240Z, 260Z, 280Z (S30) Forums Dedicated to first generation ZCars

new n42 runs bad plus no headlights

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Old Mar 10, 2015 | 03:16 PM
  #1  
7d82adz's Avatar
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new n42 runs bad plus no headlights

So i had a 76 n42 motor with big cam, flat tops, and su carbs.. i jumped timing when i floored the car.. so i decided to install a different n42 engine that is all stock into the car, this motor also running on the su carbs.

Now the car runs again, but poorly.. seems to be a electrical issue.. but i had no issues with electrical before.

Cold start it will fire up after 20sec of cranking with choke on. Run fair and free rev okay without hesitation.. carbs are synced and timing seems to be okay.

Then after a minute or two of getting up to temp.. the car really loses power and seems like it runs on only a few cylinders ( no more than 3).. then dies out..

I can start it again but it really doesnt want to run good.

My headlights dont work now either.

Could I have damaged the coil when i free reved to 8000rpm?

WOuld a improperly installed distributor cause any of this?

Any help is appreciated.. thankyou
Old Mar 11, 2015 | 08:52 AM
  #2  
7d82adz's Avatar
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I apparently have a huuuge power draw somewhere.. i checked distributor, distributor shaft, plug wires, and put a timing light on it.

Runs better without vacuum advance for some reason.

The battery was trickle charged yesterday and held a good charge all night.. Today after checking ignition stuff i started it up.. ran good for 2 or 3 minutes. then killed the battery and died out.

My lights were working while it was running, so maybe yesterday it didnt have enough power to power the lights.

This is really odd to me.. my alternator came off my other motor, which was doing the job up until i jumped timing chain.. I even tried a new 60 amp fresh outve box.. car still dies out due to major power draw.

Old Mar 13, 2015 | 07:58 AM
  #3  
NismoPick's Avatar
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From: Wild Wild West, UTAH!
Have you checked the alternator output? When running, it should be at ~14.7v. And you're using an externally regulated alternator? S30's are external...
Old Mar 13, 2015 | 03:18 PM
  #4  
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Originally Posted by NismoPick
Have you checked the alternator output? When running, it should be at ~14.7v. And you're using an externally regulated alternator? S30's are external...
Actually, the 78 is internally regulated.
Old Mar 13, 2015 | 07:31 PM
  #5  
theramz's Avatar
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Joined: Mar 2003
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From: dayton, nevada usa
I think your newer engine is bad too. Start with the basics like compression test. BTW those engines weren't supose to go 8k rpm even when new.
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