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Disco Fever


mat_the_cat

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Update on the green Discovery, which we still have. I was considering a swap with it, but after taking a look I found that storing it under a cover for 2 months had not been kind. The waterproof and breathable cover seemed to have turned into the exact opposite, and let the rain (we've had a lot...) in but trapped it from ever drying out!

Looking under the bonnet revealed a crusty mess :-(

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Battery was completely dead despite being on float charge, and sticking a new battery on produced smoke from the alternator. I did wonder whether corrosion has created a partial short inside, which has then flattened the battery and killed that too. Stripping it down shows nothing evident so far, but a fair bit of wear to the commutator. So I'll probably replace the whole thing given it's original.

Then I've got to sort out a leak from the gearbox oil cooler, and investigate why the brake pedal goes straight to the floor. I'm guessing master cylinder, but have a feeling this will lead to a full on brake overhaul...

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That's frustrating :( I really dislike that furry kind of corrosion, just something about it. It doesn't help you now (power of hindsight) but I have heard a few people mention ACF-50 as a good product to prevent corrosion but I imagine you had the impression that the cover would be beneficial rather counter productive.

It definitely reinforces my intention of never using a cover on Cedric, I know how it holds up in the unit without a cover and don't want to take the risk of having a similar situation.

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It certainly *used* to be waterproof, and seemed to be reasonably breathable too - certainly I hadn't suffered condensation under it previously. I remember one night we had heavy rain followed by a clear sky, and everything got covered by a sheet of ice, so I wonder whether that wrecked the structure of the fabric?

Hopefully it still starts anyway, so once the alternator and battery are sorted I'll move it down to the house and try to pressure wash off the corrosion. Then let it get good and hot to dry out before giving everything a spray with oil.

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New battery and alternator on, and no smoke! 

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The 120 amp unit from the P38 is a straight swap for the original 100 amp, and at no extra cost seemed like a good idea. The heater screen alone draws in the region of 50 amps IIRC, and there's the seats as well, plus the winch when required.

Will it start...?

Bit of an anti-climax really! Looks like the oil had drained from the pump a little, but pretty happy with that :-) Cold idle is slightly high so I might have an air leak. 

But (especially given the mileage) this is a really sweet sounding engine. Once I've sorted the gearbox oil cooler I'll take it for a drive into the forest and get it properly warm before an oil change.

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The gearbox oil cooler on the blue one I replaced not long before the rollover, so I removed that today. It's still got an oil/water heat exchanger built into the radiator, so I think the one in front of the radiator is likely overkill unless you're towing. So I have just replaced it with a length of hose - I believe the pressure is fairly low so jubilee clips should suffice.

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It had started to show some light rusting after 10 years, so I dipped it in Deox C, and gave it a coat of paint to extend the life.

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The old one has pinholed through with rust between the 'bog brush' and ends of the tube. It may be weldeable if the rest of the metal isn't too thin, so not binning it just yet.  

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  • 2 weeks later...

I was going to just bolt the replacement cooler in place, but then I noticed the slam panel support struts were looking a bit crusty. I popped them off to give them a clean up and paint, but I could see they were paper thin.

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Fortunately readily available new, so I ordered a pair.

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But before I could fit them, I needed to do an oil change. Why, you might ask?

Simple reason being I wanted to protect the inside from corrosion, and immersing them in hot oil seemed an easy and cheap way of doing so!

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I drained the oil and changed the filter, making sure I followed the warning sticker!

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Then once the support struts had marinated for an hour or so, I fitted them with new stainless fasteners, and the replacement cooler.

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I was pleased to see the engine still looks clean inside, a testament to regular oil changes and running on LPG its whole life.

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1 hour ago, mat_the_cat said:

running on LPG its whole life.

This will be a lot of it.  Someone I knew many years ago used to run a 1988 RRC 3.5 EFi which had been LPG converted with a very nice liquid phase injection system.  This meant that he had the opportunity to increase the compression ratio, as not only was there the benefit of 108 octane LPG, but also the cooling effect of the vaporisation occurring in the induction and compression strokes meant that he avoided pre-ignition.  It ran about 11.5:1, which meant you couldn't run full power on petrol, but it ran beautifully (and more efficiently) on LPG.

The oil came out so clean that it ended up being used for general lubrication in all sorts of other applications, and was the main engine oil in most of his mowers/other single-cylinder engines.  Without having them side-by-side, it was hard to tell which was clean and which was dirty oil.

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12 hours ago, Talbot said:

This will be a lot of it.  Someone I knew many years ago used to run a 1988 RRC 3.5 EFi which had been LPG converted with a very nice liquid phase injection system.  This meant that he had the opportunity to increase the compression ratio, as not only was there the benefit of 108 octane LPG, but also the cooling effect of the vaporisation occurring in the induction and compression strokes meant that he avoided pre-ignition.  It ran about 11.5:1, which meant you couldn't run full power on petrol, but it ran beautifully (and more efficiently) on LPG.

