My Engine

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CitroJim
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Re: My Engine

Post by CitroJim »

Excellent!
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MattBLancs
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Re: My Engine

Post by MattBLancs »

XUD Marine wrote: 27 Nov 2022, 21:15.
It seemed to run OK. I was a little dissapointed with the speed, I only managed to get a max of 12 knots, but I guess that's enough. It only revved to about 3k when working under load. Also surprised how much quieter the engine sounds out in the open, as opposed to in the shed where it seemed horribly noisy, even with 20mm of insulation inside the engine box.

There was just one issue with the engine I noticed when I examined it after a good blast around the lake. It had developed a leak at the Diesel heater, by the water pump. As found the heater had just two stubs of pipe coming out the top. I fixed the line from the tank to the inward one and the out one I fixed a pipe to the primer bulb, that goes on to the filter.
Image
I had noticed before the launch one of the pipe stubs had a wobble, but there was no leakage at the time, so I didn't worry too much.
I'm just curious how the pipes are fixed in there, as it's not obvious to me, and wonderd if I could re-fit new pipes to it.
On the other hand I could easily bypass it by putting the line from the tank straight to the primer bulb, but I suppose it will run a lot nicer with some warmth to the fuel.
Or is there a good alternative I could use? Such as an electric in-line heater.
Any advice?

The later XUD have the fuel filter sat on top of the thermostat housing and an integral fuel heat exchanger as a part of this - looking at your first post your engine doesn't have that.

The image from Marc shows the later heated filter housing:
GiveMeABreak wrote: 30 Jun 2019, 11:55
Image
I'd seek out one of those. Temptation might also be to grab a full XUD9TE if you are still disappointed with 12 knots :-D though I am not sure about your drive system, if only pulling 3000 rpm then guess it's not the engine that's limiting your boat's speed (it'll not have much more to give but would think it'd make some power to 3500, maybe 4000rpm)
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Re: My Engine

Post by CitroJim »

In the UK at least there's no real need for a diesel heater these days and in all cases when an XUD fuel heater gave any issues then completely bypassing it is the norm. and no adverse effects will be found... I appreciate I'm speaking about cars here but I cannot see a boat being any different.

These days, diesel fuel has its formulation adjusted during the winter months to avoid the risk of gelling in very cold weather. I guess you wouldn't be taking your boat out in such weather anyway...

The kind of heater on your engine was never renowned for it's long life...

Some XUD engined UK-spec. cars never had fuel heaters...
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Re: My Engine

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XUD Marine wrote: 26 Aug 2019, 19:20 Thanks for posting these. It's interesting to see another set-up.
It does look a bit different to mine. I see the heat exchanger is on the right side. Is it one of those intergrated with the exhaust manifold?
Looks like an air filter below, must be a non-standard air manifold.
I also see you are not using the main outlet of the thermostat, it's blanked off.

I've not posted for a bit as real life gets in the way sometimes and I've not done much engine work lately, Ive been fibreglassing inside in preparation for the engine beds going in.
I got my mate (plumber and boat nut) to pipe up the cooling system for me. I just had to label which port goes to where, by putting matching numbers on each pair.
It now looks something like this:-
Image
Image
Image
Image

One of the inlet ports on the water pump has been blanked off. That one will take the return from the heater (when I get around to fitting one), that will also need a T split on the heater outlet.
The only pipe I'm not so sure about is the main one from the stat to the header tank, I think I would have preferred it routed something like suggested in this pre-fitting photo:-
Image
Bending forward, horizontal, then up and forward to the tank.

In other news, I now have a propeller which I'm happy about. I was having difficilty sourcing one the right size, pitch and direction for a shaft driven inboard, so ended up spending more than I would have liked to. But I justified this to myself thinking it would be a bigger waste of money to buy a cheaper, easily available one of the "wrong" spec that would result in the engine and boat not reaching its full potential.
But this is subject to getting calculations correct, whether the prop is the perfect match for the engine, geabox and hull. There are a lot of variables and you don't know for certain untill it's in the water.

