Perkins 78hp turbo oil presuure

[Guest]

my Bro has his yatch in turkey and last outing ran revs out to give the motor a work out. Oil pressure dropped to 5 psi. will sometimes come back up but drops away again Suggestion is its pressure relief valve spring. Any ideas helpful as heading up and want to take parts from here. Cheers

[wheels 543]

I know this sounds a silly question, but you would be surprised how many times I have come across this kind of situation. But has he got the correct oil, is it clean oil i.e. not old dirty and like treakle and is it at the correct level.

Next, is the gauge electrical or mechanical.

If electrical, check all connections and not just at the gauge only.

Varify that the gauge itself is not at fault.

After all that, if you can't find anything, then look deeper into the mechanical side, which is rather rare and so that's why I suggest all the above first. Plus the pressure coming and going is not normally a broken spring, but never say never either.

[too_tall 15]

As wheels said, check for electrical issues. If you have the ability to install a manual gauge, get that onto it asap but first and foremost, check the oil level before doing anything. Also change the oil filter. It sort of sounds a bit like the pump is sucking air sometimes, then grabs a bit of oil before sucking air again. I have had this happen in jet boats, but never on a yacht. If its not able to be easily tracked down, get an eggspurt onto it. Motors are very expensive to fix.

[Guest]

Thanks. New synthetic oil, filter etc so may be gauge (electric) or wiring. Will fit mechanical guage when there and see how we go. Cheers guig

[wheels 543]

Woooo, careful on the synth oil. What is it????? Make sure it is a Mono 30 or at the very most, if you really have to, a 20-40.These engines were designed for a Mono 30 and using a thinner oil, like a 10-50 like some of these Synth oils are, ends up with the engine just chewing through the oil. Plus there are good synthetics and many many bad synths. The worse thing you can do is put some oil into it that is super slippery. It just causes the bores to glaze up. Amsoil are the only makers of a true fully synthetic Marine Diesel oil that I reccomend. I am very very weary of anything else.

[too_tall 15]

No need for synthetic oils in a low tech engine. I run pretty average cost oils in all my heavy diesels, and most get 15,000 hours without the engine being pulled down. And in tractors, thats a lot of hard work. Very different, and much harder work, than in a boat.

 

In a modern, common rail, higher power diesel, yes, then synthetic oils can be the go. Remember the molecule size in synthetic oil is often far smaller, and therefore an engine not really designed for them will burn a lot of oil, if not worse.