Since putting a Smith's electronic gauge in several years ago, I've been concerned about it's accuracy and indicated low oil pressure (~25psi).

As a troubleshooting aid, today I bought a cheap speco capiliary type from supercheap and straight away it indicates 60-70psi. I don't want to leave this one in permanently as it has minor leaks on the nut that bolts onto the adapter on the block, but will use it to calibrate and get the electronic one working.

The sender unit I used on the old one was a new VDO unit sold to me by a mini place ( I think it was Padstow).

Has any one had experience with whether the VDO sender might be the problem?
What are the genuine smiths one's worth, any ideas?

Anyone in Sydney have a spare Smith's electronic sender I can try or buy?

Thanks
KB

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Surely you don't expect your smiths gauge to be correct?
Unlike modern speedo's which are "accurately" calibrated my Smiths speedo has an error indicator built in, when I'm going about 100km/hr it wobbles up and down telling me that I am doing 100km/hr +or- 10km/hr

you can get that fixed at an instrument place.

The Smiths ones in Minis are all mechanical, not electric.
Electric ones have always been dodgy (eg Fiats, Alfas) and the price of proper electric gauge senders will just about buy you a proper mechanical gauge.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

so you've got a smiths electronic gauge with a VDO sender.... sounds like a simple case of incompatability - you ought to be able to solve it by fiddling around with resistors. Talk to Wombat about it

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did I tell you that I won a trophy?

Hey KB, it would be easier to put in a Smiths Mechanical like Doc says. I have one and it's fairly accurate (90psi actual is 100psi) but most importantly 50psi actual = 60psi so it is innacurate across the range rather than just at the top end etc.

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Lillee - 1969 Morris Mini K

Yes Simon, It does seem to be that simple.
I bought a genuine Smiths sender unit and stuck it in tonight. I had the reassuring sign of both the speco and smiths both showing 70psi

I've leave them both in whilst I go for drive in a few nights time and if all OK, I'll swap the speco back over (it's using the space normally used by the warning light sender) on the weekend.

Doing the ball bearing and rod trick Doc helped me with, seems to giving a much more consistent reading too (even on the "dodgy" gauge previously).
KB

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The ball bearing in there will give you better oil pressure at hot idle, as oil doesn't leak past it like with the valve (which never seat perfectly).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

What's wrong with the speco mechanical oil pressure sender? Never had problems with this brand. If you have a leak perhaps you're using an incorrect thread, missing a copper washer or seal or it's not sitting flush?

Personally I don't like the small copper line going from the block to the gauge... I replaced mine with a nice durable braided stainless steel line. Temp. capillary lines are pretty safe but pressure lines can be a point of failure - but obviously needed for your oil.

60 - 70 psi is a good/safe pressure to have, as long as it doesn't decrease much when hot and being revved a bit (symptomatic of oil overheating).

Doc's right about the ball bearing... bullets are bad, though you may have to cut a few coils off your spring to tailor your oil pressure if changing to a ball bearing.

The speco gauge came with a translucent plastic tubing with two little brass "grommets" for want of a better word which fit onto the plastic tubing and under the nut which you tighten onto the gauge or block at each end. If you're gentle, they leak. If you nip them up, they crush the brass grommet and you risk a leak anyway.

Poor design and not confidence inspiring.
KB

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IMO the best mechanical gauge connection was the original 2 steel pipes and short bit of tiny rubber hose, used on Cooper, S, Mini K and `Matic.
Mine is 38 years young, and still working...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.