Vacuum pump???

Old 05-08-2007, 11:10 AM
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gimmemud
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Default Vacuum pump???

I am in the process of installing a Moroso new design vacuum pump on my sbc 434. How vacuum do I need to set the regulator on for best performance. This is a nos engine if it matters.

I was told te set it at around 1/2 total rpm, so I guess around 5000 rpm, I turn it to 9600rpm

Thanks,
Randy
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Old 05-08-2007, 12:48 PM
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hammertime
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at idle set it to 6-8 on the vacuum gauge this should get you very close
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Old 05-08-2007, 01:20 PM
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topsportsman1
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Is this Engine a dry sump or a wet sump?

Are you using a 3 stage or 4 stage vaccume pump?
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Old 05-08-2007, 01:49 PM
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gimmemud
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Its the new design 4 vane Moroso. Engine is wet sump, Dart Iron Eagle tall deck. 434ci
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Old 05-08-2007, 02:02 PM
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topsportsman1
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As far as setting up the by-pass (moroso) valve,to use shims.

You'll have to experiment with the by-pass
Always set it up so at wide open throttle you have 12 to 15 inches of vaccume at wide open throttle.

I wouldn't worry about the idle,that will only tell you how sealed up the engine is.

If you use higher inches of vaccume it could result in engine damage

This is what I use for figures,12 to 15 max,on a wet sump engine
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Old 05-08-2007, 02:16 PM
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billhendren
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I agree with topsportsman1 12-15 inches unless you have piston oilers.
Your on the ragged edge at 9600 ,thats 6400 FPM piston speed and probably way past the power band.try taking enough gear out to drop the rpm to around 8000/8200 I bet you will be a lot faster and for sure the engine life will increase a bunch.Bill
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Old 05-08-2007, 03:11 PM
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slowman
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what size cam is in this thing that you make power at 9600rpm with 434? i agree with bill about not spinning it that high. my little cheif headed 414 ran out of power with a .910 lift cam with [email protected] at 8900rpms.
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Old 05-08-2007, 03:43 PM
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i just purchased a 4 vane moroso and going to run on my 622 dry sump.
i also purchased the relief valve and was advised to go with 3 shims which will open at 16 inches of vaccum..


these motor builders on here know more about this vaccum than i..but i would like to ad if you have not purcahsed your pump yet i would recommend AUTO -FAB RACE CARS for the purchase of this pump and relief valve...My total savings was $150.00 over what you can purchase from JEGS OR SUMMIT.....

Rob Hamilton is the owner they are out of Baltimore MD...410-796-8777.

They Built Gil Mobleys 10.5 69 camaro...thery are a full line chassis shop and parts house...GREAT AND TIMELY SERVICE...

ask them about their other parts...CHEAP compared to Jegs and Summit.

thanks- BRIAN
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Old 05-09-2007, 04:30 AM
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gimmemud
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I have actualy never turned it that high, thats what chip I have in it. The most it has ever turned is 9200. I run alot of nos and just have that high of a chip in it to keep it off the rev limiter. We run mud drags and you never can tell how traction will be until you make the pass, and its not nice when it does hit the limiter. :twisted:

I actualy ordered the pump from Autofab, great people to deal with.

I have the vacuum relief valve, the instructions say 4 shims is 16, 3 shims is 14. Also is it ok to put the relief valve directly in the pump or does it need to go in the valve cover??

The cam is a Harold Brookshire (top secret).l lol I will never tell.



Thanks,
Randy
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Old 05-09-2007, 04:57 AM
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gimmemud
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I also would like to know what yall do about the oil fill hole in the opposite valve cover. Will the regular push in type breather-filler cap be sufficient or do I need some type of cap that wont leak such as an expandable freeze plug, kinda like a diesel engine has.
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