BMC 1.8 Fuel Filter Change

[Flocal]

Hi all,

 

Is there anywhere out there ( a bit like a haynes manual) that shows you how to change a fuel filter on a marinised 1.8?

 

When the engineer done it when i first bought the boat, he bled the injectors, turned taps on the injection pump and other stuff and im sure there must be a simpler way to change it, like a car filter!

 

Its been over 300 hours now and i would like to replace it.

 

Regards

 

Aaron

[alan_fincher]

On line scan of the handbook available on Calcutt boats site, here

 

I'm guessing probably many modern cars will self bleed air from the fuel system, just by turning the engine over, as some more modern boat engines are supposed to.

 

A BMC needs to be bled - see page 9 of that handbook.

 

With luck you can get away with just bleeding the filter, and will not need to bleed the high pressure side.

 

Unless you have doubts about your fuel quality, I'd not be concerned about going over 300 hours, TBH.

[Tony Brooks]

On line scan of the handbook available on Calcutt boats site, here

 

I'm guessing probably many modern cars will self bleed air from the fuel system, just by turning the engine over, as some more modern boat engines are supposed to.

 

A BMC needs to be bled - see page 9 of that handbook.

 

With luck you can get away with just bleeding the filter, and will not need to bleed the high pressure side.

 

Unless you have doubts about your fuel quality, I'd not be concerned about going over 300 hours, TBH.

 

 

Just to add that if the handbook tells you to bleed the injector pump from the bleed screw on top, beside the throttle lever, please do not unless all else fails. This one screws into the idle stabilisation valve on most 1.8 pumps and if you snap the screw or inadvertently alter the adjustment odd things happen.

 

It is far better for boaters to concentrate their efforts on the 8mm bleed screw that is on the side of the cylindrical section of the pump body. Triple PLEASE keep bleeding for at least 30 seconds after you think you have got all the air from this screw - you may well find there is another lot coming in from the pipes.

 

You may find a bleed screw on one of the adaptors that join the injector pipe to the pump body. Ignore this one. It is for bleeding the high pressure system and it is far easier for boaters to loosen the large injector unions. However simply changing the filter but taking adequate time to bleed the filter and pump usually allows the engine to start without messing with the high pressure side of things.

[Flocal]

Cheers for the advice guys.

 

I am not to over worried about the fuel, it does not smoke and still runs fine.

 

What would u say is a good time to change the filter?

[BEngo]

Cheers for the advice guys.

 

I am not to over worried about the fuel, it does not smoke and still runs fine.

 

What would u say is a good time to change the filter?

 

 

About 0800 on a weekday, before you have done any boating. The engine will not be hot and you have all day to gop and get/find/buy anything that has been forgotten, lost in the bilge, or dropped overboard.

 

N

[Richard T]

Why not go on one of Tony's excellent engine maintenance courses. They are money well spent, you get good tuition and a very useful handbook.

[Flocal]

Had a look at the Manual and it looks pretty straight forward......only bleeding that needs to be done is the two fuel filter points which are plain to see and eazy to get too.

 

Will have a go at this the weekend i think and let u know how i get on.

[Tony Brooks]

Had a look at the Manual and it looks pretty straight forward......only bleeding that needs to be done is the two fuel filter points which are plain to see and eazy to get too.

 

Will have a go at this the weekend i think and let u know how i get on.

 

 

TWO filter points!!!

 

This could prove interesting - still if the manual says it and you did not misunderstand then it must be correct then.

 

If one of these filters is between the tank and lift pump it may turn out to be very time consuming bleeding from that point - it may well be under suction and certainly not under lift pump pressure.

 

Perhaps I am just getting too old.

[aracer]

Reviving an old topic, but I presume there are still plenty of BMC engines around and people doing filter changes who might be reading this for reference. I was a bit scared of doing the fuel filter change from what I'd read, but it was all a lot more straightforward than I expected. I successfully bled the system without any difficulty (twice! I only found the new o rings in the bottom of the box after I'd bled it the first time ?). Two filter points as suggested above - that's two points on the one filter, I'm not sure if Tony misunderstood. Didn't need to touch anything on the pump. Didn't find a manual pump lever either and did it by cranking the engine (with the cutoff pulled out). Engine started first time afterwards, which I presume is a good sign (in any case it's now done about 10 hours running since and running as well as it ever has).

 

If it makes any difference mine is a Calcutt conversion on a 1988 boat.

Edited June 24, 2020 by aracer

[Tony Brooks]

Tony did not misunderstand but as you have not provided an image we have no idea if this is a water trap or engine fuel filter. The water trap may have two bleed points but the normal CAV engine filter often has dedicated bleed points on it so you use the leak back union. I wonder if this engine has been modified to a spin on fuel filter.

[aracer]

You wrote "If one of these filters is between the tank" - there is only one filter. It's a standard fuel filter exactly as described in the manual provided by Calcutt, with the 2 bleed points as on this pic from the manual 

[Tony Brooks]

37 minutes ago, aracer said:

You wrote "If one of these filters is between the tank" - there is only one filter. It's a standard fuel filter exactly as described in the manual provided by Calcutt, with the 2 bleed points as on this pic from the manual 

 

So as I said - no bleed screws. The one you normally use to bleed it - 2. That is the banjo bolt for the injector leak back and if I may say so if yours is like that without the ongoing connection to the tank you are asking for frequent air locking.

 

1 is simply a blanking plug that is not a bleed screw but some may decide to use it as such. The danger is that doing so may leave air in the top of the filter head.

`

You may only have that one filter but that does not mean all boats are like that, especially as best practice suggest a water trap between tank and engine lift pump. Now there are many different designs of those and some do indeed have two bleed screws on top but as you say yours does not have a water trap between tank and lift pump.

 

I would add that the plug 1 on the more modern designs is sealed by a taper that is part of the plug rather than a replaceable soft washer so using that to bleed from is probably more likely to induce fuel leaks.

Edited June 24, 2020 by Tony Brooks

[Tony Brooks]

Further to my last reply:

 

 

Here is a BMC 108 lift pump straight out of the ASAP website. I have marked the priming lever as A. If you do not have one then either its been broken off (unlikely) or, for some reason, your pump is a petrol pump because petrol engines do not need bleeding as such. Bleeding the system as you did is fine because it worked but if any air had got into the injection pump you could end up with a flat battery from prolonged cranking.

 

 

Here is a filter that is sometimes used as a water trap. I have marked the two bleed screws B. The CAV sedimentor or agglomerator either has no bleed screws or just one in the position your engine filter uses for the leak off banjo bolt. Unless gravity will cause the fuel to flow you can't bleed a water trap via the bleed screws. How easy it will be for gravity to cause the fuel to flow depends upon where the take off is in the tank and if the pipe drained down when the bowl was removed.