Guest Anonymous Posted October 17, 2002 Share Posted October 17, 2002 i just built a 1986 351w.well i cranked it up an everything was perfect .then in about 15 minutes it lost all oil presure.i killed it let it cool off tried it again an it done the same thing,had great presure at the start then slowly lost it all.so i went back in an changed the oil pump an checked the screen an filter an made sure all my block plugs were in bolted it back together an it done the same again .it'll hold presure while its cold but when it warms up it drops all presure.i put everything new in this motor,rings,rod bearings,mains,cam bearings,new gaskets,heads redone,an had the crank an cam checked.i thought it was just something i did but i got two friends thats having the same problem i am.could someone please help.oh an it does have a hi volume oil pump in it. Quote Link to comment Share on other sites More sharing options...
gene_w Posted October 17, 2002 Share Posted October 17, 2002 Are you sure it's not just flaky wiring/guage? If you are using an electric guage you might try using an ohm-meter on the oil pressure sensor to see if the measurement changes there when the engine heats up or not. Your engine and oil pump might be just fine. Gene Quote Link to comment Share on other sites More sharing options...
gene_w Posted October 17, 2002 Share Posted October 17, 2002 Oh, yeah. One more thing. When you hook the ohm-meter up to the guage, make sure to disconnect the wire from the sensor or the guage circuit could throw off your readings. Gene Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 17, 2002 Share Posted October 17, 2002 i checked it with a maunal gauge it done the same Quote Link to comment Share on other sites More sharing options...
Guest buschj Posted October 17, 2002 Share Posted October 17, 2002 What is the pressure when it’s cold? Does it go all the way down to O when it warms up? Does it increase when you rev the motor? Is there lifter noise? Did you check the cam bearing clearance when you reassembled? What weight oil are you using? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 17, 2002 Share Posted October 17, 2002 its running about 45psi on crank up then drops two 0.theres no lifter noise till it loses oil presure.motor sounds perfect till it warms up.everything suppose to be perfect on the cam an bearings,like i said i'm not the only one thats having this same problem ,so if you could help please do Quote Link to comment Share on other sites More sharing options...
blueovalz Posted October 17, 2002 Share Posted October 17, 2002 Did you Plasti-gage the main and rod journal/bearings to make sure you don't have excessive clearance? Is the oil pump new or used? Did you check any and all gallery plugs in position prior to installing the outside parts? Quote Link to comment Share on other sites More sharing options...
Jwink25 Posted October 18, 2002 Share Posted October 18, 2002 Have you ever slowly reved the engine up right after you started it? Did it ever knock at all while it had oil pressure? Quote Link to comment Share on other sites More sharing options...
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