Yanmar 315 or volvo D6 330 hp?

Humber95 · 30 August 2011, 08:09

I currently have a Volvo penta KAD300 with dp-g leg in my Humber 9.5
I've had an incredible amount of problems with my engine, which even the dealers can't figure out.
startermotor turns but engine won't fire.
5 minutes later the engine fires but kills after releasing starterkey.
Then it won't start, and the supercharger clutch opens and closes when i push the stop button on the engine.
Sometimes when it starts, the rpm goes to 4000 in neutral and the gearbox switches itself into gear.
etc etc etc, all in different orders.
everything is replaced, from ECU to cable boom but nothing solves the problem.

Before i cerimonial burn the KAD300 in my back yard, i want to know wich engine is the best replacement: the spartan yanmar 315 with zt370 leg, or the D6 330hp?
Anyone with experience?

biffer · 30 August 2011, 08:39

Yanmar is less complicated on the wiring side which makes it a more reliable bet

martini · 30 August 2011, 09:15

Yanmar's new 8LV 320 or 370hp is lighter than the old 6LP and twin turbo's for better pick up, supposed to be a really good motor. Looks their answer to the the Volvo D series

willk · 30 August 2011, 09:53

From what I hear, the Volvo is very nice but is very complicated - I'm told that they drop into "limp home" mode if they are not happy, and they're not happy quite often. If you have a Volvo dealer nearby to do the electronics work - fine. If not, Yanmar.

I would agree with Martini about the new Yanmar V8 370hp - I've used the 315hp and it was a pleasure to drive, but the V8 is a similar weight and I hear the price is OK. C'mon - Twin Turbos! Imagine the sound!

I have personally witnessed the demise and death of a Yanmar ZT350 leg (on the 315hp) and Yanmar have upgraded the clutch packs on them since. The ZT370 has this upgraded mechanism as standard but I'll be very interested to see how they perform over time. I hope to get a 100Nm spin on Saturday with the 315/ZT370 combination, so I'll report back...

Humber95 · 30 August 2011, 10:02

Quote:

Originally Posted by willk

From what I hear, the Volvo is very nice but is very complicated - I'm told that they drop into "limp home" mode if they are not happy, and they're not happy quite often. If you have a Volvo dealer nearby to do the electronics work - fine. If not, Yanmar.

I would agree with Martini about the new Yanmar V8 370hp - I've used the 315hp and it was a pleasure to drive, but the V8 is a similar weight and I hear the price is OK. C'mon - Twin Turbos! Imagine the sound!

I have personally witnessed the demise and death of a Yanmar ZT350 leg (on the 315hp) and Yanmar have upgraded the clutch packs on them since. The ZT370 has this upgraded mechanism as standard but I'll be very interested to see how they perform over time. I hope to get a 100Nm spin on Saturday with the 315/ZT370 combination, so I'll report back...

That's my concern; i know about the electronic problems of the volvo's, but i'm also curious who stromg the new zt370 is..
we do a lot of towing here in shallow water, so the leg must be stronger compared to normal use.

martini · 30 August 2011, 10:08

If you're going to work the sterndrive really hard you might be better investing in something like this:

Konrad Marine Propulsion Products

Humber95 · 30 August 2011, 10:19

Nice.
Probably pretty expensive and doesn't it create problems with the warranty of volvo?

BogMonster · 30 August 2011, 10:51

Quote:

Originally Posted by Humber95

I currently have a Volvo penta KAD300 with dp-g leg in my Humber 9.5
I've had an incredible amount of problems with my engine, which even the dealers can't figure out.
startermotor turns but engine won't fire.
5 minutes later the engine fires but kills after releasing starterkey.
Then it won't start, and the supercharger clutch opens and closes when i push the stop button on the engine.
Sometimes when it starts, the rpm goes to 4000 in neutral and the gearbox switches itself into gear.
etc etc etc, all in different orders.
everything is replaced, from ECU to cable boom but nothing solves the problem.

If that was in a vehicle, with considerable experience in vehicle fault finding I'd be telling somebody to look for earth faults. Odd and apparently completely random occurrences are usually something to do with earth feeds, what happens is due to a bad earth things are often being back-fed power in the wrong direction from something else which might make them work normally but when they shouldn't, might make them work backwards, or might make them think something else is happening if a sensor earth is involved. Sometimes several items will share one earth point and what happens depends on which combination of them is active.

I don't know much about boat wiring - but I would imagine bad earths on a boat system would give similar results. Usually the best place to start on a vehicle is with a full wiring diagram and checking all of the main earthing points and there are likely to be several - in a 4x4 you would expect earths onto engine, maybe gearbox, certainly chassis and onto the body. All the connections have to be good and if they aren't, very random things can happen! Checking if there is a voltage from the earth on one of the faulty items back to a known good earth - usually use battery negative on a vehicle - is usually a good way to pick it up, because there shouldn't be anything and any sign of a voltage indicates a problem. Depending on how intermittent your problems are this can take a while to find though! Is the dealer able to reproduce your problems or do they just happen when you are out and about? Intermittent faults that can never be reproduced in the workshop are everybody's worst nightmare.

jwalker · 30 August 2011, 13:06

Quote:

Originally Posted by BogMonster

If that was in a vehicle, with considerable experience in vehicle fault finding I'd be telling somebody to look for earth faults. ...... everybody's worst nightmare.

