andrewthe33
Bigger Belter
I don't know what you've done to me, sir, but you've done me the power of good!
Posts: 158
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Post by andrewthe33 on Oct 12, 2011 16:03:42 GMT
I've made some interesting discoveries today! Starting from the beginning, I removed & replaced the hose from the engine inlet manifold & then measured the vacuum being produced; AMAZING!!! upon revving up the engine produced 400-500 mm Hg of vacuum-much more than yesterday! the needle also danced about on tick-over, too. Apparently this IS correct. Anyhow, I then fed the vacuum to the low-ratio valve & measured the vacuum being passed when the low hold was off (i.e. when the vacuum would be passed to the change up side) and I was only getting 180-200 mm Hg, and this was with new hoses and Jubilee clips. from this I can only determine that the low hold valve is either sticking or has a leak (perhaps caused through dirt in the valve?) The valve must work by having a spring to hold the valve shut and this is over-ridden by the solenoid when the low ratio is switched on. My solenoid seems to be OK, as when it's engergised the vacuum pattern from the change-down pipe is exactly as it is from the engine; dancing around on tick-over and building to 400-500 mm Hg on revving up.
So, today I have learnt that my valve has a leak when switched off but works fine when switched on. I also had the tracking re-set, thus making the car much easier to drive. I'm in the market for a 6 volt valve... any offers?
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andrewthe33
Bigger Belter
I don't know what you've done to me, sir, but you've done me the power of good!
Posts: 158
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Post by andrewthe33 on Oct 12, 2011 19:42:42 GMT
I've cracked it!!! The problem is, at least partially, solved!!! AsI said earlier, the vacuum seems to be at least partially lost somewhere in the low hold valve, so I decided (after 2 or 3 ciders!) to bypass it. I took the manifold vacuum valve & connected it directly to the change up valve. I then took S.H.M.B.O. ("she who must be obeyed" A.K.A. " 'er indoors") round to her friend's place, for an evening's Scrabble (=bottles of wine & discussions of husbands) The car sounded awful and never seemed to get out of bottom gear..... Ah ha, thought I, if the increased vacuum's making it stay in a lower ratio, reverse the vacuum! The result is a FANTASTIC car! All I did was attach the vacuum from the change up valve to the other (smaller) pipe leading to the Variomatic units and, hey presto, a car that sounds delightful, purrs along and behaves perfectly!
Tomorrow I intend to reverse the connections on the variomatic units and then reverse the pipe connections under the bonnet, which will put put everything back as it is now, except that the LARGER of the 2 pipes will be the change up vacuum, as opposed to the smaller as it is at the moment. Next I'll crack on with the change down side...
More cider... I'm happy!!!
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Post by 33grinder on Oct 12, 2011 20:03:36 GMT
Excellent news Andrew! I'm glad that you've found a solution so you can finally enjoy all of her DAF goodness.
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andrewthe33
Bigger Belter
I don't know what you've done to me, sir, but you've done me the power of good!
Posts: 158
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Post by andrewthe33 on Oct 12, 2011 21:26:06 GMT
Just taken "Pooh" for a run to the garage, for a good drink of unleaded; after all, if her owner is downing ciders in celebration of her repair the least I can do is let her join in! She's done 254 miles and has used 8.36 gallons, making her rate of consumption 30.4 m.p.g. Bearing in mind she's spent most of these 250 miles in the wrong ratio that's not TOO bad, I suppose!
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Post by spunkymonkey on Oct 12, 2011 22:01:09 GMT
That's better than some on the DOC used to report from their supposedly working cars, Andrew ;D As a reference, Betty (who IS generally working properly but does a LOT of local running round to shops etc) has averaged 33.9mpg over the past 20k miles but hits 40 - 50 on a good run. 'Tilly with her earlier (lower power) engine is similar on a run but seems to be averaging just short of 40mpg overall - although that could be because a much bigger proportion of her miles since we got her have been long distance! Incidentally, vacuum gauge jumping around at idle is perfectly normal. Because they've only got 2 cylinders - so only one inlet stroke per revolution - there's enough time between the individual "sucks" for most gauges to register the drop in vacuum when both inlet valves are shut. If you want to use a gauge for tuning you can damp the movement by tying a (fairly tight) knot in it's connection pipe so that the vacuum at the gauge takes time to bleed away
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andrewthe33
Bigger Belter
I don't know what you've done to me, sir, but you've done me the power of good!
Posts: 158
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Post by andrewthe33 on Oct 21, 2011 6:53:55 GMT
I'm pleased (and not a little proud) to say that Pooh's vacuum system is now 100% working! I've repaired the vacuum valves, the low hold switch and the brake light switch. I now have a beautifully running 33, currently whizzing around the roads of North London and putting a BIG smile on the face of its driver (and gaining a few smiles from passing drivers too!) I now know just how the vacuum valve works, right down to the 2 valves, the restriction on the change up side and where the rubber seals go. When I took mine apart I photographed every stage of it & once I'm organised enough I'll put the photos on the site and explain what does what.
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Post by 33grinder on Oct 21, 2011 7:35:01 GMT
Great news Andrew and glad you got her sorted. What a difference it makes when everything is running as it should be! Look forward to vacuum system master class.
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thebear54
DAF Nut
Those who say it can't be done, should not interupt the people doing it !
Posts: 1,426
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Post by thebear54 on Oct 21, 2011 9:46:58 GMT
Fantastic progress report Andrew. Glad to hear that the Vacuum problem has been solved, nice detective work. Hope to meet up next time over to "the island" John
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Post by Kenr on Oct 21, 2011 12:07:48 GMT
Well done Andrew! Nice bit of problem solving.
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andrewthe33
Bigger Belter
I don't know what you've done to me, sir, but you've done me the power of good!
Posts: 158
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Post by andrewthe33 on Oct 23, 2011 18:58:55 GMT
"Pooh" is standing in on the daily commute to work for a day or so and I've just re-fuelled after doing 240 miles since I fixed the vacuum, to find the MPG has improved from 30.4 to 35.5! That's a 15% improvement! I'm seriously impressed, particularly as all my repair work so far has been vacuum related; I've not actually done any work on the timing, ignition, points, plugs or air filter. Engine-wise all I've done is change and flush the oil. I reckon there's a further improvment to be had to this figure! The 35.5 figure includes a mad dash round the M25 at speeds much in excess of 70, so the figure is all the more impressive!
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