80hp Ford Lehman - Relocate Raw Water Pump

[Aussie Monty]

Greetings All,

i seek thoughts, opinions and comments with regards to the relocation of my water pump">raw water pump. Its current position makes impeller inspection and replacement a little difficult. See photo 1.

The motor was originally rigged to run the following from the front (a) hydraulic pump - anchor windlass, bilge pump (both with electro-mag clutches) and (c) a refrigeration compressor - for which was removed later by me when i switched to electric.

Can i not - by fabricating the necessary components - relocate this pump to the front and run it of the fridge comp pulley?...shared with bilge pump[ and hydraulic pump? Or am i missing some fundamentals such as impeller speed/water flow etc?

[GILow]

Hello Aussie Monty, great to see you back.

Your engine is pretty similar to ours, nice big plodding truck donk, plenty of space to bolt stuff on. Ours was marinised by Diecon in QLD back in the 80s. At first I thought it was all a bit crude, but I have grown to respect their work. I wouldn't recommend them if weight is an issue, they were a bit darn generous with the steel thickness, but great for a cruising boat. Somewhere I have a photo of our engine showing the raw water pump mounting point, I'll find it and post here, it may help.

As for belts and stuff, belt speed will be dictated by the drive pulley, and from your photo it would appear that all pulleys are the same size so belt speed would be the same on each belt. But I for one would not like to share the raw water belt with any other device. What if the other device on that belt seized? Then you be in trouble.

Let me find that photo, and meanwhile, please let us know which boat you finally found. Or did you post this somewhere else?

Matt


Sent from my iPad using Cruisers Sailing Forum

[Aussie Monty]

Thanks Matt,

Photo would be great. I think i was a little unclear on how it would run.

There is a triple drive pulley hanging off the front crankshaft - to run the three system devices stated. The fridge comp now being obsolete so opportunity there? So no sharing and agree with risk you have stated!...its too important. Went to boat show on weekend and high-end Volvo (large displacement) ran raw water pump via belt...so clearly engine designers do not steer away form them.

Not sure what yo mean about boat search?...bought my Adams 45 3 years ago and now getting around to refit.

Regards

Aussie Monty

[farshore]

I have the same engine and have found it much quicker to just unbolt the mounting flange and take the whole pump off to change the impeller. This way you have only three bolts to drop in the bilge.....

[GILow]

Originally Posted by Aussie Monty

Not sure what yo mean about boat search?...bought my Adams 45 3 years ago and now getting around to refit.

Sorry, I am a nitwit, I was confusing you with Aussie Geoff. Now I am back on track... did you check that Adams 45 blog I mentioned?

Where was I...?

Oh, photos... two here. The rusty old dark blue engine is our poor neglected donk when I pulled it out to clean it up and get to the keel tanks. I thought it was a better picture, but I think it is useful because it shows the bracket without the pump to obscure the view. Basically a right angle bracket from the side of the block, mounted using the timing cover bolts in our case, the slots give you the ability to adjust the belt tension by sliding the pump sideways.

The second photo is from a Nissan ED33 for sale on youtube a while back. Same conversion as ours by the look of it, but shows the water pump in place.

Having started to understand your setup, I can unequivocally say I would recommend the Diecon version in preference. We have a bog-standard Jabsco pump, and could put just about any standard raw water pump in its place. Access is a dream too.

FWIW, I too have pulled the old freezer gear from our engine and now run the 12 volt alternator from the second pulley on the 24 volt alternator (visible in the first picture), leaving the extra pulley on the crankshaft to run the electromagnetic clutch actuated bilge pump. Both of our alternators are pretty low capacity so we don't put much strain on the drive belts. I think something else would have to be done if I ever needed to fit a decent capacity alternator, but so far we get by with solar and wind. This capacity is something that you might consider, given you have the extra pulleys on your crankshaft already.

I hope this helps.

Matt

[DougR]

This looks like a doable project. Depending on the gear drive within the timing case, turning the pump around will probably reverse its rotation direction, requiring some plumbing changes.
The other thing to check is that the bearings within the pump housing are probably open bearings, being lubricated by oil splash from within the timing case. These will have to be replaced by prelubed sealed bearings.

