(Semi transistorized) Dwell question.

[tommyt]

I've looked through the "search" so as not to waste time. No answer found. My 78' 45 runs OK. It has the 2F with "semi-transistorized" ignition system. It's not clear to me whether I can set the points to the .018" gap. I don't think it's settable. It's been 20+ years since I've had to work on leaf blowers. I put my tach/dwell meter on it and found I had 31 degrees of dwell. As I said before, my manual is unclear about setting the dwell/points for this system. The numbers in the book are 39 to 43 degrees. I checked my timing and found it was advanced. My vacuum line was off, eng was up to temp. I say advanced because my timing light showed the mark on the flywheel about 1/2" before the indicator. I moved the distributor and set the timing to spec. Still runs OK. Dwell effects timing as far as I remember. So to make a long story longer. Is my dwell settable? Should it be set to 41 degrees? Is 31 degrees OK for this system? It's my piano and I'd like to tune it up as best I can. Thanx for any input. Note this eng only has 127,000Klms on it, (Tee hee hee).

 

[Pin_Head]

Adjusting the point gap will change the dwell, with a smaller gap giving more dwell. I could never get my gap set to give 40 degrees on the dwell meter on my semi transistor '76, but it runs fine set at .017 - .018. Forget about the dwell and just set the gap and timing. The only situation where you might have too little dwell is at RPMs above 7,000, so you aren't likely to have a problem with misfiring. The valves will float first or you will throw a rod.

 

[tommyt]

Thanx Pin_Head, (boy that sounds bad). I think I'm going to have to post a pic if I'm allowed. I hate yarding on things. The picture in my Haynes shows a cover that should come off over the points. I tried to get it off with no luck. What I have where my points are looks different from the pics. I'll see if I can get cruiser time today and re-post tonight.

 

[Pin_Head]

If it has a cover, it is not a points set up that I am familiar with. '78s in the US were fully electronic ignitions with a pickup that might look like a cover.

 

[tommyt]

Here's a pic of my dizzy set up. Is there an adjustment I can make to achieve proper dwell numbers?