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Re: Big block with 6/71 roots project [Re: Filex] #1467560
07/17/13 02:32 PM
07/17/13 02:32 PM
Joined: May 2011
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northern,Ohio,USA
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Clanton Offline
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I am sorry my comment did not help and is not relative to your goals.I hope you will find the help you need and the parts.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467561
07/17/13 05:05 PM
07/17/13 05:05 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Filex  Offline OP
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Loire Atlantique
Thanks for your answers !

I'm ok to buy a complete assembly kit but I just want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?

An other thing, why a 871 is better than a 671 for a street use ? thanks !

Re: Big block with 6/71 roots project [Re: Filex] #1467562
07/17/13 05:19 PM
07/17/13 05:19 PM
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northern,Ohio,USA
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Clanton Offline
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The 8-71 will be turned slower for the same hp and a little less heat but in your case I would think you would put that $$ into a water injection kit to run on cheaper fuel instead of the bigger blower.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467563
07/17/13 06:05 PM
07/17/13 06:05 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Quote:

The 8-71 will be turned slower for the same hp and a little less heat but in your case I would think you would put that $$ into a water injection kit to run on cheaper fuel instead of the bigger blower.




Ok I understand, itīs clear, thanks !

You speak about water injection to run with cheaper fuel ? It's interesting ! Tell me more

I don't know anything about this !

Re: Big block with 6/71 roots project [Re: Filex] #1467564
07/17/13 06:18 PM
07/17/13 06:18 PM
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northern,Ohio,USA
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Clanton Offline
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Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467565
07/17/13 07:01 PM
07/17/13 07:01 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Quote:

Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.




I will look that, thank you !


Somebody has a response for my last question ?

-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?
Or it's possible to install the parts (each balanced) without doing anything else ?

Re: Big block with 6/71 roots project [Re: Filex] #1467566
07/17/13 07:36 PM
07/17/13 07:36 PM
Joined: Jan 2003
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dogdays Offline
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Unless you buy a "balanced kit" from one source you will ALWAYS have to have the assembly balanced. In the aftermarket world, while 8 pistons may well come in within a gram or two of each other, rods the same way, there is NO standardization of weights between manufacturers. And many manufacturers have different lines of the same parts that have different weights.

So you can see that buying parts from two or three different manufacturers or suppliers, you will need to have the assembly balanced. A previous poster told you where you can do this in the UK.

R.

Re: Big block with 6/71 roots project [Re: Filex] #1467567
07/18/13 01:31 AM
07/18/13 01:31 AM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
Quote:

Quote:

Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.




I will look that, thank you !


Somebody has a response for my last question ?

-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?
Or it's possible to install the parts (each balanced) without doing anything else ?


Balancing engine parts has two seperate operations, balancing all the pistons to the same weight with the wrist pins, same on the rods and then you have to get both ends of the rods the same weight on each end, half the rod is considered rotational weight and and the other half is not Maybe it is consider in some other way I have forgotten about . The crankshaft is spun balanced to the specific "bob weight" that your assembly ends up having, so no ,you can not mix parts and expect them to work well together without having them check for balancing first No sense in taking a chance when using a blower and wanting it to be trouble free. I had treid to make a post several days ago advocating you using a bigger blower than the 6:71, I like and use 10:71 on Mopar V 8 over 440 C.I. You can turn them much slower and build the same amount of boost with a lot lower intake manifold inlet temps. and a lot less parasitic drive loss(HP) by spinning the smaller blower at a higher RPM to get the same amount of boost as the bigger one spinning slower Be careful of what you ask for, you may end up with a real tire burner 600 Hp from a 440 based motor on pump gas is not hard to do with one carburetor, let alone a blower Another thing to consider on a street Roots blower motor is the static mechanical compression ratio, if you set the motor up with 8.5 to 1 comp. ratio and spin the blower at 7% underdrive to make 7 lbs of boost at 6500 RPM and end up with vacume at 4000 RPM and under at part throttle you may be better off increasing the compression ratio to 9.0 or higher up o 9.5 to 1 and spin the blower even slower like 10 % under so it starts to make boost at a higher RPM and still end up with the same amount of HP at 6500 RPM but a lot more torque and throttle responce under 3500 RPM at part throttle Sorry if this seems confusing but there are many different ways to go with a blower, on pump gas less pressure is safer


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Big block with 6/71 roots project [Re: Cab_Burge] #1467568
07/18/13 11:15 AM
07/18/13 11:15 AM
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northern,Ohio,USA
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Clanton Offline
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Don't take whet I said the wrong way Buddy it was just my on MY idea of what he wants without knowing more details.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
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