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Alfa 147 2.0 Crank Pulley Wobbling/Cam Belt Untiming itself

2K views 17 replies 10 participants last post by  driver33p4 
#1 ·
Hey Guys,

Problem with the Alfa 147 2.0,

Rebuilt engine, All well and sounds lovely. Replaced all parts etc after a broke cam-belt last year..

I have re-timed this car twice now and still tonight after Giving it its daily Fun thrash, it still looses the correct timing (3rd time). I have replaced all Belts, Tensioners and Idlers, i have even double checked the Variator inlet pulley to make sure the 4 ribes are tight and not slacking to cause the timing issues.

Now it only Un-times itself maybe 2 teeth and fires exhaust causing the ticking noise, nothing dreadful like valve hit, Would the Crank pulley wobbling cause the belt to jump a tooth at high speeds? Is there a reason why its wobbling? I thought it can only sit in one place and surely the crank wont bend to make the end pulley/flywheel sides wobble?

Some help please :confused::confused:
 
#3 ·
Thanks for replying, Yeah used the Cam Locks and correct TDC every time with tool. When i've fired it up after re-timing it, the engine sounds Beautiful and uses the full 150 Horses it supposed too, its only done 68k so not much.I say 2 teeth because last time i had to move it that much to regain the correct timing. it does the usual Engine system control fault light pop up which i can reset but can not figure out why it keeps loosing its timing.

Its proper bizarre! ???
 
#5 ·
ahh Davffc, nice to hear from you again, Parts worked Brilliant :) - Good point, i shall check them issues after Christmas Holiday and get post results, going to check everything else and mark alot of metal with tip ex for any movement for the next time it happens.

The Only thing i'm worried about is would the crank bend slightly "banana" for the Bottom Timing pulley to Wobble? seems daft but i would encounter all sorts of issues like crank seal worn, massive vibrations etc..
 
#10 ·
Is it definitely the cam timing pulley that's wobbling?
Iirc the aux belt pulley can go back on out of position as it's got a cut out for the end of the woodruff. It's not that, looking like it's wobbling?
And yeah, I'd check for a sheared one ASAP as if that wanders any further it's gonna get messy!
 
#11 ·
Problem Solved (For the other searchers out there)!!

We stripped the timing side this afternoon again and found the problem, Most of you guys were right! As you can see by the picture, The Woodruff key has sheared off and basically disintegrated..

Wheel Auto part Rotor Vehicle brake Automotive wheel system


New Timing pulley will need to be ordered so if anyone encounters the same problem, Stop the engine and take a good look at the Pulley, i was very close to bending a lot of valves :thumbs:

Thanks for the advice Guys :thumbs::thumbs::thumbs:
 
#17 ·
Problem Solved (For the other searchers out there)!!

We stripped the timing side this afternoon again and found the problem, Most of you guys were right! As you can see by the picture, The Woodruff key has sheared off and basically disintegrated..

View attachment 435482

New Timing pulley will need to be ordered so if anyone encounters the same problem, Stop the engine and take a good look at the Pulley, i was very close to bending a lot of valves :thumbs:

Thanks for the advice Guys :thumbs::thumbs::thumbs:
Yer I thought that would be the problem, well done for persevering with it :thumbs:

You see this a lot when they break their belts

Ned
 
#14 ·
Nope, crank bolt was loose, the Crank bolt is left hand thread, after figuring that out i realized once the wood-ruff key had been disintegrated by force the bolt had become loose with clockwise movement, i literally undone with my fingers (which as you know, shouldn't be like this:eek:)
 
#18 ·
Glad to hear that you got to the bottom of this problem without needing another cylinder head. :)
 
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