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MG MGB Technical - Oil filter question

It's time for an oil change and I'm having trouble finding a replacement filter for my 78B rubbernose.

When I bought the car it had a Ryco Z38 filter installed. I replaced it with the same each time I did an oil change. Once a mechanic did this for me and replaced it with the Valvoline equivalent which is V067.

Now both Ryco and Valvoline don't list MG cars in their cross-reference manuals. I can't find either a Z38 or V067 at any parts shop. The shop assistants just shrug their shoulders when they can't find MG listed in their cross reference manuals.

What filter(s) can I use instead of the Ryco or Valvoline ones? FYI my filter is the "stand up" version. It doesn't hang upside down.

Any help will be appreciated as always.
D O'Brien

The Mann W917 has worked well for many of us and for many years. Common filter for various Volvo products.

Les
Les Bengtson

Buy a couple mail order from one of your classic mg specialist suppliers in Oz.
Mike Howlett

I bought a ryco z38 from a Sprint auto store in Adelaide the other day. They just went out the back and returned with one. There was no comment that they are rare or out of production.
a freckelton

What filter you can use depends firstly on the mounting thread on your spin-on adaptor. If original to your car I think that thread should be 3/4"UNF. You may find this info stamped onto the mounting face of one of the filters you have been using. If not, a parts place should be able to find the info in a catelogue or, alternatively, the Ryco website should have it if you search by a Ryco number eg Z38. Be sure you get this right because another Ryco filter used top-mounted like yours on the B in this country is the Z23, BUT this has a 1/2"BSP thread. The two sizes of thread can be easily confused one for the other, but are different in the thread cut and 'pressing' one onto the other will damage the adaptor thread.

Apart from that you will be looking for a rim seal that matches the diameter of the mounting face of your adaptor, and an anti drain-back valve fitting. I believe the Ryco Z9 (common on old Holdens) is 1/2"UNF and with the required valve.

What I don't know is whether you will also need a by-pass valve internally fitted to your filter - you wont if one is incorporated into your mounting adaptor (our USA friends may be able to advise on that). Not sure if the Z9 has one, and if so, what pressure let-off it has. Again Ryco or a decent parts place should be able to tell you for the Z9.
Roger T

Unless the filter mount has been changed for a foreigner it will have a *bypass* valve (for if the filter gets blocked). The anti-drain back consists of a tube from the mount going up through the middle of the filter for the one side, plus a valve in the filter itself for the other.
Paul Hunt

G'day Paul,
*bypass*? Not in my Leyland service manual!
Regards
Roger
Roger T

I was using a Motorcraft FL300 for many years which worked fine. Recently switched to a Purolator PL20195.

This is for the inverted spin on for a 1980.
William Bourne

The Leyland Workshop Manual shows it as item 21 'release valve'.
Paul Hunt

On page A-2 there is the reference, yes, though on page 3 (General Data) that valve is called the Oil pressure 'relief valve'.

The valve we are concerned with here, however, is the one in the oil filter mounting, or in the spin-on adapter if used. On Page 3 that is the 'By-pass valve'.

The former operates at 70 lb./sq. in.
The latter at the range of 13 to 17 lb./sq. in.
Roger T

Roger - are we both pushing on the same side of the door?

The relief valve is in the block and is 70 psi as you say. The bypass ('release' in the manual) valve is in the filter head and is the one you said is 'not in my manual'. This is 13-17psi again as you say. That is not an absolute pressure like that mentioned for the relief valve, but a *differential* pressure. It is only when the filter gets blocked that the pressure difference between the filter inlet and outlet will get anywhere near this level. Ordinarily they will be much closer, both sides being 50-80psi when running.
Paul Hunt

Paul - we probably are. I was really just (tongue-in-cheek) re-emphasing the hyphen in 'by-pass'(the hyphenated spelling in my manual), but then it might just be an 'Australian' spelling thing.

I'm the man that has never accepted the dropping of 'me' from program!!! Career-wise at one stage I had to write documents proposing/discussing training program(me)s on the subject of computer programs. You can imagine what needed to happen to conciseness in the interests of clarity.
Roger T

The frenchification of the word "program" was a 20th century thing. I have seen it as "program" in a 1904 English dictionary.

Also see here http://www.dailywritingtips.com/get-with-the-programme/

Epigram and Monogram remain unfrogged to this day.
Geoff Everitt

The illustration in the manual shows the hanging filter. I'm almost certain that the inverted filter (which is what D O'Brien says he has) does not have a bypass valve, so you'd need one in the filter....
Rob Edwards

What filter has a bypass valve as well as an anti drain-back valve?
Paul Hunt

"What filter has a bypass valve as well as an anti drain-back valve?"

