Volvo D4-260 gear reduction

loftcase · Post by **loftcase** » Aug 19th, '09, 17:24

hi every one..! new in forum, first post and poor english but... B31 lover.

there are three boats in my area. two of them out of the water since at least 15 years (no engines). the other 3 yrs since the owner passed away... (cummins diesel). all of them in poor condition
I want to buy them, (At least one ) but canÂ´t get into a deal because owners suffer from typical "bertram disease" ....(iÂ´m going to fix it some day) but iÂ´m working to buy them
the thing is that my volvo dealer has two 2008, D4 260 engines for sale at very very good price and just with 10 hours. gear reduction is 2.5...and here is the question.... good/bad for B31?. and why... please

Apologizes, thanks and congratulations for your forum.

daniel

CaptPatrick · Post by **CaptPatrick** » Aug 19th, '09, 18:30

Daniel,

Again, welcome aboard!

While the most common diesel power here in the US are Cummins and Yanmar, the Volvo D260 will be a perfect size for a B31. They're rated for a 3,500 RPM and you'd want to prop them to deliver 3,600 RPM with the boat loaded as normal, including a full tank of fuel.

If your Volvo dealer is local, dependable, and will be your main source of service and warranty, then that's probably the way you should go.

The ratio on the transmissions sounds a little high, 2:1 would be a better choice, but they might work OK, giving you more torque, but lower top end speed. Maybe Bruce will pop in with a better take on that subject...

Br,

Patrick

loftcase · Post by **loftcase** » Aug 23rd, '09, 16:08

Thanks Patrick .
About speed loss, how much drop in crusing speed do you estimate?.
hope post from bruce...
regards.

Bruce · Post by **Bruce** » Aug 23rd, '09, 16:59

Sorry for the delay in posting, been doing alot of traveling with the wife this year.

Getting an early taste of what retirement may be like while I'm still young enough to enjoy and remember it.

Here is an earlier post from 07 of a 31 I did with the Volvo D4 260 and the setup and performance report.

I long took the pics down but if your interested I can repost.

Any questions just post. Might be a day or so getting back, changing out an engine this week and the heat is murder.

You can't use the 2.5:1 reduction as you won't be able to swing the prop size you'll need in diameter.

*****************************************

"Time Machine" is done and delivered to a very happy owner.

Some comments on the D4.
1. Was lead to believe they were really quiet. They are not. Typical diesel sound.
2. Mounts have very "flexable" rubber and I found out why. At idle they shake and at 1000 they some what thrash in my opinion. At 1100 they smooth out like butter.
3. Acceleration is seamless and smooth and so is shifting for all electronic controls.

Setup:
31' FB, 1968.
Volvo D4-260hp, 2.0:1 gear.
20x24 DQX 4 blade medium cup.
100 gallons of fuel, full water, interior loaded as used, 300lbs lite of engine boxes and side deck(getting fish box made).
Clean bottom
Temp 70, wind 3 to 5 knts.
2 persons
GPS measured speed.

RPM Speed knts Fuel burn
1000 5 .6
1500 7 1.6
2000 11.5 3.5
2600 18.5 6.1
3000 23 8.2
3200 24 9.4
3400 27 11.0
3500 (wot) 28.5 11.5

Installation took some engineering because of the short distance between front and rear mounts to make it look clean.
Also because they are big 4 cylinders.

Nextgen 3.5 outboard of port engine is able to use full sound shield and it is removable in place with access, albeit not the best to outside of port engine.

I used short hi hp mufflers with surge tubes. Bottom of turbo outlet is 14" above water line.

Engine angle is about 8 degrees.

When the deck is back in and the engine boxes on I will take some DB readings. Engine boxes are non insulated.

Fuel tank has 264 gallon capacity.

Henrik · Post by **Henrik** » Aug 26th, '09, 09:58

Bruce,
New to the forum and just bought a 31 FBC -80 with the original Cummins diesels.

I'll repower it with Volvo D4-300 and would really appriciate some help with a couple of questions:
Should I use exhaust elbow or raiser?
Do you recommend to use the 2.0:1 gear or is 1.56:1 a alternative?.
Would you recommend the same propellers as for your 260 installation and did you change shafts, struts or anything else?

