Dry sump breathing on 351W V8
Discussion
Hi all
I'm racing a 65 Mustang with a Roush 351W enigine (410bhp). Good oil pressure and temp and good water temp. No smoke from exhaust and engine pulls well.
BUT: the dry sump was pushing oil into the expansion tank (front of engine bay). Up to 2 litres in a 45 minute race. At first it looked like the pipe to the expansion tank was located incorrectly from the oil tank (in cockpit). So moved it to the top of the tank and away from the scavenge pipe returns (it runs twin scavenge and one pressure line) and removed rocker breathers which I did not think a dry sump should have.
It still pushes oil into catch tank at the same rate.
I may have slightly over filled the system but not by 2 litres.
Compression seems ok in engine / cylinders.
Question: should I have rocker breathers (some schools of thought say yes others no).
The tank could be too small but I am presuming the people who originally fitted it knew what they were doing (but I'm not convinced)
What else could cause the overflow and what options could I try to stop the problem?
I'm thinking of putting a catch tank in the boot for the oil so at least it wont be in the engine bay and using the front tank for rocker breathing??
aaaaarrrgh!
Help required
Gail
I'm racing a 65 Mustang with a Roush 351W enigine (410bhp). Good oil pressure and temp and good water temp. No smoke from exhaust and engine pulls well.
BUT: the dry sump was pushing oil into the expansion tank (front of engine bay). Up to 2 litres in a 45 minute race. At first it looked like the pipe to the expansion tank was located incorrectly from the oil tank (in cockpit). So moved it to the top of the tank and away from the scavenge pipe returns (it runs twin scavenge and one pressure line) and removed rocker breathers which I did not think a dry sump should have.
It still pushes oil into catch tank at the same rate.
I may have slightly over filled the system but not by 2 litres.
Compression seems ok in engine / cylinders.
Question: should I have rocker breathers (some schools of thought say yes others no).
The tank could be too small but I am presuming the people who originally fitted it knew what they were doing (but I'm not convinced)
What else could cause the overflow and what options could I try to stop the problem?
I'm thinking of putting a catch tank in the boot for the oil so at least it wont be in the engine bay and using the front tank for rocker breathing??
aaaaarrrgh!
Help required
Gail
Hi All
Not sure about the tank but I am going to look at it in more detail as several people say it may not be baffled enough although I presume its a shop bought part designed for the job! Catch tank is higher than the oil tank. Currently no rocker breathers. Most designs suggest that the scavenge pipes create a vacuum so there should be need to breath rockers. Oil is Joe Gibbs #6.Has been changed twice now since I bought the car. Breathing was a bit better today at Rockingham in qually. Didn't check after race as needed to get home but will do later in week.
Not sure about the tank but I am going to look at it in more detail as several people say it may not be baffled enough although I presume its a shop bought part designed for the job! Catch tank is higher than the oil tank. Currently no rocker breathers. Most designs suggest that the scavenge pipes create a vacuum so there should be need to breath rockers. Oil is Joe Gibbs #6.Has been changed twice now since I bought the car. Breathing was a bit better today at Rockingham in qually. Didn't check after race as needed to get home but will do later in week.
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