The Ryco Z23 I have on my car, as well as a number of the filters in the Ryco range. The Z23 is the only Ryco I know of with both features and a 1/2" BSP mounting thread. However, they do produce filters with both features in 3/4" UNF and metric thread size.

The key to variety is in the mounting thread size. Of course a competent machine shop can make the thread units in any thread combination desired. Speciality plumbing/hydraulic shops may have the screw-in thread units on shelf. Then you are looking for a by-pass valve in/about the range of 13 to 17lb./sq" for the MGB.

With the Z23 at about A$27 a pop I am toying with going to a metric thread size for greater selection options. That or mount an under-slung filter adaptor to do away with the anti-drain back valve requirement.
Roger T

Almost all spin on filters now have a bypass valve. It only opens if the filter media blocks because of lack of service, so most B owners would never need it.
Roger the Ryco Z9 was the early Ford falcon filter and I notice that the dimensions given are the same as the Z38. I must check it out as its about 1/3 the price. I have been using Baldwin filters but the last couple have drained out over about two days lay off. Ryco in there news letter are saying that they are now fitting an anti syphon valve as well as the anti drain valve but the diagram they show puts it where my stand pipe goes. It may not be on all filters.
Denis
Denis4

Indeed, I had a sudden thought after I posted and checked Russ Knize's oil filter study http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html and most if not all there do.

The factory did revert to an underslung filter after changing to the inverted cartridge type, but only for about a year as far as I have been able to ascertain then they went back to the inverted. That must have been for a reason.

In fact although the inverted are guaranteed to make a mess at least oil isn't running down the body of the cannister when you are trying to unscrew it like it does on my V8 and ZS, both of which have slightly inclined underslung filters. It's bad enough trying to unscrew them with bare hands, impossible with latex gloves. I'd far rather do the inverted filter on the roadster, it's just a matter of putting some newspaper under the filter head to catch the majority of it, and a bit of wiping round afterwards.
Paul Hunt

I have just realied I need to make a correction to my first post, the Ryco Z9 has a 3/4" UNF thread NOT the 1/2" I posted.
Denis, you might need to note this as it will not replace the Z23.
Roger T

Roger, My car has the 3/4" thread so I picked up a Z9 to try. $7-70 at Super Cheap Auto. Better than the just on $30 I had been paying for filters that would not hold oil overnight. The dimensions are the same as the Baldwin I was using and the oil pressure is there on the first couple of turns. Ryco are now using a yellow silicon anti drain valve which appears to do the job very well. I have not had the chance to thin the oil on a long trip yet so time will tell, but its already a lot better than it was. I also like the white color better than their old gray. The dimensions of the Z38 and Z9 are exactly the same so I dont no what the difference is. Thanks for the help.
Denis
Denis4

Denis,

Worth a visit to the Ryco NZ website, just Google it and the opening GUD Industries page has a Ryco Filter 'box' with the link across the Tasman. Once there you can search 'Product Description' -use z for first line, oil second, all third and metal fourth line. Gives you a list of 161 Ryco Z series filters (a range of types) with details of diameter, height, gasket internal and outer diameters, yes/no on relief valve, anti drain valve and anti siphon valve. Five pages of data in all worth saving for reference.

In short, differences between Z 9 and Z38 are in seam diameter (95mm/94mm), height (139/137), gasket int/out (61-70/61-72). Both have relief and anti-drain valves, neither the anti-siphon. As you said, virtually identical, though there may be a difference in the relief pressures, but I wouldn't imagine by a great amount.

The Z38 is the recommended filter for the 1800 MGB from Jan 1970 to Dec 1979, EXCEPT for the 'hanging' filter mount, for which they recommend their Z 82. NOTE, the latter has no anti-drain (fair enough) or pressure relief valve, so would require the latter in the mounting adaptor.

I know club members here who use the Z9. Interesting that the anti-drain valve has changed to the yellow silicon - my Z23 have the older type black. Very quick pressure readings however, always prior to actual ignition, which gives a good feeling. I really should get the 3/4"UNF/1/2"BSP thread adaptor made and start using the Z9 - for both cost and availability reasons when touring!