If you feel you have plenty of power left then the prop might need to upsize a bit. As you say, with all the calculations, you have to pick a starting point somewhere.
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Re: My Engine

Post by Dormouse »

Another thought. Does the boat offer to go into hull planing mode by 12 knots?
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Re: My Engine

Post by Dormouse »

Looking at Freeman's specs and your own pictures, your stern is definitely down under power but there is a definite bow wave. The static picture of her moored seems to show her bow down on the waterline. Moving weight backwards might get her to plane a bit easier as the centre of gravity is well forward of the planing centre if I am right.
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MattBLancs
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Re: My Engine

Post by MattBLancs »

XUD Marine wrote: 11 Dec 2020, 21:53
Image
Sorry if I've skimmed over and missed this detail - but looking at one of the pictures of the engine on its stand, ahead of going in the boat - this picture of it in situ confirmed what I the mounts were set up for:


Normally an XUD is at 30° but your installation has it sat bolt upright - has anything been done with the oil pickup (and dipstick?) To cater for the change in angle?

Just curious. Very interesting project by the way!

Matt

Edit = quoted wrong picture!
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Re: My Engine

Post by XUD Marine »

CitroJim wrote: 28 Nov 2022, 15:44 completely bypassing it is the norm. and no adverse effects will be found...
That would be a very easy fix. All I would have to do is unclip the line from the tank (black braid in the photo) and clip it on the primer bulb.
In hind sight there are things I could have done. Note in the picture the two hoses with red valves at the top, those go to and from the heater in the cabin. The fuel line follows a simiar path for 2 or 3 meters. I could have wrapped the fuel line in with their insulation for a little warmth on its way. You see the fuel line going from the bulb to the top of the filter (bottom of the frame). From the filter it goes round the back of the engine and to the injector pump. That follows a simiar path to the water return pipe from the thermostat to the water pump. I could maybe modify that piece of line to cling to the water pipe.
But as you say, it may not be necessary unless it's very cold. At the end of the day I think cool Diesel is a lesser evil than a fuel line leak.
MattBLancs wrote: 28 Nov 2022, 10:13 if only pulling 3000 rpm then guess it's not the engine that's limiting your boat's speed
When it comes to speed on the water, there are a lot of factors that come into play, not just engine power, but the gearing, prop size and pitch and of course the dynamics of the hull and its weight/displacement. You can try to predict what a set up will do, but it's hard to get right. You just don't know for sure until you try it out.
Looking at Freeman's specs and your own pictures, your stern is definitely down under power but there is a definite bow wave. The static picture of her moored seems to show her bow down on the waterline.
Yes, she does sit a bit nose heavy at rest. I guess thats with the weight of the cabin and all that's in it. The engine is the heaviest component, as you see in the blue box about 1/3 from the stern. But the hull aft is quite broard and flat, able to carry the weight, wheras at the front it's a narrower V shape, less buoyant. Certainly weight and weight distribution is a big factor. When you set her on, the head does rise a bit, but I wouldn't say it gets on the plane. Planing is the key to getting more speed, but it's a "chicken & egg" thing, you need speed to plane, but need to plane to get speed. The original Freeman was never made to be a speed machine, though the hull shape does look to have potential. I think I would have to lose a bit of weight (at the front) and gain a bit of power to make it plane. The prop is about as big as I can fit, with quite a pitch (possibly too much pitch).
In hindsight it may have been more optimal with more reduction on the gearbox. I went for a 2 to 1 box. Maybe a 3 to 1, though less revs at the prop, would have more torque there which would cope better with the water's resistance and allow the engine to rev higher. But you could spend a fortune trying different hardware like gearboxes and props to find the optimal setup.
A bit of red showing above the water
A bit of red showing above the water
You can see the angle is different to that at rest
You can see the angle is different to that at rest
The hull
The hull
I've also toyed with the idea of putting some ribs along the under edge of the chine, to force air under the hull. From the observations in motion, there seems to be too much energy going into shooting water sideways instead of backwards.
MattBLancs wrote: 29 Nov 2022, 10:25 Normally an XUD is at 30° but your installation has it sat bolt upright - has anything been done with the oil pickup (and dipstick?) To cater for the change in angle?
Yes, the engine mounts that came with the marinisation kit have the engine block straight vertical. Though it is in fact tilted in the other axis, down at the flywheel end, to bring it in line with the prop shaft (about 11 degrees).
I've not altered the oil pick up, but I think it works, there is plenty of oil pressure showing. It's quite normal for a marine engine to sit this way. Though it's not a purpose built marine engine, the XUD is commonly used for automotive to marine conversions, hence Lancing Marine make the kit of it. So I'm assuming it's fine.
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Re: My Engine

