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928 guys have luck with a 3/8" spacer that moves the oil pan down.
they then space the oil pickup tube down to compensate.
their reasoning is to add air-gap between the crank whirlwind and the oil...
maybe we could use something like that to add more oil capacity (more oil to completely submerge the pickup tube, less likely to find air if it is "deeper")
I haven't mentioned it up until now but, personally, I think the answer is to bleed air out of oil in one of the circuits already available with an air bleed device. I had looked into this and found a company that manufactured one but there was no way I could see how to adapt it to a 944 engine.
I haven't mentioned it up until now but, personally, I think the answer is to bleed air out of oil in one of the circuits already available with an air bleed device. I had looked into this and found a company that manufactured one but there was no way I could see how to adapt it to a 944 engine.
Top 'o the day Spencer,
T
seems to me a more typical belt-driven vacuum pump would work just as well?
I used the "arrange by from" feature in MS Outlook to find emails I exchanged with Jon Milledge on reducing/eliminating oil aeration to get me in a ballpark date of sent/received emails from the patent holder of the device I mentioned above, it's called 'Spintric', patented by Armstrong Race Engineering. http://www.spintric.com/ (there's a video demo there).
The device needs low pressure scavenge return.
Jon alluded to an "in block foam elimination" modification that he was looking for pictures of to send me but I ended up (always racing... ) rushing the block in question into assembly before I investigated this further.
Just for a reference hbelow is 944 oil flow diagram. Based on it I will not risk modifying #3 main bearing to increase oil flow to #2 and #3 rod bearings (this was one of the main questions raised in the first post of this topic) unless I will find some detailed guidance and good references how to do it right.
I may increase the existing internal oil galleys going to #2 and #3 rods in the crank and perp drill (most probably 90 deg or maybe 60 deg - still have to find more info) the #2 and #3 rod journals.
As discussed in this thread, I should be fine also with other modifications and good oil that does not exceed (ideally is well below that) 125C/257F temperature on race track.
Just for a reference below is 944 oil flow diagram. Based on it I will not risk modifying #3 main bearing to increase oil flow to #2 and #3 rod bearings (this was one of the main questions raised in the first post of this topic) unless I will find some detailed guidance and good references how to do it right.
I agree. The #3 main bearing is taxed enough already. The oil supply to #3 main also feeds the thrust bearing, balance shaft and turbo. If you pull more oil away from #3 to feed the rod bearing there would be less oil for other needs. From what I've seen, the thrust bearing needs a good supply of oil to survive since it's the next weak link. I wouldn't pull oil from the thrust bearing.
Another option is to use a ball bearing turbo since they use restrictors to limit oil flow. This will keep a little more oil in the engine. A ball bearing turbo can also survive brief oil loss much better than a journal bearing turbo.
Thanks everyone for your suggestions and advice! My engine is coming slowly together and hopefully I will start it next weekend - it came out that I needed new crankshaft, as the one that I had was machined to use 0.5mm undersize bearings.
In the end I did not modify the crankshaft - did only micro polish and balancing with the new KEP stage 1 PP and OEM flywheel.
In addition did the fallowing modifications:
1) ring around the oil pickup screen
2) Oil pickup tube supporting bracket
3) Teflon crank scraper
4) additional oil cooler (0.38 liters or 23 cubic inches) - it is rather small, but I will install it in the front of the radiator with good airflow - hopefully will not have issues with water temps, but those are easier to control and keep in the norms.
5) added small windage trays between 1 - 2 and 3 - 4 cylinders (see picture below)
6) oil pan baffle
7) already had the late (87 +) oil pan with the OEm crank scraper
8) install oil temperature gauge, to monitor oil temp while on track
9) will use high viscosity oils (millers 10w50 or 10w60 race oil)
10) not directly related, but my new Wossner rods are 255 g per each lighter than the cast ones that I had till now - this also should reduce stress or crank and rod bearings at high rpms.
There are still some things that I could not do this time or would have wanted to be done little differently. Hopefully this will be more than enough for my application.
03-23-2016, 10:53 AM
) rushing the block in question into assembly before I investigated this further. 
