VP37 tear down after years and thousands of miles on bio

[julesandtash]

Here is a copy of a thread I just started on VOD - cross posted here for those of you who no longer frequent VOD

Following on from my previous thread about changing the pump on the RangeRover due to fuel actuator position sensor faults, I decided to take the pump to pieces before scrapping it.
I was interested to see what it was like inside after a long period on bio.
I have run this vehicle for nearly two and a half years on bio, Carl (Orange Vito) ran if for at least as long as that before me.
It had 171K miles on it when dismantled, probably over 60K of them on bio between Carl and I

Here are the photos of dissasembly. Not a pretty sight in places. I am surprised it was working as well as it was. Other than spurious fuel position sensor error codes, there were no other running problems (no rough running, loss of performance, poor starting or emissions problems). Maybe that is testament to how tough these pumps are.

The electronics assembly, under the main lid of the pump. Looking pretty dirty in here and no real surprises that the feedback variable transformer (right hand side of the photo) was giving error codes at times).


Looking down into the pump with the electronics removed - some dirt in places but lots of shiny metal as well.


A closer view into the bowels of the pump


Timing piston bore and cover removed


Hydraulic head, rotor and springs


the same part, viewed from above


The cam plate and rollers, surprisingly little visible wear and little contamination either


The inside of the pump body


and a different view


It was getting a bit late when I took these so I didn't try to clean the discolouration off. I'm not sure it it just a varnish coating or something deeper.

[Head Womble]

That looks a hell of a lot cleaner inside than mine did.

[Julian]

Interesting stuff, Jules.

The brown drop out seems similar to what Tony has previously described as dropping out in cubies, and I'm starting to see on the webs of my bulk storage tank and what most see when a filter is changed.

I've always assumed it's residual glycerin, but I'm surprised to still be seeing it in the storage tank despite acid/water washing.

Is the brown gunge the only adverse effect you could attribute to bio?

[julesandtash]

It is indeed.
There was no noticeable wear, pitting or anything else, just the prevailing brown gunge.

It looks like it is just a light coating, nothing more sinister as as quick wipe around with a paper towel soaked in IPA yielded this....


I wonder what the pros and cons of running the engine on IPA every few years for a few minutes are.
I suspect a diesel would run OK on it and it would certainly clean out any veg related muck. OK I know it has no lubricating properties but a few minutes at idle should be OK

[julianf]

It would be interesting (and something i keep meaning to try) to centrifuge some well settled fuel (ie fuel that you would normally put in the car) and see if any residue could be extracted.

[julesandtash]

That would be interesting.
I dont know how much of this if from Carl's bio, how much from my earlier bio and how much from my later, acid washed, bio. Ultimately I will never know but it would be interested to run some tests on bio finished in various ways and see what happens in the centrifuge
The stuff in my pump does not seem to be soluble in water (suggesting it is not soap) but is soluble in IPA

[Tony]

The Largo VP37 opened from running on diesel for the 40k miles it has had in its life wasn't that much cleaner (it also had a brown layer, quite light in colour - from dino), and that also became shiny with an IPA rinse. I've stripped the Delica's old VE pump and that wasn't anywhere near that bad on bio either (though it hadn't done as many miles as Jules' admittedly- only about three years worth) but that too had a brown layer that was easily removed.

TBH I very much doubt that unless it was blocking the actuator movement that the brown layer could interfere with the VP37 quantity adjuster feedback mechanism (how could it unless it ate the enamel from the signal/sense coils?).  On the VP37 this quantity adjuster mechanism does seem to age badly from mechanical wear even on just diesel.

The brown fallout from bio I am certain is light soaps/glycerol.  If I take bio that needs more settling and bounce it around in a drum in the boot (where it also gets nice and hot) then I get lots of fallout of a red/brown nature.  Well settled bio produces just a little of the same, but slightly thinner and redder.  I suspect those that very thoroughly water wash are unlikely to see a similar thing (though water washers do report goo in the bottom of fuel filters - but perhaps they're not washing quite as well as they should).