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Old 08-25-2014, 03:17 AM   #21
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record egt at various rpms as is
jump sw hoses across the aftercooler and go for a careful run, aftercooler o rings and tube bundle will suffer if they get too hot, watch the aftercooler body temperature somehow.
record egt at various rpms without aftercooler, (still in circuit but now doing nothing) you will soon see what no aftercooler does to your normal operating rpm and where your new maximum speed might be with your current air temp
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Old 08-25-2014, 04:45 AM   #22
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As to whether the repower engine has enough HP you can readily read power used/required off the propeller curve for your existing engine. I could not find one on boat diesel, but you may already have it. Just scale off at 1700rpm.

But realise that your new engine will deliver its 110 HP at a different rpm, so you will likely need a new gear and/or prop. I suspect the boat bucks will mount fairly quickly if you go the new engine route.
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Old 08-25-2014, 07:21 AM   #23
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>Warmer air inlet temps should not need pre-heaters. What am I missing?<

Pre-heating is ONLY to aid cold starting when down near freezing, otherwise it does not function.

The big question with Volvo is where did the source engine come from?

If its a truck block marinization the HP may be close.

If its an auto takeout running at higher loads might reduce the service life .

The usual method to discover if an engine is useful is to troll the mfg site and look for ratings.

Keel cooled with dry stack is the gold standard , IF you can live with the stack going up thru the acomidations .

Pleasure boat is very restricted , the 24/7 rating is what you need to find.

If no 24/7 rating is given , there IS a reason.

IF a wet exhaust is needed the simple method is a U shaped riser going high in the ER to get above the water line. The cooling water is inserted after the top of the U to cool the usually rubber exhaust.

If this is being fabricated a flange that bolts on to the stock exhaust manifold that has a std pipe fitting is the only custom part.

The rest can be simple pipe from the plumbing supply , they have 2-3-4 inch pipe and fittings.

Keel cooling with a dry stack is the gold standard , but its not easy to find place for the stack.

The smaller fire place lock together SS flue pipes is a good system to run the exhaust pipe inside.
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Old 08-25-2014, 09:24 AM   #24
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Just to address part of your original question, our FD Great Harbour N37s, with a waterline length of just over 36', will achieve hull speed (a tick over 8 kts) on their pair of 54hp Yanmars (slightly less than the 110hp you asked about.) They cruise easily at 2,400rpm at 7.4 knots. I am not sure how that will equate to a SD hull like your 40 OA, but I bet your actual waterline length and displacement are similar to the N37's.
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Old 09-08-2014, 11:55 PM   #25
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Tamd70c

Hi
I have one of these as well - it certainly seems to be a very solid engine. Have been working through the bolt ons for mine so have been inside all of the coolers and fixed the flame start. As we all know - these things on a cold morning can be impressive. Parts for the flame start are available - but not from Volvo. I got two new flame starters for EU$90 off Ebay - you need to know the correct Bosch numbers to locate. Check to see if you are getting voltage to the flame unit, by the intercooler top. That means the electric relays are ok - so part of it is working. The other part that fails is the fuel solenoid - once again Ebay.de will help. I can give you the part numbers if required. Do not give up on it yet - these do long hours as long as the coolers are OK. I have a freshwater flush setup on mine to protect the coolers - when we come back - connect to the dock water supply and run on freshwater for a couple of mins, then when shut down there is only FW in all of the coolers. Parts for the engine itself are a lot cheaper via the Volvo truck parts search engines. If you need help on the flame starter diagnosis - send me a message. Very little smoke when it is used. Thks
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Old 09-09-2014, 02:39 AM   #26
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Curious if the zincs in the coolers are as effective in fresh water? Are you solving one problem by creating another?
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Old 09-09-2014, 05:15 AM   #27
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Tamd 70C

Interesting point - the honest answer is I do not know if doing this will create long term issues. Having just pulled the main exchanger out for service - not sure it had ever been out in the past and was difficult to extract - it was in good condition but badly obstructed - took quite a while to get the calcium deposits out. Previous owner who had the boat for 25 years indicated that the zinc usage was very high - this has slowed with the fresh water flush. My corrosion expert indicated that most of the calcium deposit was from the zincs - the zinc creates a barrier layer. But getting the flame starter working is essential with these to prevent the smoke screen - they are not neighbour friendly in that mode. Ours is non muffled as well - so there is a real bark when she runs - its on the to do list. If you need the resistance values of the flame unit - can provide them so you can see if its OK - simple multimeter will check that. Keith
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Old 09-09-2014, 06:09 AM   #28
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IF cost IS a concern the International 360 its larger brother would be my choice.

