John fingers crossed for you. bottom end re build is no joke. hope its just a loose bolt.

"big end failure? English translation plz."
The conecting rod has two ends , the big end is the end that goes around the crankshaft . The bearing
that goes in between the big end and the crankshaft is what has failed on many 964s on this list .

"Wouldn't a big end failure have some effect on the way the engine was running?"
A big end bearing failure , H.P. wise , no real effect . Its just one part hammering another .

When you say the bearing failed, do you mean the rod bolts sheared and the end cap came off? Else what is meant by bearing failure?

Hiya Stevepaa
When the bolts break , thats a rod failure .
When the bearing fails , the rods ok per say , its the bearing in between the con rod and the crankshaft that is comeing apart . The bearing starts falling apart / "spinning" / melting / burning . When the bearing fails , the gap between the con rod and the crankshaft becomes to large and the parts do not move smoothly and nice , the two parts that are now not with a nice bearing to hold them apart start smashing into each other . As soon as they start smashing into each other the rod and crank get damaged . The little bits of the bearing thats comeing apart are in the oil thats being flug around inside the case . The bearing bits end up all over and get into places that you really don't want it to be .

This thread will give me nightmares.

Any statistics as to what appx. percentage of 964s have had a bearing failure like this? And what are the typical main contributors to the problem--if any? Or is it just bad luck?

John, I have my fingers crossed for you, your wallet, and your car!

John - All may not be lost - I had a similiar experience and it wa sthe shaft on the alternator that broke in half - can't explain why - but it made a lot of racket - the fan stayed in place and I was really stumped for a while - but finally figured it out - ran me 195 USD fior a new Alternator - Hope yuo have as simple a problem.

Not as bad as JB's nightmares..that description is very useful, Indy, but a little bit of a horror story!

In my 4 years on the 964 list, there seem to be more big end failures recently than I remember..I'm sure its coincidence, together with forums like these having a magnetic pull towards tales of anguish..or alternatively this is a 964 age-related thing which is only now just emerging 15 years later, and is going start happening more and more..

(Doomed! We're all doomed!)

Seriously - this is probably just as common as in any car, and we are seeing our cars all getting old and tired, so a few are going to turn up, I suppose. The only theoretical contribution I know of is crap getting into the oil system - e.g. lack of care taken when oil lines/thermostat etc are opened or replaced; there's usually alot of accumulated dirt around these places.

John had an oiltank replaced relatively recently..


(BTW, I'm posting more than usual cos I've been in bed with a cold for the past 3 days...sniff.)

I wouldn't go that far but I can clearly see a sword hanging from the ceiling fastened with a horse hair, pointing at our heads :eek:
I'll just keep on whistling on the grave yard. :biggulp:
Get well soon Johny

Could be related to all this super thin high performance oil ? It wasnt in the motor when they were new !!

Geoff

Geoff,

Do you run your car in the winter? If so, what oil do you run?

I'm in New York where it gets cold. Not as cold as where you are, of course, but enough so that I decided to put the 0w-40 mobil 1 in for this winter. I've seen enough postings on this that it's concerning me.

Sorry for the hijack. Just too many oil threads out there. I didn't want to start another one!

Eeek! The big end rears it's head again....
Been there, done that, emptied the wallet :crying:
Mine spun the bearing in the rod, taking out the crank and oil pump for starters....
Easier to get a recon engine than to source a crank & rebuild mine.
Not much fun however you look at it.
Hope yours isn't that bad John.

Rushjob- so you did in fact get a recon engine? How has it performed and what was the price difference vs. the rebuild?

c

I still think that the noise has something to do with the bump that John ran over. I think it would be strange (but I guess not totally out of the question) that there might be a major mechanical failure just after hitting or being caused by a bump in the road. I'm thinking that something came loose and fell into the wrong spot... Or something was thrown up off of the road into a "bad place."

I'll be following this thread until the true cause is found.

dfinnegan,
The oil gets changed once a year , round about spring. I go for 10-40 or 15-50 .
I think that as long as you let the oil get up to temperature before going for it the 911 motor is not as delicate as a lot of people believe !
Hey , it gets pretty cold down in NY . We are only at -2 C today but -12 tonight.
Compared to inland this is spring !!!!

Geoff

As to statistics, mine had a 300% chance of a spun bearing. :eek: I am amazed that with all the bearing metal going through the engine, that only the #3 rod bearing went south.