Repower

[hollywood8118]

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

 

[Nomad Willy]

"she would do 11kts fire walled.. no need to go that fast."

Don't mention that to Marin.

Wonder what the hull looks like. How much bigger is a 40' OA than a 36' GB? If lots then unless your OA is closer to FD than I thought, or than a GB .. 110hp won't be enough. In my uninformed opinion. I'd be comparing similar boats w a single Lehman. How does a 42 GB run w the single Lehman? You of course will be able to (probably) work your 110hp engine much harder so it may be more like comparing the GB36 w single.

What's the 110?

 

[psneeld]

I would think the 110 would be plenty with the exception that depending on your hull... 8 knots may be really up there in rpms.

My 40 (only about 36 on the WLL)...does 6.3 very comfortably at about 1650 rpm with a Lehman 120. At 1800 rpm I'm up around 7 but it would take almost 2200 to get to 8 maybe slightly above.

I think Jleonard said about the same for him...8 knots is all he makes too.

But your OA may have a nicer hull shape and make that 8 with maybe only 80 of that 110 HP and that would be OK in my eyes. I think I'm using about 80 hp according to the engine chart in my book out of my 120 for normal cruise.

 

[Bay Pelican]

Our 42 Krogen with a full displacement hull needs 1850 rpms to hit 8kts. This is with a Lehman 135 with a top end of 2200 rpms.

 

[Ski in NC]

A TMD 70 should be around 160-180hp. MD 70 would be in the low 100's. Does engine have a turbo or not?

There is not a whole lot of difference between the TAMD and TMD. Just no aftercooler, a little lower fuel setting, some plumbing differences. Comp ratio might be a bit higher on the TMD, but would have to look that up.

Since old engine has new coolers, that's most of the battle on these.

Not sure the TMD gets you much further ahead on the obsolescence front.

Cold smoke can be improved a bit by a slight 1 or 2 deg advance on injection timing. Cheap to try, and little downside if running at low power setting.

 

[bayview]

What do you expect to gain form all the work/expense??

 

[Underway]

If you're pulling the engine anyway, I'm curious if OA offered a different brand in that hull...perhaps a Cummins? By the way, per the prop charts and my data gathering, our 30,000 pound OA 44 twin makes 7.5 knots @ ~45 HP (total), 8.4 knots on about 65 total horsepower. 9.8@ 110 HP, 11 knots @ 120HP). Different hull from yours, but Monk did provide OA with some fairly efficient designs in the trans-hump region .

By the way, a local guy who runs Detroit 8V92' in a large Tollycraft says he eliminated the typical smoking at startup by installing block heaters and turning them on for 20-30 minutes before a cold start. Don't know if that's just a 2 stroke Detroit thang or not...

 

[Xsbank]

Waste of money. Spend some that you have saved by searching for parts cheap.

 

[O C Diver]

Currently swaping my 420hp Cummins for 107hp JD. My Cherubini is 45' LOA and 32,000 lbs displacement. I expect to get a 7 knot cruise with a low to mid 8 knot top end.

There is a magazine article (Chesapeake Bay Mag. 06/99) on the KK website showing the KK39 with the JD 3039 (80hp) and the JD 4045 (115hp). It gives fuel consumption, and speed at various RPMs for both motors. Not sure how a KK39 hull would compare to yours, but certainly a production hull with a 100hp +/- engine.

Ted

 

[Xsbank]

Call me grumpy but I'll bet you will never recover your costs of doing a swap, with lower fuel consumption or cheaper parts. Just like it takes years and years for an electric car to pay for itself. Good luck.

 

[hollywood8118]

Waste of money. Spend some that you have saved by searching for parts cheap.

the cupro aftercooler is about $ 3000 if you can find a used one!
HOLLYWOOD

 

[Xsbank]

Make one. Or dump the entire salt water thing and go dry stack. There is probably a solution out there.

Having said that, I rejected a boat based on it having two of those engines. I suppose it can't be any worse than the Perkins manicooler abortion.

