heinrich

Maybe not surprising. Here you have a high-metal content oil and perhaps something collected or sat under a particular bearing as opposed to others.

mark kibort

something to do with black 928s? im not even starting my car with the new black chassis.

smudaaar

Something isn't adding up. IDK if your bearings were the correct size, if your crank was turned, someting is way off. 300hp out of a 5.0l motor isn't all that crazy. your not running crazy enough compression or a large enough intake/injection to create major problems. I can't put my finger in whats wrong with your motors but I think its a clearance issue. Something in the setup is out of wack.

mark kibort

I agree. watch the video tape again. what the heck was all that rattling in the engine. thats a lot of stuff caught in the filter. what was all that magnetic stuff on the drain plug magnet also?

very very strange indeed!

Mk

namasgt

could be from the crank, 2 bad bearings will eat the crank, right ?

928autobahndreamer

Man, I echo the sentiments from the other 928ers here. This really sucks. I feel sick for you. How much bad luck can one guy have?

I have to give you huge respect for how you are handling it. Many have gone off the deep end here for much less.

heinrich

There is nothing Brian could have done to change what happened here. This is simply a failure of an add-in part, it is what it is. Life goes on and Brian's attitude on this is commendable.

IcemanG17

little update......and "some" good news...the 4-8 crank journal is not scratched so bad its under spec...so thats good...

Now the theory on why this happened is a couple things:

1: Somehow the rod bearing oil feed got clogged....but I thought it fed from both mains with the taylor drilling? I'd call this somewhat likely
2: The conrod was slightly oval....and quickly got worse....this is quite possible.....it also explains all the weird noises?
3: The crank itself is slightly bent......also possible and does explain the weird noises...BUT it ran fine during the break in....

I should have some better answers later today

Some other factors to consider.....it was VERY hard to start, which I attributed to a faulty EZK temp II sender....but clearly there was more too it.... it literally took 5 minutes of cranking to get to finally fire (yes I know this is a HINT)

I also was having clutch issues...which created difficult shifting...but I do not think this is related to the engine issues....

namasgt

conrod was oval ? that means both #8 and 4 were oval ?

when you do build an engine all of that should be checked.

mark kibort

I also heard that the oil thermostat was removed. Do you know why? If so, could that divert oil pressure to other areas than where it is supposed to go? the only time that should be removed, is when you remove the stock oil cooler in the radiator. (there is a WSM addition showing how to do this that 928INTL gave me many years ago). anyway, since you had an oil cooler, external, why wouldnt you use this stock system that EVERYONE uses. I dont know if that could be a factor, but thats just one more thing that was possibly done that could contribute to the failure.

If the crank is bent, then that has to come out anyway, right?

Hang in there Brian, you have got a great attitude about all of this. Its been a dark '09 for many 928 owners! Lets hope for a better 2010!!!

mk

Kevin Michael

Was it cranking normally or slowly? BTW I'm not elluding to TBF with this question. Greg Brown is probably watching this thread ,seeing all the head scratching, and will jump in at some point! Brian was this a stock crank or a custom piece milled for the application? Also I guess you might not know what kind of machining was done to the case? Years ago when I used to putz around with muscle cars, we sent a block out for line boring for a custom crank app. and it was terribly done as the clearances were all over the place. 250lbs. of scrap iron on that one. Good luck man.

Bill Ball

The cranking was normal and once it started there was no black smoke. We know tempII was off and I think it could have been leaning out the mixture too much for a cold start.

blown 87

ok, my guess, and it is just a guess from what has been posted here.

We do not know if the clearances were right or not, we do not know if the machine work was right or not, but if everything was right at the machine shop, and the clearances were checked, my guess is going to be on some abrasives left in the crank that were not cleaned up enough.

I am always amazed at the amount of brake clean (cases of Wurth) and how many times you can think you have a crank clean and still find a smudge on a crank after doing it all again with brushes and high pressure clean.

I spent hours on mine, end to end until i could not find a trace of anything.

The whole motor has to be like that, ultrasonic clean everything that will fit, pressure wash, rifle brushes, then do it again and again until nothing shows up.


That is before you start to check that things are right, and at every step of the way.

Some thing was going on in that engine from looking at the bearings on 2 and 4.

Or maybe I just do not know enough about the 928 engines or there was some defect in a part some where.

Still sucks either way.

mark kibort

yeah, those bearings dont look fine at all, even the #2-6 bearings. The 150k bearings I pulled out of my 84 looked a lot better. something surely was not right.

vwdmc16

after 4/8 failed so badly the oil was no clean and started top destroy the other bearings, thats my theory on their wear.

the oil passages are still clear in the crank, if pressurized you can feel air comeing out the 4/8 passaage when blowing air through the filter outlet. so i too am leaning toward a bent crank which is what a local machine shop has suggested. but i also dont know all the assembly details, i didnt assemble the engine internals, i just assembled the front end and installed it in the car.


well what ever you decide brian, maybe you should stick with a cheap 928 buld like the lemons cars, they wont be quite as fast on the straight but still a real blast.