

| Subject: | Re: Gap of Sparks - Note correction |
| From: | Stan Wilder |
| Date: | Sat, 15 Feb 2003 23:36:49 -0600 |
My air cooled will not even start with the electronic ignition COIL. I've been told that the electronic COIL produces more current / spark. ------------------------- On Sat, 15 Feb 2003 22:50:58 -0600 Stan Wilder <wilden1@JUNO.COM> writes: > I've been laying out of this because you guys have got the ignition > system pretty well down pat. > I've had some good and bad experiences with VW distributors, mostly > 009 > and the 205 that is on air cooled vanagons. > Good tight distributors with good cams are important to achieve > full > power from an engine with a point set ignition. > Vertical shaft movement can cause point dwell to change because the > cams > are traveling both in rotation and a vertical jump at various times > of > acceleration or just idling. > Testing the cam is easy enough just by rotating the cam to each high > cam > position and measuring the point opening with feeler gauges. You can > also > use a dial gauge if you can get it rigged properly (not easy). > One revolution isn't enough testing, it needs to be tested for three > or > more revolutions to verify properly. > I've found cam shafts with strange wear patterns that are .002 out > from > one cam high to the other cam high positions. This in effect > changes > dwell and will cause premature or late plug firing. The condition > can be > caused by slightly bent distributor drives or on drives that have > had > pitting due to rust. Running the shaft dry can cause excessive wear > down > of a single cam lobe while the others appear correct. > The spring under the Vanagon and most VW distributor drives is > supposed > to stop vertical bounce caused by the gear bouncing on the lower > crank > contact gear. However under hard deceleration the drive will draw > down on > the spring, this doesn't cause any problems but as the drive > travels > upward it gives the distributor a little advance of 1+ degrees and > can > cause an occasional backfire. > Vertical bounce happens under deceleration and acceleration of the > engine > at high RPMs. > If the brass drive gear on the crankshaft is worn unevenly or is > just a > sloppy fit it can cause advance / retard changes that you cam measure > by > accelerating the engine several times and noting the variances. > I've proven to myself that good distributors are a necessity for > proper > delivery of spark to the plugs. > Having a box of about ten distributors in various condition has > given me > the tools to experiment and disparity can be detected even with > simple > tach, dwell meters of good quality. > Carefully accelerating the engine while watching the advance on the > timing arc and multiple cycles at various RPMs can detect > distributor > advance slowdown or vacillation. > One war story I might relate here is that I've found long screws > holding > point sets down, they lock out the advance if they are longer than > 3/8" > long. > If you've had a distributor showing rust, pitting or other signs of > moisture exposure that is abnormal you can find weak counterweight > springs that will cause too fast advance. > Someone just mentioned that the point set and electronic ignition > coils > are the same ........... I doubt this. > My air cooled will not even start with the electronic ignition > distributor. I've been told that the electronic distributor produces > more > current / spark. > It has been suggested that Air Cooled vanagons could run hotter > plugs > without damage if you want to peruse it. > Hotter plugs can cause detonation in some operating environments so > take > caution on going too hot. > > Stan Wilder > 83 Air Cooled Westfalia > > ________________________________________________________________ > Sign Up for Juno Platinum Internet Access Today > Only $9.95 per month! > Visit www.juno.com > > ________________________________________________________________ Sign Up for Juno Platinum Internet Access Today Only $9.95 per month! Visit www.juno.com
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