BWA broken keyway

[turbodub]

so it turns out that my keyway on the crank snapped bending my exhaust valves and requiring replacement as well as guides ..so the head went off to the engineers .
Can anyone enlighten me as to why a keyway would snap ?
i cannot find any internet chat where this has happened .

[amstel18]

Happened to a friend of mine with his Leon FR.

Motor was rebuilt a few 1,000 kilos before this happened. I can only think the keyway was damaged or the crank pulley wasn't tightened/ aligned properly.

Was any work done to the motor recently?

[Killerwatt]

Happens on the tfsi and 1.8t motors from time to time.
Easiest way to prevent it is to put in an extra dowel.

[panic-mechanic]

**** luck or not tightened to spec with loctite as the manual recommends.

[turbodub]

thanks guys , total rebuild 2500km before it shat itself .
any idea what spec is for tightening of he keyway?

[THANAS]

That really sucks. Did it damage the keyway on the crank?

I had the same issue on my ABF. When the bolt turned loose the play between the key and keyway damaged the keyway as well. Instead of welding or replacing the crank I replaced the pulley and inserted 4 dowels (overkill), replaced the bolt and torqued it to spec with loctite and it's been perfect ever since with daily trips to 7k rpm (according to the new owner). Luckily it didn't shear off completely and bend valves.

[panic-mechanic]

you don't tighten the keyway. You tighten the bolt that holds the pulley to the crank. A key just locates the thing and the bolt holds it tight.
Spec for that bolt on BWA is 90 nm + 90 degrees. trust me it Fk tight.

[turbodub]

thanks panic , info has been relayed to the mechanic doing the assembly just in case ...as well as that he must use some loctite

[amstel18]

The same mechanic that rebuilt the motor the first time?
That bolt should not have come loose the first time. Hope you giving the mech that rebuilt the motor a hard time!

You don't mention where you situated?

[turbodub]

The same mechanic that rebuilt the motor the first time?
That bolt should not have come loose the first time. Hope you giving the mech that rebuilt the motor a hard time!

You don't mention where you situated?

i am in Cape Town and to say the least i am pissed , i am extremely demoralised as i did not spare a cent re-doing the motor and now i have zero confidence in it and am contemplating going back to stock and just selling the thing . I am pretty sure my pistons are fcked as well - set of Wossners buggered-and i planned on keeping the car and buying something serious in a year or two once i can afford it.

[THANAS]

Who built the motor if I may ask?

[turbodub]

Who built the motor if I may ask?

well ...here is where it gets interesting ...he came highly recommended to me .He is away at the moment till after the middle of next month and i have my car sitting in his workshop being fixed by his assistance ...so i have to wait for him to come back before we see what happens . I will say that everyday my patience is wearing thin .He assured me my pistons were fine ...so i went there to take pics of each one and they don't look fine to me
i will give him a chance to explain himself fully when he is back.How this gets resolved is up to him , but i am still the guy who has a motor that is potentially ruined .

[turbodub]

so i am collecting the car today. the head was already on so i did not get to smooth the sharp stuff on the pistons ...so thats now another thing to worry about . Also it turns out that the chain tensioner was not 100% and i am not prepared to take a chance so i replaced that ...which meant the cams had to come out again ....
lets hope it all holds together permanently and not just 2500kms .

[amstel18]

I am no expert, but any sharp edges on the pistons may cause hot spots and lead to failure.

[turbodub]

I am no expert, but any sharp edges on the pistons may cause hot spots and lead to failure.

thats what i am concerned about .

[THANAS]

Did you find out the condition of the crank?

[turbodub]

Did you find out the condition of the crank?

no information regarding the condition of the crank .......
i got the car back friday and have done maybe 50km since then .
the car is smoother than it was after the rebuild and it idles perfectly ..it idled like it had a 288 before but i was not that surprised as i had read that the runner flap delete can cause a rough idle ...i mentioned this to a good friend who is one of Cape Towns top mechanics and his answer straightaway that i had previously had an airleak somewhere and that caused the bad idle .the car had been back for other small things after the build and this was not picked up .The car now picks up nicely from low rpm like it should , previously it felt pap low down in comparison .
i also got presented with a fat bill Friday .

[deon rupnarain]

How much it costed to rebuild ?

Sent from my HUAWEI VNS-L22 using Tapatalk

[turbodub]

engineering of head , parts , labour ...R10k

[turbodub]

so i have the car back for a week or so and have had the software done to account for the changes made to the motor and the car is running very very nice . I am gonna dyno it soon and will see what the power looks like .
car is much quieter and idles very smooth . i still have the dread lurking in the back of my mind that something is gonna kak...
i am running water meth up top just for safety sake rather than power just to ensure temps remain nice and low .