Front mounted pump 6BTA?

[Stephen Oliver]

Hi Guys

Has anyone produced a timing gear cover with PTO mount that can be used for mounting the pump on? My boat on the port engine is a pig.. very serious pig to change. To do easily the aftercooler and HX have to come off (HX so i can stand and bend over the engine) everything is done pretty much one handed and can take anything from 4-6 hours. SB engine is 15 minutes.. kinda says it all really! If the pump was front mounted it would still be a bit of a challenge.. but far less of one than currently..

Thanks

Steve

Topic

[Dan]

welded mounts

<b><i>i guess this can be flipped from side to side,</i></b>

They can, I set mine up on the outside of each engine.

<b><i>I wonder if the gear could be pulled of the standard  pump and replaced with a toothed pulley</i></b>

It would be difficult to mount and set up the sliding belt adjuster,Marks drawing is simple to follow and already proven, the Jabsco pump used is bulletproof and way cheaper than a Sherwood, it’s overkill for the application.

If your committed to direct driving off the crankshaft at a 1 to 1 ratio (assuming the pump is capable of turning to your engines WOT) you may have options in Perth

Hamilton engineering in Henderson have been fabricating pump mounts up for years for the crayboats to drive hydraulic pumps @ 1 to 1 off the front of the engine.

They may already have what you need for a Cummins, the couplers they use are splined, simple to align and are very reliable, the Jabsco we used would be the perfect pump to mount on their existing mounts.

The Jabsco can be ordered with three different outputs (different cams) the specs are on the web sight, you may get lucky..

The half cam version pumps 62GPM @ 1750 RPM’s @ 1 to 1, mine and Marks are using the half cam version with reduction  =  50GPM @ 3000 RPM’s.

The pump we used is a Jabsco 6400-1051

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[Mark Tripi]

Steve, when I first started down this road I was thinking of driving it direct using a spider or “Lovejoy” coupling. To make it work you need to be spot on in your alignment. The belt drive while needing a good alignment is at least forgiving some in that aspect. My bracket is sandwiched between the block and mount. My friend Dan, also a member here, had welded up steel plate mounts so he just welded on an extension to his mount bracket and bolted the leg of the pump bracket to that. My brackets were cast so I went with the sandwich mount. Maybe Dan will step in with his view.

 

 

[Stephen Oliver]

Thanks Mark

I’m contemplating making something using the standard 6bt pump or equivalent (SMX, DJP etc) , so the maths required is less haha.. its flange mount which is easily replicated and i seem to recall it makes to difference which way it spins.. so by removing the gear of the 1730 (or equivalent) replacing with pulley i’d be essentially doing the same thing but without using a stock pump.. (which on the 4bt seems a bigger headache than the sherwood 1730)

If the stock pump crank to pump ratio is 1:1, then I would also suggest a decent flexible coupling could be used to drive direct from the damper? However I’m not too familiar with these types of things.. so dont know if it would effect the crank significantly. By the looks of it making a bracket wouldnt be too hard and could be mounted either side of the block to get a centrally mounted pump? I do like the belt drive idea though.. What are your thoughts?

Steve

[Mark Tripi]

Steve, the damper drive has a 40 tooth sprocket (P40-5MGT-25) and the Jabsco pump has a 52 tooth sprocket (P52-5MGT-25) on it. That under drives the raw water pump, the ratio is roughly 1.3-1. That was done to keep the water flow as close as possible to the Sherwwod pumps on my 4 BTAs. This is easily adjusted by the size of the sprocket on the raw water pump. You need about 15 inches in front to make it fit.

[Stephen Oliver]

hmmm from what I can see the PTO is 1:1 to crank… so if I used the standard type pump i could essentially run it 1:1 belt ratio with all standard items and it should run the same.. give or take.. can anyone confirm this gear ratio? I’m assuming a direct drive with a soft coupling would be out of the question?

Steve

[Stephen Oliver]

Thanks Guys

I knew I had seen something somewhere regarding this. Not sure I have the skills or time to fab such a kit though 🙁

I’m also not 100% sure i’d have the space where this is located in front of the engine as the strainers are there.. but i guess this can be flipped from side to side..

Is the 4bt the same as the 6bt at this end of the block? I’d guess fron Tonys drawings in that thread that they are.. now I wonder if the gear could be pulled of the standard  pump and replaced with a toothed pulley? Anyone happen to know the pump ratio as standard? (i assume 6bt may be different?) I really only need to do this to the port engine.. and its worth hours of time saving… from the time I have to spend changing impellers. I’ve done the SB side at sea after an impeller split.. the Port – no chance.. not even if i was 5 stone and 4ft.. 

Thanks for some inspiration

Steve

[Clark Leighs]

Thank you. 

 You clearly have some fabrication and machining skills and good thinking.

I will bookmark this  for anyone else so I can offer your photos to them.   It will still be up to them to sort it all out.  

I’ll bookmark the entire thread.  

 

 

 

 

 

[Mark Tripi]

Sure thing Clark. In no particular order. Glad to answer any questions you have.

[Clark Leighs]

Mark Tripi,  

Would you post a few photos so we can see what you did.

And of course for the original poster.

[Mark Tripi]

Do this https://www.sbmar.com/community/topic/project-finished/

https://www.sbmar.com/community/topic/project-finished/ I vowed never to buy another Sherwood for my 4BTAs in 2019 and designed this system using a jabsco pump with a half thickness cam driven by belt off the front of the crank. Never a problem.

[Tony Athens]

Dream on would be the appropriate answer  here..

[Author]

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