Fiat Dino Forum (FDF)

Hello Group
I would like to know what is every one getting on their pressure gauge reading wen cold and hot.

When I got my Dino spider 2.4 a couple years ago before getting a full restoration i got very low oil pressure reading.

I since had my engine completely rebuilt and it's running very nice and strong.

On the first day we started the engine last month we got very low reading on cold like 50 at 2000 rpm and could reach 60 at 3500.

Then wen hot the gauge read low 20s

My mechanic did not like those numbers. He put a mechanical gauge under the engine block and got 70 at 3000 rpm and then put his mechanical gauge on the top of the engine and got almost the same reading around 60-70 at 3000 rpm.


I was told my my sending VDO unit being original to the car was not accurate and could be replaced to a new VDO.
I purchased and installed the new VDO oil pressure sending unit made for our cars.
What a pain in the ass was it to replace it took me nearly 3 hours just to replace that.

Long story short I am still getting very low readings. Even with the new sending unit ?

On cold start in 2000 rpm I get 50 and at 4000 I get 60's
But as soon as the engine is hot in get 20's at 2000 and nearly 50 at 4000 rpm.

Now I am thinking that my gauge my be defective.
I just ordered an other one off ebay hoping that I get readings that are more accurate.

In over 15 of these cars I've noticed they are all the same, the gauge for some reason always reads low. also in the Ferrari Dinos, I found the same to be true.
I wouldn't worry about it unless it doesn't read at all, which I've seen also when at idle.

These original Veglia oil pressure senders show low reading 9 out of 10 times (after 45 years)
They are used in basically every italian car built between 1960 and 1990 but there are quite some different ones so just repacing it with a VDO without verifying what exact model you have will most likely not work.
Some of them are 0-6 bar / 0 -8 bar / 0 - 12bar and then between each model they can have different resistances over that scale.
What i always do (and i think i have done it about 50 times at diffent cars by now) is take the Original pressure sender unit, bend the seam open and take the cap on top of it off (not so easy first time).
Then take a 0-1000 Ohm potentiometer and wire one side to the wire going to your pressure sender in the car and the other wire from the potentiometer to ground of the engine. Put your ignition on and turn the potentiometer that the gauge in your car is reading 1 bar of oil pressure and write down the resistance of the potentiometer at that point. Do this also at 2 bar / 3 bar and so on.
Than you take your sending unit and make a connection with a mechanical gauge attached to it and a connection for air pressure from the compressor. Put 1 bar on this system and check the resistance of your sender unit at this point. Do this also at 2 bar / 3 bar and so on and write down the numbers.
Now you can adjust your pressure sender with small pliers to get it 100% correct and corresponding with your gauge.
Put the cap back on it, install and you will have correct oil pressure reading.