distributor advance

Bluesnailman · Mar 3, 2015

Hi

I feel as though I've read everything out there on this, but something isn't quite right with something to do with the timing (I think). What I'm looking for is a bit of advice/check on whether what I have is 'right'....

so lets get the obvious out the way
valve gaps? - check
plugs gaps? - check
carb working ok? - check (34pict3 Bocar) (i.e all adjustments seem to work)
Oil airfilter? - yes at the right level
Coil? - blue bosch, between one and two years old
Leads? - quality, in good nick and same age as coil
Fuel? - ok.... its a few months old
Points? - none - its an accuspark svda
vacuum advance mechanism? - yip, works ok, and connection to carb is working fine too.
Engine is a AH code twinport BTW

So here's the issue.

If I set the timing at 6.5 to 7.5 BTDC (6.5 to allow for poor fuel) - it runs ok, but at 3000- 3500 rpm the advance without vacuum attached is in the 20's. With vacuum hooked up it rises to about 30ish

if I set the timing (vacuum disconnected) to 30deg (ish) BTDC at 3000 rpm then it runs like an pig, clearly not happy and doesn't sit near any recognised advance at idle. i.e. this just doesn't work for the engine

So.... From what I've read - it should be both 7.5 BTDC at idle and about 30deg BTDC at 3000rpm (vacuum disconnected).

Am I right in thinking this?
If so, faulty distributor?
and if the distributor did give 30deg advance what's going on with the engine that means that this would be too far advanced?

I'm beginning to think I'm either going loopy, I've got a lucky combo of engine not liking advance and distributor not giving it, or I've got two things that don't work quite right that could be made better. Loopy would clearly be the cheapest answer so fingers crossed.

Perhaps I should say that at 6.5 to 7.5 de advance it does run and pull ok...

Please help me folks...

Dave.P · Mar 4, 2015

Vac pipe must be disconnected and pipe blocked at carb end, i always check deg. at idle, then do 30 deg at full advance. None of my engines have managed that and 7.5 at idle together, Usually higher at idle..
Maybe your carb mixture / idle needs resetting after timing ?
Have you read up on here ?
http://www.vw-resource.com/index.html" onclick="window.open(this.href);return false;
http://www.vw-resource.com/hestate4.html" onclick="window.open(this.href);return false;
I'm no expert and I do seem to take ages before getting it right, it'll either be dizzy or carb settings / jets no doubt.
Sounds like yours runs ok at 7.5 at idle anyway ? Sure I read somewhere that its not just 30 deg at 3000/3500 but where your advance is at full that's important ? Ill probably be proved wrong soon :lol:

matt-me · Mar 4, 2015

Check your distributor code to see what it should be timed at, they're not all the same. I had this problem on a 78 beetle, we'd assumed the distributor was correct for the year etc but it turned out someone had swapped it over for something from a 74 panel van. The timing set ups were totally different. We still couldn't get it perfect but it was better. However, in the long run we did buy a correct second hand one. Check through this link to see if it throws anything up :

http://www.oldvolkshome.com/ignition.htm" onclick="window.open(this.href);return false;

Bluesnailman · Mar 4, 2015

Thanks guys.

I'll make more effort to plug the carb, and i'll check the distributor number too.

However, in thinking about this last night I thought I'd go and fill up on super unleaded - just to dilute any 'stale' petrol that is causing problems. Job no1.

Second thing that struck me the morning was the sight of my gunson lamp on the garage floor - what the *!$%** is that on the end of it - its a knob with a dial, and the dial is turned........ arrggggggg

So, my gun is turned to around 10 or 12 deg advance - which means it's very cleverly flashing 10 deg before the acual spark.

I've a feeling that this is going to be solved very quickly, I had a feeling that there was a knob somewhere messing this up!

Job no2 - involves gaffer tape and a certain dial.

Will let you know if that solves it all

Bluesnailman · Mar 16, 2015

err - yes folks. That dial on the back of the gunson does something. all sorted and running very nicely again http://forum.earlybay.com/posting.php?mode=reply&f=4&t=64561#" onclick="window.open(this.href);return false;