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Discussion Starter #1
I have an 80 Elco with the 305, entire ignition system is new except plug wires. recently had it retimed as I originally had a broken timing light and had to do it by ear. when initially checking it the timing light showed just over 40 deg when dropped back down to 12 the idle had to be increased. when driving after it warmed up the vehicle was a total dog, would not pick up very well at all, and even when easing into the throttle once you went wide open it would run really rought and die. also when letting off the gas to coast it would backfire severely, and even dieseled for about a min after shutting it down and had 2 big bacfires out of the back and some popping out of the carb too. also I have shorty headers on the vheicle and both collectors where glowing after driving for a few min on the highway. When driving on the streets I had to ease into the throttle to keep it from poping and backfiring. When I got it back home I moved the timing back to roughly where it was set previously around that 35-40 deg mark and it runs like a champ again.
I am wondering if maybe someone has put a cam in this car and not degreed it properly or is there another explanation for this that anyone else has run into. normally I would say the car should barely run at 40 deg timing...
 

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Discussion Starter #3
initial timing with vacuum disconnected before we reset it was 41 deg, we backed it off to 12 and that is when it started running terrible. after getting it home I eye balled it and put distributor back to where we started and now it seems to run great again. I am assuming timing at this point is between 35-45 somewhere but not sure as I didnt have a timing light at home to check it.
 

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I'm glad it's running great again. Only thing I can think of is maybe the balancer has shifted? I've seen it happen once. I come from the school of if it works be happy. Maybe someone else has a better idea, but I'm out. Good luck!

Joe
 

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Discussion Starter #6
Yeah I didnt think to check the balancer to make sure it had not shifted. I think I will worry about it when we put a new cam in it or new engine I will just plan to replace the balance just in case and see what happens.
 

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I would do what JJ and others suggested. Sounds like the timing mark is off..

When you have the light on, rev the motor and see if the timing goes up. Maybe somebody locked the timing and was running full timing all the time..
 

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i know the mechanic at the 60th reunion said to run them up to 35-40 degree. Setting to what GM suggested would do as you decribe (make it a real dog).
 

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i know the mechanic at the 60th reunion said to run them up to 35-40 degree. Setting to what GM suggested would do as you decribe (make it a real dog).

One of the first things I do after buying a car is power time the motor. My 69 with a 78 454 likes 22 initial, 14 mechanical slowly in at 2600, no vacuum advance.
People who don't understand timing curves some times get upset when you change something other then factory. The factory setting was designed to work on cars all over the planet. Some have daily weather of -10 to 90 day in and day out.. When tuning timing, I usually start with 87 octane if the motor is 9:1 or under..
 

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Discussion Starter #13
I havnt really come up with anything solid other than just run it at 40 degrees. I am planning on putting a cam in it sometime this winter if all goes well at that point we will probably replace balancer in case it has spun and then follow instructions from cam manufacturer on timing. as long as it runs as good as it does I am fine with running 40 deg timing.
 

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Couple of questions I haven't seen yet.


The emissions sticker for the 80 Camino with the 5 litre (305) call for 6 degrees @ 500 rpm (with the vehicle in drive). You say its at 41 degrees with the vacc advance disconnected.


Oddly enough this is almost exactly the total timing the oem system was designed to provide. In 1980 the LG4 in the El Camino had 6 degrees initial, 20 degrees mechanical (@ 3800 rpm) and 16 degrees vacc (@40 kPa about 12 in. mercury) [6+20+16 = 42] this leads me to believe your system may have a stuck advance system.




You say entire ignition system is new except plug wires: by this you mean out-of-box new, not just new parts installed into old distributor?
  • If so, whose distributor?
  • What rpm is the motor at when you set the timing?
  • Does the rpm climb when you hook up the vacc advance cannister?
  • Have you checked the timing with it connected?
Now a few things to check, most of which assumes an old distributor with new parts:


  • Remove the cap and rotor and examine the weights, are they up against the center pole of the distributor or are they slightly extended, when you pull the weights out do they spring back to the center of the distributor. What we are looking for is sticking advance weights. If the advance weights are going full advance the moment it starts then yes dialing it back to 12 degrees would make a dog. Because 12 degrees would be your full advance.
  • Test the vacc advance with a hand held vacc pump, with the engine idling and a timing light on, pump the hand pump slowly and watch the timing mark, note how much vacc was introduced at the hand pump and note how many degrees of advance at that vacuum. If nothing is added then either the vac advance is broken or the breaker plate in the distributor is stuck.
To best check this you will need the vacc hand pump, and a decent dial back timing light. also a vacc guage to determine you manifold vaccum at idle.
 

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Discussion Starter #17
new distributor with cap rotor and ignition coil and hei module all accell. got it for free from a buddy that had it still in box just sitting. as for the advance I have moved it manually and it seems to move freely and spring back just fine, i have not checked advance with vacuum pump yet. I will check to see if idle changes with vacuum hooked up or not and see what I come up with.
 

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I have the same thing going on with a GM crate engine that a customer brought me.
When I found out the pointer was off, just tuned it by ear and seat of the pants.
 

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Discussion Starter #20
I have not tried welding rod trick, or finding TDC on one yet, I will likely have to pull headers to get to it, or possibly use coat hanger and bend it around header. for now it seems to be running good according to the butt in seat test and breaks the tires loose with ease at lower speeds. I will update once I get a chance to sort this out, currently having to put a clutch in family members hyundai not near as much fun as working on the elco...
 
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