I'm wanting to build a pre-lube/post-lube circuit for a diesel generator. I would like the circuit to pre-lube with a push button and post-lube when the ignition turns off. The pump will be controlled by a 24v relay and the timing will be controlled by a 555 timer. In this circuit, R1 will be adjustable to set the time of the post lube. The button next to R1 is for the pre-lube. I'm guessing that I probably should have added a relay before the diode so that pin 2 actually grounds instead of floating...thoughts? Please give me any and all feedback! It's been a long time since I have done any circuit design and am in no way attached to this design. I just want the most reliable and most simple circuit possible. Thanks for your help!

Questions:
How can I make the pump turn off as soon as the ignition turns on (pre-lube)?
Will the pump continue if ignition stays low (off) or does a monostable only run on a trigger FALL?
What values for Q1 and R2 (unlabled)?
What diode should I use?
Is there a good way to waterproof this circuit? This generator is outside so there is a good possibility that this circuit could get wet. I was thinking of embedding the circuit in hot glue/resin/etc but I'm not so sure I can do that with Q1 in the circuit...

 

Why use a second pump? Be sides the engine oil pump I mean. A small pressure tank (1qt?) and a solenoid valve will do the same thing.

Never heard of an engine using or needing post lube. What is the reason for that?

 

It's a turbo diesel. The main pump shuts off when the motor shuts off. The second (electric) pump allows the oil to flow through the engine and turbo bearings while it cools off. This greatly prolongs the life of the turbo and the motor.

 

Question: the turbo could be still turning while the engine has already stopped? Is that the reason or just the cooling down?

 

No, the turbo is not still running. The reasoning behind this is that the turbo is still extremely hot after shutdown. With no oil running through the turbo cooling it down, the turbo transfers all this heat to the stagnant oil and will actually burn it. This gummed up oil will later flow through your engine and your turbo and cause damage. Running a post-lube system will force oil through the turbo so that it wont stagnate and burn. Any thoughts on the circuit?

 

Hello,

Your last thread was closed for being automotive:
Pre-lube/post-lube Circuit
I have looked it up and this does not look like a generator:
http://www.buschandbusch.com/m35a2.html

I will also close this thread.

Bertus

PS a third try will result in a ban.