How long to bleed?

TiggerToo

TiggerToo

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How long does it take you to bleed the air out of the system when you have changed the diesel filters?

It takes me ages : about 3/4 HR, on a vp2030 with two filters (and water separator). Is there a clever trick to do it faster?
 
TiggerToo said:
How long does it take you to bleed the air out of the system when you have changed the diesel filters?

It takes me ages : about 3/4 HR, on a vp2030 with two filters (and water separator). Is there a clever trick to do it faster?
Click to expand...

Fit a squeezy bulb, easy peasy!
Stu
 
A lot depends on where the camshaft stops. The engine's lift pump is operated by a cam. If the engine stops with the cam partly operating the lift pump, then when you press the little lever there'll be very little fuel pumped. You should be able to feel the amount of effective movement on the lever. If there isn't much, simply rotate the crankshaft a little until the lever operates more effectively.
 
TiggerToo said:
How long does it take you to bleed the air out of the system when you have changed the diesel filters?
Click to expand...

Ten seconds or so?

My engine's fuel system, if fuel is pushed into it, will let it flow all the way through the low-pressure side and back down the return line. I don't know if this is normal but suspect it probably is. I have an outboard-style squeeze bulb between my tank and the first filter, which can push fuel right round the system.

After changing the filters, I squeeze the bulb and watch the clear bowl fill up, then keep squeezing until I hear the displaced air bubble through the fuel in the tank, then a bit more for luck. I don't even need to use the bleed screws on the filter housings, though I used to until I figured this out. In the early days with our previous boat I used to pre-fill the filters before installing them, which was fiddly and messy. Putting them on dry and then filling them in-situ with the pump is so much easier!

I believe this engine's high-pressure side is self-bleeding, certainly I've never needed to crack off an injector union despite cutting out due to fuel starvation several times, and repeatedly having everything in bits (all before I fixed and replaced it all).

Pete
 
On my VP2020 the priming pump was a button on the fine filter mounting. You undid the bleed screw on the mount and pumped the button until you had filled up both filters and it started gurgling out. 3 or 4 minutes maybe. No sweat. The high pressure side was then self bleeding.
On the VP2002 I had previously you had to use the lever on the pump. That took longer but not 45 mins! You did have to check that it was pumping properly i..e. clear of the camshaft.
If it was on the cam you would pump for ever and achieve nothing!
 
If you are using the lever on the fuel pump, make sure you push it all the way. You can spend ages wriggling the lever back and forth, but unless you move it past the free play against the spring pressure, it is doing nothing. I am not the only one I know who has done this.
 
I just start it. It starts. Every time. I think it very briefly sputtered once. MD22 (Perkins Prima).

Only time I had to prime it was when I changed all the fuel lines and filter assembly, in which case I used a 12V oil extractor pump, which did the job in seconds.
 
Yngmar said:
I just start it. It starts. Every time. I think it very briefly sputtered once. MD22 (Perkins Prima).

Only time I had to prime it was when I changed all the fuel lines and filter assembly, in which case I used a 12V oil extractor pump, which did the job in seconds.
Click to expand...
Our superb engines use a different type of pump, the Bosch VE, it has a vane pump inside it which almost could act as a lift pump. This is what makes it almost self bleeding.
Stu
 
Unless you're presurizing the fuel into the system, everything depends on the relative positions of the components. On my installation, the filter bleed screw is roughly level with the half full tank and the fuel take off from the tank is near the base of the tank. So long as the tank is more than half full, undoing the bleed screw allows the system to fill in less than a minute. of course it is possible to have a few air bubbles hanging around, so running the engine at fast tickover for a couple of minutes is wise to suck them all through.

Rob.
 
If your motor has the same lift pump as the VP2003: The non-return valve collet falls out of its seat, the plastic valve drops into the wrong part of the pump body then the collet partially reseats itself. It is then a mare to bleed, but takes 5 mins to fix if you strip the lift pump.

