Odd Noise - Dry Sump Related?

[Robert May Eng.]

Bob, this pump is an SCP (Sprint Car Products) 3 stage with the 2" dia crank pully\4" pump pully which confirms your recommendation (not exact measurement but eyeballed with a measure). Not sure if it's oversized though.

Thanks for the info regarding the cavitation.

It does sound like you are down to one of two things here. There is a possibility that the relief valve is chattering due to the oil pressure being set to high. I would have thought that 20 psi hot at idle would have been more than enough and secondly if there is an oil stat in the line it could be in the wrong way round. these gadgets can chatter if plumbed up wrongly. I hate doing armchair mechanics

bob

 

[Tim Kay]

So I reduced the oil pressure from 60psi hot to 50psi hot and it made a significant difference in the sound it produces. Not nearly as pronounce and occurs at a higher rpm. Basically right around 64-70 psi.

Bob, your arm chair diagnosis in doing well here. Thanks for the help. I don't know if I would go as low a 20psi but I'm gonna try 45 then 40 and see if it goes away all together.

Mark, those vids are amazing. At this point I won't doubt anything being relevant. Since it takes a mile or so, initially, of aggressive acceleration to produce the sound, aeration could also be contributing to the pressure valve "chatter".

 

[Robert May Eng.]

So I reduced the oil pressure from 60psi hot to 50psi hot and it made a significant difference in the sound it produces. Not nearly as pronounce and occurs at a higher rpm. Basically right around 64-70 psi.

Bob, your arm chair diagnosis in doing well here. Thanks for the help. I don't know if I would go as low a 20psi but I'm gonna try 45 then 40 and see if it goes away all together.

Mark, those vids are amazing. At this point I won't doubt anything being relevant. Since it takes a mile or so, initially, of aggressive acceleration to produce the sound, aeration could also be contributing to the pressure valve "chatter".

I think at this stage you should perhaps measure the pressure section of the pump and see which model of pump you have. If that pump is beating up the pressure relief valve at anything above idle it does sort of point to being oversized for the application. You might be able to under drive it to compensate. Just thoughts.

Bob

 

[Jac Mac]

IIRC the SCP pumps are gear type which tend to have a pulsating pressure delivery compared to the gerotor types. I concur with the others that the ~60lb @ idle is too high and it sounds like you could afford to slow the pump slightly... try not to go below 19 teeth on the crank gear, it makes life on the belt a bit tough.
In a perfect world the relief valve should only have to work in a cold start and at the very top of the RPM range when hot.