Turbo charge diesel

[missjody]

I recenty purchased a 42ft motor yacht with twin Perkins SST6.3544 turbo charged engines. The boat will reach hull speed of 8k at 1800 rpm. However, I can not hear the turbos engage at any speed up to 2400 rpm.
Any suggestions on the optimum engine speed to operate?

[ranger58sb]

Didn't know any of the Perkins engines were turbocharged...

Anyway, you might find more folks familiar with that engine on trawlerforum.com (sister site).

-Chris

[hobopacket]

Those turbos should be spinning and making a bit of noise at cruising speed. 1800. How close have you gotten to them? Just riding down the freeway you can usually hear trucks turbos pretty clearly.

That engine should be fairly sluggish without them at anything much over idle.

[SV Bacchus]

Welcome aboard! Well, I have several questions/comments:
What hull is it? Is it a planing hull? Are those engines original equipment?

I guess where I am going with this is if someone upgraded the engines and they are bigger than original you may not get the turbos to engage without pushing the engines hard for little to no gain in speed.

If 1800 is their sweet spot for that hull, run em that way and prolong the life of the engines. If you push them to 2400-2800 or above and only get 10 or 11 knots you will realize a significant fuel burn for the couple of knots speed.

[Pete7]

These are old 6 cyl turbo engines and if anything like my old Ford TD the turbo won't kick in until 1800 rpm. If you can't hear them at 2400 revs however, I would question if they are running. You should have a boost gauge which will show about 1 bar if the turbos are working hard at high revs.

Be gentle with those engines, warm them up and cool them down after a run as they are getting on a bit.

Pete

[Lepke]

If the turbos aren't working, the blades are restricting the exhaust, causing more fuel to be burned. To a lesser degree the intake side blades also restrict the air flow. Because I can, I usually rebuild turbos when I take over a boat. That's replacing the bearings and seals. Turbos usually have motor oil to lube the bearings. If an engine hasn't had frequent enough oil changes the small oil passage gets plugged or partially plugged and the bearings go bad. Then the seals go bad, oil if it's still there either goes in the intake and gets burned or the exhaust and smokes.
I've never had a turbo go bad because I rebuild at half life. It's not that hard. Clean out the oil passage, too. I recently did my Ford PU turbo and the kit was $120, but a rebuilt turbo is about $1200.

[a64pilot]

Buy a boost gauge, well installed Turbos are silent or nearly so, yes I love the subliminal whistle of a turbo on boost as much as anyone, however sometimes it just isn't there, a boost gauge removes the doubt.

[hobopacket]

Originally Posted by a64pilot

Buy a boost gauge, well installed Turbos are silent or nearly so, yes I love the subliminal whistle of a turbo on boost as much as anyone, however sometimes it just isn't there, a boost gauge removes the doubt.

+1

If you find they don't boost, time for a rebuild.

[a64pilot]

You can usually also without too much disassembly see the turbo intake turbine, just watch it, on boost that thing is really spinning fast.
However only turbo I ever lost the engine smoked badly from being overfueled and the poor thing couldn't pull the hat off of your head it lost so much power, there was absolutely no doubt there was no boost

[GordMay]

Greetings and welcome aboard the CF, Jody.