As mentioned, you will have to size the pump drive pulley to maintain a similar pump RPM to that which the pump already has. Also, it might be prudent to drive the pump from the belt groove closest to the timing case. This will give the lowest bending load on the crankshaft end.

DougR

[GILow]

I was actually thinking complete new pump. I can't imagine how you could recycle the existing pump and I would guess the bearings could not take the side load of a belt drive anyway.

Matt


Sent from my iPad using Cruisers Sailing Forum

[VOYAGER II]

You may want to save yourself some money and lots of aggravation by replacing the impeller cover with a Speedseal cover. It is made in the UK . I have the same set up on my Lehman as you and replaced the cover 8 years ago and wouldn't be without it.
It makes changing the impeller simple with no screws to lose in the bilge. Frankly if you are going to the trouble of inspecting the impeller, you may as well change it and be done with it.

[Aussie Monty]

Thanks all for thoughts to date!

In response - main issue for me is drawing out the impeller with special tool (modified) - as it all fouls the engine oil filter for starters..and is very hard to get a decent eyeball at!.Indeed I will buy a Speedseal for one for new set up though! Ditto also have previously removed via main flange bolts however, smallish pain in the arse disconnecting raw water IN/OUT HOSES every time.

Bingo Matt!...the set-up on the RHS image is precisely what I would like to do.In fact its orientated exactly as this is displayed and indeed the mount is existing from fridge comp.

Therefore factors to sort out are (?)
(1) check RPM OLD versus NEW. Whats the difference and will it actually matter if its sort of close? Not double, not half, not half of that!
(2) Devise set-up and fabricate.
(3) Mount on inner sheave to mitigate crank shaft load.
(4) Check that bearing lube is or is not engine oil (?) and match bearing accordingly, or rig different/new pump type.

Monty.

[GILow]

Monty,

Just to clarify something, and I am sorry if I am being a bit thick, but I am working on the assumption that you start afresh with a totally new raw water pump, which is going to bit a bit painful if you have to buy it new, though I've seen good ones secondhand from time to time at the local chandlery. Think au$500 plus new, I know this as I have a spare on my shopping list for when we go cruising, but not before.

I cannot see how you could possibly reuse the existing pump, aside from it being gear driven, I would also assume the bearing cannot take any side load so a belt drive, even if you could fit a pulley, would not work. If you are thinking of remaking the pump to handle the side load I guess that could be done but I suspect it would be a lot of work with an uncertain outcome. I am usually keen to give it go with this sort of thing but this one would scare me, that's for sure.

As for RPM, it's not too hard. Our jabsco is rated to a maximum of 3000 rpm, which is ok given we are propped for a maximum engine rpm of 2000 rpm, and I am guessing the Ford Lehman would be similar? Anyway, minimum rpm they recommend is 500 to give enough flow for our setup, idle speed of 650 rpm and you can see we could get away with a slight reduction in ratio, however as it is we currently have a ratio of about 1:1.4 which gives us good flow across the rev range, particularly at our preferred cruising revs of 1200 rpm. FWIW our engine is theoretically 96 HP but with the current prop we are limited to 80 which I think is smart and certainly enough power. Either way, it means we are producing about the same amount of waste heat as you will be at WOT.

Finally, you may have considered this already so apologies if I am stating the obvious, but with a conversion to something similar to our setup you can easily tap in an electric bilge pump as an emergency cooling pump. Probably possible with your current setup but a heck of a lot easier when all the hoses are at eye level.


Matt



Sent from my iPad using Cruisers Sailing Forum

[Aussie Monty]

Thanks Matt,

Indeed I believe its me that is being a bit thick!

Of course new unit for set-up is required - given all you say makes perfect sense.

Back-up via electric pump - or indeed to divert via my engine driven bilge pump - being pretty well the type of pump I seek - is of course a great idea. Obvious in its simplicity - yet I failed to consider it

Thanks again for your input...it gives me hope and reinforces the strength of having a go...after working through the problem carefully.

Monty