[orphanowner]

I'm doing a 944 SPEC engine for a racer in SoCal that had a bad experience with another shop. Apparently, the engine blew up in "spectacular" fashion at Las Vegas Speedway a few months ago and dumped about 7 qts of oil on the track. The two cars following behind this car also suffered some damage due to the poor traction available on 15-50 Mobil 1.

Don't be this guy....

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[josephsc]

Yike! That's spetacular, all right... I guess a rod when through it?

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[flash]

that is a very ugly thing to have happen - you suddenly discover muscles in your anaotmy you never knew you had - i've sent rods through blocks and pans before - not fun - i feel for the guy

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[orphanowner]

A few more pics...the typical bearing failure on the 944/968 engines is number 2 rod bearing, usually a result of low oil levels. Not sure what the postmortem is on this unit, but it did fail due to a catastrophic number 2 rod bearing seizing up from lack of oil.



Pic 1 is number 2 piston and rod remains...



The other pic clearly shows the indent from the head when the piston was "liberated" from the crankshaft. It sorta says "hey I'm free! No more piston to tie me down" All smiles that piston for the nanosecond before it hit the head...

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[jww968]

Same thing happened to my 924S at Barber in March. (Second time in 5 years) The engine I put back in has less than 50k miles and around 10 DE weekends on it. I replaced the rod bearings on it before install and found obvious scoring on the 2 and 4 rod bearings. Several vendors are claiming that adding baffles and modifying the pickup will solve this issue. I've used Accusump, but as oil pressure decreases during a race, it bleeds in oil and can cause foaming. At the Road Atlanta race a few weeks ago, three of the four 944 racers around me in the paddock had experienced rod bearing failures in the past two months. I have not heard of this being an issue with the 968. Better baffles? Newer? Fewer on the track? I already run the 1988 engine with deeper pan and later baffles, but I plan to contact one of the vendors about adding baffles.

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[GuardsRedCoupe]

Those are amazing pic's. Yikes! <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

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[orphanowner]

[quote name='jww968' date='Apr 17 2006, 05:37 AM']Same thing happened to my 924S at Barber in March. (Second time in 5 years) The engine I put back in has less than 50k miles and around 10 DE weekends on it. I replaced the rod bearings on it before install and found obvious scoring on the 2 and 4 rod bearings. Several vendors are claiming that adding baffles and modifying the pickup will solve this issue. I've used Accusump, but as oil pressure decreases during a race, it bleeds in oil and can cause foaming. At the Road Atlanta race a few weeks ago, three of the four 944 racers around me in the paddock had experienced rod bearing failures in the past two months. I have not heard of this being an issue with the 968. Better baffles? Newer? Fewer on the track? I already run the 1988 engine with deeper pan and later baffles, but I plan to contact one of the vendors about adding baffles.

[right][post="19323"]<{POST_SNAPBACK}>[/post][/right][/quote]



The single biggest factor I've found in 944 rod bearing failures is low oil levels. The second biggest factor is left hand turns with low oil levels. The late pan, baffle and pickup tube from 1987 and up is the same pan used on all 944/968 engines and is a big improvement. IMHO, forget about more baffles. The added in baffles that I've seen only slow down the oil draining to the sump. I would never use an accusump for the same reasons you mention. The accusump doesn't have a brain and there is no way to prioritize where the oil pressure goes. The Accusump will suck up oil pressure to refill itself, even when the bearings are at critical need; perhaps right after the Accusump emptied itself! The only thing I've found to make minimal improvement is to weld up the oil pickup tube screen to prevent cavitation. I tell my engine customers to run slightly overfilled (1/4 qt), and check the oil after every session. If the engine consumes or leaks oil, it becomes a lot more likely that it will run low during a session and lose a bearing.

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[jww968]

"The only thing I've found to make minimal improvement is to weld up the oil pickup tube screen to prevent cavitation."



