[Roadsters] 1600 tuning issues

[Keith0alan at aol.com]

Having the timing too far advanced will cause the idle speed to be high and 
 difficult to lower. For instructions on setting up the carbs check out 
_http://datsunroadsterranch.com/welcome.html_ 
(http://datsunroadsterranch.com/welcome.html)  .  Some backfiring on overrun is normal. The later cars had 
bits to stop it from  happening as it makes the smog folks crazy. 
 
keith
 
 
In a message dated 11/26/2012 10:44:09 P.M. Pacific Standard Time,  
aultgc at att.net writes:

Roy,

I think you're talking about two separate problems  here, which can 
contribute to one another.  Ignition and  carburetion.

The sputtering and backfiring can be a number of things,  but look for the 
simpler answer first:  ignition.  If the  condition of the ignition system 
is 
unknown or clearly aged, you need to  replace more than plugs, points, 
condenser and cap.  Did you  dismantle the distributor when you replaced 
the 
points?  You need to  make sure the mechanical advance is operating 
properly, 
that the weights  and springs are correct, and that distributor shaft is 
running true (not  worn).  Did you replace the plug wires?  I don't 
understand  "...have adjusted the timing as best I can."  What is keeping 
you  
from getting the timing essentially dead on?

The high idle is  probably carburetion.  Make sure the float levels are 
correct, the  needles and seats (inlet valves) are not leaking.  The 
suction  
pistons should drop freely with a slight "thunk".  The nozzles must  be 
properly centered in  the throttle bodies, and the tapered needles  must 
not 
contact the nozzles.  There should be no sign of wear on the  needles.  
Once 
running, the air flow through the carbs must be  balanced at idle and about 
2000 rpm.  (Opinions on this vary, but I  follow the factory instructions.) 
Once you have the air flow balanced, you  can balance the fuel flow.  I 
lift 
one piston, effectively taking  that carb out of service, and adjust the 
mixture until I get the best idle  I can.  Repeat with the other carb.  If 
everything is right, you  should be able to get a stable 500 rpm idle, but 
I 
run about 700-800  rpm.

So, I think you have more work to do before you throw up your  hands.

Gary
(219) 322-1923 (evenings and weekends; CST)

-----  Original Message ----- 
From: "Roy Haslett"  <hrhaslett at yahoo.com>
To: "Datsun Owners List"  <datsun-roadsters at autox.team.net>
Sent: Monday, November 26, 2012  8:56 PM
Subject: [Roadsters] 1600 tuning issues


> Hey  All,
> I just replaced my fried points, condensor, cap and  rotor...plugs
> too.  My 1600 was running poor and backfiring, alot  of hesitation too.
> Adjusted valves as well to .017 hot.  My  problem is its still running 
> weird,
> backfiring on  deceleration.  I have adjusted the timing as best as I can 
>  and
> acceleration is strong, just the sputtering and backfires when  backing
> off...idle is not great either....its high at about 1100 rpm  and I can't 
> get
> it lower.
> Any suggestions as to  tuning?
> Thanks,
> Roy Haslett
> 67 early 1600
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