Post by MattBLancs »

XUD Marine wrote: 29 Nov 2022, 21:19
Yes, the engine mounts that came with the marinisation kit have the engine block straight vertical. Though it is in fact tilted in the other axis, down at the flywheel end, to bring it in line with the prop shaft (about 11 degrees).
I've not altered the oil pick up, but I think it works, there is plenty of oil pressure showing. It's quite normal for a marine engine to sit this way. Though it's not a purpose built marine engine, the XUD is commonly used for automotive to marine conversions, hence Lancing Marine make the kit of it. So I'm assuming it's fine.
Obvious now you've said it, but hadn't thought about it pointing flywheel down slightly to suit the prop. 11° doesn't sound too extreme (as in picturing it's previous Peugeot parked on a slope!) but the 30° change the other way surprises me if needs no change. Happy you're following an established route and all seems well.

It was the really quiet pronounced slope of the bottom of the sump that hit my eye.

Do you use the existing dipstick as guide to oil level? Would think that quite a bit more oil than in its normal orientation! (No bad thing, unless crank is thrashing into it)


Interesting topic about the gearing / prop size / engine performance balancing act - thank you,
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CitroJim
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Re: My Engine

Post by CitroJim »

MattBLancs wrote: 29 Nov 2022, 22:10 Interesting topic about the gearing / prop size / engine performance balancing act - thank you,
It certainly is :-D I'm thoroughly enjoying this topic and good to see an XUD in another role...
Jim

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Re: My Engine

Post by Dormouse »

Don't experiment with ribs, they will not channel sufficient air and may ruin the bow wash. Your hull design is a shallow V and looking at the new pics she is lifting to the plane. However, Freeman's original design was meant for Broads cruising and they list the max speed as about 8 knots - albeit with a Watermota engine. A quick, rough calculation using a blowup of Freeman's sketches puts the Planing centre about 11 ft from the stern. You have probably removed at least 4 cwt / 200 kilos in rear superstructure and fittings, so, while the hull is lighter and higher in the water, it is now bow down as the c of g has moved forward, the planing centre is probably fractionally further back relative to draft and the centre of bouyancy has moved fractionally lower relative to draft.
What does this all mean?
The hull was probably not designed for speed so 12 knots might be it with your setup.
You have plenty of scope to add ballast/ shift weight to get the boat nearer it's trim level.
The shallow V is a stable hull and probably isn't affected much as far as stability goes with the changes.
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Re: My Engine

Post by Dormouse »

The Bow wash is designed to "peel" away from the bow in an efficient manner and effectively has a speed limitation on Cruising hulls. As a Broads cruiser, above 8 knots and the bow wave and wash would become excessive for other boaters and bank erosion. Plus the power to go above 8 knots rises exponentially. This hull design was not intended for higher speeds.
Trimming the hull and the prop are your options and you might get 14 knots.

My first job after leaving Uni was with a company that made small sports hovercraft and canoes. I have had and loved boats and boating for nearly 60 years, so it is both a hobby and been a job as a Design Engineer.
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Re: My Engine

Post by Dormouse »

One way of improving the prop you have is to fit a Kort Nozzle over it. This is a tightly fitting "collar" surrounding the prop which limits the losses at the tips of the blades. It also has the added bonus of protecting the prop from damage in some instances.
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Re: My Engine

Post by Dormouse »

Look in the very top left of the pic to see one of my prized ornaments and the only one allowed on LOML's cabinet.

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Re: My Engine

Post by XUD Marine »

I think I'll probably not lose too much sleep over the speed issue and just accept it is what it is. You are right, it does reach a point where you are pretty much battling aginst the laws of physics and can put a lot of effort and expense into making very minor gains.
Dormouse wrote: 30 Nov 2022, 12:55 One way of improving the prop you have is to fit a Kort Nozzle over it. This is a tightly fitting "collar" surrounding the prop which limits the losses at the tips of the blades. It also has the added bonus of protecting the prop from damage in some instances.
That is a worthy consideration, largely due to the protection. There is no real protection for the prop and rudder as is. I dread the thought of clicking a rock and busting the prop and bending/snapping the rudder shaft. I had previously thought about adding a skeg coming back off the keel for this reason.