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MG MGA - Problem with Moss spin on filter adaptor

I've just installed the Moss spin on oil filter conversion kit. I've read Barney's article on this, and am using the Napa Gold #1516 filter. The shoulder of the combination bolt (that holds the adaptor to the block and also holds the filter to the adaptor) has been machined down 1/8th inch, to prevent the filter screw boss from bottoming out before the seal is effected.

I've still got a fast steady oil leak between the oil filter and adaptor housing. It's not sealing well enough. Even after maximum tightening of the oil filter.

The oil pressure gauge shows I've got 80 lbs of oil pressure. I'm thinking this simply may be too much for the oil filter to seal well, and am considering shortening the length of the oil pressure bypass spring to reduce oil pressure.

Does anyone have any other recommendations?

(By the way, I have found at O'Reillys Wix filter #51088 which appears to be the exact same thing as the Napa filter. Even the picture on the box is exactly the same).
JM Morris

My first thought is you have not removed the old rubber o-ring seal on the engine side of the adapter. The rubber can get so hard as to feel like steel. You need to have a fresh one soft)installed with the new spin on adapter. Make sure it is wide enough to fill the groove they fit into. Some are too thin.

Sounds like you removed all the excess shoulder on the Moss adapter so that shouldn't be a problem.

The oil pressure is very high.

The Wix filter 51516, the Napa Gold 1516 and the O'Reilly Wix filter 51088 are the same filter.

Different number but they are all a Wix filter. Wix filters are all I use for my MG and other vehicles.

Ray Ammeter

Hi, Ray. Thanks for your response. I'm not having a problem with the engine side of the adaptor. It's sealing fine. And yes, I did definitely get the old seal out and the new one in with no problem.

Note to all: The O'reilly Wix filter 51088 is NOT the same as the Napa Gold 1516 filter. Upon closer inspection, there are 2 major visible differences (and probably other internal differences): 1) the Wix filter case is smooth. It does not have the 15 flutes on the end that the Napa filter does, thereby preventing the use of an "end cap" filter socket. 2) the Wix filter cannot be pre-loaded with oil like the Napa filter can. There is some sort of restriction plate approx. 2 inches down into the filter, and another one beyond that (you can feel the next one through the small hole in the center of the first restrictor plate). Oil cannot be poured into the filter to pre-load. Apparently it can only get by those restrictors under pressure.

Therefore, I cannot recommend the 51088. It is a step down from the Napa filter, although it will work otherwise.

In regards to the high oil pressure, according to the factory manual, the oil bypass spring length(non-adjustable) is set to allow oil by-pass at 75-80 lbs. So the oil pump and the by-pass spring appear to be doing their job, as built, from the factory.

But-I still think 80 pounds is too much and may be why the filter won't hold a seal under that much pressure. Has anyone ever tried shortening the spring to reduce pressure?

I'm almost to the point of ordering the Moss oil filter which is guaranteed to "work" with their adaptor. But if the oil pressure is too high, the Moss filter won't be a solution either.

HELP! :)
JM Morris

I have the Moss spin-on filter kit and have used it just as it came out of the box. Use the NAPA 1516 filter with it and have never had the filter screw boss bottoming out. Iím not really sure I know what you mean. Is the bolt and the lock tab installed correctly?

David Werblow

Hi, David. Bolt and lock tab are installed correctly. What's your oil pressure?
JM Morris

I use the napa 1516 filter and my oil pressure runs in the 70 to 80 psi range. Never had a leak from the filter or the adapter.
Ed Bell

Thanks fellas. Per your experience, I should be having no problems. Apparently, I've misdiagnosed the source of the leak. The only other alternative is the connection of the crossover pipe to the adaptor. But I thought I had ruled that out.

The problem is that by the time I start the car and get back under the hood to check for the source of the leak, there's already a small stream running down the side of the filter which appears to be coming from between the oil filter seal and the adaptor.

I'll have to rig up some sort of oil catch mechanism at the pipe connection to see if that stops the stream on the filter. Perhaps just a rag tied tightly around that connection to isolate that as a source.

I'll report back tomorrow. Thanks again!
JM Morris

Problem found! The inside copper washer was missing at the banjo bolt connection to the adaptor. Boy, do I ever feel stupid!

As an additional note, I thought I would be real smart and try some neoprene O-rings. They worked, and proved the connection was the source of the leak............for about a minute and a half! Two jets of oil sprayed the under side of the hood and made a fine mess before I could get the engine shut off. About an hour of cleanup and lots of paper towels later, I now have lots of "shiny" surfaces under the bonnet. Fortunately, the car has not been restored yet so I'll consider the new oil film as "rust protection" until I can get to the car wash.

So now I've got to order (2) .85 parts from Moss with the usual $10-plus shipping charge unless I can luck up at the hardware store.

Another hard lesson.

Thanks Ray, Ed, and David for helping me solve the problem!
JM Morris

Don't be too hard on yourself. When I first install my spin-on adapter I too had a big leak from the banjo connection. I actually wound up having to "tweak" the bend in the crossover tube to get it to sit flat enough to seal. A bit of a pain, but it's been fine ever since.
Oh, BTW, Moss has a $10 minimum least on their web site...
G T Foster

Thanks, GT. Yeah--I forgot about the minimum order. Seems I'm forgetting a lot of things these days! :)

It has since occurred to me that the lost copper washer is/was probably in the bottom of the oil catch pan I had under the car when doing the conversion. But it has since been emptied by a lady friend helper who was not instructed to "look for a lost copper washer".

No luck at the hardware store. So on to Moss.

I've never really trusted banjo connections. But I guess if you understand the sealing requirements, they work.

I wonder if anyone has tried the flexible steel braided hose available from Moss that's a replacement for the pipe. It looks like a more trustworthy sealing arrangement and not so alignment critical. Or is that just another flashy money grabber?
JM Morris

The correct filter to use is Unipart GFE443 - this does not bottom out.Regards
Ron Edmond

Most parts stores should have a copper or aluminum washer to replace the lost one. Common parts come in an assortment. Ask for by size. Inner diameter by outer diameter. Many things are sealed by soft metal washers.
R J Brown

The problem with dealing with parts stores (that I've found anyway, with the likes of AutoZone, Advance, PepBoys, etc) is that they want to know the year, make, model of the car before they even begin to try to find an item. They have to know the "application" or they don't even try. They've been ruined by the computer. Recent example: I needed a set of spark plug wires quickly--not willing to wait on the usual internet order. Just about ANY set of 4 cylinder wires (1980 on back) would work (in my application with a Mallory Unilite distributor). When the counterman demanded an application, I told him '59 MGA. Nope--have to order them. So I thought for a minute--" '64 Chevy Nova 4 cylinder". Nope--have to order them. Okay--" 64 Chevy Nova 6 cylinder, 193 or 230 or 292 ci". Yep--got em. 4 of the 6 wires are now in the car and, oh yeah, with a "lifetime warranty". "Just be sure to bring all 6 wires back if there's a warranty claim". :)

You have to learn to play their game. I'll have to think about it for a while to figure out how to play the copper washer scenario with those guys.

Specialty industrial parts stores are much better but they're not open on the weekends. They cater to the commercial/industrial crowd through the week.

Frankly, for small parts like that, I've had better luck at lawnmower and motorcycle repair shops. They KNOW what's in their shop, and approximately where it is.

So it's always a trade off between time and money, I guess. How much are you willing to spend for convenience?


JM Morris

This thread was discussed between 05/06/2010 and 22/06/2010

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