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bigcol

Central flex coupling

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6 minutes ago, bigcol said:

 

Got a large 4 bladed prop

 

Unusual, check what the g box ratio is ?

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20 hours ago, Tony Brooks said:

I think the lower adjusting nuts are still on the engine feet so if you can lift/jack the engine to take the lower nuts off it will probably drop bu half and inch and that would be a lot better but only if you go for an Aquadrive. I think they come in various lengths so get the engine as far forward as sensible to lessen the angle.

I see what you mean, I unable to get down their, so relying on mates etc.

but if the thread inside the mounts can be reduced I think that could get me in the right direction!

19 hours ago, Boater Sam said:

 

 

Remove the 4 brackets from the engine they are bolted on.

Carve the tops of the brackets.

Build up the brackets by welding steel on 3 sides by as much as you need to drop the engine to get it in line and weld the tops back on.

 

Can all be done off the boat at a welders once you have measured how much drop you want.

 

Are you certain that the engine will fit down in between the engine beds?

Still might not come to that fingers crossed but another good idea!

theres a good 4 inches below oil pan and bottom of boat

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I’m thinking of purchasing  compressed engine mountings

with this combined with the flexible coupling I think we could be there.

fingers crossed

 

what is the most degrees that these couplings work to anybody.?

 

many thanks for your tips and advice.

Ps I do have a water stern gland.

 

its been suggested I should have a anti thrust bearing as well, as I have the engine being measured up to fit this installation. This afternoon 

 

thanks col

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With a Python or Aquadrive you will have to have a thrust plate welded into the hull and on that wide stern of yours its not so simple as on a narrow boat.

Have you priced the Aquadrive, thrust plate and new engine mountings as against altering the engine brackets and a Centaflex or similar in line coupling?

Aquadrive for a Beta 90 will be expensive.

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16 hours ago, Boater Sam said:

Unusual, check what the g box ratio is ?

It’s a PRM 260 2.1

TA 

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1 hour ago, bigcol said:

I’m thinking of purchasing  compressed engine mountings

with this combined with the flexible coupling I think we could be there.

fingers crossed

 

what is the most degrees that these couplings work to anybody.?

 

many thanks for your tips and advice.

Ps I do have a water stern gland.

 

its been suggested I should have a anti thrust bearing as well, as I have the engine being measured up to fit this installation. This afternoon 

 

thanks col

 

Apart from the Aquadrive & Python Drive Zero mm radial displacement and angular displacement of about 2 degrees Max.

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1 hour ago, bigcol said:

It’s a PRM 260 2.1

TA 

Looking at that number its not a dropped box but inline, there is the problem. See if PRM can change it to a 260D2.1, or sell it and buy anew 280D2.1 for around £1400. It may be cheaper and better solution than all the messing about and welding.

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It’s too much

im going to place the engine up for sale today.

its a pity but it’s not going to fit our boat.

so if anyone wants a gentleman’s deal

this is going to be nice engine to buy.

its a green line 90hp was originally a keel cooled, but had over a £1000 kit supplied by beta to make it raw water cooled

so easily converted back invoices are here to view.

the engine is 8 years old, and has only done 400 hrs, it has all the loom and luxury panel

 

i will look and wait for the engine that it was currently made for

 

ive given up

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Sorry to wee on your parade bigcol but that is probably a sensible thing to do. Even of you got that engine low enough you would never get under it to do an oil change.

 

Was I right about it being an in line gearbox not a drop?

Sam.

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3 hours ago, Boater Sam said:

Sorry to wee on your parade bigcol but that is probably a sensible thing to do. Even of you got that engine low enough you would never get under it to do an oil change.

 

Was I right about it being an in line gearbox not a drop?

Sam.

Hi Sam

 

it was too much, and after all that problem with the oil sump, yes please feel free to have a pee lol

 

regards to the gear box, I’m not sure what we’re on about here lol

 

col

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8 minutes ago, bigcol said:

regards to the gear box, I’m not sure what we’re on about here lol

 

col

 

If you imaging the gearbox off the engine. At the front it has a splined input shaft. At the back it has an output shaft with the coupling on it. If you look at the two shafts are yours in-line (judge by the centre of the  flywheel housing)  or is the output shaft and coupling lower than the input shaft. Now, I have never seen a PRM hydraulic box that is not a dropped shaft one but I can not say in-line ones do note exist. If yours is in-line (not dropped) then a gearbox change may put the shaft in line.

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6 hours ago, Boater Sam said:

Sorry to wee on your parade bigcol but that is probably a sensible thing to do. Even of you got that engine low enough you would never get under it to do an oil change.

 

Was I right about it being an in line gearbox not a drop?

Sam.

Yes, the OP's box does not have D in the part no.

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If its a 260C then the input shaft is lower in the box so that it is on the same axis as the output shaft. This means that the box sits higher on the engine than the 260D.

This attached shows the arrangement.

Sam.

PRM260.pdf

 

But looking at the photos it looks like a 260D, confusing as to why the prop shaft is so low in the hull, what is the boat? Stern looks like a wide beam.

Edited by Boater Sam

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22 minutes ago, Boater Sam said:

If its a 260C then the input shaft is lower in the box so that it is on the same axis as the output shaft. This means that the box sits higher on the engine than the 260D.

This attached shows the arrangement.

Sam.

PRM260.pdf 94.5 kB · 0 downloads

The 260D has a 3 1/2" drop.

