Home > Personal, VW > “Two sparks forward…”

“Two sparks forward…”

May 29, 2005

… and one spark back.  MrsDoF is out of town, so my son and I are batching it this weekend.  He (possessing an actual social life) is busy, so I’m pretty footloose and fancy-free.

Hah!  Time to work on my Bug.  This 1967 sculpture of a car is a long-running joke, whose punch line may become less useful if I ever get it running satisfactorily.  Which is to say, as I remember how the ‘67 I had in college ran.

Yesterday and today I installed a Pertronix magnetic pickup in the distributor, eliminating the “points and condensor” that used to keep mechanics in boat payments.

Getting a classic bug running well today is a bit more challenging than it used to be due to the limited availability of vacuum-advance distributors among other variables. (Most VW parts places sell a Bosch 009 centrifugal-advance, which is fine for industrial applications like compressors or generators that use the VW engine, but not so good for, well, cars.)

Add to this the problem that gasoline now contains up to 15% alcohol, which isn’t a great match for the 34PICT-3 carburetor that VW used with the “late-model” 1600cc engine.  So there’s lots of urban legend and lore about getting smooth response.

I am using Aircooled.net‘s SVDA distributor and a beautiful NEW German 34PICT-3 carburetor, both set to specifications, and result is great… sort of.

At the moment the car is running smoothly and strongly – actually better than it has since I dove headlong into this crazy project.  But it’s hot.  The engine is really toasty after only short periods of running.  Last night it died on me, possibly from heat-induced vapor-lock.

The timing is 30 degrees max with the vacuum hose plugged (which is to say, centrifugal only).  It maxes out at about 40 degrees (!) at 3000 rpm with the vacuum connected, which seems like a lot but according to Aircooled, that’s about right. 

There’s no “flat spot” of power-loss on throttle application, which is the problem the SVDA distributor is supposed to address.  It’s really very nice!  So why is it running so hot?

Could be the gas.  The tank is full of gas that (I now realize) is 8 months old and may not be fully burning before it leaves the ignition chamber.  I’m going to add some StaBil to it (which I should have done last Fall) to see if that helps. (Update: I drained out the gas and replaced it with fresh premium, and the engine stopped dying but is still really hot.  Anyone know what to do with 10 gallons of old gas?)

On another note, if you’re running a classic VW, get one of these laser-engraved pully wheels.  It makes setting the timing SO much easier.  No more guessing which type of pully wheel you have, and how far around the (unmarked) pully is 30 degrees.  There are enough variables to driving a 37-year-old car; don’t add guesswork to them.

By the way, the pully wheel in this picture was spinning at 850 rpm when this picture was taken.  That’s about 14 revolutions per second!  The pully wheel is about 6.75 inches across, which is about 21 inches around for an edge surface speed of 25 feet per second, or roughly 17 miles per hour.  Yet it rendered sharply because this is a flash picture.  My little digital camera has a tiny flash which equals a very short duration.

(I rounded those figures starting with the estimate of the pully wheel diameter, so you calculator people just put those extra decimal places back where you got ‘em.)

Categories: Personal, VW
  1. May 31, 2005 at 16:40 | #1

    Jay says a couple of things could be wrong. Spark plug heat range could be wrong for the alcohol adulterated gasoline.  Or the cooling vent in the shroud jammed or stuck shut.

  2. Dennis Boots
    June 26, 2005 at 17:05 | #2

    I’m going to put in a new oil pump but first I need to get the crankshaft pulley off.  I have 30mm socket and pry bar and I would love to know how to keep the pulley from turning while taking the nut off.  Please email me and let me know if you know of a simple way to hold the pulley while taking the nut off.  My pulley is identical to the one you have in pictured on your web site (06-26-05).  Any help you can provide would be greatly appreciated.  Thanks Dennis Boots.

  3. June 26, 2005 at 18:49 | #3

    If your pully is like the one above, you can put a broom handle through one of the holes and rest the end against the case behind it.  Also a swift motion of the ratchet handle or breaker bar will help.  If the engine is out of the car, you can use a flywheel lock to secure the crankshaft and then no problem.

    If your pully is an original, stamped steel type with no holes, you have a different problem.  There is probably a slot through which you can put a very large screwdriver to brace against the case, which should help.

    Once the nut is off, you have another problem: getting the pully off the end of the crankshaft.  The stock type is a close fit but these laser-engraved, Scat pullies are actually an “interference fit” which means the hole is a tiny bit smaller than the shaft.  I had to soak the above pully in hot water to install it – you will need to heat your pully up a little to remove it.

    Use one of those VW pully tools to remove it – don’t try to jury-rig a regular one for the purpose.

    Good luck!  (I still have not solved the heating problem, alas.  I think there’s a fuel system problem of some kind.)

  4. Adam
    May 20, 2006 at 08:43 | #4

    Hello i see you are having a problem with overheating this is very common when you change the bottom pulley from the standard steel one to a nice alloy one. The alloy pulleys for sale are normally smaller than the standard steel so if the pulley is smaller it does not tern as many times as a big pulley so the cooling fan does not tern as many times so the fan can’t do its job properly, i would just put the old standard steel one back on and you wont have any problems, i hope this helps.
    Adam (England)

  5. May 20, 2006 at 11:01 | #5

    Hi Adam!  The overheating problem turned out to be what Jay said – it was the heat range of the spark plugs.  My Brazilian engine had shipped with nonstandard plugs.  The problem went away when I put in the correct range.

    But – you are absolutely right about the pully, many of the alloy pullies are small-diameter.  I can’t imagine the minor gain in horsepower from a smaller pully would be worth the loss of cooling! This one is stock diameter

    Now I’m trying to find a tire dealer in town who can still balance the old-fashioned 5-bolt wheels as my tires definitely need to be replaced.  If anyone has any good wheel-balancing methods I’d sure like to hear them!

  6. Joe L
    June 11, 2006 at 22:24 | #6

    Hey Fellas:

    A good way to get that crank pulley fastener loose is to simply put the car in gear and have your buddy stand on the break… Simple procedure if you can’t get an impact wrench in there.


  7. Dustin
    November 18, 2006 at 19:40 | #7

    I need help taking off a crank pulley and im putting on a lightweight one does anyone know how to do this.

  8. November 18, 2006 at 20:26 | #8

    I suggest using one of the special-purpose pully-pullers linked in comment #3.  While they say it can remove the pully with the tin in place, it is easier if you have the rear tin and the muffler off.

    Be sure your new pully is stock diameter.  If it is smaller than stock diameter, it will cause the engine to run hot.

  9. Tom
    March 15, 2007 at 09:49 | #9

    For wheel balancing, I purchased one of these a while back and it works great!


    Just be careful that you don’t overtighten the wheel to the adapter plate.  Also note that there are 12mm and 14mm stud versions.

    If the link above is outdated by the time some read this, search eBay with the keywords vw balanc*

  10. March 15, 2007 at 11:05 | #10

    Thanks Tom – that is awesome!  I am so getting one of those.  I’ve got a friend to tell about them too.

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