Volvo Outdrive

[mike88]

I've tried all the so called experts with this question but seem to get different answers or blank 'I dunno really' looks from them all so I now thought I'd ask the REAL experts! Would be most grateful if anyone can answer this question.
Can a Volvo outdrive originally off a petrol engine be used on a diesel engine? The leg in question is a Volvo SX leg with a ratio of 1.6not sure!) and was originally fitted to a 5.0L volvo petrol. The engine I have is a 180hp GMC diesel at around 3600rpm. Anyone got any idea?

Many thanks

 

[pistonbroke]

Its not perfect, but it is possible to use the drive that you have, although it probably won't like the torque of the V8. You will need quite a high pitched prop to get the revs correct, but in principal everything sounds ok. If you have the petrol motor, you can rob it of all the parts you need to install the diesel.

 

[BarryH]

Nah, he's talking petrol to diesel, not the other way round. You can do it but the gearing is all wrong for the diesel. Can to some extent be rectified by the prop pitch. Best to see what the diesel revs too comapared to the petrol. The gearing is changed in the lower case on the SX. Not a cheap proposition unless you can find some one who deals in cogs!!

 

[brianrunyard]

Take a look at http://www.lancingmarine.com/

Brian
http://homepage.ntlworld.com/brunyard

 

[tr7v8]

Not convinced the SX leg will cope with the torque of the GMC V8, it's probably around 2 to 2.5 times what the petrol will put out at the same revs. If I remember correctly then the GMC peak revs are around the 4000 mark for peak power.
You'll need considerably more pitch in the prop to absorb the power.

Jim
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[PGD]

the SX leg in question came from a V8 5.0L GL and Volvo sell this combo as a standard line, so don't quite follow you on that one.

 

[jimg]

Try your question over on
http://boatdiesel.com/
click to forums and then to right section

 

[pistonbroke]

Re:Barryh

Yes, I grasped the fact that he want's to go petrol to diesel, hence the suggestion of more pitch on the prop. Of course you can re ratio, it's not that expensive, but a prop change is considerably cheaper. Changing the ratio or prop will not sort out the problem of excess torque.

 

[BarryH]

Re:Barryh

I can't see that the torque will be an issue. The early SP's and the SX's are built like the perverbial brick out building! The 5 litre volvo has a fair bit of torque anyway. The SX was available in various ratio's depending on the engine it was coupled too. Seeing as this one was coupled to a V8 anyway and the new V8 oil burner will have somewhere near the same sort of revs, then I can't realy see a problem unless the boat is heavy and its treated like a formula one race car.

Pitch change will probably give enough change in the "gearing" to make it useable. There's been enough of these conversions done with no ill effect to the drives. Altho its not the best engine around, I've spoken to loads of people who have put them in range rovers and have had quiet a few problems with them!

 

[tr7v8]

I assume GMC V8 is diesel, in which case 5Litre petrol puts out around 250BHP at around 4,200 rpm & 260ishft/lb torque @ around 2,600RPM. Diesel will typically put out around 160 BHp at 3,800 RPM & 290 ftlb at 1,900RPM.
So not only is the torque higher it is also at a much lower RPM which gives the diesel it's "advantage" over the petrol, it's this that damages the leg.
It is a common problem when Range Rovers are transplanted with the GMC V8 diesel as the bellhousing isn't really big enough to house a clutch big enough to handle the power.
PS. I couldn't find the petrol o/p figures anywhere but the diesels are off a web site for the engine.

Jim
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[PGD]

Hi, understand where your comming from but the 5.0L Gl is a V8 petrol. VP also fitted this drive to 5.7 l as well as the smaller 4.3.

Originally made by LC is it - VP bought them a while back - supposed to be a very good drive unit, far stonger than the 280 style drives.

Peter

 

[tico]

Resident dieselisation expert here!!

Leg should take it with a bit of luck. At least you have the 1.6:1 ratio which will help.

Biggest problem will be getting a prop with enough pitch and long hub . You may need to buy a new one and get those nice people at Steel developments to chop it about for more pitch and some cupping.

Talk nicely to Mike Bellamy at Lancing Marine about prop sizing. He got mine spot-on when i fitted diesels to a petrol geared outdrive.

Been there, done that, got the oily T shirt