Oil Pressure relief pressure

[captndave737]

What should it be set at? 40# 60# something else? Are there any downsides to running higher pressures?

 

[Nick Micale]

The bypass in my performance cars is set at 0!

I prefer not to have unfiltered oil going to my engine or turbo, but you will need a filter that will pass enough oil when started cold to assure adequate oil is being supplied.

Since we do not see extreme cold weather, we can run 20W-50 all year and see 90 psi on start-up, and 30-40 psi at idle warm, a little less after 140 MPH pass!

The key is to have an oil filter which will pass enough volume when cold, as well as at operating pressure.

As always, there is a "condition" to be considered here, and it is my info applies to a performance build, as I do run a premium regular filter in my stock, very low mileage original car.

 

[Ktbregal]

Sorry to hijack Dave. Nick if we have a car that is street driven but raced sometimes me should have a bypass. I am looking at buying a K&p from you.

 

[pacecarta]

if plans are to run to 6000 rpm 60# is fine ,higher go 70#
if you go high too high on cold start you could pop the seal at the oil filter you also put stress on the cam sensor gear and cam gear teeth and stress on the roll pin in the sensor shaft and could shear that pin

 

[captndave737]

I'm a little confused. How do you set it at zero? Take the spring and plunger out completely? Or do you mean jamming the plunger in all the way so it bypasses nothing?

 

[RmvBfrFlght]

I'm a little confused. How do you set it at zero? Take the spring and plunger out completely? Or do you mean jamming the plunger in all the way so it bypasses nothing?

I think that you and Nick are talking about two different things. You are referring to the pressure relief valve that is under the large threaded nut on the front of the lower filter housing. This spring/plunger assembly limits the highest possible oil pressure. That is as long as the oil is warm to hot in temperature.

Thick cold oil can cause higher then the set oil pressure as this relief valve can't pass enough cold oil to regulate the maximum pressure. NOte that the oil that is 'bypassed' via this valve goes back into the pump, not the engine.

The relief that Nick is referring to is the oil filter bypass. This is located in the lower housing where the filter or coolant adapter is mounted. This bypass becomes active when the oil filter can't pass enough oil. The bypass will open allowing oil to skip it's trip through the filter as to not starve the engine for lubricant.

This can occur with cold thick oil, a clogged oil filter, or even a collapsed oil filter.

RemoveBeforeFlight

 

[captndave737]

I think that you and Nick are talking about two different things. You are referring to the pressure relief valve that is under the large threaded nut on the front of the lower filter housing. This spring/plunger assembly limits the highest possible oil pressure. That is as long as the oil is warm to hot in temperature.

Thick cold oil can cause higher then the set oil pressure as this relief valve can't pass enough cold oil to regulate the maximum pressure. NOte that the oil that is 'bypassed' via this valve goes back into the pump, not the engine.

The relief that Nick is referring to is the oil filter bypass. This is located in the lower housing where the filter or coolant adapter is mounted. This bypass becomes active when the oil filter can't pass enough oil. The bypass will open allowing oil to skip it's trip through the filter as to not starve the engine for lubricant.

This can occur with cold thick oil, a clogged oil filter, or even a collapsed oil filter.

RemoveBeforeFlight

Ok, that makes sense. So he's talking about the little black thing in the filter housing. With that being said what setting should I use on what I was talking about? 60# ok. I don't run above 5200 rpm and even that's pushing it with my 28 yr. 210k valve springs.

 

[fastblackracing]

60# will work fine for you.

 

[captndave737]

60# will work fine for you.

thanks, 60 it is.

 

[earlbrown]

....and get rid of those stock valve springs. They were tired over two decades ago.

You'll enjoy the top end.

 

[captndave737]

....and get rid of those stock valve springs. They were tired over two decades ago.

You'll enjoy the top end.

A little bit of a moot point nowI was driving the other day and I started getting a light knock I was 2 miles from home and by got there it was a really bad knock and squeal. I took off the fan belt and I still dad the knock. Checked the torque converter + flywheel bolts which were tight but I can move the crank shaft back and forth at least 1/8"!

I was planning on doing a frame off build in the fall. I guess I'll be getting an early start.