I can't see the point if you just told us your plans were to move on with another boat? How long will you have to "endure" this one?

 

[hollywood8118]

A TMD 70 should be around 160-180hp. MD 70 would be in the low 100's. Does engine have a turbo or not?

There is not a whole lot of difference between the TAMD and TMD. Just no aftercooler, a little lower fuel setting, some plumbing differences. Comp ratio might be a bit higher on the TMD, but would have to look that up.

Since old engine has new coolers, that's most of the battle on these.

Not sure the TMD gets you much further ahead on the obsolescence front.

Cold smoke can be improved a bit by a slight 1 or 2 deg advance on injection timing. Cheap to try, and little downside if running at low power setting.

the current engine is a detuned TAMD70C.. detuned (smaller injectors ) to the 225hp TMD70 setting. I may just delete the aftercooler and its plumbing (leaving the aftercooler housing acting as a big plenum) to take one more common failure point out of the system. The other thing I would delete is the cold start system, it is a system that meters raw fuel through a injector with a BIG 12v heating element in it that basically creates a diesel fire in the after cooler chamber to supply warn air to the engine during starting. they never worked well new.. and too many relays and crap to work long term.

The idea is to get a simplified motor that I can feel more confident in taking South..

If I wasn't concerned about the cost I would probably build up a Cummings turbo 6 with no aftercooler.. I still may.

I really like the O.A. layout and her size.. she feels big for a 40' boat. Handles good.. and is cost effective.
If I was only into Trawlers and not motorcycles, skiboats, airplanes,snowboarding and keeping the Admiral happy I could justify way more boat.

On a side note I do know O.A. did make some single lehmann 40' boats.. but I don't have a clue how they do.

We just did a overnight trip.. the boat currently runs 8.3kts in flat water with the Volvo loping along at 1700 ..and it really seems to like it at the rpm.. it "feels right"

Thanks
HOLLYWOOD

 

[Mule]

Put in a keel cooler then a welded up exhaust manifold, no cooling tubes, with a raw water pump pulling in sea water and pushing it out with the exhaust. I have heard of that I just do not see how to keep the sea water going back into the engine, but I bet someone smarter than me have solved that puzzle. Might have something with an exhaust elbow. That was addressing the cupro after cooler.

 

[hollywood8118]

Put in a keel cooler then a welded up exhaust manifold, no cooling tubes, with a raw water pump pulling in sea water and pushing it out with the exhaust. I have heard of that I just do not see how to keep the sea water going back into the engine, but I bet someone smarter than me have solved that puzzle. Might have something with an exhaust elbow. That was addressing the cupro after cooler.

I can just pull the aftercooler guts and fab a new cover, reroute the seawater to the Main heat exchanger and use the old aftercooler housing like a plenum..and watch the EGT at higher rpm's. I am not really a fan of dry stack exhaust.. on a old volvo like this it would equate to some really sooty decks... and unhappy dock neighbors on start up!
HOLLYWOOD

 

[High Wire]

I'm just thinking out loud here but if you drained and bypassed the cooling water to the aftercooler, there is nothing to leak or modify. Air temp to the turbo inlet goes up but with de-rated injectors you make less hp. Warmer air inlet temps should not need pre-heaters. What am I missing?

 

[markpierce]

...
There is a magazine article (Chesapeake Bay Mag. 06/99) on the KK website showing the KK39 with the JD 3039 (80hp) and the JD 4045 (115hp)...

That's old data. My 2010-built John Deere normal-aspirated 4045 generates 80 horsepower. (JD doesn't currently list a 3039 marine-version engine.) The turbo-charged version will get you at least 115 horsepower.

 

[stone beach]

Almost completely agree with your ...."as in most marine diesels it is the stuff hung on the outside of the block that normally fails"..i would only delete "marine" !!

