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440-6 engine dyno???? #89708
07/17/08 08:40 AM
07/17/08 08:40 AM

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I have a 70 cuda with 45 miles on it and on it I upgraded to pointless distr. At cruise I get a constant surge. I did the engine completly stock. I have been told to use the vacuum advance and no do not use the vacuum advance, set the timming a 18*BTDC not 10* as the bood says, its a carb problem and now the local guy says the only way to figure this out is to put it on a dyno. I sure don't like the way the engines sound on a dyno, is it safe and do you agree. Any ideas would really help right now. The guy with the dyno told me that setting the timming at 10* and the total advance at 36* and hooking up the vacuum and have the total advance pulled up to 52* is perfect.

Re: 440-6 engine dyno???? #89709
07/17/08 09:19 AM
07/17/08 09:19 AM
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JohnRR Offline
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don't take this the wrong way but ...

you don't seem to have the skills to correctly tune it , and seriously sometimes i don't either so it will be money WELL SPENT to take it to a shop with a chassis dyno that can duplicate actual running down the road and tune out that surge , correct the A/F ratio and get the most power out of the engine .

it's a no brainer

Re: 440-6 engine dyno???? [Re: JohnRR] #89710
07/17/08 09:48 AM
07/17/08 09:48 AM

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not taken the wrong way, thanks for your wisdom as I am a carpenter and not a mechanic

Re: 440-6 engine dyno???? #89711
07/17/08 10:39 AM
07/17/08 10:39 AM
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Aurora, Colorado
451Mopar Offline
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Surging at cruse speed is usually the carb being too lean. The chassis dyno is a good tool and they will likely hook up a wideband 02 sensor to the exhaust so they can see the air/fuel ration under different load conditions.
The quoted distrubitor advance curves don't sound unreasonable, but not all engines are the same.

Re: 440-6 engine dyno???? [Re: 451Mopar] #89712
07/17/08 10:55 AM
07/17/08 10:55 AM
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Lincoln Nebraska
RapidRobert Offline
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see what jets are in your center carb,swap to a pair 4 sizes larger & go back out for a cruise.


live every 24 hour block of time like it's your last day on earth
Re: 440-6 engine dyno???? [Re: RapidRobert] #89713
07/17/08 02:48 PM
07/17/08 02:48 PM
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dogdays Offline
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Chassis dyno time will help majorly or you can try repeated jet changes to try to narrow down the A/F problem you seem to have.

R.

Re: 440-6 engine dyno???? #89714
07/17/08 05:08 PM
07/17/08 05:08 PM
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Quote:

I have a 70 cuda with 45 miles on it and on it I upgraded to pointless distr. At cruise I get a constant surge. I did the engine completly stock. I have been told to use the vacuum advance and no do not use the vacuum advance, set the timming a 18*BTDC not 10* as the bood says, its a carb problem and now the local guy says the only way to figure this out is to put it on a dyno. I sure don't like the way the engines sound on a dyno, is it safe and do you agree. Any ideas would really help right now. The guy with the dyno told me that setting the timming at 10* and the total advance at 36* and hooking up the vacuum and have the total advance pulled up to 52* is perfect.


the 10-36-52 timing scenario is correct. you were given carb advice in a previous post. please use those jetting tips and your problems will probably be solved.

Re: 440-6 engine dyno???? [Re: lewtot184] #89715
07/17/08 07:22 PM
07/17/08 07:22 PM

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The new repo carbs come with 62 jets in the center carb--not enough--add some jet and that baby will do great--I agree that a 66 to a 69 is a good starting point depending on your type of exhaust etc







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