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Here's a question....  The older style Hillman uses a replaceable cartridge oil filter, the newer uses a spin-on canister type.  Are these two filter bases interchangeable?  That is, can I swap the adapter base from a later motor to my 1390 so I can use the spin-on filter?

Martin DeWitt
1958 Minx Series II
1962 Minx IIIC

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Yes you can swap them, but thare have been problems with the valves in the screw on base causing total engine destruction.  I am keeping my old style and just buying Triumph TR-2/3 filters.

Jan

Martin,
      The screw-on filter bases are directly interchangeable, however, the early ones have a brass pressure relief valve that is notorious for sticking open.  This typically happens at high rpm like freeway speeds: when you leave the freeway and the revs drop, the oil pressure goes to ZERO and you ruin your engine.  I bet I have seen two dozen engines damaged or grenaded by the brass version.  Later filter bases were redesigned and use a steel relief valve and they are dependable.

Jim Leach     Pacific Tiger Club     Seattle

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was discussed recently.  I asked the question.  Got the good oil off the list first :–))
Fitted one with the larger Ford style Z-9 spin on cartridge.  Works a treat and doesn't leak.
The gasket that goes under the adaptor is different to the original style however.
I used the gasket from the Hunter motor no problem.

Keith
55 Californian

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Jan:

Interesting comment.  I have a salvaged screw-on adaptor from a Husky (late) that I was thinking of using to convert one of my cars – what should I look for with the valve assembly?  I thuroughly cleaned the salvaged unit.  Can the valve assembly from a cartridge model be transferred to a screw-on base?  Please advise before I make a mistake once the warmer weather materializes?

DougB

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Good question Doug,
    I'm waiting for this info also.  I have a late Husky with a stuck engine.
Possibly it had a failure?  I guess the other thing we can do is take the relief valve out and see if it is brass or steel?  If it is steel, it will be fine.  Merry Christmas,
    Chuck

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Yeah – it's a brass one alright.

Anyway to "fix" it? Or is it worthless?

DougB

  I cannot think of any fix, for a bad one I would trust after having one stick.  You can inspect it by pushing the plunger in and looking at the walls of the tube.  Check for scoring on both the plunger and the walls.  Bad ones will sometimes be sticky when you move the plunger in and out.  The one that stuck in my car would switch between being stuck open and closed so you would have either zero pressure at idle or 100+ under acceleration.  Put a spare one back in and have had no further trouble.
  Jim E

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I'm guessing the brass ball in the relief assembly wears (not round any more) and then gets stuck in an open position.  There must be a way to fix it.
Chuck

Chuck,
      It is not a brass ball, it is a piston shaped something like an oversized pencil eraser.  The piston wears a pattern in the brass tube and it develops a 'step'.  At some point, the piston gets stuck on this step and it does not return to the closed position and the oil is returned directly to the sump before it lubricates the engine.  As far as I know no one has successfully rebuilt one, but why even bother trying?  The later steel version is dependable.
Jim Leach     Pacific Tiger Club     Seattle

The later steel version.
Are they available as a spare from suppliers or do we need to find one on a later model engine???
I haven't pulled mine apart to look yet, but losing oil pressure in this way could be a tad annoying.

Keith
55 Californian

Keith,
      I know they were installed from the factory on late Alpine sportscars (1967).  If original, all fastback Alpine/Rapiers and Hunter/Arrows have them.  I have never seen a late (steel version) fail, nor have I seen a ball check version in the old "oil torpedo filter unit" fail.  Loss of oil pressure would be more than a tad annoying to me: been there, done that ($$$$).  Merry Christmas!
Jim

The Minx was running (when *red* hot) at 35-40psi at 60mph, dropping to near zero at traffic lights (full stop).

:–(

No noises tho. And temp held steady all the time.

