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Username Post: Strange oil pressure        (Topic#357063)
305c1500ext 
Member
Posts: 243

Loc: Auckland,NEW ZEALAND
Reg: 10-23-06
07-01-19 01:51 PM - Post#2769660    

Hi all.I have a `65 Chevrolet Impala.I brought it with a 283 and turbo 350 trans in it and running well.I had the trans serviced and the shop found lots of plastic looking strips and stuff in the pan?? Put it back together and i got a quote to fix.Too costly. I got a performance 350 turbo trans ex USA. Put it in with a good friend that has a workshop and a very fussy work ethic.Couple of years goes by and strange oil pressure,pull the engine pan and the thrust surface badly worn on the rear crank journal.We put in a re-built 327 that we put together.
Ground the crank,new rings gaskets etc...2 years on and i have noticed my oil pressure has dropped when hot and when sitting idling in gear the oil pressure drops to 25-30 pounds-out of gear 50 pounds! Long story sorry! Is my crank being eaten? Can a transmission cause this again.We were very careful to set the torque convertor clearance!I even had a transmission shop check the clearance!
I am using a Autometer electric oil pressure gauge. Thank you for any input before i pull the engine pan!


Philip
1996 c1500 305 vortec.1st truck so far!350 crate motor is in....had to rebuild the engine first!!
1986 mazda 323 turbo road race car 400hp.SOLD
598 bbc in 56 chev drag car 8.62 second
1965 Chev Impala sedan 283-now 327 + turbo 350


Edited by 305c1500ext on 07-01-19 01:53 PM. Reason for edit: No reason given.

 


dgstarr 
"3rd Year" Silver Supporting Member
Posts: 145
dgstarr
Loc: Portland, OR
Reg: 04-16-13
07-01-19 02:07 PM - Post#2769663    
    In response to 305c1500ext

Normal oil pressure for a stock 327 with a standard oil pump is 40 psi at 2000 rpm. This figure is for a warm engine with the GM specified oil, 10w30 or 20 wt. The pressure is much lower at idle in drive. An engine can have higher oil pressure when breaking in. If you are using the high pressure pump used in the solid lifter engines it will be higher. Heavier weight oils like 30wt or 20w50 can also raise oil pressure. I don't think you have anything to worry about.





 
305c1500ext 
Member
Posts: 243

Loc: Auckland,NEW ZEALAND
Reg: 10-23-06
07-01-19 02:17 PM - Post#2769666    
    In response to dgstarr

Hi. We put in a High pressure or volume pump.Can`t remember!! I am using 10-40 weight oil.Just worried that it has suddenly dropped that amount! Hot idle usually 50psi and 60mph is about 70psi...

Philip
1996 c1500 305 vortec.1st truck so far!350 crate motor is in....had to rebuild the engine first!!
1986 mazda 323 turbo road race car 400hp.SOLD
598 bbc in 56 chev drag car 8.62 second
1965 Chev Impala sedan 283-now 327 + turbo 350


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-02-19 05:22 AM - Post#2769713    
    In response to 305c1500ext

your oil pressure is a bit too HIGH, to be ideal, and that does nothing to reduce wear , it should be no more than 30-35 psi at idle and 45-55 psi at cruise speed (60-70 mph).
Id suggest use of 10w30 weight synthetic oil, as the change to a thinner viscosity may resolve the issue,
and it looks like having a high pressure or high volume oil pump is not required.
all the higher oil pressure and thicker viscosity oil does is increase wear on the distributor and oil pump drive gear and cam gear interface,
thinner oil flows faster absorbing heat and transferring heat more effectively away from moving surfaces like rings and bearings


http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-02-19 03:02 PM. Reason for edit: No reason given.

 
beagrizzly 
"10th Year" Gold Supporting Member
Posts: 2047
beagrizzly
Age: 69
Loc: south texas
Reg: 08-04-12
07-02-19 06:00 AM - Post#2769716    
    In response to 305c1500ext

I will tell you what a high volume, high pressure pump does for you.
I built a steel crank, four bolt main 350. Rhodes lifters, with high volume, high pressure oil pump. Muncie 4 speed.

75 lbs pressure at idle, 100 lbs at WOT. It would lose oil pressure at shift point in second gear. EVERY TIME!! Blowing blue smoke like crazy. I thought I had blown the engine up.

I pulled the engine and found nothing wrong.

The final analysis was the oil was all in the valve covers after revving the engine to 6,000 twice.
When it got to the 6,000 point the second time, the oil had not had time to drain back into the pan. It pushed in into the intake through the pcv valve.

I switched back to a stock oil pump, and the problem went away.

I loved that engine.

Griff

if you're gonna be a bear..................

