Author Topic: LPW 3  (Read 2533 times)

Quince the Carpenter

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LPW 3
« on: April 25, 2019, 11:02:39 PM »
Hi all,
I bought an LPW3 a few years back to replace an aging (and underpowered) SW2.  Only just now getting around to it! It's going into an 8 tonne auxiliary yacht here in NZ. Belt drive variable pitch prop, so no gearbox issues...
I'm in the process of bench testing the engine, and discovered that it appears the engine is governed to about 1500 rpm. The engine has never been run before, and it came from a generator supplier who'd over-stocked on engine replacements. I got lucky.
My question is:
Can I, or should I, replace the governed system with a throttle controlled system? Is it better for the engine to run at a constant revolution? I can vary the prop pitch at will, so no issues with power output.

cobbadog

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Re: LPW 3
« Reply #1 on: April 26, 2019, 06:51:24 AM »
In my humble opinion I would prefer a throttle governed engine so you can have more control in conjunction with your variable pitch prop. Fixed revs to me scare me especially at start up. If it has been sitting for a while all the oil is down in the sump then once started it is straight to full revs while the il is being picked up, excessive wear comes to mind.
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dieselspanner

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Re: LPW 3
« Reply #2 on: April 26, 2019, 12:36:03 PM »
Hi Quince

I like the set up, the lack of a gearbox is good with the belt drive takes out all the alignment problem. I've worked with VP props - and Kitchener gear - and believe that, properly maintained they are as reliable as a gearbox.

You could get away with fixed rpm, imho, but I agree with most of the reasons above for having a throttle, and also that warming up on tick over or leaving the engine running to heat domestic water / charge the service batteries would be far more comfortable.

An outfit I've worked for before had a V8 GMC in a work boat, it was reputed to have come out of a small tank and went from tick over to flat out with very little adjustment in between, consequently it was hard on gearboxes when shifting from ahead to astern, something a work boat does a lot of...

With the revs fixed you may find the same wear issues on the VP prop. If you could link the pitch control to the throttle to drop the revs as you passed thro' the neutral point it would save all sorts of wear on the thrust bearings etc. and give you a smoother input of power to the prop.

It's not an engine I'm familiar with, doubtless others here will help, but given the numbers of the LP motors out there I don't think there would be too much difficulty with the throttle and I'd hope that a variable speed governor would be an easy swap.

Looks like an interesting project, keep posting as it develops!

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

Quince the Carpenter

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Re: LPW 3
« Reply #3 on: April 26, 2019, 09:01:10 PM »
Hi, Thanks for the responses.
Part of the reason for my query, is that I too, would prefer to idle the engine while warming up and close manoeuvring, but from my preliminary investigation of the throttle base plate it didn't seem obvious to me how to do it. I didn't want to mess with it (if it ain't broke....), and upset the governor setting.
I backed off the throttle stop, (in the foreground of the photo) and took a few turns back off the middle screw, but it didn't made an appreciable difference. The plate doesn't touch the back screw, confusing me further...
 It got me thinking that it would be smart to ask for advice, before I upset everything!

So, can I play with those screws without damaging anything?
Appreciate any comments.

PS, the prop can go from horizontal (for sailing) right through to reverse pitch. There's a lay shaft that sits on a cam to make slack for starting and charging.

Quince the Carpenter

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Re: LPW 3
« Reply #4 on: April 26, 2019, 11:50:15 PM »
Wonderful.
Just the news I want.
Thank you

sirpedrosa

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Re: LPW 3
« Reply #5 on: April 27, 2019, 12:51:49 AM »
Hi Everyone

As far as I can see in pic, I think it has the throttle linkage broken, I mean it laks that part fixes the cable enabling remote throtlle. Wont you agree?

Just my vision...

BR
VP
« Last Edit: April 27, 2019, 12:53:25 AM by sirpedrosa »
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!
Deutz MAH 914, 1952 - Zündfix in chamber and go (7Mai2023).

Quince the Carpenter

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Re: LPW 3
« Reply #6 on: April 27, 2019, 12:58:11 AM »
Ya. Something fell on the cast alloy hook...
Will have to invent something...

cobbadog

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Re: LPW 3
« Reply #7 on: April 27, 2019, 06:00:39 AM »
Now I've seen a pic of what you have I thought that a cable could be attached to the throttle cam just to the right of the very top bolt. It appears that a heavy cable would drop down that hole and the cable then go to the right and fit into what seems to be a groove. If this is the case I would certainly have a go at the adjustments suggested by Glort. In case there is an issue, count how many turns you do on each bolt to get it out of the way so they can be reset to the same position. Connecting the VP to the throttle also sounds a good idea.
Let us know how you get on.
Coopernook - the centre of our Universe.