As mentioned above:
- The pump lever should have a light portion of motion, then a firmer phase. If not, rotate the crankshaft 90 degrees and try again.
- A squeezy bulb pump or a posh electric lift pump will undoubtedly solve your problem.

All this assumes that you are opening the correct vent (machine screw on top of fuel filter) then, if required, cracking the feed, not return, pipes' gland nuts.

Some Volvo engines have decompressors which allow only one cylinder to be compressed. In which case just bleeding that one injector may work with reduced risk of messing up the threads on the other injectors.

Each stroke of the lift pump will be moving something like 10 cc of diesel. If you are replacing high volume filters fill them with diesel before you fit them.

Completely remove the bleed screw from the filter as that will reduce the back pressure, just don't drop it into the bilges .
 
If no squeezy bulb, fill the CAV filter with a syringe through the bleed screw hole.
Some engines you can half fill the fine filter bowl before slowly assembling it and reduce the amount of bleeding.
 
TiggerToo said:
How long does it take you to bleed the air out of the system when you have changed the diesel filters?

It takes me ages : about 3/4 HR, on a vp2030 with two filters (and water separator). Is there a clever trick to do it faster?
Click to expand...
There is indeed, I fitted a priming bulb, like those used on outboard remote tanks but suitable for diesel, just befor the filters. Change filter, open bleed and pump, 2 minutes later your done.
 
I blow through with my fuel polishing rig. Takes a few minutes if that, and at the same time blows back any muck in the pick up line back into the tank.
 
About 0 seconds. Just start the engine. Very occasionally it might splutter to a stop, in which case I top up the secondary filter and start it again. I make sure I run it for about 15 to 20 mins after the primary filter change before putting myself in a position where it stopping could be an issue, but that's just being extra cautious.

Yanmar seemed to have figured out self-bleeding engines at least 25 years ago.
 
I had a bleeding issue on a 2040 last year. Under pressure ( 3000 revs to beat the current at Cherbourg!) she just lost revs but didnt cut out. With a bit of coaxing came back to 2000 revs and got us in. I thought i might have diesel bug so i took a look at the fuel filter-perfect. No matter what I did I couldn't bleed. Tried turning the engine to adjust cam still no go. I had a mechanic take a look. He used a large cylinder pump to try to bleed. He initially had issues and didn't like the flow. He removed the water seperator bowl and examined the rubber seal. Showed me a little mark on the seal and told me that this was the issue. He said that this is a common problem. He was able to bleed without an issue once he re seated the bowl. I think there is a v shape on one side of the seal and this has to be in the correct orientation but I can remember which way. So check that the seperator bowl seal is correctly seated and in good condition. Check all connections in case you are drawing in some air.

I like the idea of the in line Sqeezy pump in line ! I'm going to try this.

Good luck with it!

Kinsale 373
 
Although I have no problems, I often have considered a service tank above the engine fed by an electric pump, float/auto switch or constant feed and drain back arrangement. It would have several hours capacity, but would need some sort of low level alarm and manual fill backup. Lots of advantages in terms of sediment draining and fuel polishing, particularly if constant feed and return. Also options for filling from an emergency can if any main tank problems.
My Ford 6 cyl might collapse an inline squeezy bulb. I have to bleed with the engine lift pump, couple of minutes, although the engine would do it at some cost of hot starter motor maybe.
 
TiggerToo said:
How long does it take you to bleed the air out of the system when you have changed the diesel filters?

It takes me ages : about 3/4 HR, on a vp2030 with two filters (and water separator). Is there a clever trick to do it faster?
Click to expand...

The time obviously varies considerably by engine type. After filter changes I mostly get away with no bleeding, just start up. Always starts but if it does stop before all the air is automatically bled out, then the amount of air remaining is small and just a few strokes on the lift pump with the bleed screw on the secondary filter slackened does the job.

Www.solocoastalsailing.co.uk
 
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