Speed boat

[LS7427ci]

I have aquired a 33ft excalibur speed boat it currently has 2 x 454 big block chevy engines and running mercury drive units, its been sat for a while so in need of some TLC but the hull is in mint condition no marks or repairs on it at all!! Engines are running but could do with a check over in my eyes, at some point they have had a few £££ spent on them.
It would sleep two, has a small sink/kitchentop etc up the front, its on a tri axle ali trailer all ready to go. Wanting to know if it was restored back to A1 condition what its worth??? As I'v inherited it and dont no mch about boats!! but do know about engines!! Thought a pair on LS7's in it would go a treat???

[donutsina911]

Is it a Wellcraft Excalibur? If so, have a nose on www.yachtworld.com or www.boats.com for a price. Without pics, model and conditition it's hard to guage though..

[LS7427ci]

Yes its a wellcraft, a good clean up and a lick of paint would see it good as new!! I'll go and have a look, thanks for the help.

[MOTORVATOR]

If it's one of the models I suspect then the 454s would indicate likely a late eighties or early nineties boat. I wouldn't even consider re-engining as you will not see you money back.

More to the point whilst you may think you know about engines, marine is a different world because of the duties expected. There are numerous tales of auto engines in boats but I can't recall a successful one

The Wellcrafts and indeed virtually all American powerboats have a very small market over here as they are not particularly capable in our conditions, think yank cars on our roads. Americans have big lakes and freeways, we have big seas and twisty b roads.

If you want some real info post it on www.boatmad.com.

[fortyplusfour]

If you intend to use it and wish to re engine then do, however you won't add any significant value to the boat.

You will of course have more efficent engines etc

If you thinking of tidying her up and then selling her on then just get the current engines in decent working order and give the boat an average specification.

Any help you need with sourcing things then I can point you in the direction of some very helpful guys within the industry.

You may also find the forums at www.ybw.com useful.

Good Luck!

[MartinD]

MOTORVATOR said:

More to the point whilst you may think you know about engines, marine is a different world because of the duties expected. There are numerous tales of auto engines in boats but I can't recall a successful one

Could you expand your comments please, only the V8 boat engines I have seen use car blocks/heads etc. (casting No's) So what is the difference ?

[MOTORVATOR]

MartinD said:

MOTORVATOR said:

More to the point whilst you may think you know about engines, marine is a different world because of the duties expected. There are numerous tales of auto engines in boats but I can't recall a successful one

Could you expand your comments please, only the V8 boat engines I have seen use car blocks/heads etc. (casting No's) So what is the difference ?

Wow that's a huge question and one that I could not answer in one fell swoop.

Let's stay with petrol for the moment as there are slightly differing issues with diesel.

Firstly you need to understand the different duties expected of the engines. A marine engine will be expected to give a fairly constant rise in delivery of torque to it's max power then stay there for sustained periods of time. In leisure use it will be expected to be rated to the highest torque figure possible at max revs. No point going past that level as we haven't got any gears and will size the propellor to be at max efficiency at this point. We also need sufficient torque to come on stream at low revs to allow the boat to physically plane and release the engine to deliver further. For commercial it will be down rated to give longevity. Typically marine engines are expected to last 10-100 hrs race 1000hrs leisure and 5000hrs commercial.

You can start to see from that the expectations are very different from auto.

From above the first difference will be cams to give the high outputs desired at a lowish max rpm, BUT very little or no valve overlap as the exhaust will be spitting the cooling water out and we don't want that sucked back in.

Stainless steel exhaust valves / inserts as a minimum. One slight piece of rust formation will generate huge heat build up when under power leading to catastrophic failure.

Cooling system will be generated either by raw water through the block or alternatively a heat exchanger system. Each has it's own problems however you are not just cooling the block / heads as you would in auto, you need to cool exhausts / engine oils / power steering fluids / fuel etc and it has to work. Very often the routing of cooling water in marine is different to the same engine in a car. There is no residual air cooling in an enclosed engine bay as there is with a car.

Standard gaskets at your peril, as with standard fixings. Dissimilar metals and salt and your engine will last no time at all. Ali heads / blocks and raw water cooled is an absolute no no.

Inlet manifolds and exhaust systems have to be designed to take the pound out expected from a marine engine being constantly banged up and down.

Oil systems and capacities are usually increased to allow for the fact that the engine may be working at varing attitudes. Almost certainly additional baffles in oil pans required. Higher capacity oil pumps to deal with working at max power for sustained periods.

