Oil pressure drops at hi RPM.....Stumped

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Racerrick
Expert
Expert
Posts: 697
Joined: Sat Sep 24, 2005 10:52 am
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Racerrick »

pamotorman wrote: Sun Oct 29, 2017 1:34 pm I wonder if putting breathers connected directly the oil pan would help so the pressure does not have to go back thru the whole engine and oil to get out ??
with dry sump the engine is sealed and special crankshaft seals are used to help build vacuum. Only the oil tank is vented.
pamotorman
Guru
Guru
Posts: 2802
Joined: Thu Mar 06, 2014 11:55 pm
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by pamotorman »

I guess I misunderstood what the problem was.
Newold1
Guru
Guru
Posts: 1963
Joined: Fri Apr 08, 2016 9:50 am
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Newold1 »

Have you run any current leak downs on the engine after a run or when engine is still warm?

Has your oil pressure always been in the 100psi range at the rpm points shown on your printout?

It seems that if you will ultimately boost the engine to 30-35psi boost pressure the leak downs could increase and if the pump vacuum in the crankcase is not increased proportionally and the ability of the system to maintain adequate vacuum could be significantly decreased.

Have you tried checking oil pressures at high rpms with a separate sensor or mechanical gauge that can cross check the readings you are posting?

I still think its important to remember that PRESSURE is a result of resistance to FLOW. Feeds or flow to the pump that restrict flow of oil back to the pump will lower pressure not raise it.
The Older I Get, The Dumber I Get :wink:
swampbuggy
Guru
Guru
Posts: 1575
Joined: Mon Apr 04, 2011 8:54 pm
Location: central Florida

Re: Oil pressure drops at hi RPM.....Stumped

Post by swampbuggy »

Sorry folks---i made an INCORRECT statement earlier in this thread stating that-12 hose was .750" i.d.----my mistake, just was not thinking straight at the time, i know better just shot from the hip and missed :(
Newold1
Guru
Guru
Posts: 1963
Joined: Fri Apr 08, 2016 9:50 am
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Newold1 »

Geez Swampbuggy you mean you are not perfect like the rest of us here on Speedtalk! OH MY! :lol:
The Older I Get, The Dumber I Get :wink:
swampbuggy
Guru
Guru
Posts: 1575
Joined: Mon Apr 04, 2011 8:54 pm
Location: central Florida

Re: Oil pressure drops at hi RPM.....Stumped

Post by swampbuggy »

LOL with you brother :lol: :lol: :lol:
pamotorman
Guru
Guru
Posts: 2802
Joined: Thu Mar 06, 2014 11:55 pm
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by pamotorman »

does this block have a enclosed cam tunnel because the oil being whipped by the crank gets full of air bubbles. that is why you need a good scraper and a side pocket pan to collect the oil scraped off of the crank.
Turborick
Member
Member
Posts: 125
Joined: Sat Aug 29, 2009 10:43 pm
Location: Palmdale, Ca
Contact:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Turborick »

problem solved by upgrading feed line from tank to pump from a -12 to a -16
pump was cavitating
Rick Yacoucci

Nebulous Theorem III.V
http://www.bonnevillestreamliner.com
Turborick
Member
Member
Posts: 125
Joined: Sat Aug 29, 2009 10:43 pm
Location: Palmdale, Ca
Contact:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Turborick »

Engine ran well this weekend here is a vid of our fist run of the weekend @257mph
https://www.youtube.com/watch?v=g_r29fT ... e&t=4m46s

then on sunday we set a record
HUOT4322.JPG
You do not have the required permissions to view the files attached to this post.
Rick Yacoucci

Nebulous Theorem III.V
http://www.bonnevillestreamliner.com
cjperformance
Guru
Guru
Posts: 3661
Joined: Tue Aug 19, 2008 7:20 am
Location: South Australia

Re: Oil pressure drops at hi RPM.....Stumped

Post by cjperformance »

Good to see it solved !!
Craig.
Newold1
Guru
Guru
Posts: 1963
Joined: Fri Apr 08, 2016 9:50 am
Location:

Re: Oil pressure drops at hi RPM.....Stumped

Post by Newold1 »

Love to see what sometimes appears to be a big problem solved with a small simple change!

Great Results too!

Congratulations on the record! Don't stop now! =D>
The Older I Get, The Dumber I Get :wink:
R.Brown
Pro
Pro
Posts: 325
Joined: Wed Sep 15, 2004 7:16 pm
Location: Alberta, Canada
Contact:

Re: Oil pressure drops at hi RPM.....Stumped

Post by R.Brown »

Great job!
Post Reply