Technical broken timing belt HELP !!!

[kevian]

Thanks Arc, you say the aux sprocket has an indentation and should line up with a similar identation on the crak pulley. Are they supposed to be in the same position (as in a clock face) or pointing towards one another?

I've reassembled the alternator pulley on the crank sprocket after i'd aligned the timing marks (i tried to make a similar mark on the alternator pulley, should i align the crank timing mark 1st or is there a way of doing it AFTER the alternator pulley has been re-attached?

 

[arc]

allign the crank first.

the marks on the aux pulley (ive made the assumption you were calling the altenator pulley the aux puelly here) line up at the same posistion as the mark on the crank pulley. the alternator pulley has an indent on it, where as the crank pulley has a raised bit - so the only way it can really fit is in the correct place, but it is easy to put it in the wrong place if ur not wathcing!

 

[kevian]

Ahhh, no sorry, if you look at the haynes manual, the aux pulley/sprocket is the small sprocket in between the cam sprocket and crank sprocket, almost opposite the tensioner.

I'll call the crank sprocket, the toothed sprocket, on the crank that the timing belt goes around and the alternator pulley, that attaches to the crank sprocket. So i align the crank sprocket up correctly with the engine mark, then the indentation (small 'nick') on the alternator pulley with the same mark as on the crank sprocket (say 10 o'clock). The cam sprocket at half nine ish (ignore the flywheel) and the aux pulley ??????

Thank arc

I really appreciate all you help.

Kev

 

[kevian]

Is the 'whurring' noise not a problem then?

Oh, as the crank sprocket is half the size of the cam sprocket, does it matter if i've got the crank sprocket a whole turn 'out' if you know what i mean?

Kev

 

[arc]

just to clarify things, what engine type is. I'm a Cinquecento person - but i know that most of the FIATs use very similar engines

 

[kevian]

it's a fiat UNO Start 998cc (i think). i've been told it's a fire engine, if that means anything to you?

Kev

 

[arc]

yeah, i know where i am with the FIRE engines.

the aux sprocket, thats the water pump isnt it? That doesnt need to be alligned to anything.

 

[kevian]

Ahhh, no sorry, if you look at the haynes manual, the aux pulley/sprocket is the small sprocket in between the cam sprocket and crank sprocket, almost opposite the tensioner.

I'll call the crank sprocket, the toothed sprocket, on the crank that the timing belt goes around.The alternator pulley, that attaches to the crank sprocket. So i align the crank sprocket up correctly with the engine mark, then the indentation (small 'nick') on the alternator pulley with the same mark as on the crank sprocket (say 10 o'clock). The cam sprocket at half nine ish (ignore the flywheel) and the aux pulley ??????

Does it matter on what rotation the crank sprocket is, ie, as it's half the size of the cam sprocket?

The little indentation ('nick') in the alternator pulley, does that sit at the same angle as the timing mark on the crank sprocket (10 o'clock ish)

Should the engine fire if i've aligned all 3 now?

Is the 'whurring' noise because i've got the timing totally wrong? It just seems there is no compression.

Thanks alot

Kev

 

[arc]

No, it doesnt matter - as long as the marks are lined up, then the timing will be right.

The belt itself has marks on it, they should line up with the marks on the crank and cam pulleys.

The indentation on the alternator pulley sits on the tiny raised part of the crank sprocket. Ive circled it in green on the attached photo.

If the timing is totally wrong, then its possible theres no compression at all and it may just whur as the engine is turning over much quicker than it should.

With the crank and cam pulleys alligned properly, and with the alternator pulley on and in the correct place - it should start up.

 

[kevian]

That's awesome Arc, I think i almost understand it now !!! I'll have another go tomorrow night and fingers crossed, i'll have some good news. I think i may have lined up the alternator pulley incorrectly, but i'm not 100% sure. My eyesight is fading in my old age and as i've got the car up on ramps, my eyes won't focus on the lines on the crank as there isn't much room between the tyre and the sprocket.

Thanks for all you brilliant help.

Kev

 

[kevian]

Woo Hoo !!!!! I took off the alternator pulley, and noticed i'd put that on inccorectly, also i'd mis-aligned the crankshaft pulley !!! After i'd ligned up the sprockets to the correct timing marks it took me well over half an hour to get the timing belt on correctly, but hey, 1st turn of the key and she fired. It's the 1st time i've done a cartwheel since leaving school, my neighbours thing i've lost it !!
Thanks for all your help Arc, it's very much appreicated.

Kev

ps Just as i delivered it to my sister, the blinkin wiper motor burnt out !! Anyone know where to go for good parts?