Its built as strong as most industrial engines , is cheap to buy or rebuild, and can be had in mechanical injection .

Keel cooled with dry stack means there is NO matinization piece$ to purcha$e.

Std SAE bell housing so rebuilt Twin Disc , and you are done for the next 10,000 hours!
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Old 09-09-2014, 10:36 AM   #29
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Not sure I would remove the aftercooler. While I don't think you need more horsepower than the 110 (Delfin only needs about 130 hp for hull speed), you may need all of it sometimes () and then the aftercooler would be really helpful. Were it me, I would consider keel cooling and just using sea water to mix with the exhaust and leave the ac where it is. That's what I did on the genset - keel cooled with wet exhaust. By just going with coolant through the aftercooler, I presume it isn't going to gum up, and leaving the ac in place will increase combustion efficiency.
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Old 09-10-2014, 06:44 AM   #30
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Anyone wishing to repower will do best IF they can get realistic fuel consumption numbers from the old engine (s).

Peak HP is an advertising con , fuel burn is real.

If the boat burns 2.5 gph a 50- 60 advertised 24/7 engine will do.

With a fuel map for the new engine it is possible to select a quiet efficient cruise RPM , that will have no over loading . under loading problems , just right!!!
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Old 01-18-2015, 08:42 AM   #31
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Derating a large diesel

Having a large engine de-rated to give much less power does seem to be a good idea for a trawler displacement yacht. How to do this economically is the question which I would like to put forward.
Taking a TAMD60c Volvo, the first suggestion is to de-rate the injectors.
Can one take off the turbo and if this would done what benefits might that give as turbos don't usually come in until the engine revs go over around 2000.
Perhaps it is just easier to resize the prop limiting the revs to say 1500 at 8 knots?
Any thoughts are most welcome.
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Old 01-18-2015, 11:31 AM   #32
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I would remove the aftercooler and the turbo. Timing can be advanced to the NA specs, this will help cold starts and reduce smoke. The injectors are a non issue but the IP will need to be recalibrated to the MD70 NA specifications. Scrap the Volvo preheater and install a Cummins 12 volt intake heater system, much simpler. You'll need to reprop or at least take out some pitch to match the lower rating.
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Old 01-19-2015, 07:10 AM   #33
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Quote:
Originally Posted by hollywood8118 View Post
We currently have a 225hp Volvo in our 40' Ocean Alexander.

It started life as a 275hp TAMD70C, have the injectors stepped down to the 225hp rating of the TAMD70 during a complete injector service.

We never used the upper 700 rpm of the range as it sucked fuel like a 66 Cadillac climbing a mountain pass.. we cruise the boat at 1600-1700 rpm making 8.3kts in flat water.. she would do 11kts fire walled.. no need to go that fast.

I have the opportunity to get a 10 year newer motor that is 110hp at a reasonable cost.. I would do all the re-power myself.. no big deal.

My TAMD70c has all new exchangers/coolers.. but has a lot of crap hung all over it in the form of pre heat start system etc.. the 70c motor is known as a bulletproof block.. hard to kill motor.. as in most marine diesels it is the stuff hung on the outside of the block that normally fails.. parts for the thing are very hard to get and wicked expensive.. the injection pump is almost the sive of the motor on my 7.5kw genset!

Its one really bad attribute is it smokes BAD when cold on start up.. but no smoke when warm.

So my long winded question is this...

Repower with the 110hp motor?

Strip off any unnecessary stuff ( aftercooler,cold start system that doesn't work anyway and simplify the tamd70 to a tmd70?

Is 110hp enough for the 40' hull to hit 8kts reasonably?

I am trying to keep this boat reasonable.. plan to take it to Mexico and possibly leave it for a few seasons and winter there..

The 70c motor is a monster.. a bit more room in the E.R. would be nice..

Personally I want to sell off everything and buy a Nordhavn and split .. but the Admiral isn't completely warmed up to full time cruising again just yet..But she loves the Mexico idea.

Thoughts and input from anyone ?