The oil came out so clean that it ended up being used for general lubrication in all sorts of other applications, and was the main engine oil in most of his mowers/other single-cylinder engines.  Without having them side-by-side, it was hard to tell which was clean and which was dirty oil.

That's impressive, I didn't know LPG had this (passive? ish?) cleaning property.

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The liquid injection system sounds a very I interesting idea. It's something I wondered about years ago, but when I googled it the information suggested that getting injectors with sufficient precision was the difficulty. Evidently it is possible though! 

Onto the braking system now. The pedal goes straight to the floor, so I'm suspecting that the master cylinder has failed. Ideally I'd like to prove this, but I leant out my collection of bleed screws to a mate pre-lockdown, so can't blank off the outlets to check.

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It's slightly more cramped than standard, with the LPG ECU, which isolator and control box all in the way. But an easy job to bung on a new one.

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 Unfortunately I've only got half a bottle of brake fluid, so not enough to bleed the system. Insufficient fluid might be the least of my worries, however...

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What do you reckon the chances are that the bleed screw will come out intact? :-( On all four corners!

The pad springs have completely crumbled away, although only changed 10k miles (albeit 9 years) ago. New fitting kits on the way, and hopefully the pistons won't have seized. My experience is that opposed piston calipers tolerate inactivity more than the single piston sliding type. So fingers crossed I don't need a caliper rebuild too.

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The front calipers looked in a similar state, so I was dreading cfacking open the bleed screws.

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Unbelievably, both loosened with a bit of careful force! So I've removed the pads, and cleaned/lubricated everything.

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The front pads are EBC Greenstuff, which (when working) improved the stopping ability noticeably. One side done, and bled through, but I'm getting slightly concerned that the pedal still goes straight to the floor. I'd expect it to get a little firmer at least :-(

Sadly, my luck ran out on the other side - the front bleed screw has sheared off, and the rear has been ground into a triangular shape so I've little hope for that. I'm really surprised that the garage used (it's always been garage serviced) didn't replace it when loosening it in that way!

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  • 3 weeks later...

I bought a set of Irwin nut removers, and to my surprise they gripped on the worst bleed screw!

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That's now replaced, and brakes all bled through. The pedal is still a bit spongy though, so I reckon I've still got air in the system. They're working well enough to get the ABS kicking in on gravel though, so a definite improvement! 

 I gave the engine a clean while I had it warmed up, and it looks a hell of a lot more looked after than the photo at the top of this page!

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Think I have an air leak somewhere, as the idle speed is too high. Added to that, the AC has stopped working, and some of the lines on the heater windscreen have failed. Plenty to keep me busy...

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Good to see some progression. If my discovery 1 was at home I’d be flat out with the welder. Again. But that’s typical discovery 1. Rusty everything. When I replaced my rear axle (twice) I took the rear calipers off and swung them up out the way.... as removing the pipe and bleed nipples would have opened that cab of worms again lol

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  • 7 months later...

Zinga trial on the blue Discovery still ongoing - this is 5 years later:

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No bubbling up underneath, and even in the previously rusty gutter seam nothing is coming though. The brown bits are larch needles, apart from the single scratch just left of the centre. No spreading from the rust underneath. 

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  • 1 year later...
On 8/23/2017 at 7:35 PM, mat_the_cat said:

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Note that it has not 'cured' the rust (not that it is designed to) but seems to have halted any worsening. I would *expect* the sacrificial effect of the zinc to stop the rust in the scratch from worsening under the coating, but let's give it a year or so...

Update on the Zinga trial is that there appears no difference in the scratch. The rust is still present, but has simply not deteriorated. Any kind of paint coating straight over rust would have bubbled in the last 7 (how the hell did that happen?!) years.

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It looks a bit sorry for itself now, although fired straight up at the weekend, and drove out. I didn't even need to charge the battery, as it has been kept topped up by a solar panel. 

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You need to be careful.  Keeping a working and operating vehicle like that will attract the bearded explorer to come and trespass all over your land!

Actually, that Zinga trial is really useful.  It also explains why when I've used similar zinc-based paints on welding, and then overcoated it with bitumen paint, there has been zero corrosion many years later.

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Overcoating is the ideal solution, as without it the zinc will be preferentially corroded away, slowly. At this point it'll be no better than a simple paint, and will be interesting to see if that happens during this trial. Normally I overcoat it with an underbody wax, but bitumen would be cheaper and equally effective! And also doesn't really matter if it cracks and lets in water, as you still have the sacrificial zinc layer underneath.

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