Draining "Heavy Ends"

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LairdScooby
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Draining "Heavy Ends"

#1 Post by LairdScooby » Thu Mar 24, 2016 9:34 pm

I have been wondering for a while if this was possible as i only discovered "Heavy Ends" existed a few months ago. Since then i've been wondering what happens to them, where they go, where they collect and so on.

After much thought and a bit of research, i discovered/worked out they collect in the bottom of the vapouriser. I'm guessing as they are grease based the best time to drain them is after a run, while the vap is still warm/hot so they run out easier.

How often should it be done and what are the problems caused if they aren't drained? I'm guessing every 10-12000 miles on a "normal" engine where 30-40mpg is the normal economy but on something like mine that does about 18-24mpg, that would be nearer every 6-8000 miles. Also - still guessing, i would think it throws the mixture out completely, causing rough and erratic running, cutting out and various other nasty things?
Cheers,
Dave


Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo

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Gilbertd
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Re: Draining "Heavy Ends"

#2 Post by Gilbertd » Thu Mar 24, 2016 9:53 pm

It doesn't throw the mixture out, especially on a lambda controlled system such as the Leo on yours, as that corrects for it. What I have found is that it may start to go a bit flat at larger throttle openings. Unless you are in eh habit of filling from some particularly dodgy outlets, then draining every 20-30,000 miles is quite regular enough. Yes, do it when it is hot so the heavy ends are nice and runny and just take the lowest gas outlet off. Anything in there will just dribble out. A word of warning though, wear latex gloves. The stuff stinks and if you get it on your hands no matter how many times you wash them, you'll still be able to smell it a week later.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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LairdScooby
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Re: Draining "Heavy Ends"

#3 Post by LairdScooby » Thu Mar 24, 2016 10:33 pm

Thanks for that, i'll give it a go once i get it running sweetly again! Was tweaking the vap the other day and had got it just about perfect, tried an extra bit of tweaking to see if i could get it any better and the laptop died! :roll:
I returned the screws to where they had been before the "last tweak" and all seemed well. However when i went to use it later it became apparent that i've set it all too lean and it now has a tendency to die on the over run and is a trifle flat on acceleration (still almost as good as on petrol though :wink: ) but it's been raining since!

In fact this is what prompted the question about heavy ends - the previous owner had it 3 years and i seriously doubt the LPG system was touched in that time, if it was ever even set up properly in the first place! Both the idle bleed and the bias screws were at least 7 or 8 turns out so it took me quite a while to get it anywhere near right, hence the laptop dying at the crucial moment! I think i'll take it for a spin to warm it up, drain the heavy ends then have abother go at getting it right - hopefully with more long term success!

Advice about gloves definitely noted! I'm allergic to latex so it will be nitrile but they should give the same protection, might even put 2 pairs on, just to be sure!
Cheers,
Dave


Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo

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LairdScooby
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Posts: 322
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Re: Draining "Heavy Ends"

#4 Post by LairdScooby » Fri Mar 25, 2016 11:57 pm

Well i drained the heavy ends when i eventually got the drain plug open! There were witness marks on it to show pliers had been used to tighten it - by Guy the Gorilla! had to use Mole Grips to shift the thing!

Not much came out, a bit disappointing really but afterwards i got it running rather sweetly - i've taken plenty of pics and a few vids which i'll upload tomorrow some time. Best reading i could get on my CO meter was 0.7% on gas and 0.8% on petrol so i suspect the cat has been removed and/or my CO meter is past its "Use By" date! In fairness it was secondhand when i bought it and i've had it about 10 years so there's a good chance it's died from old age!

More to come when i load the pics and vids.............
Cheers,
Dave


Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo

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LairdScooby
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Posts: 322
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Re: Draining "Heavy Ends"

#5 Post by LairdScooby » Mon Mar 28, 2016 12:05 am

As threatened, here are some pics and short videos from draining the heavy ends and retuning the vapouriser/Leo unit.

On gas before i started, about 1% CO at idle - bear in mind my CO meter is a bit dodgy so it may not be right but all the readings are relative to whatever error it has :

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Here you can just see the drain plug on the bottom of the vap, looks more like a shadow really!

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The massive amount of heavy ends i removed!

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After draining the vap, it was trying to run richer on idle :

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Pretty much as i suspected really! After a bit of arbitrary tweaking (1/4 turn on both screws outwards) i got this :

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After about an hours tweaking, measuring, re-tweaking etc, i ended up with this. Halfway into the vid i put it in D and gave it some beans with the brake and handbrake on to make sure it didn't die when i let go of the loud pedal. All seems fairly good after :

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Considering when it went for MoT it was showing 3.9% on the test stations CO meter and i got it down to about 2.5% (which my own CO meter confirmed so can't be that far out) to pass the test by tweaking the power valve built into the mixer, this is a vast improvement! The economy has already improved just by fitting the Leo system but i'm going to give it another check when i next fill up.
Cheers,
Dave


Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo

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