Sparking woes. The rain is back

57 posts · joined Feb 2003 · 22 Feb 2003, 12:12 pm

#27720

Here goes.

'74 1300 L. Not had it long. It was running pretty good for a week or two, but not real keen to pull in the lower revs especially after engine braking. I had assumed it may be lacking spark or the little squirty pump in the carb (when you put you foot down) may have been blocked.

Since the rain started it got much worse. Barely made it home. Won't idle, has no power below mid revs (no tacho to give specifics).

If have new plugs, have removed, cleaned and adjusted all conections to and from coil and all ht leads. The points show no signs of arcing and the timing seems pretty close when checked statically. Each individual lead gives a small blue spark when the engine is turned over by hand. The coil will happily jump a gap of about 6mm but the spark is definitely orange, not blue. Cleaned rotor and all connections in distributor cap as well.

I don't have the gear to check resistance of leads etc but would prefer not to just start replacing parts as the dollars are tight.

Any suggestions from the above info would be great. If you need more that I haven't mentioned, let me know.

Arthur.

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 22 Feb 2003, 7:14 pm

#27791

Spark should be blue ... but i doubt that would cause problems.
Cant borrow a coil can you?

Maybe take you car somewhere real dark and start her up. You might see that the sparks are straying real bad and not getting to the plugs.

Is it timed right?
Points gap is right?

Leads are 1-4-3-2?

What about the vacuum advance? It is connected.
Is it working or is it stuck? Suck gently on the tube and see if the plate moves.

Futue te ipsum!!!

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 22 Feb 2003, 8:10 pm

#27800

Thanks Blue74L

I wish I could borrow a coil or find my multimeter to check the lead resistance.

I'll give the dark running a go.

In answer to the other questions;

Leads are in the correct order, had to double check after pulling them off for cleaning (it's been a while since I've played with one).

No vacuum on the dizzy at all.

Timing is set to the only mark on the pulley when checked with a static timing light. (If there's only one mark, is that the timing mark or is it TDC?)

I'll give the dark running a go and let you know.

Thanks,

Arthur

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 22 Feb 2003, 8:38 pm

#27801

"Generally" speaking there is a dimple on the "back" of the pulley.
Now back is back (as Mr Muir would say) as in the "back" of the car. On the other side / front / closest to the block is a sharp cut.
The dimple is 0 degrees and the sharp cut is 7.5 degrees.
"Sometimes" thwere is a second sharp cut and this is 10 degrees.

How does it run at full throttle?
Have you tried pulling the leads off one at a time?
If no vacuum on dizzy it is a 009. The plate is a mech only advance and can stick at times. Try and see if it can moove

The vacuum port on the manifold is blocked up now it is not being used isnt it?

Futue te ipsum!!!

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 22 Feb 2003, 8:52 pm

#27804

Yes. It's a 009. With the cap off I can easily move the rotor about 10deg and then it springs back immediately. I assume this means that the advance is working. All the vacuum tubes are blocked off.

Tried the running in the dark bit. It's not fun putting your hand into the engine bay of a running motor feeling around for the throttle when you know there's a couple of pullies and a belt close at hand. Saw absolutely nothing (including no sparks) for the whole time under the covers.

Haven't tried pulling the leads off one at a time. Left that as a last, last, last resort having had many delightful encounters with high voltage in the past.

It runs beautifully at high revs. I bought it to get to work and back which is 20 mins of freeway driving at 100km/h the whole way. Seems to be revving a fair bit a 100 but is very happy to sit there and is very smooth and responsive at those revs.

Running a little better after a second cleaning of everything today. Will idle most times but not smooth. Definitely no low down torque at all. If anything it seems to get worse as it gets warmer. Not sure on that one but it seems that way.

Arthur.

geodon Wolfsburg Wizard

478 posts · joined Aug 2002 · 23 Feb 2003, 5:13 am

#27833

I'd be checking all the places where the induction system can suck air. Start with the carby & work down. Don't forget the throttle spindle. I've heard of using spray lubricant squirted at the suspect areas & watching the exhaust for smoke but I've never tried it. Oh! I have just had a thought, I had a similar problem on the KG (1600 TP) & it turned out to be the "anti- running on solenoid" on the carby. It is supposed to cut off fuel when you switch off the ign- you can hear it go click when the ign is sw on & off or you SHOULD hear it! Mine was intermittently cutting off the idle circuit & hence starving the low revs supply. If it is this & dollars are tight just get a big pair of pliers or bolt cutters & cut the knob of the plunger. The running on will be a minor problem till you can buy a new one.

aussiebug Officially Full-On Dubber

246 posts · joined Sep 2002 · 23 Feb 2003, 10:18 am

#27846

Timing is a definite possibility here - you said the pulley has only one mark.

If it doesn't have a dimple to the left on the rearmost lip as well (rear is rear of car) then you may have a 1-notch pulley which is usually 5ATDC (that's AFTER) for the US double vacuum engines.

There are 4 pulley markings in comon use and you HAVE to know which you have in order to time the engine correctly.

