Bleeding a diesel

[chuzzlewit]

There isn't much pressure in my diesel fuel line as the fuel tank is about the same level as the primary fuel filter. Bleeding the system in an emergency would be easier with a manual diesel pump plumbed in before the fuel reaches the first filter.
Does this seem a good idea and does anyone know where I could buy such a pump?

 

[sailorman]

CAV make one i have one fitted as the fuel tank fuel feed relies on suction as tank lower than the engine

 

[Col]

Peugeot fit a priming bulb to their diesels.
See top of photo, inline above filter

 

[pappaecho]

There are usually two pumps in a diesel engine the lift pump and the high pressure injector pump,
The lift pump takes fuel from the tank and delivers to the injector pump, usually via various filters. Some diesel lift pumps have a membrane which is driven by a lever which is engine driven and which also can be hand pumped, which makes bleeding the system a doddle. If you get air in the system, you can also use the starter motor to crank the system and so expel the air from the low pressure side ( lift pump and filters etc). The best way is to crack the connection to the high pressure injector pump, and ensure that when cranked, clean air free diesel comes out. Be aware that the high pressure pumps rely on diesel to lubricate them, so do not crank for any length of time - in neccesary reconnect and refill the injector pump to prevent this.
Once the low pressure side is purged, most systems will self purge the high pressure side on their own

 

[tritonofnor]

If you go to your local breakers and ask them for a filter assembly for an 84-89 fiesta diesel, then you'll not only get more filtration (it takes a standard, and cheap, CAV296 type), but you'll also get a primer button on the filter housing. Easier to operate than an out of the way lever, just a button to be pushed repeatedly. Simple flat flange, with two bolt or screw fixing to mount to a bulkhead. Bought one very nearly new this morning for a job I'm doing - cost £10.

 

[Oldhand]

Racor do a primary filter with a built in hand pump, had one on our last boat. I think ASAP are a Racor supplier.

 

[TJAGAIN]

just thinking of fitting a twin filter system so you can change over from one to another via a lever type tap(s) they seem to be very expensive though.

 

[metalmike]

[ QUOTE ]
If you go to your local breakers and ask them for a filter assembly for an 84-89 fiesta diesel, then you'll not only get more filtration (it takes a standard, and cheap, CAV296 type), but you'll also get a primer button on the filter housing. Easier to operate than an out of the way lever, just a button to be pushed repeatedly. Simple flat flange, with two bolt or screw fixing to mount to a bulkhead. Bought one very nearly new this morning for a job I'm doing - cost £10.

[/ QUOTE ]

They're good but also a very known problem area, ie they draw air when they get on a bit (like a scrappys), fit one by all means but get a new one.
Mike

 

[pampas]

Please be advised that electic pumps come in two configurations . 1-pressure feed. 2- suction feed. this means that 1 is where it is a gravity feed 2 is where the pump has to suck from lower than the engine, I have fitted No1 as my tank is simular to yours and I purchased it from LKUS (Old Lucas) then fitted the tank lower the engine forgot to change pump and have found little difference the price was around£45 if my memory is correct. The pump is fitted AFTER the main filter thus saving stripping the pump to clean its filter.

 

[Talbot]

My racor filter has its own manual pump as I have to lift the fuel out of the tank to the racor primary filter. Before fitting the racor, I had plumbed in a standard outboard squeezy fuel bulb, but it never worked 100% right.

 

[upthesolent]

My first season of having a diesel engine was dogged with problems, not least the massive amount of sludge caused by the diesel bug which actually came free with the purchase of my boat!

Prior to the tank and all the lines being totally cleaned out, I was having to bleed the system very often and it was a pig to do and I could spend a good hour or two just trying to get the air out. Also, (so I found out) one of the most important things about bleeding was that if you are using the manual lift pump sited on the engine, it is virtually useless if it is not "on cam". i.e. you have to turn the engine a bit so that the cam in the pump is engaged. There is (on my engine anyway) no visual confirmation of whether it is or isn't on cam so it is trial and error.

Secondly, the main water/fuel filter on the engine has a return for unused diesel which on my boat went back directly to the primary, in-line water/fuel filter. The engineer told me this wasn't the best system and it really should be fed back to the fuel tank. I had this work carried out. The result? My fuel system is truly self bleeding.

Apologies if you know this already.

 

[jcmmarine]

When I change a fuel filter I top it back up with diesel using a small syringe and this seems to negate any bleeding problems.

 

[TheBoatman]

Delphi (CAV) Diesel Systems make a filter with a pump on top. I can only find a very bad piccy on their web site.

If you look it's right in the middle - has black priming knob on the top.

http://www.delphidieselsystems.com/dieselglobal/eng/GDDSproductitems6651.asp

Peter.

 

[spannerman]

Its not recommended to crank the engine if its not going to start unless you turn off the seawater cock, there is a very real risk of flooding the exhaust with seawater which because there is no exhaust pressure doesn't get blown out. It can easily run back or be sucked into the exhaust manifold and cylinders, with expensive results!.
But remember to open it again when you are finished with bleeding the system.

 

[Marmalade]

yep - I've got the Racor (R15 I think) primary filter with built in priming pump - dead useful

 

[chuzzlewit]

Thanks everybody: back to ASAP for a filter with a pump.

 

[DaveS]

That's interesting. I was going to buy a new primary filter with a built in priming pump but, partly due to some of the discussions on this forum, I fitted a squeezy bulb between tank and primary filter instead and it's worked fine. My main worry was that it looked a bit amateurish, but in that regard I found the picture on this thread of the production car with exactly this set up quite reassuring. (This is of course all psychology rather than engineering!) What problems did you have with your squeezy bulb?

 

[Talbot]

my set up has the tank well below the level of the engine. The lift pump on the engine would collapse the lift bulb and hinder the fuel flow

 

[DaveS]

Ah, I hadn't thought of that! The top of my tank is only 50mm or so below the filter, and I normally keep that pretty full, so there's probably normally not enough suction to give me a problem. I'll keep an eye on it, however, if I find myself running with a low tank level. Thanks!

 

[Talbot]

if you ever get a clogged filter, it could become a real problem!