drnick

dennis, what caused the 2/6 failure? what oil, what RPM did you shift and did you use an accusump? im especialy curious to know if you were using track rubber or regular street and if you had noticed any pressure drops.

Dennis K

Well, that's the $15,000 question.

The oil was Mobil-1 15w50 and I was using a 6200 rpm shiftpoint.

After the first engine seized due to a rod bearing failure, the Accusump was cleaned and checked for operation. It was verified to be good before reinstallation.

In addition, the oil cooler was flushed and all the rod bearings were brand new. They were replaced on the second engine before it was installed. The only mileage on the bearings was the distance driven to the track and then seven laps.

I was using R-compound Nitto NT-01 tires. No pressure drops noticed. I did notice the engine wasn't pulling as strongly down the front straight, slightly hesitating. I remember looking at the speedo and not seeing enough mph. Oil pressure was OK. I backed off and put the clutch in, the motor died & I coasted to a stop. Oil pressure was zero and the light was on at that point.

I'm getting ill recalling this again. Oh well, onwards and upwards.

We're still looking for a short block so we can put this thing back together. We can make it stronger. Anybody w/ engine parts available, please PM me. Thanks.

Jim bailey - 928 International

Are you serious about this ......"They were replaced on the second engine before it was installed. The only mileage on the bearings was the distance driven to the track and then seven laps." You only got SEVEN LAPS !

mark kibort

Folks, what is different between Dennis, who is beating up on the 928 on a regular basis. we know his shift points and skill level, vs what ive seen on 4 different 928 platforms.
the only difference is AMZOIL vs Mobil 1. Im telling you folks, i dont trust mobil 1.
I had 175,000miles, 30,000miles racing on the '84, then the part euro 5 liter and now over 90 hours of beat-the-snot-out-of-the-engine racing on my curent stock S4 5 liter.
knock knock knock!!!!

Is there a possiblity that the accusump or oil cooler could cause pressure drops or lack of flow?

mk

Mike Frye

Ok, who had 25 minutes in the pool?

Just kidding MK. You're so predictable.



PS- You know I use Amsoil too, right?


Dennis,

Thanks for the detailed description of what was obviously a difficult event that will hurt until the minute you're on the track again (or maybe until you hear it run again). I wish I could offer some parts to get you out there again. Good luck!

leperboy

Bill, you know, Denver's really lovely this time of year. It'd be a shame to deprive you of the opportunity to work on 928s in the shadow of the Rockies...

Matt

Bill Ball

Ok, so it would have lasted 8 laps with Amzoil. That wasn't the issue. Even with peanut oil it should run longer than 7 laps! PULLLEASE!!!

Amzoil didn't save George's motor and it would not have saved this one. Slick50 maybe, but not Amzoil.

Bill Ball

You could always move here.

leperboy

27 years in California was about one month too long for me if you ask the ex-girlfriend who necessitated my departure.

Matt

mark kibort

Look at all the laps ive had at Thunderhill in 928s. They have the 928 engine killer, turn 2, which is a 80mph sweeping left hand U turn. if this is the problem based on what we know of the oiling issues, then it doesnt matter if takes 1, 7 or 100laps, the problem will show itself, and if it is oil film strength related, it could happen any time. Again, you know im a little religious about amzoil or redline, however, look at the luck ive had with it.

Now, the other thing that comes to mind is the gearing differences. Dennis rolls around turn 2 at 80mph near 6000rpm while i am near 5000rpm. Maybe that, in worse case scenerios could be a factor too.

Im thinking George's failure is due to something else. if the oil was milky when they checked the dipstick that would mean that was mixing while running.

why dont we all run slick 50 anyway???

Mk

FlyingDog

Dennis, If this is a track only car, why not install an 85-86 short block to get 11.8:1 CR? Shark tune it for either 92/93/94 octane pump gas or race gas. The short block would probably be less expensive. I know Scott M has one for sale, but shipping might be prohibitive to CA.

Mark, give it a rest. We don't care. Mobil 1 vs Amsoil had nothing to do with this failure.

Bill Ball

That's already been covered. The oil and water did not mix. The water disappeared into the pan post mortem. Dave said they layered nicely in the pan. When we looked the the dipstick that night the level was high and the fluid was clear. It just looked like clean oil on the dipstick, but as this was after the water disappeared from the ovberflow bottle, it was probably oil on water but we couldn't tell that sicne the oil runbs down the stick when you pull it out. However, I recall some froth in the oil filler under the cap, but that can be normal.

jorj7

Dennis, Bill had been keeping me informed about you're misfortune. I'm sorry to hear about
your engine. I'm glad Jim and Bill are able to help you out. In fact we might be getting our
cranks machined at the same place. Let me know if there's something I can do to help. Also
thanks for your contribution to my engine fund. Considering the situation you're in, that's truly
an unselfish act of generosity.

Jim bailey - 928 International

Dennis what was the history of the replacement engine before it had new bearings installed ? By any chance was this out of Tim Dey's car ?

mark kibort

I dont know how long it takes for separation, but what did the dipstick look like on the course?

mk