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Now What Have I Broken :(


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I know what you mean Donald.

There was a product that replaced the standard starter motor with a modified unit that had a piggybacked oil pump. It worked by spinning with the bendix disengaged till the oil pressure was up before allowing the engine to turn. There is a considerable amount of wear on startup which is why we always prime our marine engines before we start them.

I have been thinking for a long time about using a modified turbo lubricator that would charge during normal running and then fire a priming charge into the engine before starting, never got around to putting it into action :(

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I am sure I've read about that style of independent pump which is more critical on Turbo's that rely on the engine driven pump supplying the oil to them. Apparently they continue to feed the spinning turbo for a number of minutes after the engine is switched off until it has stopped too.

One of the worst things you can probably due to a turbo is give the throttle a good "blip" to get the turbo going fast, then shut the engine off... :o

With the V8, (and no turbo's), the critical time is at the start so could you not fit a simple switch to the line to the coil... Leave the switch off while the engne is winding until the oil light goes out then flick it on and hey presto... Although I suppose you may be at risk to flooding the engine with fuel? :(

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Yes that is more or less what I was thinking. The turbo unit is a small cylindrical resevoir with a bladder inside, there is an inert gas charge between the cylinder and the bladder. When the LO system is under pressure the bladder is filled with oil which is held by either a pressure release valve or solenoid with pressure switch. When the machine stops or the pressure drops below a set point the stored oil pressure is fed back into the system.

We use these quite a bit in the marine industry to store enough pressure to operate emergency equipment for hydraulic systems in the event of hydraulic pump or prime mover failure, to release brakes or retract equipment for example.

My idea was to use the resevoir same as usual but have the solenoid operated to release the pressure when the ignition was switched on rather than off.

I have to concentrate on getting the project on the road though, smart arse ideas will not get it passed an MOT :(

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Interesting idea.... and I am familiar with the principals behind accumulators too. When woud you want to charge it though? Once the engine is off, the valve opens and it weeps its contents into the oil lines. However, that would always mean that it will be empty when you want to start up. The downside being that there is the potential for the oil pump to be busy charging the accumulator when you'd rather it was supplying the engine. :( It takes a fair fill to fill a new filter let alone a useful volume in an accumulator.

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Sorry :o you never know till you try ;)

Yes I thought about that and had the intention of having two solenoid valves contolled by pressure switches.

One "normally closed" for filling, through a check valve & restictor to minimise losses, that only opened when the pressure was above 2.5 bar say and then shut when the differential between line and accumlator was minimal.

The second "normally closed" to supply down stream that opened when you put the ignition switch to III, wait till either the light goes out or a set time to empty the accumulator.

Admittedly all the pressure controls could make things complicated, it would probably be easier to use 2 standard Lucarse pressure transducers and a PLC but I haven't bothered to sit down & work out the details but now that we have gone this far ;) .

1 x appropriately sized accumulator - work it out by feeding pressurised LO of a known quantity through the engine till the light goes out and then measure whats left.

2 x solenoid valves 5 bar & 100 deg C 15 mins duty cycle.

2 x pressure transducers 0-5 V similar

1 x PLC & assorted bits of plumbing.

Don't start me or I will never get the project on the road :unsure:

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so are you just wanting to make sure there is oil at the pump as soon as the engine turns over? i.e. no pick up time for the pump to suck anything from the sump.

or are you wanting the whole block to be primed and under pressure?

if the first, why not have a header tank thats filled by the general flow with a solenoid controlled downpipe into the pump. IGN on opens the solenoid, IGN off closes it.

If you turned the IGN on, but didn't crank, the header tank would simply dump its contents down into the pumpcause the solenoid opened.

or is that too simple?

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