why is #3 spark retarded?

Vwjunkie · Post by **Vwjunkie** » Fri Aug 22, 2003 12:27 pm

Hi guys I'm new on the forum and I hope you can feed me some useful information here. I'm trying to find out why the spark on the #3 cylinder is retarded. I can understand that on an early type 1 with the oilcooler inside the fanhousing, the #3 cylinder gets its air a little warmed up and because of that you retard the spark in order to keep the cylinder from overheating. But we have the oilcooler in the doghouse not to mention the completely different fanhousing/cooling of a type4 and still the spark retard remains! Even in the electronic hall sensor type distibutors it's there! I can't figure out why #3 would get hotter than the other cylinders.
Any input would be appreciated.
Dirk.

dstar5000 · Post by **dstar5000** » Fri Aug 22, 2003 12:29 pm

It isn't that *IT* is so retarded, it's just that the other THREE are SO advanced!!!!

BUWAHAHAHAHAHAHA!!!!

Number three cyl in the hottest, so VW retarded it to allow it ccooler operation!

Don

raygreenwood · Post by **raygreenwood** » Fri Aug 22, 2003 12:45 pm

The spark on type 4 has no retard to my knowlege. That was an early type 1 feature. It went the way of stone tools with the advent of the "doghouse" style cooling tin that took the oil cooler out of the way of cooling air. Pancake style engines likethe type 3...had little of that problem...and type 4 even less. Chances are, you are running an early distributor. I just finished the degree markins on my type 4 fan two weeks ago. I can assure you they match the movement of the dizzy and there is no retard on a type 4 for #3. Ray

dstar5000 · Post by **dstar5000** » Fri Aug 22, 2003 12:49 pm

raygreenwood wrote:The spark on type 4 has no retard to my knowlege. That was an early type 1 feature. It went the way of stone tools with the advent of the "doghouse" style cooling tin that took the oil cooler out of the way of cooling air. Pancake style engines likethe type 3...had little of that problem...and type 4 even less. Chances are, you are running an early distributor. I just finished the degree markins on my type 4 fan two weeks ago. I can assure you they match the movement of the dizzy and there is no retard on a type 4 for #3. Ray

....... as long as you are NOT using an OLD dizzy.....
Right Ray?

Don

Vwjunkie · Post by **Vwjunkie** » Fri Aug 22, 2003 3:18 pm

Look at the disk triggering the hall sensor inside the distibutor of say a CU engine and you will see that it is not completely symmetrical, I mean that the opening in the disk for one of the cylinders is narrower, compare that disk to the disk of say a rabbit and you must see a difference. I can only conclude that that is done to shift the ignition point of #3. If so that would mean that #3 on a type 4 would also tend to run hotter and this I can't explain.......

njv · Post by **njv** » Fri Aug 22, 2003 4:03 pm

hi
il take a look ! cant say ive ever noticed any difference but i will look tommoro.

raygreenwood · Post by **raygreenwood** » Fri Aug 22, 2003 4:45 pm

Hmmmm....Asking me to look at the hall disc in a CU engine might get us in trouble. For all I know you may be right. It would help us further if you had a chance to get the# from the side of the distributor. There are more than one # that may have been fitted. The one you have may not be the correct one. Ray

Vwjunkie · Post by **Vwjunkie** » Sat Aug 23, 2003 4:29 am

I forgot to mention I' m from the Netherlands Europe. I take it you don't have CU engines in the states. They were used here in what you guys call vanagons. It's a two litre hydro valve with carbs. The numbers on the distributor are 0 237 023 007 and 071 905 205, I have several of them they all came from a type 4 and they all have the same disk

Vwjunkie · Post by **Vwjunkie** » Sat Aug 23, 2003 4:43 am

I would send a picture but I can't seem to add an attachment!

njv · Post by **njv** » Sat Aug 23, 2003 1:36 pm

mmm wow.
well here are the mesurments around the disc that makes and breaks the spark. the size of the cutout portion . exactly the same dizzy 007 as mentioned above .

no1 12.7mm
no2 13.8mm
no3 11.4mm !
no4 13.7mm

now i didnt have a great deal of time so i just stuck my outside vernier in the holes and took the measurement on the dial weather they are also staggered in any way around the disk at this point i cannot tell.

but it is initially obvious that if when we set timeing on cylinder 1 no 2 is running the most advance then no4 just a hair less than no2 no1 itself and least advanced of them all wil be no3

im not sure what to make of this revelation pointed out to us!

perhaps this is what jake means by funky.

tin snips and very carefull measuring and cutting could change the whole thing mind.

ill have to go to the local scrapyard and look if all the other hall sensors dizzys from golfs and audi have funky cut out arangements or if they are all the same proportions.

this leads me to presume that vw testing ended up showing that cylinder three ran hotest then 1 then 4 cylinder 2 running coolest of the 4.

crazy stuff what do you make of that ray.

raygreenwood · Post by **raygreenwood** » Sat Aug 23, 2003 2:15 pm

I think a lot of answers have been laying in front of all of us for years...but we never felt the need to ask the questions. Last week or so...a mini poll foundthat lots of people had problems with dropping #3 exhaust valve the most. Personally...I had never had the trouble. Maybe I'm just lucky. Then Jake confirms that #3 does indeed run warm.

