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Non return valve

Posted: 29 Mar 2023, 17:44
by nicktennear
I think I already know the answer to this but should there be a non return valve where this fuel filter is?Image

Re: Non return valve

Posted: 29 Mar 2023, 17:56
by shepster
There shouldn't be anything, goes straight into the carb on mine.

Re: Non return valve

Posted: 29 Mar 2023, 18:12
by nicktennear
Same as my last one, early DG. This is a DF but there's no reason to have a second filter there, maybe a previous owner went belt and braces because it has had a fairly recent new fuel tank and maybe this was a hang up from when it had the old and presumably manky tank.

Re: Non return valve

Posted: 29 Mar 2023, 21:04
by SurfT25
It's been mentioned before that having a filter in the engine bay is a fire hazard. :o

A VW trained mech I know says to have one there so if there's a prob with carb you can see if the fuel is getting through. :roll:

Which boat to jump on :wink:
I've removed my filter from the bay. 8)

Re: Non return valve

Posted: 29 Mar 2023, 21:46
by davidoft1
SurfT25 wrote: 29 Mar 2023, 21:04 It's been mentioned before that having a filter in the engine bay is a fire hazard. :o

A VW trained mech I know says to have one there so if there's a prob with carb you can see if the fuel is getting through. :roll:

Which boat to jump on :wink:
I've removed my filter from the bay. 8)

I’m quite happy with the filter in the engine bay, never seen one spontaneously combust :)

Re: Non return valve

Posted: 29 Mar 2023, 22:18
by Mocki
The mechanical pump cannot manage that filter there , there should not be any restriction in the return line , it’s dangerous , firstly by restricting the return from the float chamber , risking over flow , secondly a egg cup full of petrol in a plastic filter suspended above the HT leads and hot exhaust cannot be a clever idea .
One filter, down by the tank outlet is all that is needed , no belt, no braces, Mr Volkswagen didnt design it to have any other filter

You also do not need a non return valve in the return line , its there to allow return

Re: Non return valve

Posted: 30 Mar 2023, 11:29
by Robsey
My common-sense layman's brain says.
It doesn't need to be there.

Me personally -
I would simply run one length of fuel hose from the carburettor return stub to the plastic hose just the other side of that engine wall.

Better to keep things simple as VW originally intended.
Less opportunities for leaks. And it also removes another piece of clutter from an already over-fussy engine bay.

---------------

Check same for the other side - inlet side.

Fuel tank, with filter nearby.
To fuel pump (electric upgrade or original mechanical) and to carb.

Fuel hoses in the engine bay should be reasonably direct to minimise running or starting issues from heat-soak etc.
Fewer joins = less points of weakness for leaks.
Fewer things to go wrong.
And also to minimise engine bay clutter.

Re: Non return valve

Posted: 30 Mar 2023, 21:51
by nicktennear
It is an early DF with a Solex carb, looking online I found the attached, looks similar. Image

A look on Brickwerks offers this https://brickwerks.co.uk/product/fuel-l ... -dg-return

I think I'm getting rid of the filter either way and will give the non return valve a go.

Re: Non return valve

Posted: 30 Mar 2023, 21:58
by Mocki
That picture is not a DF, it’s a DG.

Re: Non return valve

Posted: 31 Mar 2023, 06:48
by nicktennear
Mocki wrote: 30 Mar 2023, 21:58 That picture is not a DF, it’s a DG.

That's the thing, most info is for DG and some have the valve, others don't. Brickwerks only list it for DG but the DF does sometimes get forgotten, like that cousin who everyone forgot about until they turned up at a family wedding.

I wouldn't have bothered but I've spent so much time in the engine bay and all the while I've been thinking, must look into that.

Re: Non return valve

Posted: 31 Mar 2023, 07:42
by Robsey
I noticed this too, in my travels to do-up our van.
The DF is a little known set-up confined to the world of voodoo or mythology.

Ours was a DF before it blew it's valve seats twice.
Info is scarce, same as for the EY, GW and DH.
(engine codes many will not have heard of).

Because of this and a desire for improved efficiency and speed, I have looked towards fitting a DJ instead.

Sadly I have no before photos of the DF, as it had blown it's head twice and had been left partially dismantled from winter 1999, before I took it on as a project many years later.

But here is the very sorry looking engine bay on the second day of it in my tenure in May2012 - the fuel line is there, but it is a direct run from the carb to the bulk-head.
No valve, and no filter.

Image

I suppose - If the van is working fine, and you are not having any running, stop, starting, and cooling issues, then the phrase of choice is - 'don't fix what isn't broke'.

Obviously fix anything that looks dodgy or faulty, but otherwise - leave it alone until it needs servicing or fixing.
It is far too easy to look too deep into these things, and we create problems that aren't really a problem.

I looked too deep into mine, and that is why I am still rebuilding it 11 years later, with no end in sight.

Re: Non return valve

Posted: 31 Mar 2023, 08:52
by slowcoach
I used to have a DH engine, 1.9 digijet.

Was it you who I sent a video of it running, for reference? Dunno if that's useful to you or not

Re: Non return valve

Posted: 31 Mar 2023, 10:17
by Robsey
Yes it was me, so that I could use the early cooling set-up on the later DJ engine.
It was very useful, thank you.

I was eventually able to source a cross-engine coolant pipe, that I can modify to fulfil the cooling system conversion.

Image

Hopefully have a running engine later this year.
Just awaiting finances to get a bunch of early exhaust pipework.

Re: Non return valve

Posted: 31 Mar 2023, 12:18
by Mocki
Image
This is DF

Re: Non return valve

Posted: 31 Mar 2023, 17:20
by nicktennear
Thanks all. I've taken the filter out and replaced it with a single run of hose and glad I did because the run from the new tank was new but the bit that the filter was on was definitely reused. I shall probably get 40mpg now that's out and that quarter mile at Santa Pod should be a doddle.