RedlineMan

Indeed;

Good call by Evil. You really do need to inspect the pick very carefully for cracks, as this is not uncommon. I plan on reinforcing mine during the build of my spare engine.

Another thing is to make sure the oil seal on the pickup is proper. There are different styles for different years/models included in most pan sets, so you have to choose the right one.

TD in DC

Yeah guys, I might know a little more by tomorrow. Yeah, I have video from the fated last run, but it is too painful to watch. I suspect that something had started to go south before the last turn through Karussel when it started knocking. The two theories I am running with is that (1) either, as you say, the bearing had already started to spin and Karussel was the straw that broke the camel's back; or (2) I broke a ring, which caused the oil to overheat, which made it easier for starvation to occur.

Here is a question for you guys. If the oil pickup is on the right side of the motor, why wouldn't left-handers be worse on the cars than right-handers?

Also, I could have been at a higher RPM in Karussel. I felt like I was really in a groove during the last run session, so I could have been a little higher than 4.5k. However, I was not that close to redline.

In any event, don't worry about Shenandoah. Just watch your gauges extra carefully and consider taking it easy through karussel. My engine problem may well have nothing whatsoever to do with Shenandoah. The only reason I brought it up was that I knew you guys were coming down, and I thought I should pass on the rumors I had heard.

If I could have gotten my motor swapped out in time, I would have joined you guys despite the rumor and, knowing myself well enough, I proably would have ended up pushing through karussel by the end of the weekend.

Adam Richman

I am a bit suspicious of the baffled pan/extended pickup apron thing. I bought into in wholey but now, not so much. I had the one most folks here recommended back in the day (trap door baffle, extended pickup apron) and really thought, along w/ the bearing replacement, synthetic motor oil and changes (o&f) after every event that I was doing everything I needed to to prevent a catestrophic failure. I *think* the bearings had somewhere around 8k but I could be wrong (this was my daily driver and DE car for a bit over a year).

TD, I have been told by some folks that I tend to listen to that Mobil 1, although a great synthetic oil on the street and very good detergent qualities, does not cover well on those momentary starvations. If you run that oil and really like it, I am not telling you to quit - just my little FYI.

I am with John's comments on volume and bearing (which I moreso think of as oil) temps. That's why I took the oil cooler off the race car and donated it permanently to the 944. FWIW, its a #12, 13 row Mocal that if you can get ahold of a shorty wiper resevoir, will fit under it behind the headlamp. Keith at Eurowerks figured out how to mount it up there, I'd hit him up if you are interested in how he mounted it up there. They were the guys that suggested the coated bearings and I think it too is a wise idea (if that momentary starvation can be patched to any extent by the teflon coatings). I am not sure if that's a common item out there but if not, give the Eurowerks guys a call and see if they can order you a set.

Oh, mine let go in 3rd gear around 5k - this was exiting a hard braking zone coming down from 6200 in 5th gear down to 3rd (that's probably about a 75mph drop ??). These are best memories (the 6200 I am all but positive about) - the 3rd is a best guess (T1 entry at LMS).

evil 944t

The only other thing my machinest/ engine builder told be me was, watch the pressure drop you get accross the aftermarket oil cooler. Some are very high and are hurting you more than helping. He has tried many and found Mocal to be the best.. I'm not for sure but thats what I heard..

38D

Buying a properly dry sumped 911 would solve it (I just couldn't resist!)

kurt M

TD did you have temp issues before the last run?

TD in DC

I was waiting for this, and was frankly shocked it took this long

TD in DC

Great question. Until the day of the problem, I had never had temp issues while on the track. In fact, oil temp rarely rose above 150 degrees. During the last two or three runs during the day of the problem, temps started rising. Nothing problematic, until the last run. Then it appears that temps started rising even higher than they ever had before. I was pushing the car very hard, but nothing out of the ordinary.

I didn't miss any shifts (well, ok, once I went into 4th when I wanted to go into 2nd when Dave and I were playing tag and he was right on my tail), and the only times I bumped against the rev limiter is in 2nd mid-way through little bend and 3rd mid-way through big bend.

evil 944t

LOL, Don't worry, you can dump tons of money into a 944 just like any other P car.. hee hee

Flirting with over reving is bad, as I can you show you pics of my block...with a rod through the side..nice.

dougoh

wellllllll...i am too a victim of the shanendoah karussel..after 4 months of not driving my car because of taking my turbo in and out 3 times and having running rich issues...finally got it running .(thanks to john at vitesse )it was the last run session for me with 5 minutes to go and i was coming out of the karussel and made a quick right hander and then the car began knocking.even though i havent gotten the chance to take the pan out of the car..i am certain i am going to need a motor..so be sure a baffled pan and a sump is on my list of upgrades on my future engine...as far as engine temp i was between 2nd and 3rd bar and oil pressure was between 4 and 5 bar in the straights ..couldnt tell ya what it was in the karussel...so just like TD said just pay attention to your gauges at shanendoah and you might want to back off a little in the karussel and if anyone has a 951 engine for sale let me know.

