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Old 02-23-2011, 10:08 AM   #21
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RE: Can large diesel engines be run at minimum RPM continually?

What HP and do you have turbos?

If no members chime in, your Perkins operating manual*may*have a fuel burn curve for various RPMs and prop loading. If not there, try either the Perkins website (that is where I got mine for my PS 225s) If not there, maybe Jay Leonard would have one from his old Perkins days. If not there, post on boatdiesel.com.

Can you achieve top rated RPM with your current props? If not, I would* not advise running at 80% +*load without knowing your exact (use IR gun as well as gauge) engine temps.
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Old 02-23-2011, 06:04 PM   #22
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RE: Can large diesel engines be run at minimum RPM continually?

"maybe Jay Leonard would have one from his old Perkins days"

I only have the curve for a T6.354 at 160 hp (turbocharged version). *That was the engine I had.
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Old 02-24-2011, 05:07 AM   #23
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RE: Can large diesel engines be run at minimum RPM continually?

Run the engine at full throttle OUT of gear for 10 seconds. Note the RPM in the log

Take her out and see if you get that , or less RPM under way.

A 2400 RPM mfg rated will usually pull 100 to 150 RPM over the rating with no load .

IF you get 2400 the prop is correct for the mfg, full load.

I agree with the folks that slightly over prop , and get longer engine life ,less noise and better fuel use.
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Old 02-24-2011, 07:12 AM   #24
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RE: Can large diesel engines be run at minimum RPM continually?

However, BEFORE doing any WOT rpm test, you must first make sure your tachometer(s) is calibrated. You can do this with a hand held photo tach.
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Old 02-24-2011, 11:29 PM   #25
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RE: Can large diesel engines be run at minimum RPM continually?

I'll second the phototach.** The dash tach can be off a lot.
Get a phototach that has the laser pointer for about $50-100 online.

After I got mine and did my engine I found quite a few more uses for it.
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Old 02-25-2011, 07:38 AM   #26
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RE: Can large diesel engines be run at minimum RPM continually?

Quote:
Screwdriversteve wrote:

*
I run my twin TAMD 60 Volvos at the factory recommended minimum operating speed .................*

Where did you find this information?* My TAMD41P manual lists a maximum RPM of 3900 but not a minimum.
*
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Old 02-25-2011, 09:26 AM   #27
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RE: Can large diesel engines be run at minimum RPM continually?

I found it in the operation manual for the engine, not the service manual. Often there is very good information in the small leaflets the come with equipment that gets disregarded because we "think" we know how to use it.
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Old 02-25-2011, 07:58 PM   #28
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RE: Can large diesel engines be run at minimum RPM continually?

Quote:
jleonard wrote:

"maybe Jay Leonard would have one from his old Perkins days"

I only have the curve for a T6.354 at 160 hp (turbocharged version). *That was the engine I had.
Hi Jay, I just PMed you with my email to ask if you'd send this to me.* We have the*wo T6.3544s with 210 HP so not the same but we are curious to see your graph anyway if you don't mind.

*
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Old 03-01-2011, 12:46 PM   #29
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RE: Can large diesel engines be run at minimum RPM continually?

Quote:
jleonard wrote:

However, BEFORE doing any WOT rpm test, you must first make sure your tachometer(s) is calibrated. You can do this with a hand held photo tach.
And you must also ensure that your engine can turn up the required and specified NO LOAD RPMS in neutral. If it cant then you will never reach max specified WOT .

*

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Old 03-02-2011, 10:32 AM   #30
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RE: Can large diesel engines be run at minimum RPM continually?

Jay!

I have those exact engines, could you post the info you have?

Thanks!
Brent
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Old 03-02-2011, 12:47 PM   #31
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Can large diesel engines be run at minimum RPM continually?

Brent,
It's a pdf file and I can't figure out how to post it.
I can't attach it as an image because it's the wrong file type.
It won't "paste".

HELP!

And after really reading your post if your boat is a 1984 tou don't have the exact engine...I had a T6.354 which were discontinued in 1980 (IIRC). You should have T6.3544 AKA "Range 4" engine.


-- Edited by jleonard on Wednesday 2nd of March 2011 01:49:24 PM
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Old 03-03-2011, 01:33 PM   #32
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RE: Can large diesel engines be run at minimum RPM continually?

this is another one of those "which anchor is best" questions.
* FWIW, before we purchased our current boat, I called Caterpillar (we have 375 hp turbo 3208's) and asked all the questions I was curious about on these engines.* On the question about operating rpm range, the answer was that the engine can be continously operated withing 10% to 100% of it's rated*hp subject to the rating restrictions that Cat publishes (E rating, C*rating etc) providing the engine cooling water temp is 180 degress fahrenheit to 210 degrees, period.* Operation below the 10% can be conducted subject to maintaining the min. coolant temp provided the load is increased periodically (no definition here of the period) to reduce any white smoke or rough running.* They also recommended running up to 80% rpm for 20 minutes out of every 8 hours running at very low rpms.* To translate*hp to rpm you need the cat sheets which are in the manual (also on boatdiesel.com) supplied with the engine.* In my case* 10% on a displacement prop curve is 1200 rpm (I am not displacement but I use this as it is the only thing they produce and at such low speeds I don't think there can be much difference.
They also said my 507 twin disc transmission can freewheel for up to eight hours, as I wondered about running on a single engine, but I haven't had the nerve yet to try this.
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Old 03-03-2011, 10:47 PM   #33
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RE: Can large diesel engines be run at minimum RPM continually?

