M20 Engine Hydroplane???

[Widge]

Hi,
I'm thinking about putting a 2.5 M20 in a hydroplane boat , and I'd like to pick some brains!! Does any one know roughley what the engiine minus the gear box weighs? Including Alt. and inlet manif but not the cast exhaust, I'm gonna fabricate my own stubs. Also the engine bay will probably be only 500mm wide but I'm quite confident I can cram everything in.
I can't wait to hear a straight 6 growl with stub exhausts in my back yard . My Marine engineer mate recons it'll be good for 130+MPH
Does any one know of any other wierd uses the six has been put to?
I'm thinking of getting a rusted out 3 series and using as much as I can on the boat like the drivers seat pedals steering wheel and colum and the instrument cluster, I think it could be an interesting project, and look great with a big BMW emblem on the side of the hull.
Cheers guys

PS for me it has to be the 6 just because of the sound. Ever heard 50's Grand Prix Maserati up close??? Then again the Bugatti straight 8 is somthing else too!

[Widge]

Ignore the poll I cant get the 3rd option to work.

[Paul325i]

lol, don't it's a pig iron lump of an engine.

If you want an engine for a fast boat then use one with an Alloy block. Later BMW engines or a rover V8 perhaps.

[Widge]

lol, don't it's a pig iron lump of an engine.

If you want an engine for a fast boat then use one with an Alloy block. Later BMW engines or a rover V8 perhaps.

1. Later BMW lump will be Expensive this is going to be backyard cheapo engineering

2. V8 wont fit as engine bay is long and narrow and dont produce that much power.

3. m20 engine is totally unstressed and so will put up with long periods of high revving. And they are reallly very cheap. And I know how they work.


Speed is not the issue here, with a surface drive and a trimmable prop and a nice air flow tunnel going on between the sponsons there will be little water resistance. Once it works getting an M20 to go faster and not explode will be easy, because as i said they are very over engineered / under stressed.

Any way its only an idea for a project not a race boat.

Other than just being a pig do you know howmuch it weighs?
Cheers

[Paul325i]

I meant pig as in made of pig iron, cast iron. Can't remembr exactly now but it's a fair amount, something around the 150kgs mark.

Surely in a boat you'd be better off with something that is carbed? less wring etc.

M20 isn't that easy to tune up to big power but it's ok at running hard ish, they do tend to get pretty hot and you'll need a good cooling sytem for it. Personally in a boat i'd want something with either gear or chain driven timing, the m20's belt might be hassle at constant high revs.

[Widge]

I meant pig as in made of pig iron, cast iron. Can't remembr exactly now but it's a fair amount, something around the 150kgs mark.

Yeah That will be just right for the bouyency of boat I have in mind, get the engine low weigh the boat down for cornering.

Surely in a boat you'd be better off with something that is carbed? less wring etc.

Fuel injection appeals to my technical nature, have you ever heard of a BMW engined boat??

M20 isn't that easy to tune up to big power but it's ok at running hard ish, they do tend to get pretty hot and you'll need a good cooling sytem for it. Personally in a boat i'd want something with either gear or chain driven timing, the m20's belt might be hassle at constant high revs.

As I said it's just a project and will only get used a couple of times a year. The fuel tank will probably carry 10-15 mins of fuel anyway so timing belt is not really a worry, I'll change it before I put the engine in the boat.

As for cooling Im thinking an air/oil cooler and two radiators either side of the engine housing rather like the pod's on an F1 car, with electric fans.

[Paul325i]

Wow that's some project for such little use!

Good luck with it, and whack some pics up if you do get started on it.

[Rearwheel_nick]

straight 6 is my favourite sound ever

great project. when your idea bagsy going for a ride in it

[Widge]

I'll Stick some pics up when / if we get started.
Big project for little use yeah, but it's between 4 of us and the fun as you will know I'm sure is in the fabrication and the tinkering as well as the driving.
I only thought about it as we were offered a hydro hull on the cheap, cheaper than the materials used to make it and thought it would be an opportunity missed.
I just like the idea of making it an BMW on water with the interior from an E30 and wing mirrors etc. Part of the appeal to me is making the different bits not designed to work togeater gel properly and fabricating parts that would cost a lot of money for penuts in my shead with a bit of thought and lateral thinking.
Like I'm thinking of making a prop out of carbon fibre, might not work but worth a try as s/p props aren't cheap and if I break one I'll have the mould to make another. Might have to bond an ali plate in the leading edges for damage prevention.

PS Rides will be on a first come first served basis, the first tests will be on the Tyne!!

[Widge]

HYDROPLANE UPDATE

The hull has been bought

I'll update when we have collected it and will take some more pictures.
Once we have measured the hull, the plan may change , we may be looking for a rusty E30 to give a new life to!!!


Sorry guys can't get the phto to work, any clues??

[Geeman]

We used to have a ski boat with a BMW 3.5 big six in the back with a Z-drive... boy did that thing fly!

Sounded awesome too.

Looking forward to your project... The hull looks GREAT!