with dry sump the engine is sealed and special crankshaft seals are used to help build vacuum. Only the oil tank is vented.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 ??
Oil pressure drops at hi RPM.....Stumped
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Re: Oil pressure drops at hi RPM.....Stumped
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Re: Oil pressure drops at hi RPM.....Stumped
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.
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
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Re: Oil pressure drops at hi RPM.....Stumped
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
Re: Oil pressure drops at hi RPM.....Stumped
Geez Swampbuggy you mean you are not perfect like the rest of us here on Speedtalk! OH MY!
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Re: Oil pressure drops at hi RPM.....Stumped
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.
Re: Oil pressure drops at hi RPM.....Stumped
problem solved by upgrading feed line from tank to pump from a -12 to a -16
pump was cavitating
pump was cavitating
Re: Oil pressure drops at hi RPM.....Stumped
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
https://www.youtube.com/watch?v=g_r29fT ... e&t=4m46s
then on sunday we set a record
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Re: Oil pressure drops at hi RPM.....Stumped
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!
Great Results too!
Congratulations on the record! Don't stop now!
The Older I Get, The Dumber I Get