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Rgds Chris
Thanks for the re-post. I don't think the type 3 list never got to see this whole description.I'VE FITTED A NEW BOSCH SET OF SILICON LEADS AND CAPS AND ALSO TRIED SUBSTITUTING A COPPER CORED LEAD INTO EACH CYLINDER IN TURN. - NO CHANGE.
On 26 Sep 2005 at 10:02, chris wright wrote:
You can imagine it best by imagining accelerating on a very bumpy road so
that the car jerks over the bumps.
To me this sounds more like ignition "miss" than anything else. I would be looking at ignition problems.
Under acceleration, the throttle is open more so more air/gas gets in the cylinders; this leads to higher chamber pressure when the spark occurs. Higher pressure air/gas is a better insulator, so higher voltages are needed to break down the spark gap. At higher voltages, there is a greater chance that the spark will jump over somewhere else first.
Things to check:
Measure the resistance of each of the spark plug wires. These may have been resistor wires originally, but you'd be best off now with the Bosch SP connectors that have the 1000 Ohm resistor in them. Make sure they are used with copper core wire and that the resistors haven't gone open. Measure each wire from end to end. Measure the coil wire, too; it should measure zero, unless it has one of the coil end resistors in it. Individual connectors which have gone open can be replaced; they are cheap.
Around '71, Bosch/VW came out with some nice red silicone rubber covers for the ends of those connectors. They seal the SP insulators from dirt and water and make the engines much easier to start in damp weather. They are a worthwhile investment. DON'T buy the earlier (~'67) version which is just a cap on the connector; these don't work as well and usually come off on the SP.
Same with the dist rotor. I believe they should be 5000 Ohms, but some are zero Ohms. Just make sure that it isn't open.
I'VE FITTED A NEW ROTOR OF THE CORRECT TYPE. ITS 4800 ohms IIRC.
Check the SP wires. They should be copper core with no cracks in the insulation.I'VE FITTED NEW PLUGS AND ALSO SUBSTITUTED ANOTHER NEW ONE INTO EACH CYLINDER IN TURN
Check the spark plugs and make sure they haven't worn so that the gaps are excessively large. The gap should be .028". The center electrode should have nice sharp square corners.
Check the cap, inside and out, for dirt, carbon tracks, and moisture.IT'S CLEAN AND NO APARRENT DAMAGE, BUT I'VE ORDERED A NEW ONE. I'M STILL ON THE ORIGINAL SO THIS IS STILL A POSSIBILITY. GETTING ONE FOR A 64 ONE YEAR ONLY DIZZY IS NOT EASY!
Your dwell should be 45-55 degrees and should be stable regardless of rpm.
IT'S 47 DEGREES AND STABLE.
I've also seen startup ignition problems in rainy weather when water collects in the air intake system and gets sprayed over the cylinders and heads at startup. The SP connector covers mentioned above help that a lot, but another thing to do is to make sure that the drain hole at the bottom center of the fan housing is clear. They often get clogged with dirt; clean it out with a small stick.
IT'S BEEN CLEANED OUT RECENTLY WHEN I DROPPED A NUT DOWN INSIDE!
Where are you located? Has your weather been rainy/damp lately? A bit of condensed moisture can certainly cause problems like this, and the moisture will be driven off by engine heat once the engine warms up.I'VE NOT USED IT IN THE RAIN LATELY AND IV'E DRIVEN TO WORK SEVERAL TIMES IN THE SUN, A 40 MILE EACH WAY TRIP.
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