Oil Presure sender

[davidj]

Hi,

My Oil pressure sender unit has failed. The oil pressure dropped suddenly. First I thought it was something serious but I earthed the gauge wire and the gauge moved and I replaced the sender unit with a mechanical gauge and it read 20psi with the starter motor spinning the engine. Phew!

So where can I get the correct replacement sender unit? Mick Miller does not stock them and Matty only stocks 100psi sender units and says the correct ones for our cars and unavailable. There are also loads of 100psi units on ebay. I am at work at the moment and cannot remember whether the full deflection on the pressure gauge is 60 or 80 psi, but obviously if I fit a 100psi sender unit, the gauge will read incorrect.

Any suggestions anyone?

Thanks, David

[gerrym]

David, original fitment to my S130 was a 60psi FSD mechanical gauge. You should be able to pick up one of these on Fleabay or speak to Speedy Cables. Will probably be more accurate than the electric pressure gauge in any case.

Regards

Gerry

[Hawksfield]

davidj

Sometime ago around 6years my sender failed not to be beaten I cut gently around the metal can and removed it, found that the contacts were dirty cleaned them then soldered the metal can back, been like that eversince.
I had to remake the the wiring connection but that is easy
Better than throwing it away.

JH

[msd1107]

http://www.gaugeguys.com/Smiths/accessories.htm
http://www.nisonger.com/smiths-parts.htm
http://www.powertorque.co.za/caismiths.htm

PTR1812-06 is 60 PSI 1/2" UNF.
PT1811-06 is 60 PSI 1/4" BSP

David
1968 36/7988

[davidj]

Hi,

Does anyone know the model number for the Smiths 60psi gauge. I think I have found a supplier for the sender unit but the lady on the switch board would not talk to me unless I knew the model number, and I don't fancy pulling mine out of the dash to find some id!

Cheers,

David

[Craig Elliott]

Not sure if it's a help - I've just checked mine and the only number I can find on the case of the gauge is 103...

C

[msd1107]

The model number is usually in small letters and numbers at the top or bottom of the gauge. Sometimes it is partially hidden under the bezel. Other times it is by the needle, over or under.

David
1968 36/7988

[paddy]

A 60psi sender just popped up on ebay: item number 130305222707

Paddy

[kcrossle]

Golden Gate Lotus Club has senders and gauges (and parts numbers) in their cross reference at http://www.gglotus.org/ggpart/ggpart.htm


Keith

[davidj]

Hi,

I followed JH's advice, but rather than cut the unit, I discovered it is very easy to prize the case apart at the bottom, where the metal is rolled over the base. I then cleaned the contacts, reassembled and it is working again! There is also no obvious damage to the unit.

D

[john.p.clegg]

I don't suppose anyone has measured the resistor in the sender while they had it apart?

John

[surveyor]

John,

Had to take my oil pressure sender apart to clean dirty contacts, oil pressure reading was all over the place. Scary moment. The resistor is a 1/4 watt carbon composition type, +/-20%, the colour code reads 200 ohms (a non-preferred value) but the resistor actually measures 30 ohms on my meter (0.5% accuracy) so must be wired in parallel with the switching heater coil.

I thought about replacing the resistor but it shows no sign of deterioration or overheating so I did a test with the sender unit temporarily reassembled and the oil pressure reading is back to its normal 40psi at 2,000rpm hot, 20psi idling. So I've reassembled the sender properly and left the old resistor in place.

dennis

edited to correct a mis-reading of the resistor colour code value.