Z-man

Centripital force will push the oil towards the right in a left hander, where the oil pickup is. But too many g's in any direction for any prolonged period of time is not good. (Another argument against the whole g-sum debate, but I digress! - just kidding)

-Z-man, planning on taking it easy through that Karousel this weekend.

TD in DC

That's why I started this thread. Since I reported what happened to me, I have been hearing several rumors and they all sound remarkably alike. Thanks for the report Doug.

I am so tempted to take the 996 this weekend just so I can join you all . . .

Z-man

Why not? There is plenty of room, and we'll be running three groups, five runs a day. That equates to a whole lotta track time!

Email Arlene... NOW! It would be great if you could join us!

-Z-man.

M758

I have suffered 2 rod bearing failures in a little over 2 years.

Sadly they are a weak spot on the 944. In my mind there are really only two weak spots on a 944 NA stripped with 225/50 R 15 tires.

AGE and Crappy PO's

Rod Bearings.

I have seen more any a few cars pop rod bearings.

Here in Phoenix we have PIR. This track is onyl 1.5 Miles and we use turns 3 and 4 on the nascar oval. These in a 944 are taken flat out in 4th gear. A good exit speed sees about 6000 once the car goes straight. Banking is "gentle" 7 or 8 degrees. G-load are pretty intense.

Anyway I have spun two rod bearings. One was on a 46k mile street motor I first put in my 944 spec car. I think this one was cracked oil pickup tube, but it failed at 5500 RPM, in 4th, full throttle in the banking at PIR. It sized and blew up my block and consider myself luck that spin on my oil did not cause me to contact the inside or outside walls. Head was the only thing to survive.


After this I built another motor. This time I baffled the pan (trap door and pick-up ring). I also made sure the oil was Full, but not over. Every single session on the track. I did not want to run the car any bit low on oil. I ran this motor for along time. Maybe 20-30 races. I then took it down and pulled it for rod bearing maintence. I also switched over to Amsoil Series 2000 racing 20w50 for the last 5-6 races from Mobil 1 15w50 because my Mobil 1 would see only 3 to 3.5 bar at 6000 RPM after 15 min on track. Amsoil stayed up to 4 bar. I figured better protection from the AMSOIL.


Anyway at that time I got my hands on the "high compression" 88 motor and built that instead of trusty 84 block. (this motor seemed no more powerfull than my "low comp" 84 block however)

This motor got new mains and rod bearings and a baffled pan. It also got a 951 oil cooler. I ran it for 5 or 6 races before at PIR again I spun the #2. This time I caught it before I toasted the block. I pulled the motor and had to replaced the crank. In the mean time I did the rods on my 84 motor and found something interesting. The crank had been cross drilled. It was not me that did it, but someone had done it. Both motors that spun bearings did not have any cross drilling. I built this motor back together and put it back in the car. It is in the car now.

I aquired a used crank for my 88 motor and this time on advice of Greg Fordahl who did some crank oil passage flow testing I had #2 & #3 rods drilled. I drilled ONLY the #2 & #3 has his testing seems to have show it superior as compared to drilling even all 4. It had to do with a better flow balance between all 4 rods. This seems to make sense with avaliable data as I have never see a #1 or #4 failure, but have seen mostly #2 and often the #3 is not far behind interms of failing next. Seems like the flow properties are such that #2 is the weak spot.

Anyway this motor is built and sitting waiting for the day it will be needed.

BTW... I have seen cars with accusump fail #2 bearings. Seems to me that this is weak spot on these motor and there is little nothing that is a "100% fix".

To keep the rods happy you need good supply of clean, cool quality oil. Anything that may cause that supply to be compromised even by a small ammount is danger. Also duty cycle that increases the volume of oil require and increases the heat this oil must pull from the bearings (like high RPM) also taxes an already marginal system.

The good thing is that 944 motor are not that expensive. Also note that a 2.5L 944 NA uses the same crank as any 2.5L 951.

TD in DC

Thanks Joe. How hard is it to drill the #2 and #3 rods? Any instructions on how/what to do? What about the baffle?