Don't know for sure, but it sounds to me like an ignition problem. Maybe
the distributor jumped and threw the timing off. I know you said the timing
is right, but check one more time.
Set it at 0 degrees TDC with the rotor towards #1 on the distributor. Pop
off the valve cover and check that the #1 valves are in the right position
(end of compression stroke so both valves are closed). If not, then the
distributor is not oriented right.
If okay, then try starting it there, and then start advancing the
distributor little by little until it runs okay. If you have to advance much
beyond 15 degrees then it's likely that the distributor jumped position
somehow.
I had a similar problem with my '70 1600 when I bought it as a parts car.
According to the P.O., it hadn't run in years and she thought the engine was
blown. I got it running, but it ran like crap, backfiring constantly
although it did idle okay. The distributor was all screwed up. Once I
replaced it the car ran like a champ.
Fred
----- Original Message -----
From: "Dave Stoll" <dgstoll@mint.net>
To: "steve car" <steve_car@hotmail.com>; <datsun-roadsters@autox.team.net>
Sent: Sunday, October 22, 2000 2:39 PM
Subject: Re: Backfire problem
> backfire thru the carbs maybe a sticking intake valve
>
> dave stoll
> ----- Original Message -----
> From: steve car <steve_car@hotmail.com>
> To: <steve_car@hotmail.com>; <datsun-roadsters@autox.team.net>
> Sent: Saturday, October 21, 2000 9:57 PM
> Subject: Re: Backfire problem
>
>
> > A couple more things: It seems to be backfiring at the carbs most of the
> > time verses at the exhaust pipe. But I am not sure it is actually the
> carbs
> > but it seems like it.
> > Also, it doesn't run quite right when I give it some gas and before it
> > starts backfiring.
> > I just noticed that I didn't mention that the tube with the screw is at
> the
> > intake manifold that used to go to the smog stuff. I already have the
> > nonemission distributer installed.
> > Thanks again,
> > Steve
> >
> >
> > >From: "steve car" <steve_car@hotmail.com>
> > >Reply-To: "steve car" <steve_car@hotmail.com>
> > >To: datsun-roadsters@autox.team.net
> > >Subject: Backfire problem
> > >Date: Sun, 22 Oct 2000 02:44:28 GMT
> > >
> > >I was out today and all of a sudden my 69 1600 started backfiring like
> > >crazy
> > >when I gave it gas. This happens during acceleration and a constant
> medium
> > >speed. It ran good at idle and low speeds though. One thing I noticed
> was
> > >that my tube with the screw in it had popped off. But it did not solve
> the
> > >problem when I put a new one in.
> > >
> > >Timing is ok, fuel level in carbs is ok, vacuum advance mechanism moves
> > >when
> > >I suck on it. Points, plugs ok. Choke is not stuck. I tried looking for
> > >manifold leaks with no luck. Maybe I am doing it wrong though. I
sprayed
> > >some carb cleaner at all gaskets and throttle area without noticing any
> > >stumbling. This was done at idle.
> > >
> > >I am out of ideas. Does anybody have any suggestions? How do you
> determine
> > >for sure if it is fuel or ignition?
> > >
> > >Thanks,
> > >Steve
> >
>_________________________________________________________________________
> > >
> > >
> >
> >
_________________________________________________________________________
> >
> >
> >
>
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