Diesel fuel return

[PaulJ]

I am still at the "head scratching" stage of my installation and wondering how to route the excess fuel return. If I take it to the tank I will have to drill yet another hole in the tank to fit the fitting which is not a big problem but the simplest and neatest thing to do would be to install a T-piece in the supply from the tank to the engine and feed the surplus straight into the supply. This seems so neat and simple, there must be a good reason why it isn't normally done - can anyone please explain why not?

 

[andy_wilson]

Part used stuff will be hot, and possibly foamy. Best practice is therefore to tank to dissipate this.

T-ing into supply line before primary filter might be worth an experiment if a small capacity installation is being considered.

 

[alanporter]

Paul. When I replaced my diesel engine four years ago I led the fuel return to a T-fitting at the air vent hole. It has worked perfectly, the return is only a dribble and it doesn't interfere with the air intake.

Alan Porter

 

[Guest]

It is always best practice to send your return feed directly to the tank. There are several reasons for this but mainly, as mentioned in previous strings, the returning fuel hot, frothy and possibly contaminated. Hot fuel oil is thinner and provides less power than fuel at ambient temperature. The reason that you have excess fuel oil is that it is used as a coolant and lubricant for the entire injection system, hence the possibility of returning fuel containig abrasive particles which should be returned to the tank and then through all those fuel filters you have installed.

 

[PaulJ]

Gentlemen thanks for your replies, that makes several good reasons so it looks as though I will have to drill another hole in the tank or I may be able to Tee into the fill pipe. Thank you again.

 

[AndyL]

Good points

Now I will have to reroute mine! I've not noticed any problem with it so far but you have convinced me it is not good practice to put the return directly back into the feed.

 

[kingfisher]

Guide it to fill hose

Mine is rerouted to the fill hose (connection between filler cap in cockpit and tank).

Group of people on the pontoon: skipper is the one with the toolbox.
http://sirocco31.tripod.com

 

[Strathglass]

Re: Guide it to fill hose

Mine goes to one of the return ports on the CAV fuel filter.
It is a Ford 1.8D and I only use it at 2600rpm, with a 3600rpm max.
Iain