High RPM oil pressure

Reply Subscribe

Thread Tools

08-07-2008 | 03:53 PM

#11

Griff

Charter Member # 55

Joined: Oct 2000

Posts: 20,244

Likes: 2,491

From: Omaha/LOTO

Quote:

Originally Posted by Vicious22

the filter housing has a sending unit port machined in it

If the sneding unit is not completely immersed in the flow of the oil, it will not read accurately.

What oil cooler and do you have a pic of where the sender is mounted???

You can also check oil temp with a laser IR temp gun and shoot it at the oil pan.

08-07-2008 | 04:01 PM

#12

stevesxm

Registered

Joined: Aug 2005

Posts: 1,491

Likes: 0

From: sint maarten

geeze... if we assume that the temp is wrong and its really 265 or something and thats the problem it seems to me that those motors would be creaking and pinging and smelling bad and you wouldn't need a temp gun to know there was something wrong but who knows.

either way... as mentioned earlier... a mechanical gage to confirm and if it really does this then you sure as hell better find out what it is before you have to put out a fire .

as for oil level... the pick up ought to be within a half inch of the bottom of the pan... it would have to be 6 quarts or more low to even think about sucking air... seems to me that while a quart low in an 10 quart pan is not likely to be the issue...

haven't read the thread recently but has anyone suggested just throwing a new filter at it ? maybe something bizzare going on in there...

08-08-2008 | 02:13 AM

#13

Griff

Charter Member # 55

Joined: Oct 2000

Posts: 20,244

Likes: 2,491

From: Omaha/LOTO

Could be that the oil is too cool and the condensation is causing the paper element in the oil filter to swell. Try some Mobil 1 15-50 oil and a Mobil 1 filter. The use a synthetic filter media in the filter and the synthethic oil will hold up to higher temps better.

Bottom line is the actual temp of the oil needs to be verified mechanically. The oil can easily be getting to 260-290* without burning. It will just break down much faster and loose viscosity.

Last edited by Griff; 08-08-2008 at 02:15 AM.

08-08-2008 | 07:32 AM

#14

kvogt

Registered

Joined: Aug 2003

Posts: 1,129

Likes: 32

From: Racine, Wisconsin

Is it a stroker motor? Try running at a half to one qt low on the dip stick. This will help tell if you are frothing the oil.

What is your oil pump pickup to pan clearance? Might be to close and starving the pump at higher rpm.

Kris Vogt

08-08-2008 | 08:08 AM

#15

kubcat

Platinum Member

Joined: May 2005

Posts: 228

Likes: 4

From: Sydney Australia

Quote:

Originally Posted by Vicious22

I'm running a 515ci BBC. On a long 5000 rpm run my oil pressure starts to slowly fall off. 3000 rpm it's at about 55psi. after about a minute at 5000 it starts down.

Stats: 10 qrt pan, Valvoline Racing 20w-50, mechanical gauge, Fram HP4 filter, Oil temp 195-205 (at filter before cooler).

If I stay on the throttle it'll drop to 30 psi.

I just changed the Oil. Found no metal in the filter.

Where do I start?

Do you have a high volume oil pump? Do a search on a thread comparing High Volume Oil Pumps to standard. Apparently they can sometimes suck an oil pan dry.

Though not sure why it would be getting worse over time.

Just taking a wild guess here.