HOLLYWOOD
Hi.
You asked "Is 110 hp enough for the 40' hull to hit 8 kts resonably?"
Yes, provided that you have a fair reduction on you gear, at least 3:1 ratio, that will multiply the given torque by 3 (i.e. 600 Nm x 3= 1800 Nm.)
so your OTTER can swing a big propeller, that will push hard tru the Water.
-and by no Means a egg beater. I think you,ll hit 8.8 @ 1900 rpm.
You said it yourself: The MTD.70 is a monster, but it a workhorse as well!
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Old 01-19-2015, 07:24 AM   #34
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Full displ.boats alwayes need big slow turning propeller, has to have a big diameter,


in order to shovel a large a quantity of Water astern, so full bodied hull will go tru Water, but also be able to stop boat fast.
IF in doubt, please confirm fact. Experienced over many year.
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Old 01-20-2015, 10:09 AM   #35
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Quote:
Originally Posted by mikecambrai View Post
Having a large engine de-rated to give much less power does seem to be a good idea for a trawler displacement yacht. How to do this economically is the question which I would like to put forward.
Taking a TAMD60c Volvo, the first suggestion is to de-rate the injectors.
Can one take off the turbo and if this would done what benefits might that give as turbos don't usually come in until the engine revs go over around 2000.
Perhaps it is just easier to resize the prop limiting the revs to say 1500 at 8 knots?
Any thoughts are most welcome.
Mike.

You dont have to remove turbo or intercooler at all, if derate to 1500/1700 rpm.-first get at bigger propeller, (prop.is turning slower,so a more slow srew tru water!) maybe some 2 inc./ or if same dia. 3 inc. more on pitc. NEVER a SMALLER prop.!

To max. engines performance and fuel burn: Lock the trottle at fuelpump,
set to max. 1600 rpm. (do this in idle rpm.) Make sure your new prop.are measured to new HP+/rpm!!
I have done this with good result, from 60 HP down to 40 HP. get better fuel, from 9 liter/h. to only 3.5 litre/hour. same speed, because my boat is a heavy disp.- so FAR too many HP. install. by former owner.
Removed the small 16"x11" prop" to a 18"x12"- all worked out very good.
Real many trawler/ tug type boats are often. far overpowered,
almost embarrassing,!-and for what use.??
What matters are engine slow rpm.1800-2000 rpm. and a deep red.ratio 3 or 3.5:1 for max. TORQE where the power+torque is to be transmittedd: Namely to the propeller.
Propeller move ship, engine only turn propeller. yes, for propulsion!
Its not the horsepower that moves ships or boats, no, its the important PROPELLER.! We all sometimes forget..
Seems like this: How many HP.to move my boat at a given size?
Its more rigth: How big a torque, to turn propeller, do I need to push my
boat? Said by f.eks. by mr.Dave Gerr, in his "Propeller Handbook."
Quote from GERR: Its all about TORQUE.! his book are worth reading.
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Old 01-21-2015, 09:10 PM   #36
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The problem with having an aftercooler at very low power settings is that it cools the air WAY to much resulting in more smoke because of low cylinder temps. and inherent cylinder wall glazing that is the result of it. Its a vicious circle. And, the turbo is just not needed as it wont produce boost at the power output that you want.
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Old 01-21-2015, 09:15 PM   #37
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Railroads have been known to down rate the locomotives (as in removing turbochargers) when downgraded to local/switching service when superseded by more modern locomotives. This reduced maintenance costs. Don't know if this would apply to small diesel engines and typical recreational use, however.
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Old 01-24-2015, 07:47 AM   #38
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Quote:
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The problem with having an aftercooler at very low power settings is that it cools the air WAY to much resulting in more smoke because of low cylinder temps. and inherent cylinder wall glazing that is the result of it. Its a vicious circle. And, the turbo is just not needed as it wont produce boost at the power output that you want.
KULAS44.

You are quite rigth,the way you describe the "vicious circle":
Not mush boost, low cyl temps.If at partly loaden engine.

But it seems that you have clean overlooked the bigger propeller.
It will fully load "OTTER"s engine at wanted ex. 1600 rpm.
A fuul boots will be present to Work the turbo blower at full speed,and temps,will be rigth, (engine exaust teperature at its normal.
Higth load more fuel more power, more boost to turbo.

But of importance: Engine MUST be Locked ( best if plumbed.)- so it will not exeed 1600 rpm. - otherwise exausst Black as Coal..!

All because of a Bigger Wheel,( or same prop. with more pitch adjusted for the new lower turning speed.(on prop.)
If you keep the old prop., engine will just be partly loaded at 1600 RPM. It as simple as that. And the vicous circle will occur!
KULLAS44 are fully rigth, - in this situation.

