Hesitation with new motor

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  #1  
Old 07-20-2018, 05:41 PM
MikeJ67's Avatar
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Default Hesitation with new motor

Hey guys


Well, the 67 is "finally" running and on the road now. 327 sounds awesome. Fires right up, idles very nice but I have a hesitation when I take off. Everything is new. I mean everything. Newly built motor (for the second time), fuel pump, distributor, plugs, wires, carb, etc.. A friend came over to help me set the timing and we ended up pulling the plates off the carb (Holley Avenger 670) to replace the power valve and then the jets. All of the vacuum hoses are new and tight.


Where should I start? The distributor is an HEI and it might have an adjustable vac adv ?? with an allen wrench? Fuel pump is pushing 5 lbs, all wires & lines are connected.


Just trying to see if I need another carb? Or if this is something simple to chase out? I need to get a few hundred miles on this thing in a 5-6 day period before Hot August Nights when my wife & son will be driving the car up and I tow the 5th wheel trailer so we have a place to stay.
 
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  #2  
Old 07-20-2018, 08:17 PM
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Check the accelerator pump.
 
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Old 07-22-2018, 12:01 PM
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It takes time to work out the "bugs" in most new combination.and if you are in a hurry. Maybe put it on a scope by a reputable shop.instead of just guessing.
 
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Old 07-23-2018, 12:13 AM
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True that Zspoiler. I'll have to check to see about scoping the car.

Al Loyrat - for sure. I need to check and adjust the accelerator pump. We put a new power valve in the carb and when putting it back together the acc pump was tight (short - so came on real quick) I need to adjust it out a bit to see if that doesn't help some.

Wife took off in the car today while I was helping my son install a new phantom type screen door. I was also in the middle of replacing a door myself. She said she had to run home and put another coat of paint on a door she was painting, then said she was 3 towns away and loved the car. Haaaaaaaa That women. That is why I need to dial this thing in and quick.

Thanks guys
 
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Old 07-23-2018, 07:07 PM
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She, Camaro, might need a little more initial timing.
 
  #6  
Old 07-24-2018, 01:35 PM
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.015" gap at WOT should do it. Is this the engine that had oil pressure problem a while back? If you didn't drain the gas out of the bowl & pump, you might need to replace the acc. pump diaphragm. Cool wife story...
 
  #7  
Old 07-26-2018, 07:33 PM
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Best money you will spend is a dyno tune on your car. Go to a few car shows and ask around, They will know who is the best locally. I have seen race teams spend half a season just to get where a good tuner with a dyno can get in an hour or two.

Hesitation can be: (base timing/ weight/spring issue or an incorrectly working Vacuum advance)
Timing related
Acceerator pump adjustment
Accerator pump volume
Power valve
Secondary mechanical or vacuum adjustment

 

Last edited by Gorn; 07-26-2018 at 07:39 PM.
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