Oil Pressure 2.5 non Turbo

[ogri211]

[b][/b]
I have 2 x 2.5 non turbo (fsd 425) engines fitted to my boat. They always start first time and run perfectly, the concern I have is the oil pressure, because my boat has large props I normal cruise with the engines running at 14 - 1500 rpm, one of the engines is showing 1.5 bar and the other is showing 2.5 bar when hot ( I replaced the gauges at the begining of the year and the old mechancal ones were reading the same), I am concerned that this is a bit low, also I have turned the tickover down to about 700 rpm and again when they are hot my oil lights /buzzers flick on. I was going to firstly change the oil relief valves and springs and if that did not work I was thinking about replacing the oil pumps, the engines dont overheat they perform there is no knocking. I would be grateful for any input regarding the oil pressure and the replacement of the relief valve and the oil pump.

[bazw]

at 1.5 bar they should not give an oil light i would think , have you changed the senders ? i think this may be a cause of the light flickering

[ogri211]

Hi the oil light isn't coming on at 1.5 bar I am getting 1.5 bar at 1400 rpm, the light is coming on at tickover when it drops to about half a bar, I am also getting 2-3 bar when I rev the engines over 2000 rpm in neutral.

[Terry]

As you have replaced both gauges and the readings haven't changed I would change both senders too. Then if no improvement start thinking about upping the spring rates on the oil pressure relief valves. Generally with oil pressure providing you don't get huge fluctuations whilst revving, all should be well, but your readings do seem on the low side. (I am not familiar with these engines so am unaware of what they should run at.).

[MrMPuk]

Just swap the senders over and see if the problem moves with the senders.

[ogri211]

hi thanks for the replies, but the senders are brand new, I replaced them with the gauges, the old gauges were piped as they were mechanical bourden tube type gauges so I am pretty sure the readings are true as they also read 1.5 and 2.5 bar , the readings I get when the engines are hot are 700 rpm- .5 bar, 1400 rpm 1.5 and 2.5 bar and 2000 rpm 3- 3.5 bar.

[V184]

Check the crank pulley is tight, if its not the oil pressure drops

[Frag]

Check the crank pulley is tight, if its not the oil pressure drops

Good call,the oil pump gear is driven by a gear on the crank which is only held tight by the crank pulley bolt tension,make sure the washer between cambelt gear/pulley & crank is in place also.

[Dave S]

Hi

I too have a transit 2.5 in my boat and as the engine gets hot so the pressure drops on tickover to about what you suggested.
The book says it should run at 1.0bar at tickover and 2.7 - 4.8bar at normal speeds also the idle speed should be 800-850rpm on non turbo engines.
The other thing to remember is that if you have a standard oil cooler, i.e. the engine water cools the oil around the oil filter block, this goes get very hot so many marine installations fit a small external fitted oil cooler where the sea (raw) water cools the oil and greatly improves the pressure by keeping the oil within the temp range of the oil, approx 80 degrees C.

Hope the above helps

Dave

[ogri211]

Thanks Dave thats a great help it looks as if the oil pressure isn't as bad as i thought I think it is a combination of my tickover is too low also, I have no oil cooler fitted I would be greatful if you could give me some details on a Bowman type cooler like I have on my gearboxes IE where to get one and where to pipe the oil too and from the engine,

Regards Stevie

[Dave S]

Have a look on the Lancing Marine site. http://www.lancingmarine.com/
Mike is the contact and what he does not know about Ford marine engines is not worth talking about.

You will only need a small cooler and the raw (sea) water will keep it nice and cool, I have yet to do this on my boat but have also been looking at a bolt on heat sink to the oil filter to aid my cooling as I have a turbo with intercooler so the first place sea water goes is the intercooler and to re-plumb the engine bay will be a nightmare for me.
As we don't have cool air rushing past the engine most boat engines need as much cooling as they can get.
Keep an eye on Ebay as some come up for sale quite cheap.

I have even thought about this "water wetter" you can get which is supposed to aid cooling.

Dave

[nokites]

Oil temp @ 80 C
The oil pressure at idle must be at least 1 bar. 850 +/- 50rpm
The oil pressure at speeds in excess of 2000 rev/min must not be more than 5 bar.

[ogri211]

Thanks alot for all the advice I can sleep easier now knowing that the oil pressure is not bad i think I will still try the pressure relief valve on my stb engine as 1.5 bar at 1500 rpm seems just a bit low especialy when there is an identical engine with the same hours giving 2.5 bar next to it.

[fishingchris195]

I am running twin 2.5 di turbos in my boat your tickover is to slow as has already been said.
good luck chris