If it DOES have the dimple on the rearmost rim to the left of the notch, then the notch is indeed 7.5BTDC and suggested by Blue.

When tuning a 009, you can rough-set it at 7.5BTDC to get the engine running but you must then set it at 28-32 degrees at 3000+rpm with a timing light. The 009s vary (cheap build) and since max advance is more important than idle advance, you MUST set them at 3000+rpm for max advance.

The other possible issue not covered above is jetting. For a 30PICT/2 on a 1600 engine with a 009 distributor, you need a 55 idle (should have that already) a 127.5 main jet and a 120 or 115 air correction jet (it MIGHT work OK with the 125 air correction usually fitted to Aussie 30PICT/2s).

This sets the carby a little richer which helps avoid the flat spots caused by the 009s lack of vacuum advance.

Lots more tuning info on
http://www.geocities.com/aussiebug1970/30PICT2.html and
http://www.geocities.com/aussiebug1970/34pict3.html

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com

555bug WRX Bug Boy

1,123 posts · joined Aug 2002 · 23 Feb 2003, 11:25 am

#27852

change the coil to a bosch black (the oil filled one) I had the same problem on a engine I builtl 🙁 your spark should look like the ark off a mig ...well kind of

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 23 Feb 2003, 12:22 pm

#27864

The update.

The pulley does have the small dimple on the front/rear/back/opposite side of the pulley to the notch.

I've investigated the vacuum leak possibility with the aid of some aerostart. Need to be super cautious. Don't even think about spraying this stuff 'til you've done the "check for sparks in the dark" bit Sprayed it at possible vacuum leak areas and had no change in engine revs. Sprayed it into the air cleaner and had a definite increase in revs. Then noticed something interesting.

Giving a little more throttle than idle actually causes the engine to stall although the introduction of a little more highly volatile substance increased the engine revs. When the engine is near stall it is only revived by short blasts of throttle rather than a gradual increase.

Does this imply something more along the lines of partially clogged jetting? I'm starting to get confused. It will be worth a lot of beers when this one is finally solved. Pitty we can't enjoy them together.

BTW, I had checked the run on solenoid early in the peice and it gives a very audible click when switched on and off. Forgot to mention that one earlier.

Am very tempted to put on a new top notch coil. It certainly isn't going to hurt anything but the bank balance.

Not able to check the 009 advance at 3000rpm yet as I don't have access to tacho or timing light right at present.

Thanks again. I'll make sure that the final solution is posted once it is found. I know how frustrating it is to follow a whole post about a problem you have only to find that the solution was never posted.

Arthur.

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 23 Feb 2003, 3:10 pm

#27874

OK. The electrics are now no longer to blame.

Bought new leads. Much better. Now has some low end torque and pulls much better.

Still rough on idle so I relented and started pulling individual leads. Cylinder No. 2 is not running (at idle at least). I have pulled the plug and attached it to the lead, run the motor and the spark is fine. With the plug and lead in I can pull it while the motor's running and it has no effect on the idle. Put it anywhere near it's hole in the dizzy cap and a big strong spark jumps across.

Does this mean stuck valve or something worse?

Arthur.

geodon Wolfsburg Wizard

478 posts · joined Aug 2002 · 23 Feb 2003, 5:01 pm

#27891

Well done so far mate! You've narrowed it down real well! It might be time for a compression test. Looks like that is the source of the rough idle. The rest may be the old perennial Bosch 009 flat spot problem. I can only fix them by running the mixture a bit richer than usual with a slightly larger main jet. Others say the flat spot can be tuned out but I haven't had much success. Your little experiment with the throttle lever & the spray points that out- if you put in more fuel, no flat spot! I'm assuming of course that the accelerator pump is working OK.

[Edited on 23-2-2003 by geodon]

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 23 Feb 2003, 6:47 pm

#27911

Ralph

What about valves ?
If you are pulling the lead, its sparking but not effecting you might have a tight exhaust valve.
(should have suggested this earlier...d'oh)
If it is holding the exhaust valve open you wont have compression and wont fire at idle.

Go on..... get your feelers and off you go.
Even if you dont have feeler gauges go and test them. They should all have a bit of play. NONE should be tight.

Futue te ipsum!!!

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 23 Feb 2003, 8:39 pm

#27946

I was (actually still am) really hoping to own a beetle for at least 1 month without having to drop the motor out.

Sticky valve does sound like the likely culprit. I've dropped some octane booster / head treatment stuff in the tank and will run that for a bit. I don't have the opportunity to look at the valves for a couple of days now so will just have to grin and bear it.

Do I have to drop the oil out to check the valve adjustment or can I leave it in? It's been a while.

I'll see if I can get hold of a compression tester during those few days as well.

With reference to the 009, what is the benefit of having one or am I better going back to stock for day to day driving?

