Major Failure - F355 broken prop shaft

Yep!

 

I would like to know who makes them for you to see what cost is

 

Invougjt a 355 like this, then i have seen a hand full of issuues of these breaking.

Very rare in my opinion. Thats why you have never seen one.

 

The shaft needs to be hard for wear. Needless to say it must be tough. Toughness, and hardness for wear is a balancing act. Too hard = too brittle. The right balance of hardness for wear and toughness is required.

Based on the fracture, my guy tells me the hardness is over 50 Rc. That's dangerous depending on material. 45 Rc is likely the better option.

 

Dave incoukd send you a broken one for testing

 

Do you have dual mass or solid flywheel?

 

Stock, dual mass. The seals are intact and grease in place I have not phisically checked myself as I am on a business trip for the hole month. The workshop garantees the flywheel dampening system is fine and there is no need to refurbish

 

My car has the same failure:
had to drive a few miles with 4 cyl, and then when starting on 1st gear the prop shaft broke...

First thing to investigate is why it works on 4 cyl (only after heavy rain, might an electrical problem)...

 

Mine was an intermittent failure in one of the fuel pumps. Expensive fix this prop shaft and hard to get your hands in one.

I used this opportunity to change clutch as it was reverse-slipping (rpm drop) when half of the engine would loose power in high gear. I have a video on it.

You will have to drop the gearbox to replace the shaft. before reassembling, it is also a good idea to balance the assembly clutch/flywheel/damper. It is a good practice, as such parts spins up to 8 000 rpm

Keep sharing what you find, so other member dont have to go throught the same!
Good luck!
Fred

 

I think I will go for the shaft made by Formula GT in Germany, maybe to change the flywheel in the same time...

 

Will require further diagnosis, but one common cause is failure in the catalyst protection circuit. If the catalyst ECU fails, or acts up, it will shut down one bank. This is what it is supposed to do if it detects an overheat situation with one of the catalysts. Instead, this system is fraught with failures, and the causes inadvertent shutdowns of one bank when not actually required.

Determine which bank is shutting down, and swap the catalyst ecus and see of the problem moves to the other bank.

Another cause can be the catalyst thermoprobes can fail. But start with the catalyst ECUs...a known weak point.

 

Can't be the problem. Internet experts here say these cars are perfect in the rain.

 

Yes, of course this is how the BS about these cars starts. 1 car out of a 1000 has an issue that MIGHT be attributed to something getting wet and the 999 owners that never have an issue are all wrong and the cars should never be driven in the rain or even washed with water.

 

They shouldnt have any issues driving in the rain.

They came with wipers.

 

Hey, I wondered what those floppy rubber things were! Mine are new and never used. I replace them only for the aesthetics and appearance. I assume they function, but I won't tempt fate.

 

I suppose a plus within this story is, our 5 valve engines have enough power to snap (shear) these prop shafts. Now thats some powa

 

Some news about my broken shaft:

Bought the one from Germany (Formula GT), looks much better than OEM my mechanic says, should not break again!
Installed and now he just need to change to spark plugs connectors and I'll have my car back on the road!

 

So your bran new shaft looks better than your broken remains of your old shaft? Not much gets past your mechanic

 

Good one ha ha.

 

Great Marius. thanks for the link.

Gives me an excuse to get to Frankfurt and take my monster back to Bavaria!

 

so next time when you're having severe engine trouble let's not rev it to 7000rpm

 

My shaft just broke too and in the interests of getting ready for the Maranello Cup at VIR next week I am fitting a used one. Formula GT does not have these listed on the link we are using in this thread so do you happen to know if they still sell this product.

My shear was in the same place and also caused by rough running. An intermittent misfire between 7300 and 7800 rpm that has been around for some time. We have tried everything to sure including replacement of crank and at least 2 rebuilds. The car is a CH model and is only used for racing. No cruising, DE, or display.

 

If they don't still sell these, it appears that secret sauce is to anneal the last inch of the shaft closest to the clutch in order to make the shaft less susceptible to work hardening and snapping. Whether it is fully annealed or what the final hardness that results in the best outcome is unknown, but at least you have a direction to experiment in.

Good luck

 

It doesn't look like they do anymore. Does anyone know if there are other sources for these?

Mark - if it's anything like the Testarossa prop shafts, if you make them stronger you move what gets damaged from one highly expensive shaft (prop) to an outrageously expensive one (main)!!
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Best,
John

 

I like forumla GT's fancy clutch and flywheel parts. Man, those are sweet.

sjd