Thanks in advance,

Henrik

Bruce · Post by **Bruce** » Aug 26th, '09, 10:27

As you can see from the pics I just used the elbow. The bottom of the turbo was 14" above the water line exceeding Volvo's requirement so no riser was needed.

Since I replaced all the deck structure with composite I took the exhaust back thru the bulkhead and crossed over behind it allowing plenty of access to the gear on the port side and the std side was already outboard.

Used mufflers and surge tubes.

Props will have to be changed in size(pitch)for the 300hp version.
Also shafts will need to be upgraded to 1.5" with the 300.

I used 1.5" shafts on the 260 since the running gear had a complete make over anyway.

I would use the 2.0:1 gear.

Henrik · Post by **Henrik** » Aug 26th, '09, 19:59

Thanks Bruce!
Enough to get started, there will for sure be some more questions a long the way.

Best regards,

Henrik

In Memory Walter K · Post by **In Memory Walter K** » Aug 26th, '09, 20:53

Wow! What a beautiful installation! Walter

Bruce · Post by **Bruce** » Aug 27th, '09, 06:29

Henrik,
If you ever run into a Bo Lindgren who splits his time between Sweden and the Netherland Antilles, say hello from me.

I've lost track of him the last few years. He used to have a 50 Bertram, sold it and was looking for a 31 and had contacted me then.

He's a boater also and you might run in the same circles.

Thanks Walter.

loftcase · Post by **loftcase** » Aug 27th, '09, 09:29

Thanks Bruce for info.
No Bertram project yet..:(
BEST REGARDS...!!!
daniel

Henrik · Post by **Henrik** » Sep 9th, '09, 09:47

Hi Bruce,

Haven't met Bo yet, but will for sure send your regards if I do.

Do I need to change shafts to 1,5" if I go for the D4-260:s or is the original size from the Cummins diesels ok?

Thanks,

Henrik

Bruce · Post by **Bruce** » Sep 9th, '09, 11:57

On a 20x24 4 blade with a medium cup I would go to the 1.5" shafts.

I have seen even with A22 shafting on 1 3/8 breaks behind the strut with 20x 22 4 blades on what I call modern performance diesels.

Since the late 90's I've done a couple dozen shaft upgrades for people who tried to save money and go with the smaller shafts only to have one or both break at some time into a few hundred hours.

It only took 1 of my early repower boats to have 1 then the other break using 1 3/8 with 20 x 22 or larger wheels.

Both those shafts were spooned at the key also.

Luckily the owner had insisted and I made more money upgrading.
Now I won't do a repower without up grading if the engine/prop combination calls for it the way I see it.

ken j · Post by **ken j** » Sep 9th, '09, 13:26

Re: d4-260's
I instaled a pair of d4-260's,650 hours ago, and we ran 1 3/8 "aquamat 22 shafts with 156 gear and 17 x 20, 4 blade medium cup Michigan props.
No problems with anything, cruise speed fully loaded 23 knots at 2800 RPM, burning 7 gallons per hour per engine, top speed 30 knots.
I use this a charter boat and am very happy with the preformance, it may be possible to run slightly larger props. I perfer to be slightly under proped.

Ken J

Bruce · Post by **Bruce** » Sep 10th, '09, 05:55

I instaled a pair of d4-260's,650 hours ago, and we ran 1 3/8 "aquamat 22 shafts with 156 gear and 17 x 20, 4 blade medium cup Michigan props.

Since your running 1.5:1 gear, 1 3/8 shafts wouldn't be a problem.

JeremyD · Post by **JeremyD** » Sep 11th, '09, 13:46

those look pretty compact - will they fit a B-28 without raising the hatches?

Bruce · Post by **Bruce** » Sep 11th, '09, 16:13

Looks are decieving. They are tall engines.

The front lifting ring has to be unscrewed to close the engine box on the 31 and since the old Yanmar 4LH fit some 28's by mm's the D4's are much taller.

bertram31.com

Volvo D4-260 gear reduction

Volvo D4-260 gear reduction

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