Club 80-90 Forums

I haven't got around to trying the electronic set-up again. This is what I'm going to try out to pin down the problem :-

I'll fit the dizzie and leave the vacuum connections on the carb and balance pipe blanked, and not connect the pipes to the vac can. I think this should mean the dizzie will work like the 009 with a purely mechanical advance but with a Hall sensor instead of points. If I set the timing to 7' BTDC and check it advances to 30' BTDC at +3000 RPM that will prove the electronics and mechanical side of the dizzie are working.

Next I'll connect the vac pipe from the balance pipe to the vac can and see if this retards the timing back to 4-6' ATDC. This shouldn't effect the 30' BTDC as the vacuum signal stops working above idle speed. If the timing doesn't retard I'll know there's a problem with the vacuum.

The last thing I'll do is connect the carb vacuum pipe to the vac can and see if the 30' timing has advanced to nearer 40' BTDC. If it doesn't advance then as before there's a vacuum problem somewhere.

Hopefully by doing it systematically like this I'll be able to pin down what's working and what's not. My gut feeling is my problem is with the strength of vacuum being pulled, so air leaks are a likely cause.

A systematic approach it the way to do it. It is possible if the dizzy has been stored and combined with a lack of lubrication throughout it's life the centrifugal advance has seized. The rotor arm shaft turns relative to the drive shaft when being centrifugally advanced. Remove the lubrication pad under the rotor arm and drop some penetrating oil down the shaft and then work the two shafts back and forth relative to each other until the spring tension is able to return the shaft to it's stop. Then lubricate the shaft with light oil, replace the lubricating pad and lubricate with engine oil.

bigherb wrote:A systematic approach it the way to do it. It is possible if the dizzy has been stored and combined with a lack of lubrication throughout it's life the centrifugal advance has seized. The rotor arm shaft turns relative to the drive shaft when being centrifugally advanced. Remove the lubrication pad under the rotor arm and drop some penetrating oil down the shaft and then work the two shafts back and forth relative to each other until the spring tension is able to return the shaft to it's stop. Then lubricate the shaft with light oil, replace the lubricating pad and lubricate with engine oil.

Thanks for that, i whipped out the dizzy stripped down and everything is clean and moving well so re fitted and strobed up can only get it running at 20-30 degs, and now the left carb is popping and farting and i have pritty flames coming out...???


any ideas..

Did you check the centrifugal advance is advancing correctly with the strobe light?

with out sounding thick..how do i check that???

thanks again..

Remove both vac pipes fron the dizzy and blank. Start the engine the timing should now be 7.5 deg BTDC slowly increase the engine speed to 3500 RPM the timing should steadily advance to around 32 deg BTDC

Hi, thmpptrck how are you getting on?
I had another go today after leaving the dizzie a few days to absorb a drip or two of oil and swapping the vac can off the DF dizzie on to it. (the retard side of the vac can wasn't working on the CU dizzie.) I set the timing at 7' BTDC with the vac lines blanked and the engine spun smoothly up to 3000+ RPM and the timing advanced up to +28' BTDC. All good so far!

Then I connected the vac line from the left hand carb to the inboard (retard) side of the can and the timing dropped back to 4 ATDC. Still looking good!

And then it went to poo? When I connected up the advance side of the vac can the timing shifted up to 26' BTDC and the idle went up to +1200 RPM? I tried dialling the idle back down but couldn't get it any lower even with the adjuster full in.

I'm guessing that my carbs were adjusted to run smoothly with the 009 fitted and the advance vac signal is now coming in too early? I blanked off the advance vac line and the idle dropped back to 850 RPM. I took the van for a quick spin and it pulled happily with no obvious fluffiness or hesitation so is the 009 finally redundant? I'll leave the dual-vac system fitted and "half working" and give the van a longer run later in the week to check the mpg and engine temp.

What do people think about resetting the throttle gaps to try to correct the advance vac signal?

Got to be done. Disconect the operating rods back off the throttle stops, then screw in till they just touch then one more full turn.

Tried and failed.

