Am I a whimp/wimp? Part 2; 6000 rpm and it broke

[LIRS6]

For anyone who read my initial post, and for those who didn't, I'd say about 90 pcnt of the feedback was "drive it to the redline."

Am I a whimp?

So after 34 years of ownership I decided to do that - perfect opportunity to get "that smile" up shifting 2-3 passing a slower car. Took it to 6000 and shifted. About a minute later I hear grinding and screeching as I'm slowing down approaching a red light. With a "thump" engine died. Re-started, fine for about 10 seconds, then more squealing and screeching. Engine dies as I pull into side street. Pop engine cover. Nothing obvious. No evidence of oil leak or such. Re-start, watch fan and it looks like it is oscillating. More of the same, alternator light is on, engine dies. I mange to drive it home keeping revs at/under 2000. Alternator light stays on for the 15 min slow crawl.

At home upon further examination I could see some scarring at about 5 o'clock on the fan shroud. Upon reading my Bentley, my suspicion that it has to do with alternator bearing(s) seems to read true. "Relplace alternator." Well crap, that short-lived smile just cost me a few $.

Jason

[RedCoupe]

Bad alternator bearings would have reared their ugly head anyway, so don't let this stop you from enjoying your car. BTW, you can change the bearings yourself, so a new alternator isn't necessarily needed. FWIW my 160k mile 1986 Targa doesn't get babied.

[walt]

If it makes you feel any better, it was probably on its way out anyway. You just found it sooner than later. If that's all it is not a major job.

[rwest]

Of course, they might have failed on you at 4,500 rpm as well. May or may have not been because of the higher revolutions.

[jac1976]

Bearings. Belts. Shims.

[Bigtoe32067]

Did you look at see if it’s just the belt that came off?

[1979-930]

See if there is a shop near you that rebuilds alternators. Get the whole thing checked and rebuilt while out.
R&R is kind of a pain on these cars. I just had to do mine. You don’t want to do it again next year.

And don’t forget the spacer between the bearing and fan going back together...


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[pmax]

Well, 34 years is not bad for an alternator.

Just replaced the VR on mine. Easy job, just time consuming with the limited access. Remove the alternator and have it rebuilt.

[Bill Douglas]

Ha, I bet you were pleased it was the alternator.

[creaturecat]

bad luck x coincidence x shoulda' left well enough alone. : )

[Trackrash]

OK, my $0.02. I did read the other post, btw.

I have owned my car since '78. Meaning in the last century.

I rebuilt my car in the '80s, and it was my DD until 2005, when I was talked into joining the PCA and autocrossing.

I autocross a dozen times a year and take place in a couple of DEs as well. I also continued to drive it to work until recently. Never trailered.

To give one example, I drove three hours down to Laguna Seca to do a DE. Drove probably 50 laps on the track with speeds over 100 on each lap. The next day I drove it home.

Finally two years ago, I retired that motor. It still ran perfectly, no smoke or excessive oil consumption with good power. It has been sold, so it will have another life.

So after 90K miles and hundreds of AX laps and dozens of track days the motor was unfazed.

At one point I was concerned about babying my car, but that was unfounded.

Good luck with your alternator.

[stevej37]

The belt was still on?

[NYNick]

I was one of the 10% that said "only once in a while", but that's not what broke your alternator. Age did. You got off easy.

[LIRS6]

Originally Posted by stevej37

The belt was still on?

The belt was on.

Mind you, I'm assuming it was the alternator bearings - for those of you who have had this happen, does my description of events/sounds match the diagnosis?

And yes, for those who have said that it could have happened at any time or RPM, I resign myself in the knowledge that could be very true. Murphy's Law I suppose - or **** happens.

Any further suggestions/guidance welcome. Is removal of the alternator a DIY for someone with basic tools/skills?

Jason

[faapgar]

I use to race at Bridgehampton.What a track when you exit the 4th turn with the grandstands on the right and you see the boats in the water just to the left.Ciao Fred

[pmax]

Originally Posted by LIRS6

Any further suggestions/guidance welcome. Is removal of the alternator a DIY for someone with basic tools/skills?

Jason

I'll say that's an emphatic yes. Porsche even provided all the tools needed in the toolkit. Fan nut, 8/10mm wrenches. Just make sure you unhook the battery first and double check all wiring to the alternator. The rest is just fiddling with nuts and bolts.

[boyt911sc]

Jason,

Before you could detach the electrical connections at the backside of the alternator, you need to remove the air deflector mounted to the alternator. Make a marker on the air deflector and alternator housing with a mark pen so you will have the correct orientation when you install it back. You could easily put it back the wrong position. Lastly, take some pictures or make a note how the wires are connected to the alternator. Just take your time and you will be fine.

Tony

[stevej37]

I've had both of my 911's alternators go bad. Neither one made any unusual sound or thump. The red light came on and the battery went dead. That was all.
If you do change it...it's an easy job. Just take your time and it'll work out. Lots of threads on here about the removal.

[Funracer]

Just went through this this past Spring. My car had 107k miles. Ugly noises from the engine compartment. To confirm its the alternator remove the belt and start the engine. If no bad noise then you have found the problem.

Several comments from above on this thread are important. Before you start, number one thing, disconnect the battery!! Ask me how I know! Take your time, take pictures of the wire connectors.
Get good look at the air deflector, mine was on wrong I had to sort that out myself but when you put it back together it seemed pretty obvious to me how it goes.

Take it to someone who knows what he is looking at. The first place I took mine had it for 2 weeks before I walked in and took it back. Second place I went in the guy says “That looks like an old Porsche alternator” Bingo! Had it done the next day and charged me $100.

While the alt is out for rebuild its a great time to change the belt and do a general cleanup in the area behind the fan, as well as clean the fan and shroud. Some guys paint or powder coat but I oiled my fan and it looks great. Removing the fan from the alternator shaft can be a challenge (mine was). I had to remove all six nuts and pull out four of the bolts to make it happen. I highly recommend the “knock it with a wood block” method that many recommend. It works.

There is a heavy gauge brown ground wire that runs from back of alt to the top left side of the engine case. Besides cleaning up the attach point I replaced mine with same guage wire that was 3-4 inches longer. This made access to the wire connections easier when it went back together. If yours is long enough then no worries.

If your handy you can do it. Plenty of help here if you need it.

[Geronimo]

I have had my car for 2 years, I has broken every year so far. I have accepted that this will be the case until the whole car is new again. It's old and German.