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| 03-20-2026, 11:08 AM | #45 | |
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dunno if he wants to disclose anything. although he hasn't mentioned what failed. so who knows.
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| 03-25-2026, 12:47 PM | #46 |
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This is why I am doing a comprehensive fix for this lubrication situation. All of these conversations are amazing and I am so happy to have it at my disposal. For someone who will be pushing the cars capabilities on track I was afraid of doing a band-aid fix and wanted to do a number things to increase the probability of the engine lasting for a long time.
1. SRD gears - I think Peter said it best, more oil pressure via oil pump gears can't hurt, ever. 2. Baffled oil pan - This is important but needs to be done by a VERY good aluminum welder. I got AAF involved on mine and am very happy with the results. 3. Oil Diverter valve - With the mention of the amount of track use I plan on doing the oil temp is important. For primarily street driven vehicles you'll want to second think this. 4. Accusump- Poor man's drysump. $1000 and you can add 1.5-2qts of oil at any time and also help with precharging the system before cold start (which is a big wear activity on our bearings.) 5. D088 Coolers - This is obviously a must. 6. Bimmerworld physical dipstick kit - I am over waiting for the electronic sensor to do its job and change its mind every 5 minutes. Rubin Last edited by former 240 s14; 03-25-2026 at 01:07 PM.. |
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03m_plus36.50 Chrisyphus474.50 |
| 04-23-2026, 08:57 AM | #47 | |
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I love your detailed analysis of these topics, I’m curious of what your feedback would be on installing an accusump on the S65. Installing the oil pump gears seems like an absolute no brainer if you already have the oil pan removed, but for those of us who have the larger clearance bearings already and would have to remove the pan a second time to do the gears, it’s a little less DIY friendly. Is the primary issue the oil pressure drop during high rpm throttle modulation, or is it that there isn’t an adequate amount of oil getting to the main bearings at all times since opening the clearance on the rod bearings? And if it’s the former, does installing an accusump system (installed down stream like near the oil cooler) solve the issue, or no because it wouldn’t be able to increase oil pressure adequately near the main bearings. Thanks for your insights, love your work 👌 |
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| 04-23-2026, 05:32 PM | #48 |
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Check that, if there's still time. People don't always get lower temps with these. Not saying they're bad; just that they're no guarantee of better performance vs. new OE coolers.
The do88 oil cooler uses a bar-and-plate design, which gives it more mass than the stock tube-and-fin design. And it's bigger, so more capacity and even more mass. So, temps might climb more slowly. But bar-and-plate dissipates heat less efficiently, so peak temps during long sessions might not be any lower. The do88 engine coolant radiator looks like it's just a bigger version of the stock piece, but not by much. Neither piece can be expected to be up to OE standards in build quality; sometimes they are, sometimes they aren't. And the additional size can cause fitment headaches. I can't speak to DCT, so maybe there's some benefit there. For MT, AFAIK, there's zero evidence the stock cooler isn't enough. In fact, it has a block-off plate from the factory, so if you're worried, maybe you can just remove that (I have no idea what the implications would be – it must be there for a reason – so don't take this as advice). The stock cooling system is quite good, honestly. When new, it can handle hot summer track days easily. Performance degrades with time, so you'd probably see an improvement by putting in new OE coolers and making sure all the ducting is in place (including the stock undertray/splash guard – that's important). |
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| 05-02-2026, 09:23 PM | #49 | |
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Today/tomorrow, I will be wrapping up my S62 VANOS control system redesign, and then I will be fully committed to designing our new S65 oil pump. The details I am willing to share now: with OEM gearing, my solution will deliver 27.8% more oil volume per pump revolution than the OEM oil pump. That means that, paired with an overdrive kit, my design will deliver nearly 50% more oil volume per crankshaft revolution than the OEM configuration. All while maintaining 100% of OEM functionalities. To include variable displacement pressure control. To your points- 1- Yeah, at the moment, that is the best option short of a dry sump. (for a month or two at least) 2- Double-check your oil pan. A contact bought two oil pans from AAF, and both were cracked in the same place. The shop he was working with had 4 in stock, and they found the same crack in the same place on all four. They probably just had a bad batch, but still, you should take a look. 3- I have a solution for this incoming too, but it's lower on the list. All the benefits of deleting the thermostat... while still keeping one. I have a thermostatic block designed; it's pretty clever, with only one moving part, to achieve 100% unrestricted flow to the oil cooler when the temperature is above 100 °C. I am just stuck in my usual crash-out lane of "using a traditional wax thermostatic actuator is fine, but doing an entirely digital standalone unit based around PID control with a full flow fail state would be way cooler." 4- The OEM oil pump flows over 15 gallons per minute. If oil pressure drops below 2 bar, your accumulator will exhaust itself in 2 seconds at most. Our pump upgrade will not cost much more than $1000. 5-love DO88 products. 6- Love this mod too.