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One last pop at this engine

with my new knee op last week, I’m relying on others to look at the situation

my son-in-law came over and had a look, and took the 2 photos

it shows that the sump tank is not on the floor but nearly touching a cross member

so if this was cut down 3 inches eg and the beams where mountings would go get cut down just to lower where the mountings will go

1) if the gearbox flange married up to the  prophaft flange,

would that be it,?

nothing has to go in the space in photo, ?

ideal world engine just slid up to meet prop-shaft flange.

 

2) looking at engine mountings, the current height is 5.9 cm but looking arround at other mounting sites there’s low profile ones available

is there a reason I can’t use these instead?

i looked at these

 

again I so Thankyou all for your help and post

 

http://www.randdmarine.co.uk/enginemres.asp or http://www.randdmarine.co.uk/enginemres.asp

CB8C47C8-12D4-463F-B4B0-185FE88847E3.jpeg

9E171338-D70E-4953-898F-AA158B491DDD.jpeg

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When someone said that the if you lowered it then the engine may foul something I look at the photos. If you look at the engine feet they have an angle to them and it looked to me as if lowering the engine in some way might bring those angles into contact with the edges of the beds but I am in no way certain.

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42 minutes ago, Tony Brooks said:

When someone said that the if you lowered it then the engine may foul something I look at the photos. If you look at the engine feet they have an angle to them and it looked to me as if lowering the engine in some way might bring those angles into contact with the edges of the beds but I am in no way certain.

Hi Tony

 

it seems as tho it can come down about 2/3 inches plus the engine bottom will just fit in between, but soninlaws coming back over at the weekend just

to check on your comment.

 

thanks very much

 

 

on the mounting shown, there’s a big nut and smaller nut, just thinking what if I take out the thicker nut.

theres still locking nuts there ? Lol

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1 hour ago, bigcol said:

Hi Tony

 

it seems as tho it can come down about 2/3 inches plus the engine bottom will just fit in between, but soninlaws coming back over at the weekend just

to check on your comment.

 

thanks very much

 

 

on the mounting shown, there’s a big nut and smaller nut, just thinking what if I take out the thicker nut.

theres still locking nuts there ? Lol

I don't think you need any nuts below the engine foot, but maybe a washer directly ob to the  shroud that covers the rubber. So it would go engine bed - engine mount - metal shroud - possibly a large washer if needed because of oversized holes in the foot (probably already on top of the lower nut) - engine foot - another large washer - top nut, preferably a self locking nut.

 

Its unusual and I am not sure how it got fitted but one photo seems to show an inverted self locking nut under the foot. I doubt you need than and maybe not the thin nut below it but that depends upon the design of the mount. Unless anyone actually knows I would suggest its take the nuts off and see if the stud is still firmly in the mount. getting rid of the two nuts would drop the engine by about 25mm

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Without the bottom nut, the threaded pin will push through the rubber until it comes up against the engine bed, very noisy.

Just modify the engine brackets!

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21 minutes ago, Boater Sam said:

Without the bottom nut, the threaded pin will push through the rubber until it comes up against the engine bed, very noisy.

Just modify the engine brackets!

In that case leave the thin nut there but how an engine sitting on a metal shroud that is in turn sitting on top of a block of rubber can exert a downward force on the stud is beyond me. It woudl be true if you removed the thin lower nut and suspended the engine part way up the stud.

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33 minutes ago, Tony Brooks said:

In that case leave the thin nut there but how an engine sitting on a metal shroud that is in turn sitting on top of a block of rubber can exert a downward force on the stud is beyond me. It woudl be true if you removed the thin lower nut and suspended the engine part way up the stud.

I take your point Tony, I misinterpreted that, but it is not how these mounts were designed to be fitted, and of course then there is no way of adjusting the height of the engine.

There may be little or no sideways compliance in the mountings either.

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15 minutes ago, Boater Sam said:

I take your point Tony, I misinterpreted that, but it is not how these mounts were designed to be fitted, and of course then there is no way of adjusting the height of the engine.

There may be little or no sideways compliance in the mountings either.

Pleased I was not wrong and I agree that using them that way may be outside their design parameters but Big Col has a problem and getting shot of the nuts just might get him over it, at least until he has had time to recover. Actually I reckon an awful lot of engines installed without two point flexible couplings could do with reduced sideways compliance and fore-aft come to that.

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havent been in engine bay yet due to a new knee op but

everytime t get a visitor, I send then down there to take photo.

soninlaw went down again yesterday, freed of the drive shelf pulling the shaft more into the boat

the prop did look as tho it was too close to rudder.

 

ist thing took photos of all four of mountings, and all seam to have spacer nuts on

the mountings themselves are 5.5 mm high.

 

looking there are mountings that are only 41cm high

but was distinguishes one mounting to another.

engine is 425kg in total there seem to be so many?

if current mountings are 5.5mm height plus 25mm in spacers and nuts

and if the 4.1 mounting can be used that’s  4cm reduction in height!

just with new mountings.

The drive shaft has a water lubricated, it has Strong on it, is this the name as I can’t find this on google.

Re the engine just got to find out if this is workable. With help from yourselves.

 

im desperate to have a look my self, but the body says no

 

col

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A13D758C-FC9A-4096-9E9A-DD2B599DB8FC.jpeg

70821D4A-F8D5-4ECE-8EFF-E8E387E4B976.jpeg

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