Oil Warning Light - for the 4-cylinder engine ?

[Bfg]

12 hours ago, monty said:

Just done a few miles road test & all is well with no leaks! Thanks to you & Hamish for your advice etc.

[BlueTR3A-5EKT]

On 5/13/2022 at 10:51 PM, Hamish said:

When I fitted mine I thought of a a buzzer and light. It can be quite a busy time on a sprint.

but then I realised that it would be damned annoying to have the buzz every time the ignition was on and engine not running.

and I wouldn’t be able to hear the elec fuel pump tone change when the carbs are full.

So, Hamish, you have an electric fuel pump.    Did you consider wiring it’s relay via the oil pressure switch so if the oil pressure fails the pump cuts off?    I had a Metro Turbo with that arrangement as fitted standard.

[Lebro]

 

2 hours ago, BlueTR3A-5EKT said:

So, Hamish, you have an electric fuel pump.    Did you consider wiring it’s relay via the oil pressure switch so if the oil pressure fails the pump cuts off?    I had a Metro Turbo with that arrangement as fitted standard.

Starting would be delayed if float bowls were not full, as the pump would not start until pressure had built up. maybe that's a good thing ?

Bob

[Hamish]

3 hours ago, BlueTR3A-5EKT said:

So, Hamish, you have an electric fuel pump.    Did you consider wiring it’s relay via the oil pressure switch so if the oil pressure fails the pump cuts off?    I had a Metro Turbo with that arrangement as fitted standard.

No didn’t go that route. As Bob says not sure how the car would start as I let the fuel pump run with ignition before starting. 
I do have an impact cut out switch that’s  now within reach in the driver compartment.

[Bfg]

1 hour ago, Lebro said:

maybe that's a good thing ?

Surely not ..for the starter motor, or the battery and its wiring, especially if the car is often used for short runs. 

Nor, I suspect, is it good for the engine which relies on oil-splash to lubricate the bores and many other interacting components.

As I understand it..  engine lubrication a balance of both pressure and  flow rate.  An engine which starts easily and has a good oil pump will pressurise the oil within all  its galleries almost instantly ..while the engine is under very little load. From the rate of spin / centrifuge - there will be good oil splash (intensive spray) and subsequent return flow of oil (over cam-followers for example).  Whereas an engine that is slowly turned (..relatively speaking) will not offer the same magnitude of pressure wave throughout its oil galleries, because any localised losses (manufacturing tolerances & wear) will be to the detriment of oil pressure further along a circulation route.  It's oil splash will be weak, and the smaller streams of returning oil will likely be evident as streaks rather than as a wash.  

Of course, the counter argument is that with combustion loads - the started engine does have higher loads on its big end and main bearings.  I think it is a question for the engine's designer.  As very likely different engine designs will have a different answer.

Pete

 

Edited May 15 by Bfg

[BlueTR3A-5EKT]

6 hours ago, Lebro said:

 

Starting would be delayed if float bowls were not full, as the pump would not start until pressure had built up. maybe that's a good thing ?

Bob

You wire an override circuit from starter push switch/relay to the pump.  
 Press the starter and the pump runs, when engine catches you release the starter push and the oil pressure of the engine maintains the pump relay as energised.

 

[stuart]

That arrangement is in use on lots of cars, it did cause some head scratching on an XJ years ago when the switch in the oil gallery failed, you couldnt tell the pumps werent working as theyre in tank so you couldnt hear them.

Stuart.

[Charlie D]

I’ve never believed that any device that automatically stops the engine running while the car is moving, either by switching off the fuel pump or switching off the power to the coil, is a safe idea.

I just imagine being in the outside lane on the M25 or just going into a blind bend on a country road and having the engine stop.

Personally I’d rather have to rebuild an engine than have the possibility of an HGV pushing me down the road.

Charlie.

[Bfg]

^ been there on a very busy motorway section with no hard shoulder - when 'the modern' suddenly went into limp mode ..caused by a faulty sensor on the throttle pedal.  It's not an experience I'd choose to repeat.