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former 240 s14558.50 |
| 05-03-2026, 12:38 AM | #50 |
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I’m not an expert in anyway and more just a downstream consumer. Does this have any effect on an average driver with BE bearings like myself that won’t ever track the car but will do the occasional 8k redline from time to time? I might average like 3-4k rpm most of the time anyway. Thanks for all the work and info!
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| 07-30-2026, 05:35 PM | #51 |
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Another super thread res, Gasblip, I am just now seeing this response while trying to find a link for another post. To answer your question- yes. I think so, but I have no proof of that beyond the motors we have gotten in the shop over the last year or so since we picked up in the number of S65 orders we've gotten.
Every single motor that has been brought to us, save ONE motor with a torched piston, has had a spun #1 main bearing and oversized rod bearings. The brand does not matter IMO; whichever brand of bearing kit is the most popular is going to be the most prevalent in this sample group, so I will not name names. The fact is that of all the motors we have had in the shop with a spun main bearing, 100% of them have had oversized rod bearings, which all looked brand new despite having 20-40k miles across the board. Of those cars, 90% have been well-maintained and cared-for street cars. One had 60k miles on the chassis and 20k miles on the rod bearings. I have done significantly more research since the making of this post, and I am even more confident now in my finding that the issue is not the bearings; it is the lack of oil flow capacity in the OEM oil pump, which is exacerbated by increasing the engine's base oil flow demand by increasing the rod bearing clearances.
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| 07-31-2026, 11:22 AM | #52 | |
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| 08-02-2026, 12:26 PM | #53 |
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I think the sample is skewed. At this point, pretty much everyone who tracks has increased tolerance rod bearings.
I instruct a lot of e9x cars at the track, and I always ask if they have stock bearings. The last driver that told me they had stock bearings and the rod bearing topic was overblown was a few years ago, and they blew their engine that same weekend. My BE bearing S65 has been running around for 50k miles. This is not something I'm worried about. |
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| 08-02-2026, 11:19 PM | #54 | |||
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That car did have oversized rod and main bearings, a baffled oil pan, fairly significant aero, and Sport Cup 2s. He saw no change in datalogged oil pressures from switching to the baffled oil pan, and saw as low as 14 PSI in corners. But that wasn't actually what killed that motor. He had another shop refresh a junkyard motor for him, and within 2,000 track miles, a hole had been torched through a piston. The rest have been street cars that have either had extremely limited track time or none at all. Most of the rest come from eBay or private sellers as "good running" cores. Of all of those, to our knowledge, only one came from a track car. It had ~60k miles on it, and of all the S65s we have ever received, it was far and away the cleanest and in the best shape internally. That is not to say it was perfect- it had moderate main bearing wear, and as ever, the BEs in its rods looked brand new, and it had a few other small issues like a cracked timing cover on the alternator mounting boss (I imagine this is why it was pulled. A careless prybar can crack this thin section of aluminum while trying to remove a seized alternator.) I think that the excellent service schedules that track enthusiasts typically put their motors on significantly reduce the risks of rod and main bearing failures. Quote:
The guy who said "rod bearing failure is overblown" is probably the same type of guy who says "BMW says 10,000 miles between oil changes, any more is a waste of time," and then proceeds to take his car to Walmart and buy whatever type of oil they're running a special on. Quote:
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| 08-03-2026, 02:13 PM | #55 | |
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Can't wait to see more on this pump of yours! Thanks for what you are doing for the community! Rubin |
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