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Re: Plugs and their gaps

To: "Roadster List" <datsun-roadsters@autox.team.net>
Subject: Re: Plugs and their gaps
From: Ronnie Day <ronday@home.com>
Date: Fri, 6 Apr 2001 08:22:14 -0500
>When I had points I had the same problem as the dwell was not in spec when I
>set the points to the correct gap. I read that dwell was more important than
>the gap and you should go for the correct dwell.  And I always thought it
>was just me!!!

The dwell is direct effected by the point gap. It's the measurement (in 
degrees of rotation) of how long the points are closed. The smaller the 
gap, the longer (or greater) the dwell, the larger the gap, the shorter 
dwell. Dwell is the more accurate way of adjusting the points because 
it's not effected by pitted or nonparallel point contacts. You need to 
set the dwell before you set the timing because the timing is determined 
by the dwell.

If your points are pitted it's best to replace them, but they can be 
filed flat. You should also use a little bit of high temp grease to lube 
the rubbing block where it contacts the cam lob. Realize that as the 
rubbing block wears the point gap closes and dwell increases. If you 
don't use the right lube at this point, the wear will be faster.

IMHO, the best thing to do is to adapt a breakerless (magnetic pickup) 
from a later model (late '70s) L-series motor. We've discussed it on the 
list before and while I don't remember all the details, I think it 
involves combining the top end of the L-4 electronic distributor with the 
base from the U-20 if not also on the R-16. Point wear and timing drift 
become things of the past. If you want keep the point type distributor 
for shows and such, that's great, but I think you'll be amazed at how 
much better a car will run with this setup, if everything else is in good 
condition. It's not a cure all for a sick or worn out engine.

Maybe TMI, but since you asked.

FWIW,
Ron

Ronnie Day
ronday@home.com
Dallas/Ft. Worth
'71 510 2-dr (Prepared Class Autocrosser)
'73 510 2-dr (Street Toy)

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