correctly installing ARP BBC oil pump stud

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
ARP Oil Pump Stud Torque?
Can anybody tell me the nut installation torque for the ARP 230-7003?
This is the oil pump stud kit for bigblock Chevy. I am using the Melling Select 10774. ARP's website only gives generic instructions for the torque and not specific to the application. Unfortunately they do not say what grade steel the 230-7003 is made from. The torques listed range from 70 lb.ft for 170,000 PSI all the way to 90 lb.ft for the 220,000 PSI. And that is with their Ultra-Torque lubricant. I am rather reluctant to crank it up to 90 lb.ft even if the fastener turns out to be 220,000 PSI as the factory setting is 65 lb.ft as the last thing I want is to strip the threads in the rear cap. Looking on the net I see all sorts of figure bandied about. For example 60 lb.ft with oil, 55 lb.ft with ARP lube, and then 70 - 90 lb.ft with ARP lube! That is quite a variation! Personally I am leaning towards duplicating the factory setting and using 65 lb.ft with oil.

Any thoughts?


this is one of the very commonly screwed up , during installation, parts !
the most frequent way to screw it up is to install the stud incorrectly, too, do it correctly youll simply install the rear main , torque it in place and spin the oil pump mount stud in to the main cap AFTER FIRST degreasing the stud and main cap threads with a solvent like CARB OR THROTTLE BODY SPRAY then coating both the main caps female threads and the studs male (shorter coarser threads) with RED LOC-TITE, (HIGH STRENGTH)
redtitez.jpg

, you spin it in until it touches the back of the bearing shell then back it OUT at least one half too one full turn, install the pump, verify clearance, install the load bearing washer and thread on the retainer nut and tighten it down while you make sure the stud itself does NOT move further in, it must NOT touch the rear or the lower rear main bearing shell or it can potentially cause bearing wear issues or in extreme cases crank failure.
use the BLUE medium strength thread loc-tite on the nut threads
https://www.summitracing.com/parts/lct-37418
bluetite.jpg
(MEDIUM STRENGTH)
http://www.qmuniforms.com/galls-sta...gclid=CPS5sJqMis4CFQERaQodvEkFeQ#.V5OnSfkrLcc
many engine builders add a bit of extra insurance here by using a pointed punch to lock the upper nut to threads to the stud threads, in two or three locations to be absolutely sure the nut won,t back off under vibration
punchpoint.JPG

1012307003.jpg

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https://www.summitracing.com/parts/...srese1-_-arp&gclid=CKGo4oeDis4CFZCLaQoduT4C-A

arp-230-7003_xl.jpg

mounting the oil pump to the rear main cap
Pump-Stud%20Clearance.JPG

failure to use the correct oil pump,mounting stud, bolt or nut or carefully check clearances when mounting an oil pump can cause problems, AND THE HEIGHT OF THE MAIN CAPS AND OIL PUMP CASTINGS DO DIFFER, ESPECIALLY ON THE LATER BIG BLOCK VS THE EARLY BIG BLOCK COMPONENTS
pumpss1.jpg

pumpss2.jpg

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BE 100% SURE that the oil pump bolt or STUD doesn,t protrude past the inner main cap surface , because if it bears on the rear main bearing shell it will almost always result in a quickly failed rear bearing[/b
ONE RATHER COMMON MISTAKE IS USING THE WRONG OIL PUMP STUD OR BOLT TO MOUNT THE OIL PUMP AS IF EITHER EXTENDS THRU THE REAR MAIN CAP SURFACE, IT CAN AND WILL BIND ON THE BEARING SHELL BACK SURFACE AND CAN LOCK OR RESTRICT, SMOOTH CRANK ROTATION.
STUDS ARE PREFERRED BECAUSE THEY GET THE THREADS THAT ENTER THE MAIN BEARING CAP COATED WITH THREAD LOCKER, LIQUID , THEN SCREWED IN TO THE MAIN CAP UNTIL THEY TOUCH THE BACK OF THE BEARING SHELL THEN BACKED OF 3/4 OF A TURN , THE OIL PUMP MOUNTED , AND THE WASHER AND FINE THREAD LOCKING NUT SECURED PER THE TORQUE SPECS.THIS INSURES THE STUD DOES NOT BEAR ON THE REAR BEARING SHELL , A BOLT WHEN TIGHTENED MUST BE TURNED DEEPER INTO THE THREADS IN THE REAR MAIN CAP, AND ITS MUCH HARDER TO PREVENT IT FROM BEARING OR CAUSING PRESSURE ON THE BACK OF THE BEARING SHELL IF ITS A BIT TOO LONG (A COMMON ISSUE, IN REBUILDS WHERE THE WRONG BOLTS USED.)

oilcappass2.jpg

notice the open slot between the rear main cap supporting the oil pump and bearing shell support and the area supporting the rear main seal, this prevents PRESSURIZED oil from the bearings reaching the rear main seal.
oilcappass3.jpg

the as cast recess in the rear main cap where the oil pump mounts can be rather restrictive and shallow, and if your replacing a missing main cap , with one from a different block you'll very likely be required to have the block?cap too be line honed to get the correct alignment and fit clearances for the crank shaft
oilcappass4.jpg


mainoilcap1.jpg

mainoilcap2.jpg


mainoilcap3.jpg



viewtopic.php?f=54&t=2187&p=5890#p5890
bbcoilpumpnom.png

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]yes the oil flows around the mounting stud,from oil pump to main cap to reach the engine oil passages, thru the oil filter
oiltofilter.png

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just keep in mind that you'll need to very carefully blend and smooth and carefully clean,the edges of the beveled area where the oil port feeds the bearing surface with some 600 grit sand paper so the oil flows well and theres no edges to cause bearing wear issues or crud left from the process that would get embedded in the bearings.

chamferedhole.jpg

http://garage.grumpysperformance.co...-on-the-cheap-well-to-start.11739/#post-55481

http://garage.grumpysperformance.co...ing-an-oil-pump-pick-up-tube.1800/#post-43094
 
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