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Q: I have a Festiva that has been set up for Solo Modified with a 323 1.6 with Weber carb and it is doing the same thing the 1.3 did last year which is blowing oil out the top with total loss in oil pressure, after high g turns and high rpm. once the car is stoped and sits the oil pressure is reestablished. Vacuum and compression seem ok. Is this some thing I need aN Accusump or some similar equipment to resolve. This problem kept from last event last year a several this year.- J. Little
A: Loss of oil pressure in this case is from the oil pump pickup tube/screen uncovering and "sucking air" during cornering . Possible causes are the pan's oil level too low, which can happen when it is underfilled during engine maintenance or due to poor oil drainback from cylinder head. The latter will increase risk of pump sucking air because the oil from the pan is pumped through the galleries at a rate faster than it can be replenished in the pan. Cleaning and improving the oil drainback holes in the head can help a little and is good practice to follow for competition prep. But then what is needed to resolve this scenario is increased oil capacity around the pickup.
Loss of pressure can also happen simply cause the oil sloshes too much around the pickup. Accusumps are better than nothing, but is sort of a band aid rather than a suture IMHO.
My suggestions begin by first modifying the stock pan to increase oil capacity to at least 5 quarts (this will require kickout of the sump to retain ground clearance) and baffle the low part of the sump to keep oil around the pickup. You might look into a cast aluminum pan from a B6 16 valve engine. It may fit and might have more capacity and/or superior baffling. Then work on enlarging / smoothing out the oil drainback holes in the head.
Wet sumps can only do so much and can be easily overworked being asked to perform two primary duties at once ( primary oil reservoir and pump collection), especially with smaller pans. That's why serious race cars use dry sump systems. Additional scavenge stages on these systems can remove the top end oil during hard cornering.
3/22/02
A: Loss of oil pressure in this case is from the oil pump pickup tube/screen uncovering and "sucking air" during cornering . Possible causes are the pan's oil level too low, which can happen when it is underfilled during engine maintenance or due to poor oil drainback from cylinder head. The latter will increase risk of pump sucking air because the oil from the pan is pumped through the galleries at a rate faster than it can be replenished in the pan. Cleaning and improving the oil drainback holes in the head can help a little and is good practice to follow for competition prep. But then what is needed to resolve this scenario is increased oil capacity around the pickup.
Loss of pressure can also happen simply cause the oil sloshes too much around the pickup. Accusumps are better than nothing, but is sort of a band aid rather than a suture IMHO.
My suggestions begin by first modifying the stock pan to increase oil capacity to at least 5 quarts (this will require kickout of the sump to retain ground clearance) and baffle the low part of the sump to keep oil around the pickup. You might look into a cast aluminum pan from a B6 16 valve engine. It may fit and might have more capacity and/or superior baffling. Then work on enlarging / smoothing out the oil drainback holes in the head.
Wet sumps can only do so much and can be easily overworked being asked to perform two primary duties at once ( primary oil reservoir and pump collection), especially with smaller pans. That's why serious race cars use dry sump systems. Additional scavenge stages on these systems can remove the top end oil during hard cornering.
3/22/02
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