Not sure what to check next

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22dog22

22dog22

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this is a fresh rebuilt 318, comp. cam, hi dome pistons,had a issue with a rebuilt holley 600 cfm duel pumper carb, which I had posted here, I think I have taken care of the carb problems , I think, does not leak fuel any more, set fuel float level, adjusted the air/fuel mixture screws, got engine to idle a little better, I can not tell if I have a miss or some other carb problem engine will not hold an idle checked for vacuum leaks since I have an aluimuim manifold, sprayed carb cleaner around did not change the engine condition, have a none mopar electrionic ignition system with out a resistor block [needs full 12 volts],how do check for a misfire ? to rule out the ignition system. or how check out the carb more?
 
How big of a cam do you have...(idle vacuum)? And, how are you timing the engine currently...(initial/total)?
 
it has comp. cam number 20-223-3,duration 268,duration @.050 lift 224,valve lift 0.477,lobe lift 0.318, have basic timing set at 10' btdc . with vacuum line pluged to dist. vacuum advanced.
 
Assuming the carb is now in good shape, I'd try bumping the initial (at idle) timing up to the 15/16* range and see if it makes a difference? Without a timing tape or degreed balancer, you will have to eyeball it, but it will tell you if the engine likes more timing. If so, you can get to what it likes at idle and then worry about your total timing by moding the mechanical advance later. By the way, do you have any paperwork on what advance was initially installed in your new dizzy?
 
With the new cam and fresh startup and carb issues, were you able to run the engine for 15-20 minutes at 1500 RPM or more at initial startup for cam/lifter break-in?

Cam sounds like it ought to idle OK, perhaps a bit lumpy.

If you really think you have a miss, set it where it will idle fair, and pull each plug wire one at a time at the distributor end and see how the idle changes; if not much change, there's an issue. Have you taken compression readings
 
Forgive me if I am wrong (I am pretty sure someone will correct me if I am).
I have basically same setup.
Doesn't the initial timing need to be set WITHOUT the vac connected?
Mine finally settled on *14 BTDC and liked it alot. (Set without Vac)
And don't forget to plug the vac port when you do it.
Good luck!
 
I've used a $10 Harbor Freight temp gun to check each exhaust port.
I found one about 200 degrees cooler and sure enough, bad wire.
 
22dog22 said:
it has comp. cam number 20-223-3,duration 268,duration @.050 lift 224,valve lift 0.477,lobe lift 0.318, have basic timing set at 10' btdc . with vacuum line pluged to dist. vacuum advanced.
Click to expand...

A little more advance is a good start. How much difference do your idle mixture screws make? You may have exposed transfer slots. Try bumping the secondary stop screw to get some idle air bypass so you can back off your primary stop screw.
 
Though not grammatically correct I think he is saying the vacuum is disconnected and plugged.
 
TIMING FIRST!!!

Increase initial timing. 10* is not enough for that cam/engine combination. I run that type of set up in the 16-18 range for initial, it makes a HUGE difference. Fix mechanical advance so your total number doesn't go out of bounds.

You may have killed the rings/spark plugs with your break in carb issues. Hopefully it's just plugs.
 
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