As you know, the top 700 rpm guzzling fuel is because of the higher hp being absorbed by the prop at that speed, so if you are now staying out of that range you arent using the top end power and probably dont need an aftercooler as you have already concluded

If you dont use the top end now you are only losing the bit you dont use....but it wont be there if you ever try to use it, well not for long anyway!! A halfway position could be achieved with jacket cooled aftercooler if you are in to the modifying stuff and dont like the seawater ??

If your existing engine's "guts" and all the main stuff is good then simplifying it by doing away with aftercooler as you have described will work as long as you accept to lose the power output that the aftercooler brings, if you are going to down size in an engine change anyway this is effectively the same result without all the engine swap chain block work and replacing all those bits you will no doubt damage in the process, never as easy as it sounds at the start !

Anyway, I absolutely do not see the point of changing one old engine that you know (if it is running well enough) for another relatively unknown old one ....your "smoke" doesnt mean much without colour but anyway if it goes away when the engine is hot I would not worry about it, its an old engine right ???

Not sure how you will achieve engine protection for the derated (by no aftercooler) existing engine, needs at least the rack limit changing....if you can read egt on your set up and are disciplined enough to watch it and control accordingly you wont come to any harm. You will become the engine protection !! Simply resetting the top rpm will stop others less disciplined in trying to get that top end power but it wont protect in the event of fouled propellor etc, you may be willing to take that chance, your boat etc etc

 

[hollywood8118]

Almost completely agree with your ...."as in most marine diesels it is the stuff hung on the outside of the block that normally fails"..i would only delete "marine" !!

As you know, the top 700 rpm guzzling fuel is because of the higher hp being absorbed by the prop at that speed, so if you are now staying out of that range you arent using the top end power and probably dont need an aftercooler as you have already concluded

If you dont use the top end now you are only losing the bit you dont use....but it wont be there if you ever try to use it, well not for long anyway!! A halfway position could be achieved with jacket cooled aftercooler if you are in to the modifying stuff and dont like the seawater ??

If your existing engine's "guts" and all the main stuff is good then simplifying it by doing away with aftercooler as you have described will work as long as you accept to lose the power output that the aftercooler brings, if you are going to down size in an engine change anyway this is effectively the same result without all the engine swap chain block work and replacing all those bits you will no doubt damage in the process, never as easy as it sounds at the start !

Anyway, I absolutely do not see the point of changing one old engine that you know (if it is running well enough) for another relatively unknown old one ....your "smoke" doesnt mean much without colour but anyway if it goes away when the engine is hot I would not worry about it, its an old engine right ???

Not sure how you will achieve engine protection for the derated (by no aftercooler) existing engine, needs at least the rack limit changing....if you can read egt on your set up and are disciplined enough to watch it and control accordingly you wont come to any harm. You will become the engine protection !! Simply resetting the top rpm will stop others less disciplined in trying to get that top end power but it wont protect in the event of fouled propellor etc, you may be willing to take that chance, your boat etc etc

excellent info, today as I ran through a area with 5kts of current I did shove the throttle to the wall for about 12 minutes.. she now tops at 2400 rpm ( vs the old 2600 rpm ) and does about 10.5kts in flat no current water. The EGT. hits 850 and holds there. If I remove the aftercooler I will limit the W.F.O running to keep EGT in the 800's max. My old Ford Powerstroke was good into the high 1200 without damage.. so I feel pretty safe. The EGT @ 1700 currently runs about 650
Thanks
HOLLYWOOD

 

[sunchaser]

The idea is to get a simplified motor that I can feel more confident in taking South..

If I wasn't concerned about the cost I would probably build up a Cummings turbo 6 with no aftercooler.. I still may. HOLLYWOOD

Now you're talking

 

[stone beach]

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

 

[Insequent]

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.

 

[FF]

>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.

 

[kraftee]

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.

 

[keo1]

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
Keith

 

[Xsbank]

Curious if the zincs in the coolers are as effective in fresh water? Are you solving one problem by creating another?

 

[keo1]

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

 

[FF]

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!

 

[Delfin]

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 (I'm giving it all she's got, captain! - Loaded Weapon - YouTube) 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.

 

[FF]

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!!!