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MG Midget and Sprite Technical - oil pressure 1500

I changed the oil and filter today as I have only had the car a week and could not guarantee the age of the black goo that was lubricating the engine. I used 20w50 Classic oil and a genuine filter. I am now seeing my oil light come on at idle and flickering at 950 - 1000 rpm. Is it likely to be bearings or pump related. Is it worth trying a new switch first. Should I just buy another pump/bearings/engine or car?
N Sayle

What was the light doing before you changed the oil?

Do you have a mechanical test guage: engine/transmission pressure tester, you can screw into the sender hole to verify oil pressure?

My 1500 did a similar thing last summer, then the light just stayed on. I tested with a screw in type pressure tester & verified pressure was good, then changed the faulty OP sender switch.

I've since installed a mechanical guage to keep my eye on it.

It may only be the sender...or not?


Dave Rhine ('78 1500)

Hot oil pressure at idle on a 1500 should be of the order of 20-30 psi. The light comes on at 3-7psi.

I would suggest your bearings are on the way out and need changed asap since you will likely knock a big end out (followed by a rod making a bid for freedom through the crankcase).

Typically the oil pumps don't wear badly but I would source a new pump if doing the bottom end. Ensure you get the later pump with the extended, angled, pick up pipe.
Deborah Evans

Sorry N,

There is a therory that if the oil has never been changed in several years...then Dont change the oil "EVER" as the black goo acts as a cusion for the bearings....you might try using some really thick oil to help fill the voids...I dont know if that will work, but new bearings are most likely inorder

Prop
Prop

Deborah

I agree with you completely, if the pressure IS actually low, but I would verify it first.
Dave Rhine ('78 1500)

I have been doing some reading and it is looking like bearings. Could I get away with changing them without removing the engine? With the sump off I will change the pump just in case
N Sayle

Aye Dave.

Deborah Evans

N

Check this out, tells you how to do bearings with engine in car, step by step.

Dave

http://members.core.com/~ckotting/1500_bearings.html
Dave Rhine ('78 1500)

Thanks Dave, I found that last night and spent most of the night going through the process in my head. My only stumbling block is choosing the bearings to install. Would it be wise to buy std bearings and assume no re grind has been done. Are the old shells marked in anyway? Where in the UK is the best place to buy the mains and big ends from in UK. Jet washing the engine today, bang goes another weekend!
N Sayle

The bearings should be marked on the backside (non wear surface).

Have you tried a mechanical guage in the sender port to verify low pressure?

You may very well need bearings, but I'd check pressure first.

Like I said, last summer my sender & light said no pressure, but I actually had 30 @ idle & 60+ @ 4000rpm (hot).
Dave Rhine ('78 1500)

STOP PRESS ! ! ! !

Thank you for all the input regarding the low oil pressure. I connected up an old smiths oil pressure gauge I have discovered great oil pressure. Changed the sender switch. Green light now out. dodgy LUCAS had me worried once again! (under a load test it was showing variable resistance and irregular readings when I pump pressure tested it.) On the up side, the roads are dry around Herefordshire today, I'm off out to play. I have bought a load of new wire fuse boxes switches (an Oil Pressure gauge) endless list of electrical parts. So instead of spending the weekend on my back covered in oil I am in my zone with electrics. Thats what I do should anyone want help in that direction. I'm a happy bunny again today. I love my little car!!
N Sayle

I'm happy for you! :)

BTW, I use both a mechanical guage & idiot light now...very simple to hook up at the sender port using a brass T.

Enjoy your day & read up on the 1500 thrust washer problem, it's something all 1500 owners need to be aware of.

Dave


Dave Rhine ('78 1500)

here's a thrust washer link:



http://www.teglerizer.com/triumphstuff/thrustwashers.htm
Dave Rhine ('78 1500)

And another (but, if you do need new washers, ask for advice on this board first...it's a problem many of us 1500 owners have had & solved):



http://www.customthrustwashers.com/
Dave Rhine ('78 1500)

Thanks again Dave, I am going to drop the sump anyway to have a look at things. When I have determined the bearing oversize I need I will order a complete shell set for the bottom end as well as whatever thrust bearing I need. I have worked on B's for donkeys years and I am starting to really like the Triumph lump. It is very easy to work on even though it has its drawbacks. I am not trying to increase to power as it is quick enough for me already but I do want a solid engine.
N Sayle

For bearings and thrusts contact Mark Field at Jigsaw Racing.

http://www.jigsawracingservices.co.uk/



Rather than go into the why's and wherefores again with the 1500, have a look at:

http://www.visn2.com/Flash%20Website/1500_Replacing_Main_and_Rod_Bearings.html



Deborah Evans

N

There it is, Deborah's given you a UK source for top quality parts.

Listen to this Lady, she knows her stuff!

And yes, the 1500 does have abit of grunt, we just need to keep tabs on the bottom end ;)
Dave Rhine ('78 1500)

ordered a set of plus 20's. They look good but will change them anyway as I have the sump off now. Ordered the hi tech thrust washer as well. There was very little play but best be safe. The pump mesh was very clogged up so that is now in the kitchen sink bowl.. I have also ordered the ACCUSPARK kit, not too sure about it but will give opinions after a few weeks running in, spin at 25 quid if it works out.
N Sayle

we've heard some good things about a/that spark unit in here recently

wasn't it for sale by a Land Rover specialist at way less than the very similar pertronix units?

I think you 're right to opt for new +.020 shells while you have the caps off, far better than risking a piece of old crud getting stuck under the shells when you bolt it all back up again

soon be back in business then
bill sdgpm

Looks like Dave and I took the same approach, using using a gauge but keeping the idiot light intact:

http://www.ketcherside.net/oil_pressure_gauge/frameset.htm

-:G:-
Gryf Ketcherside

I have a few old Smiths gauges somewhere in the garage. Going to a friends workshop at the weekend and with turn down a bit of brass bar and make an adaptor. I think I have a couple of the old dual gauges so it will save me fitting a holder
N Sayle

The light gets my attention quicker than the guage, but the gauage lets me know the actual pressure.

Gryf, yes we took the same approach, but I credit you with idea!!!

I saw your post awhile back in the archives, but then forgot where I saw it (an old age thing)...a belated thanks for the idea!
Dave Rhine ('78 1500)

This thread was discussed between 24/03/2010 and 26/03/2010

MG Midget and Sprite Technical index

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