Perkins 6-354 T

[donvigus]

What is the healthiest rpm to run a Perkins 6=354 T on a Monk 36 size trawler

 

[Dwk]

Dont have a Monk 36 but do have a Perkins T6.354 in a 34 Mainship. Our normal cruising RPMS are 1650-1850 with 2450 being WOT. If we push it to 2000+ fuel consumption increases dramatically with little increase in speed. (you'll have heard this before!).

 

[donvigus]

I just bought the Monk 36 with the Perkins which has 4141 hours on it. It runs great, starts fast. Is there some guidelines on how ofter the turbo should be rebuilt or the fuel injectors be serviced?

 

[donvigus]

Also, on another subject, many of the Monk 36 trawlers that I looked at had 600 pounds of ballast in the stern. How does that affect the trawler?

 

[DavidM]

Watch for hard starting or smoke that doesn’t go away after warming up for a few minutes. That is an indication that the injectors are going bad. Watch for lube oil leaks on the turbo for an indication that the turbo needs attention.

David

 

[jleonard]

I just bought the Monk 36 with the Perkins which has 4141 hours on it. It runs great, starts fast. Is there some guidelines on how ofter the turbo should be rebuilt or the fuel injectors be serviced?

A little oil "drool" out of the intake side of the turbocharger is common and not harmful. Put a small piece of oil diaper to catch it.
With the engine NOT running you can remove the intake screen (or filter if there is one) and grab the center shaft and wiggle the impeller slightly. If it does not touch the housing the bearing is fine. Move it both radially and axially.
These (Holset 3LD) are easy to rebuild if you are modestly handy. I've rebuilt 2 of them in the past.
Locate a rebuild kit and keep it in your spares.
If the exhaust smoke goes away when the coolant temp reaches 140 F and you're not making black smoke the injectors should be ok.
Any diesel injection shop can rebuild them if you decide to do it as a PM item.

 

[STB]

If you check your injector pump's label plate, I think. It'll show that the maximum governed rpm is 2400rpm. This is usually designed to be 115% or so of the WOT (under load) rpm. So, if you are clean on the bottom and propped and geared as I'd expect, I'd guess you'll see 2000rpm to 2100 rpm as a WOT (under load) rpm.

I think you should get up to this rpm cleanly or with only a little grey (not blue and not clouds of white) in the smoke. If you see a lot of dark smoke, barring some engine problem, you might be over propped and might want to note the rpm before it gets really dirty as your WOT limit.

The maximum sustained cruise rpm is usually 80% or 85% of this number. So, I wouldnt hesitate to cruise it at 1650rpm to 1750rpm or whatever you 80% number is, all day long. Even 85% would likely be fine if runs clean and smooth.

It doesn't really make sense to cruise a diesel at less than roughly the maximum torque per stroke. On this type of engine that is usually a wide band from 1200-1300rpm to 1500rpm-1600rpm. Looking at the low side of that, that many likely much of a limit.

I've got torque/hp performance curves for many of the classic perkins engines, but ai can't find the one for yours for the life of me. Sorry!

 

[High Wire]

From what I’ve read they came from the builder with a bow down trim. The lead was added to level them out, especially once a generator was added stateside. No issue with it at all. Mine is an 84 and the lead has not moved a millimeter from Ontario to the Bahamas.

 

[SeaDogAK]

I have the same engines. I get a lot of smoke at startup which gets less but never goes away entirely. Mechanic who inspected them when I bought the boat 2 years ago said not to worry about it, these engines do that. PO said they always did that when he owned the boat and his mechanic said not to worry about it. The engines run fine.

Should I check the injectors? What would be involved if the injectors are “going bad?”

 

[PhilPB]

I also have the same engine at about 3200 hrs. It starts right up very quickly. I generally run between 1400 rpm (6 kt, 140°f) and 1900 rpm (9-10 kt, 160°f). Fuel burn for me is approximate at 2 gal/hr average. WOT is approximately 2250 rpm.

 

[sunchaser]

​

I also have the same engine at about 3200 hrs. It starts right up very quickly. I generally run between 1400 rpm (6 kt, 140°f) and 1900 rpm (9-10 kt, 160°f). Fuel burn for me I approximate at 2 gal/hr average.

Hi Phil
You may want to verify your water temperature and oil too with a heat gun. Ideally your water should be 170-180 and oil 175–190.

Do you know your thermostat rating?

 

[PhilPB]

​

Hi Phil
You may want to verify your water temperature and oil too with a heat gun. Ideally your water should be 170-180 and oil 175–190.

Do you know your thermostat rating?

I don't know the rating of my thermostat. The temp will go to 180° if I run 2000+ rpm, but it generally stays around 170° at 1900rpm. I thought 160°-170° was a good target range based on one mechanic that worked on it.

 

[PhilPB]

All things considered my numbers are off my temp gauge and are estimates since gauge #'s are in 20° graduations.

 

[jleonard]

Those engines came with a 172 F thermostat.

 

[sunchaser]

Those engines came with a 172 F thermostat.

My 2003 Perkins Sabres (Cat 3056) came with 172s as well. Once warmed up the temperatures remained at 175 whether at 1200 RPM or 2000.

 

[jgwinks]

If you check your injector pump's label plate, I think. It'll show that the maximum governed rpm is 2400rpm. This is usually designed to be 115% or so of the WOT (under load) rpm. So, if you are clean on the bottom and propped and geared as I'd expect, I'd guess you'll see 2000rpm to 2100 rpm as a WOT (under load) rpm.

The last four digits of the injection pump serial number is the max RPM. There are many different versions of this engine and they're not all the same, my 6.354MGT's are 2750. I normally run about 1800 which is 8kn or if I'm in a hurry 2000 which is about 11kn. I can get more out of them but haven't wanted to pay for it. Coming from a 5kn sailboat 8 feels fast but I'm glad to have the extra speed available if I need it.

 

[Gypsyjon]

Perkins 6-354

Thats a great engine. It will last longer than you will.

 

[RichHurst]

Consider joining Monk Owners association. It is very active. One time fee and lots of Monk specific answers. That and trawler forum good source of guidance

 

[DC36Monk]

My Monk 36 has twin Perkins naturals (135 hp). WOT is 2650-2700. My sweet spot is 1750-1800 rpm at 8 knts. 2.4 kpg. At 7.5 knts I get 2.7 kpg. Pretty bullet proof engines.