Regards
Roger
Roger T

Roger I dont think the relief valve mean a lot to us as it only comes in to play in the event of a blocked filter element. I will have a look at that sight for interest as the OZ sight I looked at had the dimensions exactly the same, but logic says there would be some difference.
Denis
Denis4

Denis, I agree on the use of the by-pass valve and have never had a filter element fail but, gee, I am more comfortable with a valve (either of in the mounting unit or filter) - because I believe in the adage "if something is statistically possible, sooner or later it will happen" (LOL)
The value of the NZ site is the greater info. On measures, as you have noted, the two filters are effectively the same dimension. Perhaps Ryco AU measured on a Friday!
Regards
Roger
Roger T

" I agree on the use of the by-pass valve and have never had a filter element fail "

How would you know? BL in the 60s started fitting switches and warning lights to that valve (when it was in the filter head), my Mum's Mini had one. But they proved very unreliable, coming on when they shouldn't due to faulty switches, so they were disconnected under warranty and deleted from later models. At least, they *said* they were faulty switches ...
Paul Hunt


Regarding Paul's observation above: "The factory did revert to an underslung filter after changing to the inverted cartridge type, but only for about a year as far as I have been able to ascertain then they went back to the inverted. That must have been for a reason."
My recollection is that the first "inverted" cars had no standpipe, and every one rattled like crazy on startup. I made one standpipe, for a customer, then there was some change that made the procedure unnecessary, either the reversion to earlier type or the standpipe. I suspect that those first inverted no standpipe ones were retrofitted by the factory/dealers, haven't seen one since. (We were not dealers, so we did not see the latest thing from the factory very often.)

For anyone sorting filters, following is a copy of a post I made several years ago - still applies. The proliferation of computer references copied from each other induces widespread dissemination of evil errors!

"This might save an engine, so listen up!
I have been puzzled by repeated mention of oil pressure drops related to filter changes, and now have come across one possible cause. A long distance customer (79 MGB) called to say that he had taken his car to have the oil & filter changed, and on driving away had 10psi, instead of its normal 60, so he went back, gingerly. They admitted that they had put a modern 5W-20 or somesuch in, rather than the 20W-50 requested. They changed the oil and said it was now OK, so he drove off, NOT looking at the gauge, since it was "OK". Fortunately he was in the city and driving gently, because when he did look at it, it still had 10psi.
He called me, and then sent it the 100 miles up here via AAA.
The very small filter was a dead giveaway, since it was about the same height as the length of the standpipe. On examination, the standpipe had been in contact with an internal support in the filter, in fact bending it. The standpipe was effectively 98% blocked; if he had made one heavy acceleration run, he would most certainly have scattered the engine. Other filters may have similar but less drastic effects if the standpipe is a bit less restricted than this one was. A difference of 1/8" in the internal construction could give normal performance at low speed and total disaster at full throttle. I would recommend that any filter be examined to be certain that all internal components are at a minimum a full diameter away from the standpipe when fully tightened. I have noted that many parts listings list things like "MG, all, 71-80". This filter screws on to an A-series and may in fact be correct for that app, but it certainly isn't for a B. Be really careful if you let anyone but yourself change filters. I have long hated standpipes that could reasonably be expected to allow the possibility of total blockage under abnormal conditions, and have taken to cutting notches in the end of them so that even in a case like this it is impossible to block them completely. The same thing applies to oil and fuel pickup pipes, as in Magnette, where if the sump gets mashed it can block the pickup."

FRM
FR Millmore

FRM I had taken your advice on board from previously reading that post and now one of the first things I look for is the inside clearance. As you say there are a lot of traps and things to look out for. One that I found only by reading the construction info on the filter sight. The Baldwin filter I had been using was unobtainable and the supplier gave me a Balwin filter of the same size. I fitted it to the car with no problem and it worked OK but I noticed it, starting from cold did a sort of double prime. The pressure would rise then dip to zero then rise again. Not happy with this I went to the Baldwin sight and found this filter has a "built in" standpipe, so I had a pipe within a pipe. I am sure it would have been a restriction to flow as well although the cold pressure was normal at idle. The difference was not easy to spot.
Denis
Denis4

"How would you know?"

EH Holdens, Kingswoods, UC Toranas, Centuras and XF Fairmonts didn't have the BMC/BL problematic switches, and I never had a warning light in near 40 years of driving cars of three manufacturers. Nor any sign in any filter changed that there was a filter failure. I did have one Ryco filter can with a tiny pin-hole, only found when repeated wipes of a tiny amount of sprayed oil on the filter mounting indicated the need to look closely. Exchanged without problems.

All in all, I have been entirely pleased with Ryco over the years. Mind you, I have always changed oil on schedule and the filter with each change.
Roger T

This thread was discussed between 30/09/2009 and 15/10/2009

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