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Old 03-31-2013, 02:49 PM
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I agree that you can improve the characteristics of the motor with proper spark advance and improve the characteristics of performance of the vehicle with a looser converter, but the fact remains that you have used too much cam timing for the available static compression ratio of the motor and nothing can fix that, short of using less cam or more static compression ratio. Anything else if just a crutch. Please refer to this wiki article to get an idea of what cam should be used with what static compression ratio.....
http://www.crankshaftcoalition.com/w..._compatibility

Don't feel like the Lone Ranger though, the majority of fellows who change cams will use too much cam for the available SCR. It takes a while and a few engine builds to understand that each part you use to build a motor has to compliment all the other parts to make a good COMBINATION. No single part stands alone, they all have to work together toward a final goal.

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Last edited by techinspector1; 03-31-2013 at 02:58 PM.
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Old 03-31-2013, 02:58 PM
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And to think that aid in choosing the right parts has been all along................................Just incredible!!!!.

You taught me awhile ago two things,don't sweat the small stuff and you can only teach the willing.
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Old 03-31-2013, 03:20 PM
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Quote:
Originally Posted by techinspector1 View Post
I agree that you can improve the characteristics of the motor with proper spark advance and improve the characteristics of performance of the vehicle with a looser converter, but the fact remains that you have used too much cam timing for the available static compression ratio of the motor and nothing can fix that, short of using less cam or more static compression ratio. Anything else if just a crutch. Please refer to this wiki article to get an idea of what cam should be used with what static compression ratio.....
http://www.crankshaftcoalition.com/w..._compatibility

Don't feel like the Lone Ranger though, the majority of fellows who change cams will use too much cam for the available SCR. It takes a while and a few engine builds to understand that each part you use to build a motor has to compliment all the other parts to make a good COMBINATION. No single part stands alone, they all have to work together toward a final goal.
Thanks for the link Tech. I will read it thoroughly and change out the cam down the road.

I did want to ask Fbird a question. While i have your attention. At what RPM do i set the timing? 34-36 deg at idle? 3000 rpm? Im printing off the link you gave me and heading to my shop after typing this. Going to try and get this squared away.
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Old 03-31-2013, 03:43 PM
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FBird is suggesting that you eliminate the centrifugal advance altogether and lock the spark advance in at 34-36 degrees, depending on the combustion chamber design in your heads, so that you put all the advance in at the crank and have 34-36 at idle and all the way through the rpm range. The only other variable would be vacuum advance needed at cruise (light load) to raise total timing to 40-50 (or whatever) total degrees of advance for fuel mileage improvements.

This much ignition timing will cause the motor to fight against the starter when cranking to start, so some means of freeing up the system will have to be used. Down and dirty, cheap and simple is to interrupt the coil wire and install a (normally-on) momentary-off push button switch in the line with the switch mounted in a convenient location in the driver's compartment so you can push the switch while keying the starter. (Normally-on) means there will be an electrical connection through the switch except when the button is pushed to interrupt the current flow to the coil. When you hold the button and stop current to the coil, this will allow the starter to spin the motor free of firing the spark plugs when cranking it over. Once the motor is spinning, let go of the momentary switch to restore current to the coil and fire the plugs and you're off and running. There are electronic devices which will do the same thing, but suffice to say they are not as cheap as a plain old momentary-off push button switch and some 12 gauge wire.

This operation assumes that you have verified TDC at the crank and that you know positively that the mark on your damper is correct.

Last edited by techinspector1; 03-31-2013 at 04:00 PM.
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Old 03-31-2013, 03:52 PM
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If you are using locked out timing, the timing does not change with rpm. It is the sameat idle as it is at higher rpm.

If you are going to use a modified advance curve, then you want it to max out at about 2800-3200rpm.
It must stay stable at idle.
When checking timing with a light be sure to rev the motor high enough to see max advance.

Vacuum advacne is a separate issue. use ported vacuum for this cam. Should be limited to a max of 10-12deg at highest applied vacuum.

36deg BTDC is 1/10th the circumference of the balance from TDC.

Last edited by F-BIRD'88; 03-31-2013 at 04:03 PM.
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Old 03-31-2013, 05:28 PM
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Well I locked out the dizzy and stabed it back in after finding tdc and pointing the rotor to number one cylinder. I had to spin the cap has far counter clock wise as it would go to get it to fire and idle. I check it wirh a light and it shows 8 btdc. I guess my question is how do I get it to 34-36 with out anymore adjustment in the dizzy? Do I need to restab the distibutor closer to say 15-20 deg mark to start? It sure starts easy where its at but has a very slow and laggy rev, and will spit through the carb if revreved higher then abiut 3 grand
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Old 03-31-2013, 05:32 PM
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the timing at idle needs to be set at 36
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Old 03-31-2013, 05:33 PM
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I'm sorry I just checked and had the vacuum advance hooked up with trying to time it. After unpluging and capping it I just rechecked and had 2 btdc. I might have not got true tdc after all. That still dosent tell me if there is that much adjustment in the dizzy. I'm at my shop right now, so anything yall recomend I will try while I'm here.
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Old 03-31-2013, 05:49 PM
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advance the timing to 36,if you have to move the wires in the cap,then do it

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check for restart issues after road tests
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Old 03-31-2013, 05:52 PM
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You never set the timing with the vac adv connected.

if the distributor needs to be turned more to get to 34-36deg BTDC then yes you will have to re "stab it"

To get it close set the crank to 30deg BTDC, then install the distributor.

You will need the switch to allow easy hot starting with locked out timing.
Beyond that its pretty basic.
Let it warm up and readjust the carb. Will need 4" rated carb power step up springs.

The model 1406 600carb will likely need re jetting.
Look to the 1409 marine 600 carb's jetting/rods for a performance motor base line.

Last edited by F-BIRD'88; 03-31-2013 at 06:00 PM.
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Old 03-31-2013, 05:53 PM
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Yep reset the dist, may take a few trys. Try having the timing pointer at about 30 deg BTDC and drop in the dist so the vacuum advance is mid way from limits, may need a large slotted srew driver to turn the oil pump shaft so the dist engages in the correct manner and the rotor ends up near #1 tower.
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Old 03-31-2013, 05:58 PM
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Quote:
Originally Posted by vinniekq2 View Post
advance the timing to 36,if you have to move the wires in the cap,then do it
Way easier to move the wires counter-clockwise in the cap than to pull the dizzy. Thanks Vinnie.
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Old 03-31-2013, 08:23 PM
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I would have never believed this truck would have been able to do what it just did. I cant thank yall enough. Amazing wealth of knowledge and patince with a novice like myself. Amazing results!


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Old 03-31-2013, 08:42 PM
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now you can have fun,whats the next upgrade?
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Old 03-31-2013, 08:46 PM
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now you can have fun,whats the next upgrade?
I really dont know where to go from here haha.
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