[Roadsters] 68 Datsun Problems - The Remedy

Charles Kyle chuckkyle at mac.com
Fri Sep 21 21:06:06 MDT 2007


Good Evening,

Several months ago I posted the below information regarding an issue that I was having with my roadster.  Well finally (after 4 months)  I have solved, or at least paid for a solution to the problem. So here was the solution:

Symptoms that were not solved:

1.)  The temp gauge is not working properly, using a temp gun, the engine is around 180 not nearly the 250 that the temp gauge reads
2.)  Oil pressure gauge goes crazy - acts like a tachometer when you push on the gas, basically jumps from 0-60 and back down. - no solution but an oil gauge at the shop shows that the oil pressure stays steady.


BUT:

So the car was running about 45 minutes then backfire, no power.  The fuel was not getting from the tank through the filter and to the carbs causing the car to "vapor lock".  After replacing the fuel tank, fuel lines, filter. No joy.  So what Datsun Dynamics (defunct shop in Alexandria VA owner suggested), we (actually a shop) added a mechanical fuel pump inside the gas tank.  The car runs great now.  Any one ever done this before?  or heard of such a thing?

So any suggestions on the gauges?  Should I just replace them?  Oh the light is burned out in the speedo, is there a trick to that too?

Chuck


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I have a 68 1600 R16 engine.

The car runs good for 45 minutes or so.  Then it begins to backfire.  This 
backfire is toward the manifold or carbs not through the tailpipe. If I am 
going 45 mph and it begins to backfire, no matter how much or how little 
throttle I give it it continues to backfire and rolls to about 5 MPH.  At this 
point it has NO power what so ever.  I can stop the car and wait 20 or 30 
minutes, it will start and then go for a little while and do the exact same 
thing.  So here is what I have had done so far:

1.)  Replaced thermostat and radiator
2.)  Engine rebuild
3.)  Replaced carbs (from Z-Therapy)
4.)  Replaced fuel pump, fuel line and fuel tank


Conditions that occur each time:

1.)  Temp gauge goes to 220
2.)  Oil Pressure gauge starts to look like a tach, jumps from 20 to 40 and 
then to zero.  While it is backfiring and you are giving it gas, the oil press 
gauge moves up and down the way a tach would do it.
3.)  Backfires
4.)  Engine is on but the car has NO power.

Observations:

1.)  There is NO steam or overheat conditions at the radiator that would 
suggest that it is over heated, no antifreeze in the oil
2.)  No oil leaks

Any suggestions would be greatly appricated.

Chuck





Chuck

Hm 512-225-4501


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