Whole system must be linked to a suitable sacrificial anode system to stop corrosion. Volvos in particular drill the block and heads to insert zinc anodes.

High power outputs from relatively low revs demands different con rods etc.

Electrical system must be suitable for water use. Forget standard coils etc, won't last 2 minutes.

Uprated fuel system, this thing will be working in an enclosed space.

If you think about it there is a bloody good reason for Honda / BMW / Ford not just turning up at the boat show with their latest car engine and selling loads of units. What Chevrolet and Ford will do though is sell units on to specialists like Mercruiser to marinise and sell on. Volvo will buy in petrol units from other manufacturers and do the same although for their diesel range they designed marine from scratch.

Want it insured? You will need a survey and the surveyor will condemn standard car engines due to the potential failures.

That's about as broad and brush as I can be, but hope that gives a few of the answers. How did I learn? From experience having a big block chevy built by a top fuel drag builder and it sticking a rod through the side in a matter of a few hours even though he was convinced it was capable of taking 1000hp through the block and we were running with about 500.

[MartinD]

MOTORVATOR said:

MartinD said:

MOTORVATOR said:

More to the point whilst you may think you know about engines, marine is a different world because of the duties expected. There are numerous tales of auto engines in boats but I can't recall a successful one

Could you expand your comments please, only the V8 boat engines I have seen use car blocks/heads etc. (casting No's) So what is the difference ?

Wow that's a huge question and one that I could not answer in one fell swoop.

Let's stay with petrol for the moment as there are slightly differing issues with diesel.

Firstly you need to understand the different duties expected of the engines. A marine engine will be expected to give a fairly constant rise in delivery of torque to it's max power then stay there for sustained periods of time. In leisure use it will be expected to be rated to the highest torque figure possible at max revs. No point going past that level as we haven't got any gears and will size the propellor to be at max efficiency at this point. We also need sufficient torque to come on stream at low revs to allow the boat to physically plane and release the engine to deliver further. For commercial it will be down rated to give longevity. Typically marine engines are expected to last 10-100 hrs race 1000hrs leisure and 5000hrs commercial.

You can start to see from that the expectations are very different from auto.

From above the first difference will be cams to give the high outputs desired at a lowish max rpm, BUT very little or no valve overlap as the exhaust will be spitting the cooling water out and we don't want that sucked back in.

Stainless steel exhaust valves / inserts as a minimum. One slight piece of rust formation will generate huge heat build up when under power leading to catastrophic failure.

Cooling system will be generated either by raw water through the block or alternatively a heat exchanger system. Each has it's own problems however you are not just cooling the block / heads as you would in auto, you need to cool exhausts / engine oils / power steering fluids / fuel etc and it has to work. Very often the routing of cooling water in marine is different to the same engine in a car. There is no residual air cooling in an enclosed engine bay as there is with a car.

Standard gaskets at your peril, as with standard fixings. Dissimilar metals and salt and your engine will last no time at all. Ali heads / blocks and raw water cooled is an absolute no no.

Inlet manifolds and exhaust systems have to be designed to take the pound out expected from a marine engine being constantly banged up and down.

Oil systems and capacities are usually increased to allow for the fact that the engine may be working at varing attitudes. Almost certainly additional baffles in oil pans required. Higher capacity oil pumps to deal with working at max power for sustained periods.

Whole system must be linked to a suitable sacrificial anode system to stop corrosion. Volvos in particular drill the block and heads to insert zinc anodes.

High power outputs from relatively low revs demands different con rods etc.

Electrical system must be suitable for water use. Forget standard coils etc, won't last 2 minutes.

Uprated fuel system, this thing will be working in an enclosed space.

If you think about it there is a bloody good reason for Honda / BMW / Ford not just turning up at the boat show with their latest car engine and selling loads of units. What Chevrolet and Ford will do though is sell units on to specialists like Mercruiser to marinise and sell on. Volvo will buy in petrol units from other manufacturers and do the same although for their diesel range they designed marine from scratch.

Want it insured? You will need a survey and the surveyor will condemn standard car engines due to the potential failures.

That's about as broad and brush as I can be, but hope that gives a few of the answers. How did I learn? From experience having a big block chevy built by a top fuel drag builder and it sticking a rod through the side in a matter of a few hours even though he was convinced it was capable of taking 1000hp through the block and we were running with about 500.

Wow, thanks for a comprehensive reply, not I'd agree 100% with you re. differences but its given me a lot to research.