Its used and tried every day by commercial fishermen in the North Sea and by norwegians, where easy adjusting to more pitch on prop, when decreasing engine speed , from full ahead to half speed. By VP
props.)
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Old 01-25-2015, 08:22 AM   #39
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Hi, guys:

FF has it right. Your fuel consumption will tell you what power the boat is using. If you can establish the fuel consumption reliably at the cruising speed you desire, then use the slightly inaccurate, but conservative for this purpose) rule of thumb that one GPH of diesel equals 20 horsepower, you'll have the power the boat is using.

As far as the rest of the conversion: I did convert an Isuzu industrial diesel for marine use. I mounted a surplus heat exchanger purchased off of E-Bay which incorporated the expansion tank, mounted a Yanmar sea water pump that a friend gave me, and made a wet elbow using stainless steel pipe with a seawater injection pipe inserted through the elbow, down into the discharge pipe, with the end plugged and slots milled in the pipe to direct the water flow against the sides of the pipe. It works well, the outside of the pipe is cold to the touch at full engine power. I used a new ZF gear with a Borg Warner adapter to the Isuzu's SAE standard bell housing, and a drive disc machined by a local machine shop to the flywheel. Works fine. It'll do nine-point-something knots at full tilt boogie, and cruises at 6.5 knots at a gentle 1850 rpm.

That engine replaced the Albin AD-21 diesel in my Albin-25. I do 6.5 knots on 0.4 - 0.5 GPH. I have about 400 hours on 'er now. Curiously, the replacement shaft, screw, dripless seal, drive saver, line cutter, cutlass bearing, etc. cost more than the engine.

Go figure...

Of course keel coolers work well also. Hamilton marine sells the bronze through hull fittings for mounting a copper tube outside the hull to make a homemade keel cooler. There are many lobster boats in Maine running around with truck engines using these setups.

I repowered a friend's Marine Trader 40 from Lehman 120 to an Isuzu 4BG1T, 4 cylinder turbo. WHAT AN IMPROVEMENT! Starts instantly, almost inaudible in the main salon and in the 6 years it's been in, has never leaked a drop of anything. Uses 1.5 - 2.0 gph at six-point-something knots. That was also an industrial engine, and I made the stainless wet elbow for it. We reused the heat exchanger from the Lehman (it had just been renewed) and an expansion tank from a 3208 Cat generator set. Sadly, it is no longer available, a victim of advancing emissions regulations. We adapted the Paragon transmission from the Lehman to the SAE standard bell housing on the back of the Isuzu using a Twin Disc adapter. The conversion, including the engine and all the parts cost about $6,000.

With respect to the discussion of Cummins engines (Note the spelling: there is no "G" in Cummins). The "B" series engines (the six cylinder is 5.9 liters, the four is 3.9) absolutely are magnificent machines. Old Dodge pickups rot away to nothing and the engines are still good. They are great for all applications, except (in my sincerely humble opinion) boats.

The reason is the older ones (the ones with two valves per cylinder) are NOISY! (What did you say? I can't hear you.)

They never break down, parts are readily available and inexpensive and they're very economical. All of which makes them great for lobstermen, but if I had one in a long distance cruising boat, it would drive me round the bend.

I'm a huge fan of John Deere engines. I just got a quote on a new 4045 marine one, and the pleasure boat rating of it is 220 HP! Yikes! That's way more power than I thought they were good for, but if John Deere says it's true, then I'll believe them. I forget the continuous rating, it was probably 160 or so.

That was in connection with a daydream I had about a 32' Lobster-Cruiser. Have you seen a contemporary lobster boat out of the water? All I can say is WOW!. The keels are huge and, well beefy doesn't do them justice. These are boats you can run aground on a granite ledge and wait for the tide to float them off. Built double strong and reinforced. Check out Young Brother's boats as one example. But, they're definitely semi-displacement and built for speed. Eight hundred horsepower engines are no longer uncommon.

Not my cup of tea.

Glad you allowed me my two cents worth. As always, YMMV. Contrasting opinions welcome.

Stay strong and cruise on!

Cheers

JS
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Old 01-25-2015, 08:46 AM   #40
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John,
You seem to really have your ducks in a row (just as FF) on marine power. Call me crazy but I just bet when you prop your repowered boats you do it according to tried and true reccomendations from the engine manufacturers. Cummins (the no g verison) for instance specified 2800 neutral and 2600 rpm WOT. No reccomendations to "overprop" to save fuel. There is a reason the manufacture does the research, the test, use highly educated engineers, sensors and goes to the trouble to make these highly informed reccomendations. Are we on the same page here?
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