Too much oil pressure in my racecar?

[cstreit]

I noticed this weekend that my race motor has oil pressure that often exceeds 100 psi on the guage...

I haven't checked it's accuracy yet, but it makes me think maybe one of my pressure relief pistons is potentially blocked...

I've also noticed that I am getting more air out of the crankcase.

Could the two be related?

Any thoughts, I think I will pull the pressure relief pistons, check the springs, etc... But when I had it apart this winter the pistons looked good...

I have also done the cam-line restrictor update.

[jplavanjr]

Chris- While not relating to your post AT ALL... nice picture of you/car in Vintage Racecar Journal I just got yesterday. Didn't know if you saw that or not.

[cstreit]

bump...

[TimT]

Chris, when you open the oil filler cap, what do you see? is it just steady steam of vapors? or does it pulse?

Oops 100 psi at what rpm?

Isnt the rule of thumb 15psi per 1000rpm?

until the relief blows at about 90?

How old is you oil pressure sensor....? they do fail over time

[cstreit]

Tim, dunno, but the crank vent once again feels like a steady stream, just like before I tore the engine down the 2nd time to re-orient the rings. After another track session having done this it was back and forth pulsing as normal. Now it's back to a stream.

I spend most of my time above 4500 RPM and it's almost always close to and above 100, but the sender is old. I can replace it with a known good one from the other car... But clearly if the sender is good, the pressure release isn't working...

..or could it be something else, ideas?

[J P Stein]

The latest pressure relief valve spring set-up now has an internal sleeve/support to keep (I am told) the spring from getting cocked in the bore possibly jaming the piston. Cheep and easy to install if you're without.

[350HP930]

Blowby will normally be unrelated to oil pressure.

That being said there is the possibility that the higher oil pressure is putting more oil into the case and reducing the amount of air that the scavenge pump would normally remove but I am skeptical that this would be noticable since the scavenge rate would be fairly constant.

Unless your rings are shot just ignore how much air comes out of the case.

[cstreit]

I can't imagine the rings being shot after a few thousand miles... What I don't understand is how them might "unseat" themselves.

I checked the plugs and they look good, so I doubt that it is a oo rich mixture washing down the cylinder walls, so I'm a bit perplexed...

[Bill Verburg]

Chris, You do know that a new sender('78 and later) and an old gauge(pre '78) will read double the actual value?

[cstreit]

No. But I do now... Hmmm... I think I need to do some homework.

[Wayne 962]

Right - check the sender first - these things are mechanical inside and fail often...

-Wayne

[cstreit]

I haven't checked it yet, but with an 83 motor and a 70 chassis, I bet I have this issue!

[Wayne 962]

Hi again. At about 4000 RPM, your car should be putting out 4 bar, or about 60 psi.

-Wayne

[cstreit]

Hey everyone, and welcome to todays winner, audience meet Bill!

"HI BILL"

"For helping out Chris and for getting the correct answer of a late sender with an early gauge, tell 'im what he's won Bob"

"Well for beginners he's won Chris' gratitude and thanks, plus, several beers of his choice should he make it out to Naperville for some reason."
"...but that's not all!" "He's also won the admiration of many on-line"

"...but no MONEY Bob?"

"No. Sorry Bill, no money. But what's a few greenbacks compared to the fleeting thing that is internet fame?!"



Thanks Bill!

Chris