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GMC V6 and V12 Engines Engine repair and rebuilding

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  #1  
Old March 5th, 2016, 10:58 PM
atomman atomman is offline
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Default oil pump question

I am looking for a new oil pump for the V-12. Can you find them or are you looking at the gears and cleaning them? GMC #2460187, Melling 70-C?
Atomman
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  #2  
Old March 6th, 2016, 02:28 AM
AZKen AZKen is online now
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Default Re: oil pump question

I don't know anything about V12's But I can figure things out from time to time. The pump you listed is for V6.
1. Are the V6 pumps used in V12?
2. Melling 70C pump is available all over the place.

Trivia:
3. There is a V12 external oil system available for $1800. (ThunderV12.com site)
4. The 702 V12 has over 60 parts used form a V6.
5. The famous Blastolene "B702" has a GMC V12 motor. (It's in the Peterson museum I think)
6. Gear driven pump rely on tight clearance between gears and the sealing of the chamber. Don't know the reason for the question. You must not have proper oil pressure? or you just want to be safe. Anyway: Inspection, testing and refurbishing may be necessary if you can't find a new one.

Last edited by AZKen; March 6th, 2016 at 03:11 AM.
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Old March 6th, 2016, 02:06 PM
atomman atomman is offline
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Default Re: oil pump question

Building two new engines. Going to open the old pump and check clearances. Wondering if the Melling 70C will work? What have others used? Stock motor, not interested in $1800 for an external system.
atomman
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  #4  
Old March 6th, 2016, 03:07 PM
bobdylan bobdylan is offline
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Default Re: oil pump question

There is a great write up on crank shaft coalition, on rebuilding the v12, it shows how to modify aa stock v12 oil pump.
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  #5  
Old March 6th, 2016, 03:21 PM
bobdylan bobdylan is offline
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Default Re: oil pump question

. clearance between inner and outer rotors ( gears) 0.0010-0.0060 clearance between cover and rotor 0.0011-0.0039
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  #6  
Old March 6th, 2016, 05:14 PM
atomman atomman is offline
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Default Re: oil pump question

I have read the write up on modifying the pump. Looks like there are a couple of pix missing to fully explain the finished product.
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  #7  
Old March 7th, 2016, 03:09 AM
AZKen AZKen is online now
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Default Re: oil pump question

Will a Melling 70C work? If it fits and has the output, sure. Maybe the gears will fit a V12 pump? Seems like you will not find a new 702 pump. You need to devise a test jig for your pump or any used pump to test pressure/flow. I believe the RPM's will be 1/2 motor RPM.

Modify a stock pump? In what way? Do you have to start with a good pump? The experts say the achilles heel for 702 is the oil pump/distribution.

The $1800 system uses a Peterson Pump, very pricey.

Last edited by AZKen; March 7th, 2016 at 03:20 AM.
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  #8  
Old March 8th, 2016, 01:37 PM
bobdylan bobdylan is offline
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Default Re: oil pump question

The stock pumps move a lot of oil, yesterday I put a socket on the oil pump shaft, and 1/2 inch drill, did not know that there was a small line open, it shot a massive amount of oil all across the shop, and myself.
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