Quote:
jleonard wrote:


Brent,
It's a pdf file and I can't figure out how to post it.
I can't attach it as an image because it's the wrong file type.
It won't "paste".

HELP!

And after really reading your post if your boat is a 1984 tou don't have the exact engine...I had a T6.354 which were discontinued in 1980 (IIRC). You should have T6.3544 AKA "Range 4" engine.


-- Edited by jleonard on Wednesday 2nd of March 2011 01:49:24 PM


PM Sent.* Thanks Jay!
*
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Old 03-08-2011, 08:05 PM   #34
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Can large diesel engines be run at minimum RPM continually?

Quote:
DavidM wrote:

Steve:

I believe that you have the normally aspirated (no turbo) 135 hp Perkins 6.354 engine. The rated rpm is 2,400.**



Hold on....* I have 6.354s and they will turn 3000.* There are many different flavors of 6.354, does anyone know the rated RPM for sure?* Mine seem to be happy at 2100 and cranking them up to 2500 doesn't produce black smoke or excessive heat.* I ran them this weekend at 2900* for a few minutes and other than the boat going very fast and burning a bunch of fuel there didn't seem to be any ill effects.

Woody
-- Edited by Egregious on Tuesday 8th of March 2011 09:07:02 PM
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Old 03-09-2011, 04:53 AM   #35
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Can large diesel engines be run at minimum RPM continually?

Have you verified the accuracy of your tachometers?

The old* T6.354 I had was rated at 2400 rpm. That's straight from the book. Mine would turn almost 2700**at WOT even though I was "over propped" by comparison to other like boats.
That was with a calibrated tachometer. (I'm pretty anal about that)


-- Edited by jleonard on Wednesday 9th of March 2011 05:53:22 AM

-- Edited by jleonard on Wednesday 9th of March 2011 06:04:49 AM
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Old 03-11-2011, 09:31 PM   #36
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RE: Can large diesel engines be run at minimum RPM continually?

jleonard,
You said:
" I was "over propped" by comparison to other like boats." Who gives a squat about other boats? This is w a previous boat**** ...right? Under propped isn't the end of the world if one dos'nt over rev. Actually I prefer to be about 50rpm underpropped. That way you can't get overloaded. 100rpm underpropped is ok too but not ideal at all. Overpropping definitely will burn a bit less fuel but you don't know where (rpm wise) the overloading starts and nobody can tell you. The only thing I like about it is that it's a little bit like installing a smaller engine. Does anybody know the rated rpm for the 330 cu in engine that preceded the Lehman?
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Old 03-12-2011, 06:05 AM   #37
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RE: Can large diesel engines be run at minimum RPM continually?

"Who gives a squat about other boats? This is w a previous boat**** ...right"

Hey I'm in agreement with you , I was only making a point. That was with my ex, a 34 Mainship model I, 1978 vintage. Performance wise those boats were all very close dependant of course on the particular engine model that they came from the factory with.

But here's something...I was plannning an eventual *repower and using info from a boating pal who had the same boat and had repowered. So little by little I did the upgrades so when I finally did repower the boat would be ready.
Just by fairing the back edge of the keel ahead of the prop I gained 250 engine rpm.
The Mainships had a flat end to the keel and fairing it (by adding a bullet shaped piece) that stopped the water from "eddying" and gave clean water to the prop.
I was then able to add an inch of pitch plus a cup to the wheel.
It was a fun project with positive results
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Old 03-12-2011, 09:10 AM   #38
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RE: Can large diesel engines be run at minimum RPM continually?

Jay,You've hit on something that will be big stuff for at least several Willard owners. See my picture of the stern of a W30. The flat part of the trailing edge of the keel is quite large.
When I did my refit I wanted badly to reshape the keel but we just didn't have time. As you can see the trailing edge of the keel and the prop are quite close together and can't be faired
in the manner you described. It would be a BIG job on the Willard. But some may want to do it after reading your testimony of increased performance. I would like to post most of your post on the Willard Boat Owners Group * *....with your permission.
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Old 03-12-2011, 09:11 AM   #39
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RE: Can large diesel engines be run at minimum RPM continually?

Quote:
Avista wrote:

On the question about operating rpm range, the answer was that the engine can be continously operated withing 10% to 100% of it's rated*hp subject to the rating restrictions that Cat publishes (E rating, C*rating etc) providing the engine cooling water temp is 180 degress fahrenheit to 210 degrees, period.
That is great information Avista, and conforms to what I was told by a CAT engineer who worked on the 3306 design team.* Said these engines were designed to idle for long periods during Arctic duty so make great trawler engines.* Emission requirements have fundamentally changed the name of the game for small diesel design - some for the better, and some not so much.

*
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Old 03-12-2011, 09:44 AM   #40
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RE: Can large diesel engines be run at minimum RPM continually?

"with your permission."

Go for it. I have no problem sharing my experiences.

I may have some pictures I took during and after the job. Send an e mail to me at work** jleonard@usa.norgren.com** I have a CD there with some older pictures.

I basically started with a leftover length of 4x4 pressure treated post. Cobbled up a piiece for aboe the prop and one for below.*West system glued*them in place (held with duct tape). Then the next weekend I used my 4 inch grinder and 36 grit paper and shaped the blocks, and ground the boat to make room for 3 layers of 1 1/2 ounce mat and poly resin. Cleaned it up and did 3 laters of gelcoat, bottom paint done.

Not much room on the Willard judging from the picture. You'll have to get creative
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