bl1300
Posted a lot
Posts: 1,678
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Jul 20, 2011 12:40:12 GMT
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Had a problem with my Daily driver DAF 44 today.
When accelerating hard the back end squeels like a banshee and not a lot happens. When you back off the squelling stops and the car lurches forward and pulls to the right.
I stopped the car and looked underneath. The left hand belt has some tension but will need some more, however the right hand belt is near enough hanging loose. This present a problem in that the belts cannot be tensioned seperatly. Both primary drive pulleys are fixed to a sliding carriage used for tensioning. Any ideas as to what could cause one side to wear substantially quicker than the other?
The other problem I'm having is very annoying and very persistant. When you start the car cold it will not idle at all. As you pull away the judders and hesitates, pops back through the carb and then goes. Once its rolling theres no problem.
Points gap is set to the book, timing is set to 5 ATDC as per the book instructions for emissions control engines. Carb has crypton tuned. Idle is set to 940rpm when properly warm and with the main vaccum feed off the inlet manifold disconected and plugged. With the feed connected idle is about 800rpm. If you remove it with the engine running it just dies and blocking the same pipe with your thumb before it dies causes it to pop back through the carb and then the idle picks up again.
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Current fleet.
1967 DAF 44
1974 VW Beetle 1303s
1975 Triumph Spitfire MkIV
1988 VW LT45 Beavertail
1998 Volvo V70 2.5
1959 Fordson Dexta
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ChasR
RR Helper
motivation
Posts: 10,307
Club RR Member Number: 170
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Jul 20, 2011 13:14:21 GMT
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If the belts are old, they will start to die in the weaker parts of the belts IME. I have had it happen to me on a number of very old belts on cars (fanbelts I admit). I assume you are talking about the belts for the transmission.
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Jul 20, 2011 14:22:26 GMT
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Vacuum feed from the manifold to what? Variomatic, carb, dizzy advance unit?
Lack of idle and hesitation sounds like retarded timing to me. I have a pet theory - ENTIRELY unproven - that modern unleaded takes a bit more time to burn than older unleaded and 4 star, so you need a bit more advance than you might expect.
Doesn't sound like a manifold leak to me - I'd expect that to cause lots of revs, although if the leak was present before the carb was tuned it might be an issue.
Since the belts operate as the differential - and, presumably, therefore, do slip to a certain extent - is it possible that one of your wheels has spent more time going faster than the other? Maybe when accelerating with the LH wheel in a patch of mud on a rural road? Uneven tyre pressures or sizes? One rear brake more effective than the other?
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bl1300
Posted a lot
Posts: 1,678
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Jul 20, 2011 14:48:42 GMT
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The belts are about 4 months old and have done about 3000 miles. I know its time to tension them but they shouldn't be wearing down hugely uneavenly. You do get a bit of extra wear on one side from the fact that you spend more time turning right than left in every day driving (roundabouts). I normally wouldn't expect it to be noticable untill the drive belts where 2 or 3 years old. Yes the drive belts operate as a rudimentary limited slip diff. Ive also included a basic diagram of the vaccum control system.  |
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Current fleet.
1967 DAF 44
1974 VW Beetle 1303s
1975 Triumph Spitfire MkIV
1988 VW LT45 Beavertail
1998 Volvo V70 2.5
1959 Fordson Dexta
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Jul 20, 2011 16:20:18 GMT
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The bogging down sounds almost like it could be a lack of manifold/carb heating. Do I recall you (or one of your alias's) posting asking about repairs to an inlet manifold that's heated portion was damaged/corroded?
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bl1300
Posted a lot
Posts: 1,678
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Jul 20, 2011 16:32:31 GMT
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The hotspots are missing but have been all the time I have owned the car and this problem is recent. Hotspots are missing on 90% of british DAFs without too much problem.
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Current fleet.
1967 DAF 44
1974 VW Beetle 1303s
1975 Triumph Spitfire MkIV
1988 VW LT45 Beavertail
1998 Volvo V70 2.5
1959 Fordson Dexta
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Jul 21, 2011 14:45:44 GMT
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Hmm, are the belts actually worn uneven? As in: are the belts different widths now?
Because it's not uncommon for diaphragm springs to break in the primary and secundary vario, causing
it to slack up. You'll have noticed a change in how the car shifts as well then, and it pulling to one side when accelerating/decelerating. As well as imbalance at speed, sometimes.
Either way, even if the second belt is completely slack the remaining shouldn't slip. I've had to drive quite a while on one belt in my 80bhp 55, with little problems.
Vacuum leak will more likely than not come from the vario side. Check than all the hoses in the engine compartment arent perished. Also worth checking if the hoses on the primary vario are still on (they slip off sometimes), and that the part on the primary drums where the hoses feed into (in Dutch it's called 'doorvoorpotje', loosely translates into throughput drum), is air tight. These leak very often, again causing poor idle, and bad shifting of the vario.
The slip you mention could be a worn clutch, or the rubber of a propshaft on its way out. All of these are common and easily fixable faults.
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bl1300
Posted a lot
Posts: 1,678
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Jul 21, 2011 14:57:31 GMT
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I hope it not a worn out clutch as the clutch shoes are only 4k old and drum look fine when I changed them. Although not a difficult job its a faff as the engine has to be removed.
Last set of belts changed one was a good 5mm narrower than the other. Which was the reason I changed them. Both belts are in need of tensioning but one looks like it does more so than the other.
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Current fleet.
1967 DAF 44
1974 VW Beetle 1303s
1975 Triumph Spitfire MkIV
1988 VW LT45 Beavertail
1998 Volvo V70 2.5
1959 Fordson Dexta
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