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

General engine tech -- Drag Racing to Circle Track

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

Post by Racerrick » Mon Oct 30, 2017 9:13 am

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.

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

Post by pamotorman » Mon Oct 30, 2017 10:38 am

I guess I misunderstood what the problem was.

Newold1
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Re: Oil pressure drops at hi RPM.....Stumped

Post by Newold1 » Mon Oct 30, 2017 10:46 am

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.

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

Post by swampbuggy » Mon Oct 30, 2017 11:00 am

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 :(

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

Post by Newold1 » Mon Oct 30, 2017 11:09 am

Geez Swampbuggy you mean you are not perfect like the rest of us here on Speedtalk! OH MY! :lol:

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

Post by swampbuggy » Mon Oct 30, 2017 3:10 pm

LOL with you brother :lol: :lol: :lol:

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

Post by pamotorman » Tue Oct 31, 2017 11:21 am

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.

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

Post by Turborick » Wed Nov 15, 2017 2:20 am

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

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

Post by Turborick » Wed Nov 15, 2017 2:32 am

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

Post by cjperformance » Wed Nov 15, 2017 2:54 am

Good to see it solved !!
Craig.

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

Post by Newold1 » Wed Nov 15, 2017 8:19 am

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>

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