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low oil pressure rebuilt 77 mildly built 360 La engine

bbodybeater75

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:eusa_think:hi i have a oil pressure problom with my pro, rebuilt mildy built 360 la engine ,has 4000 miles at about 2000 mile range pressure dramaticly droped why is this happening? i pulled pan a replaced oil pump thinking it may have been defective but nothing changed. so now i have pulled engine out of the car
an comenced a serious inspection,started with cam an lifters, cam bearings got a good track an visably look fine an no spining but, on the #3 cam journal bearing is about 0.10s out of the journal would this cause the problom stated? oil viscosity is 10/30 /fram filter/hp/ hp/melling pump tryed 3 diff, types of oil an viscositiy ranges no difference.

oil pressure range cold idle 50/65
oil pressure range hot idle is 5/15 full rev 25
drops 10 at a time between 150 degrees temp an 190 never touching gas whats wrong with my baby rarely beat on it an never overheated???
can somone whos knows or had similar probloms please help???:sSig_thanks:
dont want to wreck this engine i cant afford another rebuild have 8000 in this one allready
 
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Low oil pressure

Is your oil pressure gauge mechanical or electric? I have seen electrical gauges fail when the sending unit spring gets soft at one particular point in the range.

Your description of the gauge as the car heats up seems to point to this.

The readings go real low and it scares the heck outta you!

If the gauge is mechanical, don't know. They are not generally affected in this manner.

Not sure this correct, but if you changed the pump and checked all the journals and see no obvious damage, this may be it.


Jeff
 
Good call in the upper post! Verify your pressure readings with a mechanical gauge if you are using electric, and even if currently using a mech gauge then it might not hurt to cross check it with another mech gauge.

If gauges are OK then check to see if the rocker shafts are installed up side down.
 
good call in the upper post! Verify your pressure readings with a mechanical gauge if you are using electric, and even if currently using a mech gauge then it might not hurt to cross check it with another mech gauge.

If gauges are ok then check to see if the rocker shafts are installed up side down.
how would i know if rocker shaft was upside down on la,360?
Checked with to mech, oil gauges, same reading, cam bearings lined up with oil passages.
 
is your oil pressure gauge mechanical or electric? I have seen electrical gauges fail when the sending unit spring gets soft at one particular point in the range.

Your description of the gauge as the car heats up seems to point to this.

The readings go real low and it scares the heck outta you!

If the gauge is mechanical, don't know. They are not generally affected in this manner.

Not sure this correct, but if you changed the pump and checked all the journals and see no obvious damage, this may be it.


Jeff
thanks very much YES NO DAMAGE YET, bearings just got were track, is 2 mechanical oil pressure gauges same reading i really appreciate all opinions an ideas thanks keep intouch!! :)
 
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all the oil galley plugs in the block? sometimes they leave that one at the rear out and it causes this
 
oil pressure

B body

What I have done with problems like this is I took an old brake pressure bleeder
and cleaned it out real good.I put motor oil in the bleeder and adapted the hose to fit in where the oil sending goes.Remove the oil pan and pressurize the system, if you see excessive oil gushing out more and likely you found your problem.Turn the engine over slowly when it is pressurized with a socket and watch for excessive leakage. Normally the oil will just drip slowly I have done quite a few times and it works out.This could tell you if that 3rd cam bearing is the problem.You can also remove the valve covers and the intake to do this testing.Any gushing or free flowing oil would be a problem.This will also tell you if your valve train is oiling properly. I also use the bleeder to pre oil fresh engines.

Hope this will Help
Jeff
 
how would i know if rocker shaft was upside down on la,360?
Checked with to mech, oil gauges, same reading, cam bearings lined up with oil passages.

The rocker shafts have oil holes in them to lube the contact point of the rockers. If the shafts are up side down the holes will be in the up direction basically oiling the under side of the valve cover. The holes should be facing down but that is specific as well because the holes are not aligned with the shaft bolt holes. There is a diagram in the FSM that shows the holes pointing away from the crank center line.
 
several things could cause your problem from failling presure relief valve to spinning bearings on crank.presurising the system is a great idea,as long as you get a bad result.
 
B body

What I have done with problems like this is I took an old brake pressure bleeder
and cleaned it out real good.I put motor oil in the bleeder and adapted the hose to fit in where the oil sending goes.Remove the oil pan and pressurize the system, if you see excessive oil gushing out more and likely you found your problem.Turn the engine over slowly when it is pressurized with a socket and watch for excessive leakage. Normally the oil will just drip slowly I have done quite a few times and it works out.This could tell you if that 3rd cam bearing is the problem.You can also remove the valve covers and the intake to do this testing.Any gushing or free flowing oil would be a problem.This will also tell you if your valve train is oiling properly. I also use the bleeder to pre oil fresh engines.

Hope this will Help
Jeff

thanks very much interesting trick gonna have to try that one lol ill keep ya posted!! :icon_salut:
 
several things could cause your problem from failling presure relief valve to spinning bearings on crank.presurising the system is a great idea,as long as you get a bad result.


hey man are there any consequances for pressurizing the system that can be costly or unrepairable ? :)
 
The rocker shafts have oil holes in them to lube the contact point of the rockers. If the shafts are up side down the holes will be in the up direction basically oiling the under side of the valve cover. The holes should be facing down but that is specific as well because the holes are not aligned with the shaft bolt holes. There is a diagram in the FSM that shows the holes pointing away from the crank center line.


thanks very much im a mopar man an never new that lol good thing i marked an placed them in there respected positions when i did work on em thats a wonderful piece of advice!!! thanks again!!!:icon_salut:
 
]il pressure

The engine runs under pressure,some run 80-100 psi and no problems.I have done this for years without any ill effects and I usually pressurize 45-60 psi.I have done this to find a pressure problem and also to pre oil a fresh engine.

Jeff
 
also i checked the other stock unmolested E58, it had 50 psi at cold start an once warmed did drop to 35 psi at idle but would still rev 50psi at driving temp of 189f so somthings definatly up!!! thats around what the other one had till the 2000 mile mark!! thanks for all of you alls ideas an exsperiance ive got more useful info out of you all then the local machinest an the guy who built it!!!!
thank you all so much!!! keep em coming!!! ill check them all!!!! :)

THIS IS AN AMAZING MOPAR SITE!!!!
 
The engine runs under pressure,some run 80-100 psi and no problems.I have done this for years without any ill effects and I usually pressurize 45-60 psi.I have done this to find a pressure problem and also to pre oil a fresh engine.

Jeff
THANKS ILL LET YA KNOW HOW IT TURNS OUT!!!:icon_thumleft:
 
cool.
the galet plug im speaking of is the one that is in the block around the rear of the cam/distributor mounting area inside the block.

some times a shop removes it for cleaning the block and does not reinstall it because its hard to see and out of mind when the work is done.

steve
 
cool.
the galet plug im speaking of is the one that is in the block around the rear of the cam/distributor mounting area inside the block.

some times a shop removes it for cleaning the block and does not reinstall it because its hard to see and out of mind when the work is done.

steve
thanks steve if the plug your refering to is by the dist,oil pump drive inside the block then, yes it is present and acounted for
thanks an keep em coming!!! chris :sSig_thanks:
 
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