[egyptgto]

When starting my brand new 455 HiPerformance engine the oilpressure goes up to 50 psi. when engine gets warm in heavy traffic the pressure can go down to 20 psi in idle. Accelerating again
brings it up to 40 - 50 again. are these figures acceptable as the engine manufacturer gave a cold
pressure of 60-80 and warm 40-60 ? i use 20w 50 esso oil.

[egyptgto]

When starting my brand new 455 HiPerformance engine the oilpressure goes up to 50 psi. when engine gets warm in heavy traffic the pressure can go down to 20 psi in idle. Accelerating again
brings it up to 40 - 50 again. are these figures acceptable as the engine manufacturer gave a cold
pressure of 60-80 and warm 40-60 ? i use 20w 50 esso oil.

[Tim Swain]

In my opinion you oil presure is within a safe range. To much presure is a big problem. I believe 60lbs is perfict but 50lb will do the job fine.

[78 GHOST]

IMHO, you should be fine.

-Matt

[egyptgto]

Hi

here in Egypt the weather rises to above 100 but at the moment its more like 85. I don´t know how accurate the gauge is. its relatively new and I tried another sensor and it gave about the same readings. but is 20 psi in idle still safe if the readings are correct. if I change to another oil will it be better ?

[Guy Mazza]

Hi Egypt, Your oil pressure sounds normal, but if you are using a electrical guage, Id replace it with a good mechanical guage w/copper oil line. The best place to tap into oil presuure line is the gallery by the distributor. Nothing wrong w/taking it at the oil filter housing, but better up top IMHO.
Good Luck,
Guy

[Half-Inch Stud]

I have an idea:

How about adding 1 or 2 more quarts of oil and see if the oil pressure jumps up to 80+cold and 60hot at cruise. After that experiment, you may want to re-level the oil level.

My 455 has a deep pan and will pump air and the gauge will show it as 40PSI. Only indicator to this false reading is when I rev the motor and the oil pressure reading stays the same or goes down. Creapy = low oil level....

Have a nice hot day.

H.I. Stud

[Ed Neasham]

Not that I'd recommend it, but do you have any idea what the Idiot Light for the oil pressure comes on at? Most of them are around 3 to 5 psi. Basically the factory is saying that you can safely operate at that pressure. I wouldn't want to do it, but that means that 20 psi at idle is OK times 4.

Ed

[78 GHOST]

Seems like somewhere, someone mentioned the rule of thumb of 1 PSI/100 RPMs ...sooo, a typical 750 RPM idle with 20 PSI should be way above that margin. Don't bet your engine on what I'm saying though, I would recommend dropping Pontiac Dude or the Kaufmanns an E-mail as they specialize in building these engines.

-Matt

[egyptgto]

so like HalfStud says it could be too little oil, although at the dipstick its showing full. shall i go with some more oil till the readings go to 70 cold and 50 hot ?

[Old Man Taylor]

20 psi at idle is no problem. I had an engine that had bigger clearances than I wanted and hot idle would get down to about 12 psi at 1200-1300 RPM with 20-50 oil.

[Half-Inch Stud]

egyptgto,

Old Pontiac trick;
If you can make a right turn and observe the oil pressure taking a dive toward zero, then the motor could use 2 more quarts of oil.

Problem is...typically the motor could use a better oilpan design.

I don;t know if you are low on oil or if the motor has enough loose bearing clearances to drop the pressure down....I'm leaning toward your motor having loose clearances.

H.I. Stud

[Tim Swain]

Mechanical gauge is a good idea. Pressure Gauges do not tell you your low on oil, not till the oil is so low the oilpump won't pick it up just off the oilpan floor. Over filling your crank case will cause the oil to oxygenate and is just like being low on oil.

[Half-Inch Stud]

Tim,

In my case, My oil pump will pump air and register a pressure. That fooled me twice in 6 years. The first time was after 45minutes on the highway.

Added 3 quarts.

The second time was last week. Same oil gauge symptom but I was too inept to recognize it (fooled me twice). Added 2 quarts and later diagnosed a compromised head gasket between Cyls 2&4.

H.I.

[Tim Swain]

Half inch
I see how that could fool ya. Dipsticks have been known to read wrong also.Egyptgto how meny quarts of oil do you run in your Pontiac?

[PROBRD]

Egypt- If you put too much oil in it the crank will whip it up full of air bubbles and then you will have problems. Fill it to the full mark and leave it alone. 20 psi at idle is normal. Don't worry about it. Everything is Ok! [img]/infopop/emoticons/icon_smile.gif[/img]

[egyptgto]

as i have a combination oil cooler installed the amount of oil is about 1 quart for oil cooler and about 5 for engine. this gives and exact full mark on the dipstick. the only odd looking thing in the engine bay is that the oilfilter is installed much higher than the engine and oilcooler. would that have any influence ?
thanks guys for your quick replies and help. that is my only source of information in a country like egypt which only drives F**** hyndays, daewoos and kias and only tools mechanics know are a screwdriver and his wax clogged ears

[Tim Swain]

Egyptgto, A 455 requires 6 quarts of oil with filter. If you have additional plumbing on you oiling system, you may require more. This does does not affect your oil pressure though. Unless in a tight turn. When you engine was rebuilt, there is a dipstick tube extention in the oilpan, that often gets lost. This will cause a faults reading on the dipstick.
You can put the filter anywhere but the additional plumbing and oilcooler will require additional oil.

[wholio]

An oil level that gets high enough to get into the crank can cause anumber of problems. The crank travels at a very high speed. The hammering of the crank into oil at speed will give you the opportunity to check your clearances again.
Bearing and rod to rod clearances will cause the fluctuation you have.
As long as you have the 20 psi the engine should be OK.
I like to run straight wieght 40 or 50 myself.
Good luck Julian

[egyptgto]

would syntetic oil be better and why ?