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MG MGA - Moss oil filter spin-on adapter

I have just modified the hex bolt in the Moss spin-on adapter, as recemmended in Barney Gaylord's website -
see - http://mgaguru.com/mgtech/faulty/ft026.htm - by grinding off about 1/16" from the face of the large hex bolt to eliminate any close-tolerance jamming or leaking of the filter to adapter joint.
That will hopefully make it OK for any half-decent makes of spin on filters in future. I may not have explained that well but it is probably clear to those of you who have been through this process before me, and Barney explains it well in the link.
However, the question arises - when I look at where the oil will flow through the filter, it will be directed through the hex bolt via six radially spaced 4mm diameter drilled holes. They can be seen in Barney's first photo.
Sorry about the anorak stuff now, but my simple maths says that that means each hole has a cross sectional area of 12.6 squ.mm. and, so the total area for oil flow of all six holes is 75.41 squ.mm. This equates to an equivalent single hole size of 9.8 mm diameter.
So my request is - can anyone technical out there reassure me that a, very roughly, 10mm diameter equivalent hole is large enough to not cause any uneccesary limitations to oil flow around the engine. I certainly don't want to go to a nice labour saving device, re filter changes, but sacrifice good lubrication around my Twin Cam engine.
If necessary it looks like it would be relatively straightforward to ease the six holes' 4 mm diameters out to 4.5 or 5 mm. in diameter if necessary before installing the adapter finally.
Grateful any thoughts.
Bruce
Bruce Mayo

Do not enlarge the holes. The bolt is weak enough already. Click on link above, and see picture of broken bolt at bottom of page. I suppose that broken bolt is an exception, not the norm, but you can see there is not much metal holding it together. The holes are angled, so they get closer together with less wall thickness near the hidden ends.

An engine in good condition will pass about 12 quarts of oil per minute at relief pressure, 1 quart in 5 seconds. An oil pump in good condition will move that much oil at 1500 rpm crankshaft speed. Excess flow at higher speed goes over the pressure relief valve. Those holes are big enough to pass that much oil being pushed at pressure by the oil pump. If there was significant restriction there it would show up as low gauge pressure, as the gauge port comes after that point in the oil flow circuit.
Barney Gaylord

Thanks Barney.
Bruce Mayo

Bruce,
no problem with this little holes on my Twin Cam engine for 20K kilometer so far.
Siggi
Siggi

Thanks Siggi. With your and Barney's comments I shall just install it now as is.
Bruce
Bruce Mayo

I've had one of these for ages and initially took it on and off several times before I got it to stop leeking.

Have anyone informed the manufacture or Moss to get this resolved once and for all?

Cheers
Mark.
Mark Hester

Yes, I did, a long time ago. Moss insists there is nothing wrong with it, refuses to fix the problem, and continues to sell the parts. I don't rag on Moss very often, but this is a real bone head decision on their part. We hear more complaints about this problem every week, but Moss continues to turn a deaf ear. Apparently all we can do is to advise folks that every individual buyer will have to fix their own part if they want to keep it.
Barney Gaylord

Mark. You refer to yours leaking. Was this the filter-to-adapter rubber ring leak, due to the well-documented tolerance problem at the hex bolt head? Or was it at the seal between the adapter and the engine proper? Or something else? Would just like to be aware of all the problems out there before putting mine on.
Bruce
Bruce Mayo

Hi Bruce,

seal between the adapter and the engine.

Also I found if I tightened the adapter to hard to cure the leak, then the centre piece began to press out. From memory however my adapter looks slightly different to the one on Barney's site, but since this is now back in Perth and I'm in London I can't photograph it.

Cheers
Mark.
Mark Hester

Thanks Mark. Seems that I should heed carefully the max torque figure given in the Moss instructions for the adapter-to-engine hex bolt, if your experience is anything to go by. Thanks for your caution.
Bruce
Bruce Mayo

This thread was discussed between 17/10/2008 and 21/10/2008

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