#2 Rod bearing oil starvation problem?
08-28-2005, 10:42 PM
#16
Rennlist Member
The oil squirters have a check valve to prevent operation when oil pressure falls below 1.8 bar.
The 968 crankshaft indeed has a 944 p/n. I show 968 Crankshaft 944-102-015-15. Seems last 944 series crank had a final prefix of -13.
The 968 crankshaft indeed has a 944 p/n. I show 968 Crankshaft 944-102-015-15. Seems last 944 series crank had a final prefix of -13.
08-29-2005, 01:55 AM
#18
Rennlist Member
Good information from Jon Milledge.
He does neglect to inform you that the exit angle of oil really does matter. I have built a large number of 944 engines over the years and have seen many failed rod bearings and punched blocks from broken rods.
The 944 and 968 cranks all have the same oiling angle.
The one reason that I can think that the 968 cars have less failure is that they can't pull out of the turns like a 951 and they also have a better limiting valve in the head that keeps more oil on the bottom end.
The best way to avoid bearing failure is to:
1) place a scraper plate like that one pictured above in place
2) add an oil cooler with a thermosate inline and get the engine up to full operating temperature prior to running it hard
3) install baffles in the oil pan with a modified sump pickup
4) use a better air oil separator on the oil filler neck assembly
5) run a good dry sump....costs a lot of money
6) examine the check valve in the cylinder head and install a later 944S type
7) run a good quality motor oil
8) have the crank feed passages modified for straight shot oiling.
These are the problems that over the years I have addressed in problem engines.
Good luck.
He does neglect to inform you that the exit angle of oil really does matter. I have built a large number of 944 engines over the years and have seen many failed rod bearings and punched blocks from broken rods.
The 944 and 968 cranks all have the same oiling angle.
The one reason that I can think that the 968 cars have less failure is that they can't pull out of the turns like a 951 and they also have a better limiting valve in the head that keeps more oil on the bottom end.
The best way to avoid bearing failure is to:
1) place a scraper plate like that one pictured above in place
2) add an oil cooler with a thermosate inline and get the engine up to full operating temperature prior to running it hard
3) install baffles in the oil pan with a modified sump pickup
4) use a better air oil separator on the oil filler neck assembly
5) run a good dry sump....costs a lot of money
6) examine the check valve in the cylinder head and install a later 944S type
7) run a good quality motor oil
8) have the crank feed passages modified for straight shot oiling.
These are the problems that over the years I have addressed in problem engines.
Good luck.
