Dry sumping
04-09-2006, 11:12 PM
#106
Former Vendor
Call Mark at 714 632 9288. He tries to stay out of the business of marketing racing pieces for the 928's, but he might be able to help. If he doesn't want/have the time to help, let me know.
04-09-2006, 11:48 PM
#107
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Ok, thanks. I do recognize Mark stays out of the racing parts business. I will check with him first. I will also have free access to JV's drysump project plans as well 
04-10-2006, 01:29 PM
#110
Drifting
stan, be sure to share what you are able to find as there is definite interest in a working drysump pan.. ive not heard detonation mentioned as an issue before, very interesting. but wouldnt it lead to failure of other rod bearings equally??
also interesting is the fact that rod bearing failure only occured on mark A's drysumped engine with a change in pan. previously it has been suggested that drysumping alone wont cure 2/6 failure and mark A's experience cited as evidence but it seems there was more to this story. also interesting to hear that the 944/968 engine dosent spin bearings when drysumped. im inclined to think that drysumping really might be substantial insurance against 2/6 bearing failure and a nearly essential addition to any hard driven 928.
also interesting is the fact that rod bearing failure only occured on mark A's drysumped engine with a change in pan. previously it has been suggested that drysumping alone wont cure 2/6 failure and mark A's experience cited as evidence but it seems there was more to this story. also interesting to hear that the 944/968 engine dosent spin bearings when drysumped. im inclined to think that drysumping really might be substantial insurance against 2/6 bearing failure and a nearly essential addition to any hard driven 928.
04-10-2006, 02:24 PM
#113
Former Vendor
Mild detonation only occurs on the hottest cylinders when there is an octane problem. For clarification, Mark has experienced rod bearing issues with a good working pan. It is actually something that is watched all of the time. He actively takes oil samples and the oil checked for metal traces. When the bearing material traces starts going up, he gets really concerned and will check the bearings. One of things that is difficult to control is the quality of fuel at the race track. One bad tank can kill the bearings.....unless they are Chevy sized/quality bearings.....as I mentioned. The 944/968 engines also kill the bearings with dry sumping and crank drilling. The stock 928/944 bearings are very, very soft and they pound very easily. Let's not forget that these engines were designed to last for long periods of time.....on the street. Soft rod bearings are very easy on crankshafts and connecting rods.
04-10-2006, 02:32 PM
#114
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To bad we couldn't get a run of Clevite 77's for the 928/944/968 engine. I bet there is enough interest to have a small batch run. Then again, a small run might be 2000 sets!
I'm going to be running Clevits in my motor and will change when oil analysis says so or once a year.
I changed the stock 928 rod bearings once a year on the old hybrid motor. To me it was cheap insurance, $120.00 bearings and 8 hours under the car during the winter off season. This approach kept my motor together.
I'm going to be running Clevits in my motor and will change when oil analysis says so or once a year.
I changed the stock 928 rod bearings once a year on the old hybrid motor. To me it was cheap insurance, $120.00 bearings and 8 hours under the car during the winter off season. This approach kept my motor together.
04-30-2006, 11:32 AM
#116
Nordschleife Master
Thinking about the design of the 928 oil pan it's clear that dry sumping is the best solution for 928 oiling problems. This includes both bearing failure and oil ingestion. A front sump with a shallow and also shallow-angled pan is horribly bad for track use.
Could someone elaborate on how the tank is connected back to the stock pump?
Could someone elaborate on how the tank is connected back to the stock pump?
04-30-2006, 01:35 PM
#118
Nordschleife Master
So you're saying to use another pump stage to pressurize the system or another pump. If that case it'd be plumbed to an adapter plate and forced to the inside passage of the filter? It'd be tricky to get the pressure and volume set right.
04-30-2006, 01:54 PM
#119
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Couldn't you machine a cover with an internal pass-through to replace/delete the stock oil pump?
An idler (EG. cogged 944 tensioner pulley) would take the place of the oil pump gear.
An idler (EG. cogged 944 tensioner pulley) would take the place of the oil pump gear.
04-30-2006, 02:09 PM
#120
Nordschleife Master
A gravity feed from the tank to the inlet of the stock pump sounds like a good idea in terms of cost and performance. Going through the pan to the regular pick-up location seems like extra complication.
What would be sweet would be to tap into the block into the feed channel and attach the hose there. Then cap the stock pickup connection on the bottom of the block. Unfortunately, I don't recall that the passage runs along the ourside of the block but wasn't studying it.
What would be sweet would be to tap into the block into the feed channel and attach the hose there. Then cap the stock pickup connection on the bottom of the block. Unfortunately, I don't recall that the passage runs along the ourside of the block but wasn't studying it.