Maybe I'm having a Homer moment but this is what I did. First I tried setting the "throttle adjusting screw" as per bigherb's suggestion but they appeared to be bang on one turn in after touching the stop anyway. I started the engine and it was the same as yesterday. Idled at 850rpm @ 4' ATDC with the vac advance disconnected, +1200rpm @ 26' BTDC with it connected.

The Haynes says the throttle valve gap should be 0.65mm so I took off the carbs to check this next. Now unless I'm missing something the gap on mine was way too small? I had to check it with feeler gauges rather than a drill but holding the choke flap closed and letting the throttle close from half open gave a gap about half what it should be. The link rod had yellow tell-tail paint on the nuts, is this standard VW or an indicator that someone else had adjusted them before? I adjusted the length of the rod to give a gap nearer the 0.65mm and put the carbs back on. Now when I started the van the idle was over 1200rpm and connecting the vac advance took it even higher. Deciding I must have misunderstood the Haynes I put the link-rod length back to where it started and gave up for the day.

Now having had a cup of tea and a think, I'm wondering if I could have lowered the idle adjusting the timing with the dizzie rather than just on the idle screw? I'll try this tomorrow unless someone can offer any other suggestions?

0,65 is the throttle gap when the choke is fully on with a cold engine, you shouldn't need to adjust that. The throttle gap is 0.1mm or one turn of the throttle stop when the choke is off (hot engine). Are you sure you have the vac pipes connected correctly.

Doh!!!!!!!!!!!!!!!!!!!

You know what? I've just read what I typed yesterday and it looks like I might have put the vac pipes the wrong way around (again)?

Then I connected the vac line from the left hand carb to the inboard (retard) side of the can and the timing dropped back to 4 ATDC. Still looking good!

I'll check tomorrow morning.

Sorted !!!!!!!!!

I switched the vac lines around this morning. At first the problem was still there, so I started from scratch in case any of my other "adjustments" had cocked things up.

Vac lines disconnected & blanked. 850RPM @ 8' BTDC.
Air box vac line connected & a tiny tweak of the dizzie and 850RPM @ 6'ATDC
Carb vac line connected and 1000RPM @ 18-20' BTDC. Ok not right but better than yesterday.

I unhooked the balance bar between the carbs and popped off the connecting rods. Then I backed of the "throttle adjusting screws" until I could see daylight between the screw and the stop. I pulled up on the link rod on the left carb and there was still a bit of movement that closed the gap between the screw and the stop. I gave the rod and throttle flap a squirt of carb cleaner and a wiggled them about a bit. Once they were freed up I wound the adjusting screw one turn past just touching. After putting everything back together the van started and idled at 850RPM @ 6'ATDC and the timing advanced to just over 40' BTDC at +3000RPM. The throttle flap must have been sticking just a smidge too far open at idle letting the vac advance kick in too early.

I took the van for a spin and it all seems good, 75mph down the dual-carriageway, 30mph in second up the local "test" hill and a nice steady idle. I can't say the van felt hugely different from when the 009 was on but it did seem to have a bit more torque. It was a bit more reluctant to hot start after stopping to buy celebratory beer for later, but I can live with that. The decider will be if the mpg goes up over next few weeks.

Thanks for the help, advice and motivation to finally get around to doing this after two years of ownership

009 is back on.

The van chugged to a halt this afternoon so I decided to make use of my AA membership. The man in the yellow van diagnosed a fault with the dizzie. Fortunately I had the 009 in the spares bag so could get going again after a bit of roadside tuning. Is there a way of testing the Hall sensor, and would one from a DF engine's dizzie be inter-changeable with CU engine's dizzie?

Yes the hall chip is easy to test just remove the centre HT lead from the distributor and hold it about 5mm away from a metal part of the engine or bodywork and away from the fuel system, remove the three pin plug from the distributor and probe a piece of wire into the centre pin of the plug, switch on the ignition and then scrape the other end of the wire along a metal part of the engine this should then produce sparks from the HT lead, if you get sparks then the rest of the ignition system is OK and the hall sensor is at fault. before you replace the sensor check there is more than 5 volt across the two outside pins of the three pin plug

Looks like I'll be stripping down a DF dizzie next week.