That's nice long post but the Volvo engines use an isolated earth where there is no earth connected directly to the block or drive. I'm not suggesting it may not still be a negative fault but on my engine, it misbehaves if the block is grounded. I've no idea why.

Turbodiesel · 30 August 2011, 20:09

Yanmar every time!

Dirk Diggler · 30 August 2011, 20:20

Quote:

Originally Posted by Turbodiesel

Yanmar every time!

Is that because of the profit in spares and repairs?

captnjack · 30 August 2011, 20:58

Quote:

Originally Posted by jwalker

That's nice long post but the Volvo engines use an isolated earth where there is no earth connected directly to the block or drive. I'm not suggesting it may not still be a negative fault but on my engine, it misbehaves if the block is grounded. I've no idea why.

Sounds exactly as Bogmonster describes, while isolated grounds (earths) are extremely common in boats the engine should still be at ground potential or nearly so. They are isolated only to avoid current leaks into the sea.

When you properly ground the engine you are creating problems - which suggests to me that you have a fault somewhere which is "leaking" into the isolated engine. When you bring the engine to earth potential the fault is complete and it dies. When the engine is isolated the fault is incomplete and it runs. Which basically means nearly any circuit not at earth potential maybe to blame.

Ribliam · 30 August 2011, 21:05

I have a Volvo D6 350 hp with a DPR leg in my Excalibur 8.7, I have personally had no problems bar a supercharger belt wearing, easily replaced. although from reading post's in other forums the Volvo seems to give trouble with regards to it's electronics. Volvo parts can be quite expensive. I have no experience with Yanmar engines but they would appear to be less complicated than the Volvo.

Turbodiesel · 31 August 2011, 20:29

Quote:

Originally Posted by Dirk Diggler

Is that because of the profit in spares and repairs?

If only!!!

Cookee · 01 September 2011, 08:22

I would echo the Yanmar recommendations - don't forget the drive for the 320/370 is a duoprop drive as well!

BogMonster · 01 September 2011, 11:01

Quote:

Originally Posted by jwalker

That's nice long post but the Volvo engines use an isolated earth where there is no earth connected directly to the block or drive. I'm not suggesting it may not still be a negative fault but on my engine, it misbehaves if the block is grounded. I've no idea why.

Interesting, not come across that idea before but IMHO the automotive 'common earth through the block' system is relatively robust because there are lots of earth points onto a whopping lump of metal.

If there isn't a common earth and there are lots of fiddly little earths to every individual circuit, probably via a few earth header joints as well, I'd probably be even more likely to think it is an earth fault. Header joints can be a PITFA on dry land never mind in the world where electricity is green and furry.

From what you say, maybe also worth the OP checking to see if his block IS grounded, that may be the problem?

boofy · 19 August 2013, 03:51

Hi, I am just installing a Yanmar315, ZT370 combo & was wondering if you have any further info (from memory) on the ZT350 failure, was it an alignment issue or overheating? Was the the raw water intake a leg only, leg/sea cock combo or was the engine sea cock intake & leg separate? Also did you get to go out on the 315/ZT370 combo?

ncp · 19 August 2013, 05:30

Quote:

Originally Posted by martini

If you're going to work the sterndrive really hard you might be better investing in something like this:

Konrad Marine Propulsion Products

If you are towing and need heavy duty, Martini is correct. Their most robust stern drive can handle 1200 Nm of torque. I have a feeling no other manufacturer can say that.

boofy · 19 August 2013, 06:03

Quote:

Originally Posted by willk

From what I hear, the Volvo is very nice but is very complicated - I'm told that they drop into "limp home" mode if they are not happy, and they're not happy quite often. If you have a Volvo dealer nearby to do the electronics work - fine. If not, Yanmar.

I would agree with Martini about the new Yanmar V8 370hp - I've used the 315hp and it was a pleasure to drive, but the V8 is a similar weight and I hear the price is OK. C'mon - Twin Turbos! Imagine the sound!

I have personally witnessed the demise and death of a Yanmar ZT350 leg (on the 315hp) and Yanmar have upgraded the clutch packs on them since. The ZT370 has this upgraded mechanism as standard but I'll be very interested to see how they perform over time. I hope to get a 100Nm spin on Saturday with the 315/ZT370 combination, so I'll report back...

Hi, I am just installing a Yanmar315, ZT370 combo & was wondering if you have any further info (from memory) on the ZT350 failure, was it an alignment issue or overheating? Was the the raw water intake a leg only, leg/sea cock combo or was the engine sea cock intake & leg separate? Also did you get to go out on the 315/ZT370 combo?

willk · 19 August 2013, 08:55

Hi Boofy,

The ZT350 clutch wasn't up to the job. I don't think it had anything to do with heating/cooling, more that it couldn't handle the torque. The water for the combo was all introduced from the leg, IIRC. Yanmar issued a FOC replacement clutch mechanism for existing ZT350s and further beefed this arrangement up for the ZT370s as they have to cope with the huge torque from the new V8.

I did get a drive in the 315/370 combo. It was a very smooth change and ran well, although I think that the leg gearing didn't suit the boat in question at that time - since swapped out I believe.