Arthur.

geodon Wolfsburg Wizard

478 posts · joined Aug 2002 · 24 Feb 2003, 5:35 am

#27987

Historically, mech advance distributors were 1st fitted by VW to the early Kombis. Because of the small eng pushing alot more body, the factory reasoned that the accelerator pedal will effectively have 2 positions - straight up or on the floor! So they put in a dist to suit it & it was cheaper to make as well! This dist was also put on industrial engines because they go at a constant speed. The 009 can't handle changes in accel pedal as well as the stockie. I have one on my SC because I have a 1600SP but have chosen to use the stock 28PCI carby because it looks more orig & it has a manual choke. Now, the stock 1600 dist & this carb are incompatible so I used a 009 for expediency. I could try for the 36hp vacuum dist but I figured it had a different advance curve anyway so what the hell! Early Kombis had mech distributors anyway. We had flat spots as expected but overcame these with a larger main jet.
No leave the oil in- there will be a bit of oil in the bottom of the rockers.
You may be lucky re stuck valves seeing it's No2. If it had been No3 I'd say the motor will have to come out!

[Edited on 23-2-2003 by geodon]

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 24 Feb 2003, 7:44 am

#28000

Ralph

with any luck it might just need adjustment.
Easy to do - do a seach or get your manual. Otherwise tell us and i can send some sites on how to do it. Very easy - 30 mins max.

Futue te ipsum!!!

aussiebug Officially Full-On Dubber

246 posts · joined Sep 2002 · 24 Feb 2003, 12:31 pm

#28041

The complete tune-up process (including valves) is on my site:

For the "two adjusting screw" carburettors, 34PICT/3, 31PICT etc...
http://www.geocities.ocmaussiebug1970/30pict3.html

and for the single adjusting screw carburettors (28 and 30 series mostly)...
http://www.geocities.com/aussiebug1970/30PICT2.html

Hopeful as others have said - you just have a tight (raised) valve.

If the valve adjustment doesn't fix it, I'd be worried about a head leak or a burned valve (it's very nasty if a valve breaks).

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com

aussiebug Officially Full-On Dubber

246 posts · joined Sep 2002 · 24 Feb 2003, 12:32 pm

#28042

Oops - typo in the first URL above...
http://www.geocities.com/aussiebug1970/30pict3.html

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 24 Feb 2003, 9:50 pm

#28212

OK So the full tune up is the go. I'm picking up some bits from a 71 beetle later in the week so I'll see if he's got a standard dizzy while I'm there.

At the moment I'm heading off early in the mornings (not a morning person) so the valves probably won't get done properly until the weekend. I'll have a look and see if there are any real tight before then though.

Thanks for the tune up details. I've done a few on previous engines so have an idea but it's good to get the exact detail.

BTW the second posting of the 34pict3 link didn't work either. Went to the main site and followed prompts from there. Lucky 'cause that's the carby that's on it.

While on the carby, is there a specific distributor that I'll need for a 1300 running a 34pict3 carbie?

Arthur.

LittleRalph Commited Dubber

57 posts · joined Feb 2003 · 25 Feb 2003, 8:56 pm

#28406

Maybe the last installment.

Checked the valves last night and they seemed fine. No different to the no. 1 valves (wasn't about to pull the other side off after that). So where does that leave us? I got to thinking.

The old plug I pulled out of No. 2 looked like it was running a little lean, maybe a slight vacuum leak on the inlet manifold gasket perhaps (had one on a previous one and nothing external showed it up 'till I sprayed some Aerostart in the area and it dissolved the paint someone had put on the inlet manifold and it dribbled down and leaked in and the revs picked up. Left a nice little trail to follow too.) ANYWAY it was only a bit lean so I'll leave that.

There was some spark to No. 2. Maybe the coil was still sus but the new leads masked it a bit. I was still confused that it would idle but if a little throttle was applied it would stall. Then I read the carbie adjustment instructions. The bypass screw. AHA.

Maybe, just maybe, a combination of weak spark, some sort of lean running on No.2, not enough fuel getting though the idle bypass and a 009 distributor were causing poor idle and serious flat spots.

I adjusted the bypass screw out about 3/4 of a turn this morning and guess what. I had a new car. Still not absolutely perfect but it is running a 009 that hasn't been timed at 3000rpm and hasn't had a full tune up but it really is a different car. I can put my foot down a low revs and it will chug away and pull.

BTW I got an oil filled coil (GT40) to replace the GT40T. Couldn't get the basic black one because it didn't come with the mounting brackets like the red one. The spark is definitely better but has made nowhere near the difference that the idle screw did.

Thanks again for all the help. Hope reading this has helped (or maybe will in the future) someone else trying to understand the finer points of VW ignition.

:beer:beer

Arthur

aussiebug Officially Full-On Dubber

246 posts · joined Sep 2002 · 27 Feb 2003, 10:35 am

#28689

Glad to hear it's running better now Arthur.

Those who have previously tuned the carbies with only one screw in the left side are often confused by the additional (larger of the two) bypass screw on 34 and H30/31 carbies, since adjusting the idle speed is no longer on the throttle arm with these carbs.

Sorry about that "missing" link - when I posted the correction I retyped the typo - it should be
http://www.geocities.com/aussiebug1970/34pict3.html

(I posted 30pict3 twice - duhhh)

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com