Oil pressure in right sweepers
03-14-2017, 09:52 AM
#31
The graph looks very good. What all did you do to your engine/oiling system to get these successful results? Is it a proprietary system?
Thank you,
Steve
Thank you,
Steve
Well, you can see on the graph I just posted that the oil pressure changes only in response to changing rpm. If you look closely you can also see very small dips at 4900rpm. The Variocam solenoids steal a little oil pressure when they activate.
My previously posted graph shows the oil pressure going up and down wildly in response to G forces. This is what is happening inside most M96 or M97 engines when they are being driven hard.
It is not uncommon for the oil pressure to drop below 1 bar due to G forces. I accidentally and expensively proved to myself that the oil pump generates about .75 bar worth of air pressure even without any oil in the engine. So, if the pressure is below 1 bar there is essentially no oil being delivered to the bearings. The engine fails once it accumulates enough run time without oiled bearings.
These engines are remarkably tolerant of this situation. I cannot explain that.
Chris Cervelli
Cervelli Technical Service
My previously posted graph shows the oil pressure going up and down wildly in response to G forces. This is what is happening inside most M96 or M97 engines when they are being driven hard.
It is not uncommon for the oil pressure to drop below 1 bar due to G forces. I accidentally and expensively proved to myself that the oil pump generates about .75 bar worth of air pressure even without any oil in the engine. So, if the pressure is below 1 bar there is essentially no oil being delivered to the bearings. The engine fails once it accumulates enough run time without oiled bearings.
These engines are remarkably tolerant of this situation. I cannot explain that.
Chris Cervelli
Cervelli Technical Service
03-17-2017, 10:56 PM
#32
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I am curious to.
I am planing on plumbing two electric oil pumps to the heads. Pump the oil down into the deaerators in the sump. Kind of poor mans version of Porsches tandem scavenge pumps that run about $4000-$5000.
Ad this to a deep sump, improved horisontal baffles and an Accusump. Then monitor the result in similar way that you have been doing and see if I still get fluctuations....
I am planing on plumbing two electric oil pumps to the heads. Pump the oil down into the deaerators in the sump. Kind of poor mans version of Porsches tandem scavenge pumps that run about $4000-$5000.
Ad this to a deep sump, improved horisontal baffles and an Accusump. Then monitor the result in similar way that you have been doing and see if I still get fluctuations....
03-19-2017, 02:22 PM
#34
Rennlist Member
Chris did you add another scavenge pump and pickup? I had the TTP pump on my 987.1S along with accusump, X51 baffle and 996 Defoamers. It has held together for quite a while now (on the third owner). Expensive setup but cheaper than new engine.
04-03-2017, 08:48 PM
#35
Rennlist Member
EDIT: Looks like Chris has a solution: https://rennlist.com/forums/racing-a...mp-system.html
Last edited by cbracerx; 04-03-2017 at 08:57 PM. Reason: Added link
