It’s quite an en­gine, but...

Canal Boat - - Back Cabin: Experts - CHRIS WARD, via email

QWe are a char­ity restor­ing a boat which was fit­ted with a Ford-based Thorny­croft en­gine and BorgWarner Vel­vetdrive gear­box. Firstly, what are the two drain pipes (marked A and B in the first pic­ture) for? They come out into a union and are a very thin tube go­ing down in to drip tray. A comes out of the in­jec­tor pump and B from the side of cylin­der head.

Se­condly, in the side of the en­gine there’s a wooden plug (marked C) which goes into a hole with a dog in the bot­tom. If it were a petrol en­gine I would have said a dis­trib­u­tor drive. What is it?

We think this is a hy­draulic drive be­cause you can turn the out­let flange with­out the en­gine turn­ing. We know it needs an oil cooler and as­sume it goes to the two sock­ets (marked A and B in the se­cond pic­ture). Does this cooler nor­mally go in the ex­ter­nal wa­ter feed be­fore the en­gine oil cooler and en­gine heat ex­changer? Or are there air ra­di­a­tor cool­ers?

Fi­nally, does it mat­ter whether the prop ro­ta­tion is left or right as long as the gear lever is mounted the cor­rect way?

ATONY REPLIES: Re­gard­ing the en­gine: pipe A is a drain for the in­jec­tor pump cam box. This box should be filled with en­gine oil to lu­bri­cate the pump cams and roller fol­low­ers, but when the pump wears, fuel can leak down into the cam box. This causes ex­cess wear but shows it­self by weep­ing from that drain.

Pipe B seems to be the in­jec­tor leak-off pipe and should run back to the fuel tank. If you take the rocker cover off I think that you will see a thin pipe con­nect­ing all the in­jec­tors that links to this pipe.

I sus­pect the hole marked C used to house a me­chan­i­cal rev counter drive (in which case I would use an elec­tric rev counter driven from an al­ter­na­tor W ter­mi­nal in­stead), or it may have driven an ex­hauster, air com­pres­sor or hy­draulic pump. Make up a sim­ple plate and gas­ket to seal the hole.

Re­gard­ing the gear­box: this is a hy­draulic box, not a hy­draulic drive. It re­quires Dexron au­to­matic trans­mis­sion/power steer­ing fluid. I think the same oil goes into the re­duc­tion box.

If it is raw wa­ter cooled, the oil cooler wa­ter sup­ply is usu­ally fit­ted into the pipe be­tween the in­let strainer and the raw wa­ter pump. If this is a keel cooled dry ex­haust en­gine, the gear­box oil cooler is fit­ted into the re­turn from the keel-cooler so the heat ex­changer is fed by the coolest wa­ter pos­si­ble.

On the in­ter­net,­sets/ Vel­vetDriveIn­stal­la­tionMan­ual.pdf shows where the oil cooler con­nects to the gear­box. It seems that A is one of the con­nec­tions but B, the yel­low cap, looks more like the gear­box breather to me.

I would ad­vise against run­ning it in re­verse be­cause it is likely to cause ex­ces­sive wear. Try to get the cor­rect handed pro­pel­ler. Nor­mally the op­er­at­ing lever moves for­ward for ahead gear.

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