25-35 oil pres.----how much more time?

NKau

Founding Member

Dec 15, 2001

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Jefferson, WI

Nov 28, 2004

#1

• Nov 28, 2004

• #1

25-35 lbs. oil pres.----how much more time?

The engine in my car has already been rebuilt once in it's 98K mile life (by previous owner) and the oil pressure pressure has me worried. On cold startup it will hover in the 45-50 psi range (good electrical autometer guage), but after it warms up, and regardless of how hard it's driven, the pressure will not crest 35 psi, but does not dip below 20-25 psi at idle. I know it's pretty hard to predict how much time this engine has left, but I'm more or less curious exactly how bad an idea it is to be running something like this at the track? I've been thinking about bringing it down to Florida where I work over winter to do some light wrenching on it/have fun with it, but am kind of worried about ending the shortblock without having a place to work on it. Any opinions?

 

5.0 HOtrain

Founding Member

May 20, 2001

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New Hampshire

Nov 28, 2004

#2

• Nov 28, 2004

• #2

What do you run for oil? I would not really worry about, when it has no pressure at idle then worry. I would use a 10/40-20/50 mix in it, or run some 15/50 mobil one.
mike.

 

NKau

Founding Member

Dec 15, 2001

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Jefferson, WI

Nov 28, 2004

#3

• Nov 28, 2004

• #3

I normally run some 10w30 dino oil in it, but have since put in 10w40 and not really noticed a difference.
The whole situation kind of sucks, because I bought the car thinking I would be able to do the h/c/i on the existing shortblock. Guess that's what I get for trusting the factory guage when I purchased the car.........
I'm probably just going to go with my gut and your advice and just run it. Thanks.

 

2

2002BLGT

Well-Known Member

Dec 18, 2003

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59

Bedford VA

Nov 28, 2004

#4

• Nov 28, 2004

• #4

previous rebuilder probably didnt put cam bearings in it , thats where the oil pressure is getting lost , dont worry about it till its under 10 LOL

 

NKau

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Dec 15, 2001

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Jefferson, WI

Nov 28, 2004

#5

• Nov 28, 2004

• #5

2002BLGT said:

previous rebuilder probably didnt put cam bearings in it , thats where the oil pressure is getting lost , dont worry about it till its under 10 LOL

Click to expand...

I was wondering the same thing; figured maybed a couple of the cam bearings got nicked when the cam was installed, or just were never replaced. I'm guessing those can't be replaced without tearing down the whole engine either.........

 

C

crunchie12268

New Member

Aug 4, 2004

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Manhattan, KS

Nov 28, 2004

#6

• Nov 28, 2004

• #6

I think the harder part would be getting the bearings out, then it wouldn't be that hard to put new ones in......sure would take some time though. Might as well just rebuild it. I wouldn't worry about it until it us really low.

 

saniutza

New Member

Oct 28, 2003

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born in Transylvania, Romania...live in Lusby,MD

Nov 28, 2004

#7

• Nov 28, 2004

• #7

rule of thumb: 10 psi every 1k rpms... if so you are doing great... if at idle you have 25-20 that's great.... i just rebuilded the engine i have over 2k on it and at cold idle i see 70, warm up 35-40 ... i'm using 10-30 and i have a 7qt oil pan... you don't have to worry you're stiull in good shape

 

saniutza

New Member

Oct 28, 2003

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born in Transylvania, Romania...live in Lusby,MD

Nov 28, 2004

#8

• Nov 28, 2004

• #8

crunchie12268 said:

I think the harder part would be getting the bearings out, then it wouldn't be that hard to put new ones in......sure would take some time though. Might as well just rebuild it. I wouldn't worry about it until it us really low.

Click to expand...

to put bearings in and get them out you have to take the block to a machinist... you can't just take them out

 

NKau

Founding Member

Dec 15, 2001

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37

Jefferson, WI

Nov 28, 2004

#9

• Nov 28, 2004

• #9

saniutza said:

rule of thumb: 10 psi every 1k rpms... if so you are doing great...QUOTE]

Problem is that at 5K, the pressure maxes out at 35 psi.......that's where my concern is.

Click to expand...

 

M

MatthewP

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Dec 7, 2001

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Calgary, Alberta

Nov 28, 2004

#10

• Nov 28, 2004

• #10

I wouldn't sweat it too much. If you are really worried, try running 20-50.

-Matthew

 

Michael Yount

Mustang Master

Apr 10, 2002

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Charlotte, NC

Nov 28, 2004

#11

• Nov 28, 2004

• #11

It's pretty hard to predict. My SCCA racer a few years back (Toyota Corolla) suffered from low pressure when the oil temps would climb. In July/Aug. in Houston, not uncommon to see 250-300F oil temps during 2 hr. enduros. When temps would get high, oil pressure would drop. I was alarmed the first time it happened. Pressure dropped into the 28-35 psi range. The engine would literally spend an hour at a time between 4500-7000 rpm with a 5 minute pitstop, and then another hour at the same revs. Nothing happened at all. I finally got used to it. The car lasted 4 more (about 30 races) seasons, and then I sold it to a fellow racer. The engine didn't seem to care.

I don't share the story to try and give you comfort that it will be ok - but just to let you know you'll get folks who'll tell you theirs blew up the next day, and then there's folks like me where the engine saw extreme abuse, and didn't seem to care that it had only 35 psi at 7000 rpm. Go figure.