Alan P

Alan,
      You need to determine if you have the early or late screw-on base and brass valve.  If you do, it needs to be replaced ASAP.  It seems to me the Aussies have so many Hunter Range cars down under, they ought to be able to find one for you from a parts car.  My guess is Chrysler changed the design in mid 1967, so all Hunter cars should have the superior unit.  There are no NOS new-style units left in England or the US to my knowledge.

      If you find a source for them, I'll take two right now!
Jim

Hmm, think I may have this problem too.  According to my parts book the early screw on base was introduced in the Alpine S3 production, 700 units before my chassis number making it mid 1963 – mine definitely has a screw on cartridge, so probably the brass valve as well.

So I gather that if I get a base and valve from a Hunter this will fit and stop the problem.  Any Aussie Hunter owners with a spare laying around?

Until I do, is there anything I can do as a short term measure (like taking out the relief valve and cleaning it) that will help prevent low oil pressure?

Thanks, Vic

Alan,
      Which oil filter assembly does your car have on the engine?  If it is the early Tecalamet "Torpedo" it uses a ball check valve which never sticks open.

      If it is the early model "spin-on" filter, it has a tubular brass oil pressure relief valve and they regularly stick open, causing dangerously low oil pressure at low RPMs.

      Rootes resolved that problem by redesigning the valve, made it out of steel, and altered the filter base to accommodate it.

Jim

Vic,
      The sliding brass piston wears a pattern in the brass tube (or cylinder) and the stick open.  Its not a matter of cleaning them, its a matter of wear.  I have seen at least a dozen good engines GRENADED by this fault.
Jim

Jim,
You mean to tell me that we should not dump all those old oil filter bases off Hunters!
I'll try to save as many as I can clean them then see who wants one.  Weighty for mail but who cares!?
Graham.R.

Graham,

In the light of what Jim says, I am certain my '60 pump is doing exactly as he describes.  Start up oil pressure is 50+.  Hot running at 40/50 MPH it drops to about 35-40, but at tickover drops to almost zero.  The engine has only done 60K miles, so it isn't worn.

Put me down for one.  I'll gladly pay shipping.

At least I'll know that I've done all I can!

Alan P

Alan

Before you blame the pressure relief valve in the filter assembly.
Try checking the little pipe that feeds oil to the timimg chain.
Fits in a 1/8" fitting and has a restrictor orifice in the end of it, if it is broken then all your oil pressure will dissappear on idle.

Keith

There seems to be a lot of dialogue on this loss of oil pressure thing.  We had the same problem with ours, talked to a lot of people, and made a decision.  We undid the bolt holding in the little brass piston and spring (this is in the base), de-burred the piston then polished it with some fine wet and dry sandpaper.  Re-assembled. works perfectly.  Did this two years ago.  No problems with oil pressure since.

Murray

Murray again.........I should add that our car is a 1966 Series VI Minx with the 1725cc motor (brass plunger/piston in oil filter base)

Gents,
Can I suggest that you all check the oil filter bases now fitted as if yours has only one hex head for relief valve then that is the later 'resolved' version and there is no need to change it over.  You all can't have early spin off versions?
The relief valve is designed to 'restrict' (not improve) oil pressure to 40/45 psi (in a 1725) when it opens and any excess is flowed back to the sump, so the pressure has to be 'up' before it opens. Low pressure at low revs is not effected by this valve, moreover it's wear in the oil pump vanes and base plate and these should be reversed when the oil pump is removed to give a smooth surface for the vanes to pump effectively.  Keith's remark about the timing chain oiler is also a reason for low oil pressure, this check valve is used in Super Minx only.  Also some spin on oil filters do not have the check valve in them that can cause low pressure when the filter becomes choked up.  Change the filter to one with an internally fitted check valve.
Any blockages in any of the oil lines/passages would only increase pressure not lower it, so if low something is too clean/loose or worn!  Also have the 40 year old gauge fully tested too as this could be off at lower pressures.
1390 to 1600 = 50 psi, 1725 is 40/45 psi Oil pressure at best.
Graham. Remembering our ANZACs!