It's pretty easy to recurve a distributor as long as you have needle nose
pliers to get the springs off and on. The rest is a snap. Just clean up all
the crap inside and voila, a new dizzy. I think everything costs about $30 -
40 to do.
Since I don't use my car for long periods of time I don't like points as
they can rust and stick which has happened to me 3x. Plus the points made
today are crap. I have a NOS set of Standard points from the early 70s and
the new points are not comparable to them. Even my friend who works for them
in NY agrees.
Mike
----- Original Message -----
From: <jon_wissler@pngc.com>
To: <datsun-roadsters@autox.team.net>
Sent: Friday, July 20, 2001 6:27 PM
Subject: RE: Re-Curving the distributor (Long)
> Brian,
> Best understandable description I have seen on the subject. I've
> always thought my off the line performance was dismal. It's only when I
> get revved up above 1500 to 2000 rpm's that I have power, and then I get a
> load of it. I advanced my smogger to about 10 last fall and it ran better
> in the low end, but getting on it caused it to ping. I just set it back
> to zero and it's running pretty darn good with fresh plugs, points, cap,
> rotor, and condensor. Since I'm an idiot mechanic, how difficult would
> you say it is to "recurve" my current distributor. At one time Les and
> Sport Imports claimed to have new in the box non-smog dizzy for $135 that
> I should have bought right there and then. Any chance there is a NOS
> version of the non-smog dizzy in the Nissan system anywhere? Do our
> vendors have them? That way I don't have to worry about my cam lobe being
> worn, bad springs, bearings, etc etc etc. My mechanic put a pointless
> distributor in our 69 510 with an L20B and it runs awesome. Could that
> distributor be modified? What the hell is the advantage to points over no
> points, or is there any. It sure seems like the hassle with points better
> come with some performance gains.
>
>
>
>
> "Brian Hollands" <bholland@hayes.ds.adp.com>
> Sent by: owner-datsun-roadsters@autox.team.net
> 07/20/01 10:08 AM
> Please respond to "Brian Hollands"
>
>
> To: <Robert.Long@CSDInc.com>, "Datsun Roadster Mailing list"
> <datsun-roadsters@autox.team.net>
> cc:
> Subject: RE: Re-Curving the distributor (Long)
>
>
> Before the emission controls were put on the roadsters, the distributor
> had
> 15 degrees of internal mechanical advance. If you set the ignition timing
> at 16 degrees BTDC and then rev the engine you will see - with the timing
> light - that the ignition advances or in simpler terms, that the spark
> happens sooner. At full mechanical advance, you would see the timing
> light
> fire at 31 degrees BTDC in the above example. In order to meet emissions
> regs - readings were taken at idle at the time - Nissan retarded the
> timing
> at idle. Emission controlled cars are supposed to be timed at TDC - 0
> degrees. The emission cars still need 30-35 degrees of ignition advance
> in
> order to make power so Nissan changed the distributor so provide 35
> degrees
> of mechanical advance. This way they could time the car at 0 degrees at
> idle but still have the required amount of advance at speed. The problem
> is
> that the cars don't run well with the smog distributor. They don't make
> good power right off idle don't idle well and are very prone to
> overheating
> when timed at 0 degrees. Nissan tried to fix that problem by adding the
> thermal modulator on top of the water neck which is supposed to open up a
> vacuum passage when the engine gets too hot. That vacuum goes to the
> vacuum
> advance unit which advances the timing until the engine cools back down.
> The thermal modulators are often not working or have been disconnected by
> people who thought that it's better to just disconnect that emissions crap
> not knowing what they are really doing. Many of those folks then time the
> car at 16 degrees not realizing that they now have 51 degrees of total
> advance which is way too much.
> The solution is to put a new distributor cam and weights into the
> distributor so that it will provide the correct amount of total advance as
> well as the correct advance curve - the amount of advance at any given
> engine speed. This is called recurving the distributor. It is very easy
> to
> do, you just need the correct parts which, I think are still available
> from
> the vendors. One other option which I am considering is to change
> distributors entirely. The later electronic distributors like those used
> on
> the B-210 can be adapted to the Roadsters and can also be recurved with
> many
> different curves being available.
> You can tell how much advance your dist. has built into it by removing the
> breaker plate so that you can look inside the dist. You will see a number
> stamped on the plate at the bottom of the cam. Most common are 7.5 and
> 17.5. This number is the degrees of advance the distributor has in
> camshaft
> degrees. Multiply that number by two to see how many crankshaft degrees
> that amounts to. 7.5 x 2 = 15 degrees which is a non-smog distributor.
> You
> can set the timing at idle at 16-20 degrees. 17.5x2=35. You must time a
> car with that distributor at 0 degrees or risk hurting your engine.
> There is more info on dist. swaps at
> http://home.att.net/~jason510/Dizzy_FAQ.htm
> This is L-series info but it applies to the roadsters as well. It just
> might not be cook book simple in an R or U series engine.
> Brian
>
> -----Original Message-----
>
> What does it mean/do, when you say you re-curved the distributer?
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