1960 Biscayne (the 6T)
2005 Yukon XL
2007 GMC Sierra Classic 8.1
2009 Silverado
2011 Escalade ESV


 
Shepherd 
Frequent Contributor
Posts: 1786

Loc: Lake George, NY
Reg: 11-11-15
07-02-19 01:05 PM - Post#2769742    
    In response to grumpyvette

High volume Melling pump in my warmed over hydraulic valves SBC. Hot idle around 20#, 45-50 at 2,000. 10/40 high mileage Valvoline.




 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-02-19 02:21 PM - Post#2769746    
    In response to Shepherd

  • Shepherd Said:
High volume Melling pump in my warmed over hydraulic valves SBC. Hot idle around 20#, 45-50 at 2,000. 10/40 high mileage Valvoline.




that simply means your engines clearances are larger allowing more oil flow with less resistance,
GAUGE PRESSURE simply is a measure of RESISTANCE to rapid FLOW volume


keep[ in mind your oil temp should generally be in the 180f-250f range, ideally 180f-215f

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-02-19 02:25 PM. Reason for edit: No reason given.

 
Shepherd 
Frequent Contributor
Posts: 1786

Loc: Lake George, NY
Reg: 11-11-15
07-02-19 02:29 PM - Post#2769749    
    In response to grumpyvette

Agreed on larger clearances lowering pressure, basic hydraulic theory. But are you saying the stated oil pressure is too low?



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-02-19 02:30 PM - Post#2769750    
    In response to Shepherd

no that oil pressure "Hot idle around 20#, 45-50 at 2,000. " is fine

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-02-19 02:30 PM. Reason for edit: No reason given.

 
305c1500ext 
Member
Posts: 243

Loc: Auckland,NEW ZEALAND
Reg: 10-23-06
07-02-19 02:34 PM - Post#2769752    
    In response to grumpyvette

I was just worried about destroying another crankshaft.I will try 10-30 oil. We put the higher oil pump in as a stop gap when the 283 was dying.Just thought it was strange that the oil pressure dropped 25psi from what it was.Thanks all.
Now to put on the better heads i have.

Philip
1996 c1500 305 vortec.1st truck so far!350 crate motor is in....had to rebuild the engine first!!
1986 mazda 323 turbo road race car 400hp.SOLD
598 bbc in 56 chev drag car 8.62 second
1965 Chev Impala sedan 283-now 327 + turbo 350


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-02-19 02:48 PM - Post#2769756    
    In response to 305c1500ext

a sudden drop in oil pressure might indicate a problem, like a bearing wear issue,bad oil pressure sensor, or gauge, defective oil filter, or oil passage plug coming loose but you certainly still have more than adequate oil pressure, still sudden changes warrant close inspection to locate the cause/
an oil pump pick-up coming loose or a defective oil filter are suspect but not the only potential issues


http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-02-19 03:10 PM. Reason for edit: No reason given.

 
305c1500ext 
Member
Posts: 243

Loc: Auckland,NEW ZEALAND
Reg: 10-23-06
07-02-19 02:52 PM - Post#2769757    
    In response to grumpyvette

Might be time to drop the pan.

Philip
1996 c1500 305 vortec.1st truck so far!350 crate motor is in....had to rebuild the engine first!!
1986 mazda 323 turbo road race car 400hp.SOLD
598 bbc in 56 chev drag car 8.62 second
1965 Chev Impala sedan 283-now 327 + turbo 350


 
beagrizzly 
"10th Year" Gold Supporting Member
Posts: 2047
beagrizzly
Age: 69
Loc: south texas
Reg: 08-04-12
07-03-19 05:36 AM - Post#2769804    
    In response to 305c1500ext

Pull an oil sample and send it in for analysis. It will tell you if you have Copper(bearings) Aluminum, (Piston wear), Iron (metal to metal contact)
http://www.motorchecklab.com/get-my-motor-oil-anal ...
It is the easiest, and best way to "look" into an engine without tearing it down.
Pull the sample hot. Do not pour it out of the filter.

Sudden loss indicates something happened. Gradual loss, not so much.

I supervised a heavy equipment facility with over a hundred pieces of rolling stock. I never had a catastrophic failure after I started using oil analysis faithfully.

I truly believe in it.

Griff


if you're gonna be a bear..................

1960 Biscayne (the 6T)
2005 Yukon XL
2007 GMC Sierra Classic 8.1
2009 Silverado
2011 Escalade ESV


 
305c1500ext 
Member
Posts: 243

Loc: Auckland,NEW ZEALAND
Reg: 10-23-06
07-03-19 06:13 PM - Post#2769867    
    In response to beagrizzly

Thank you. I will look into that!

Philip
1996 c1500 305 vortec.1st truck so far!350 crate motor is in....had to rebuild the engine first!!
1986 mazda 323 turbo road race car 400hp.SOLD
598 bbc in 56 chev drag car 8.62 second
1965 Chev Impala sedan 283-now 327 + turbo 350


 


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