Volvo TAMD 31 P in Nimbus 280

[Karisma]

Two issues. Firstly have just bought a 14 year old Nimbus 280 with about 1000 engine hours. At full throttle it seems to rev at 3600 as opposed to the 3900 quoted in the Volvo owners handbook. Speed at 3400 (200 down from max) is about 17 knots. How does this compare with others experience or should I be getting down to trying to improve this.
Secondly - local Volvo agents says I should be concerned about the oil cooler which mounted at the bottom of the engine and is prone to corrosion and catastrophic failure. Any experience or comment on this.

Many thanks
Read more at http://www.ybw.com/forums/showthread.php?490181-Volvo-TAMD-31-P-in-Nimbus-280#gGqqO6Cs50rUyj1T.99

 

[No Regrets]

It's not awfully old, and doesn't sound like anything is wrong, if you consider the boat probably weighs a bit more than it did new due to on board rubbish and perhaps a bit of moisture in the hull!?

The oil cooler is a non maintenance item so little you can do about it apart from perhaps keeping an eye on Ebay for a cheap spare one if you're concerned.

 

[alancollins]

17k sounds about right to me with that engine in a well-built semi displacement boat of that size.

 

[NBs]

Hi, the engine should be able to reach the manufacturer's specified RMP range while the boat is loaded with water, fuel and passengers. It seems that the previous owner has chosen the propeller too big. The engin and the gearbox are all over a bit over load and will not achieve good maintenance despite its age.

I recommend switching the propeller to a smaller diameter or pitch, one inch is about 200rpm.

NBs

 

[Chris_d]

My 31P's hit approx. 4000rpm when lightly loaded on a clean hull, if your down to 3600 it sounds like a dirty bottom/fouled prop. Before you start changing anything you need to try it with a freshly cleaned bottom first. I get knocked back to less than 3000rpm with a years growth underneath!

 

[petem]

Hi, the engine should be able to reach the manufacturer's specified RMP range while the boat is loaded with water, fuel and passengers. It seems that the previous owner has chosen the propeller too big. The engin and the gearbox are all over a bit over load and will not achieve good maintenance despite its age.

I recommend switching the propeller to a smaller diameter or pitch, one inch is about 200rpm.

NBs

I would ascertain what propeller is fitted now and what was originally fitted before potentially wasting money on swopping props (which is never something done lightly IMO).

 

[Bandit]

Chris hit the nail on the head, start with a very clean hull and prop just pressure washed and remove all the non essential stuff from the boat and then check it. While it is out of the water check the markings on the prop for size.

Bear in mind that if the oil cooler fails and it dumps the oil it will total the engine, how much is a new one? I dont know the layout of the 31 but it is related to the 6 cylinder 40, 41, 42, 43, 44 and 300, the poil cooler on these is a weak spot and corrosion happens north of 12 to 15 years which corrodes the outside of the aluminium casing f the oil cooler when it leaks salt water at the bottom. corrosion will lead to dumping the oil.

 

[Karisma]

Many thanks for all the advice, I will get the cooler inspected.

 

[swifty]

Having been a Nimbus owner for many years with a TAMD engine I have never had any problems with the oil cooler and the TAMD engines are well thought off in the Marine Environment. Catastrophic failure I have never heard off, one for Volvo Paul to comment on.

 

[Kawasaki]

Speed at 3400 (200 down from max) is about 17 knots. How does this compare with others experience or should I be getting down to trying to improve this.
17 kts is fine
Secondly - local Volvo agents says I should be concerned about the oil cooler which mounted at the bottom of the engine and is prone to corrosion and catastrophic failure. Any experience or comment on this.

Many thanks

On the TAMD 30/31 series. Yes be aware of the heat exchanger and the oil cooler. Its the end caps that cause a problem. the body of said units is aluminium and the end caps are a' ferrous' metal. This can cause an electrolysis problem, ie,'metal rot'. Some have an 'o' ring type seal, stupid idea of Volvo of that era. Well, imho! Check them by looking of there is any 'Fur'/White stuff forming around the end caps of said units. If so attend to immediately. My 270, the forerunner of the 380 suffered so. In fact My heat exchanger was the first to suffer albeit a slightly different configuration and unit on your engine but the same in Principal. a 'Happy' cruising speed for your 280 should be 12/14 kts. You may get the 'Catalogue' speed of 20 with a clean bottom but remember She is not new. My old Nimbus with a TAMD30 used to 'Max' at 3500 rpm but would purr along at 3200 giving 12 to 14 kts depending on tides and currents etc. They are good boats swifty!

 

[Kawasaki]

Forerunner of the 280 I meant!!

 

[NBs]

Here's a short article about OVER LOADS ENGINE / OVER PROP. This is written in a clear way and does not require a specific technical understanding, there are a lot more profound articles on google search.

NBs


http://www.scottmarinepower.com/tec...-proper-engine-loading-aka-wide-open-throttle

 

[oldgit]

Always nice when first back in water after a scrub off / antifoul and probably a good pre-winter cull of all that O so vital stuff you needed for those "just in case events".
Watching the revs quickly whizz up to what the builder claimed you should achieve, is always reassuring
Watch with increasing dismay as the revs slowly disappear as the season progresses. !

A set of existing props are the last thing would be fiddling with, intil all else has been eliminated.
Growth on the hull will gradually slow you down, growth on the props is more dramatic and obvious.
Chap with Princess 41 came back from a trip to Holland at 25 knots,left boat idle for about 2 months and could not get it to more than 10-11 knots and in his wake a destroyer type smoke screen.
On arrival in one of the London marinas got local diver to go down for quick look.
Both props were covered with barncules, a quick scrape and all back to normal.

 

[Karisma]

Many thanks for all your comments. The boat was newly anti-fouled when I bought it and I came from Poole to Cowes on about 11 gallons of fuel (about 32 miles).
In answer to prop fouling, I have just converted from an XOD (1907 design wooden racing day boat). I had the bottom coated with Silic One. All I did from April to October was haul out and sponge off. When I sold the boat, and it was lifted out, the anti-foul was in excellent shape so that all the new owners will need to do is apply one new coat in the spring before launch.
As a result of this I bought a Silic propeller kit which was applied before launch. Silicclain tha a speed in excess of 10 knots will clean of any growth. Will report in the spring but it is worth watching.