There is probably no way the VW did NOT know this. I know the regular type 4...has no retard on the stock 205 series distributor...but then...as evryone is confirming....they run warm on #3.

Maybe we should take another mini poll. On Vanagons...CU series or identical...how many have had problems with #3 (now possibly knowing that VW may have corrected for it by retarding the spark)....it would not surprise me to find that LESS people have had problems with the vanagon...and stock distributors.

That being said....and watching Jakes testing...and reading conversations....I have been looking at both the type 3 and type 4 cooling manifolds...internally...side by side for the last week or so. It is obvious to me... that on both of them (more so on the type 4)..that the left side flows less air. It has too much volume....and is too circuitous.

On another thread...I think I have been reading that the type 1 fan is outperforming the type 4 stock fan? Interesting....it uses a reverse canted blade on the fan. Its supposed to be less efficient in high torque environments. But....it may also be less parasitic. Perhaps.....a stock type 3 manifold grafted to a type 4 with a type 1 fan and type 3 stator blade set up.....would be a cool thing? That...and making sure the windows on the hall shutters are equal.....Ray

Vwjunkie · Post by **Vwjunkie** » Sat Aug 23, 2003 2:43 pm

Ray, what do you mean by the regular type 4?
I' ve been told that even a 009 has #3 retard!

njv · Post by **njv** » Sat Aug 23, 2003 2:51 pm

hi
well the cu was the last incarnation of the typ4 engine so mayby vw had took note of problems that had previously come to the fore with typ4 motors in their earlier guises .

quite a lot changed with the cu series sqr port heads with real gaskets an external alternator with its own fan to cool itself an all new fan shroud design.

the cu series was fitted with electronic hall ignition from the onset of production i would be interested to know if right from the start it came with no3 retarded !

what i dont quite understand is why make the windows smaller rather
than just move them backwards or forwards in position. surely this smaller window means less dwell and less spark as well as it being retarded!

nice window of oportunity to do a bit of tuning by grabbing a golf disc and sticking it in seeing what occurs.

your fan sounds interesting but mayby just a touch to much work to be realistically acomplishable .

what i need are easy ways to make my stock late cu fanhousing cool beter it is all i can use in a typ3! im ok now mind ive managed once to get my cht up to 375 (mounted under the plug on three) what would happen if i gave no3 full advance i may push 400f so a little extra air would do me no harm .

the only time i can get this temp is when the thermostat on my additional oil cooler is not fully opened ie at a transitionally yet fully warmed up tempreture in the engine .

i would like to know if any vanagon users have had problems on 3 somehow i doubt it.

after many years it seems vw went full circle on this one!!

Vwjunkie · Post by **Vwjunkie** » Sat Aug 23, 2003 3:19 pm

I stumbled across this whole thing when I tried to make an electronic ignition for my 181. I wanted electronic ignition because it's easier for me to build in an immobilising circuit which I think is necessary because it's extremely easy to steal. I live in a let's say theft prone part of the country (Amsterdam is not far away). i also think it's superior to points because the spark is stronger and you never have to adjust it anymore!
So I thought I'd use a distributor from a type4 (CU for that matter) but I didn't want the idle stabiliser circuit so I thought I'd take the wiring harness of a Golf, but that has a different connector to the hall sensor so I also used the Hallsensor from a Golf. It almost fits right away in the distributor the only difference is the gap in the dizzie housing where the connctor slides in, that's a little wider for the golf sensor so I cut out out some metal to make it fit. It looks like stock!
When I installed it in my 181 it worked perfectly and I noticed that Idle had gone up by about 150 rpm. I assume this is because #3 is now working harder. I'm just not sure if I should leave it in there because I don't want to fry my #3, but then again there's loads of people driving arround with MSD and the like and are they all frying their #3?

njv · Post by **njv** » Sat Aug 23, 2003 3:34 pm

hi
why didnt you just use the cutter disc?

one thing i havenoticed with these ignition systems they are very sensitive as to the control module you use.

i cant help myself its two screws and there are normally loads in the scraoyard golfs scirrocos audis anything with a hall sender has the little black box i found some work much better than others even if they have thew same no in them i have noticed drops and rises in rpm of up to 200 rpm difference is there built in advance and retard in these moduals as well?

i have allways binned the DIS box as these are crap and do nothing but give a wavy idle it was one of the first things i allways did when i used to run a lot of mk1 scirroco gtis

i must say thanks for bringing this most interestring point to my attention more stuff to fidle with. when ive finished respraying my car that is.