I'm not understanding what you are describing here. I have seen a collar welded onto the oil pickup to force it to pull from the bottom of the pan. Is this what you are describing?

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[orphanowner]

[quote name='jww968' date='Apr 17 2006, 07:25 AM']"The only thing I've found to make minimal improvement is to weld up the oil pickup tube screen to prevent cavitation."



I'm not understanding what you are describing here. I have seen a collar welded onto the oil pickup to force it to pull from the bottom of the pan. Is this what you are describing?

[right][post="19330"]<{POST_SNAPBACK}>[/post][/right][/quote]



Yes, that is exactly what I meant. I was running out of time this morning and didn't put as much detail in my post as I should have.

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[Eric_K]

Those are ugly pictures. I have no real evidence but the spun #2 seems to happen less in the 968. I have seen it happen to numerous 944's. I have a hard time thinking of a 944 race car around these parts that it hasn't happened to.



This has been discussed here before. Whether it is the fewer numbers, younger cars or something changed, but you don't hear about it much for the 968. I think getting the oil too hot plays a factor and the 968 has better oil cooling. I'm not sure but isn't the baffle different in the late 2.5 compared to 3.0 liter pans?



Running enduros, I've gone 3-4 hours at a time without adding oil and run it down over 1/2 quart under full. I changed the rod bearings last year and the old ones looked perfect. Who knows? I'm either really lucky, the problem is less severe on the 968, or Mobil1 racing oil is really good. YMMV.



Eric

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[orphanowner]

[quote name='Eric_K' date='Apr 17 2006, 10:27 AM']Those are ugly pictures. I have no real evidence but the spun #2 seems to happen less in the 968. I have seen it happen to numerous 944's. I have a hard time thinking of a 944 race car around these parts that it hasn't happened to.



This has been discussed here before. Whether it is the fewer numbers, younger cars or something changed, but you don't hear about it much for the 968. I think getting the oil too hot plays a factor and the 968 has better oil cooling. I'm not sure but isn't the baffle different in the late 2.5 compared to 3.0 liter pans?



Running enduros, I've gone 3-4 hours at a time without adding oil and run it down over 1/2 quart under full. I changed the rod bearings last year and the old ones looked perfect. Who knows? I'm either really lucky, the problem is less severe on the 968, or Mobil1 racing oil is really good. YMMV.



Eric

[right][post="19348"]<{POST_SNAPBACK}>[/post][/right][/quote]



The late pan, baffle and pickup tube is a big plus, and of course all the 968's and mid 1987 and up 944's have that. The pickup sits lower in the pan and has a small mini-sump that helps the screen stay covered with oil. All the "oil level sensor" pans have this mini-sump and it's visible from the outside of the pan. The late baffle actually has a crank wiper that cuts down on oil aeration and aids oil flow back to the sump. The 104 mm blocks also have windows at the bottom of the bores to reduce sump windage from the amount of crankcase volume the large pistons displace as the run up and down the bores. All this really improves the oiling and combined with synthetic oil and an oil cooler, work well on the track. I had over 15,000 track miles on my 400 hp 944T and when the new owner had me rebuild the engine due to an over heat, the bearings looked perfect and could have been reused! I ran Mobil 1 exclusively and a huge oil cooler that was properly ducted kept oil temps in the 220 range.



My theory is that most track 944's are pre 1987 and are running the early pan. Combine this with worn and or leaking original engines, and the chances of running low on oil and damaging the engine are greatly increased.



Eric, you have been very lucky running your engine low on oil and not doing any damage. At one track out here in SoCal that can be run in either direction, when they run it reverse and do their longer races, I usually get at least one 944 engine job due to the long sweeping right hand turns and low oil levels.

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[xsboost90]

i installed a lindsey racing oil pan baffle, pick up collar, crank scraper and cross drilled my rod bearings after a rod spun up at putnam park last year. Very important to also make sure you top off your oil between runs- my car tends to use oil on the track when it wouldn't usually.

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