I have seen, had a steel pipe between the rear of the block and the oil filter adaptor, rather than the more commonly seen rubber hose.

Dan. As I remember it, it was possible to replace the bolt that holds the oil filter adaptor to the engine without removing the starter. But, as I remember it, I have only done that a single time in the last 25 years. Much more commonly, I have replaced the oil filter adaptor when the engine was out of the car for some other maintenance.

For removing the old rubber ring, I have used a sharp pointed tool like a scribe. Today, I would most probably use a dental pick to pry out the old ring. Insert the new ring, place the oil filter adaptor against the ring, insert the bolt and tighten it sufficiently to hold the adaptor lightly to the engine. Having an assistant under the car to help makes for a much easier job of it. Use an inspection mirror with a swivel head to make sure the square O ring is fully into the block and the adaptor is firmly against it. Loosely fit the hose connector to the front of the adaptor. Tighten the adaptor to the block, then the hose to the adaptor.

Les
Les Bengtson

That's helpful Les. Thanks.
Dan Hiltz

Dan,

I removed the adaptor bracket & then replaced it using a new sealing ring (& copper for the bolt) without any need to remove the starter.I recall having the car quite high on axle stands at the front & used a couple of socket bars with a articulated link between them to be able to get enough clearance away from the underneath to be able to turn the bars / bolt head.
When i first did it i only raised the front of the car & found i had to remove the front wheel (right side UK) so that i had better access & see what i was doing. No need to remove the starter as you can see from the attached photo (apologies that it is the wrong way round). Some time later when i had the car up on axle stands all round i used the opportunity to nip the bolt up a bit more.(Jon Twist refers to this as being one of the regular points where oil leaks occur)!
You of course don't have to deal with the steering column on your side of the pond.
Cheers
Charles



Charles9

Dan - it didn't for me as I recall.

Clausager does say that oil coolers were no longer provided for North America (for some reason) for the 1975 model year on but Dan's is a 74. I agree that photos of component placement and pipe and cable routing is of marginal benefit as he only had access to owners cars many years after manufacture. He is also not beyond making an error for example describing the V8 radiator as a cross-flow, which it isn't. I do set more store by the dates for changes which would have come from factory records, but that doesn't always agree with the Parts Catalogue, which is right and which wrong is unknown.
paulh4

Missed Charles' post. I don't recall using a UJ, certainly not to clear the starter, maybe the chassis rail although it doesn't look like it. Although the end of the starter overlaps the adapter a little once the bolt has been removed and the adapter lowered a few mm it has plenty of room. This is an 18V with the later starter and no boot that Charles seems to have, an earlier starter may be different. However to get a clear run at the groove if replacing the O-ring maybe removing the starter would help, but I didn't do that :o)



paulh4

Thanks gents! The pictures are very helpful and reassuring! Now I just need to do the work!

Dan
Dan Hiltz

As is always the case for me, what I expected to be the hardest part of the project went ok, and what sounded like the easiest is frustrating me. I removed the hose from the filter head and got the head off the block. but removing the o-ring from the channel is rough! Dental instruments just bend. I'm using a common nail as a scraper to see if I can get through it but so far no luck. I'm reluctant to get too aggressive since it's the block, but do you think a small drill bit in a Dremel tool is too risky. All suggestions welcome!

Dan
Dan Hiltz

Dan, I've successfully changed the O ring on the block to filter housing adaptor. You can get the old O ring out using a car pick like these:

https://www.amazon.com/hook-pick-set/s?k=hook+and+pick+set

I had great advice form William Revit, who advised me to use a magnifying mirror to help to see what you are doing. The old O ring may be a bit tough to get out, but by forcing the pick in, it came out ok. Make sure the seating for the O ring is thoroughly cleaned and use a little grease when refitting it.

Andy
Andy Robinson

Thanks Andy. I've ordered a set.
Dan Hiltz

I replaced the spin on filter head successfully after mis-threading a new filter during an oil change. The bolt was totally accessible with a long 1/2" extension. Seating the copper washer to avoid leaks required some care as did replacing the rubber seal. The replacement was much easier than it looked.

The quality of the replacement filter head was questionable. The casting was porous and I had to smooth the surface where the copper washer seats. I am now very careful to thread new spin-on filters correctly.
Glenn Mallory

Well done. It's quite easy to cross-thread them as mine at least is almost but not quite vertical. I them mine started incorrectly a couple of times in the early days, more careful since.
paulh4

Success! The heavy duty hooks and the magnifying mirror, when the filter head was illuminated from underneath, enabled me to remove the O ring. Thanks to all for your assistance. Now if I can install the new head without screwing it up, I'll be back on the road soon!

Dan
Dan Hiltz

I finally finished the job today (after some business travel interfered. The only glitch I had was on my first attempt to spin the new filter on, it wouldn't cooperate, so I removed the oil filter head, put the filter on at my workbench (where it went on very smoothly) and then reinstalled the filter head with the filter attached. Thanks again for your assistance.
Dan Hiltz

The head thread is slightly off vertical and you have to be careful with the angle of the filter or it can cross-thread.
paulh4

This thread was discussed between 06/05/2023 and 17/07/2023

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