Big Problem! Now Solved

[Len]

No way am I taking that crank out again!
Its only a very small piece of metal internal where the pulley sits onto the shaft.

[Len]

Len, drop me a PM with some pics and a description of what you need done and I'll machine it for you for return postage/a pint 

Will take pics tonight.

[Len]

Timing will be out wont it?
I would just get the right one

No that wont be a problem as I can establish TDC from the pistons. I will then mark the abf pulley with a new timing mark when its sat in the right position.

There is no right one!

[VW BUSH]

Timing will be out wont it?
I would just get the right one

No that wont be a problem as I can establish TDC from the pistons. I will then mark the abf pulley with a new timing mark when its sat in the right position.

There is no right one!

If the Diesel pulley has 22 teeth and the ABF has 26 teeth then the gear ratio will be out, one turn of the crank will turn everything else less or am I missing something here?

[Len]

The number of teeth only relates to the spacing of the teeth on the cambelt.
The distance travelled is covered by the diameters of the pulleys.

[Len]

Thinking about this now (damn you BUSH!  )

The cam pulley is about twice the size of the crank gear/pulley so does that mean the cams turn twice as fast?
Or is it the other way round as the smaller diameter has to turn the fastest?


Whichever way it is, the relevant diameters are exactly the same.

[VW BUSH]

Thinking about this now (damn you BUSH!  )

The cam pulley is about twice the size of the crank gear/pulley so does that mean the cams turn twice as fast?
Or is it the other way round as the smaller diameter has to turn the fastest?


Whichever way it is, the relevant diameters are exactly the same.

One rev of the crank will turn the cam less than a rev if it is bigger than the crank the pulley.
So if its twice as big it will turn only half a turn.
With a toothed belt or any gear you go by how many teeth it has not the diameter, so if the ABF has 24 teeth and the diesel has 22 you will have a timing error.
The tooth form may be the same but in this if you have say a 100mm dia gear with 24 teeth and a 100 dia gear with 22 teeth then the spacing or pitch between the teeth will be different as well.

Its been a long day I could be wrong,

[boneybradley]

so what about a 22 tooth pulley and a 78 tooth belt vs 18 tooth pullet and a 82 tooth belt


would that solve any issues or does it need maths and stuff to works it out? (or some mad science!)

[spikenipple]

You can have a belt 2 miles long but as long as it stays on the pulleys the ratio won't change one bit.
The important part is the relationship between the diameters of the pulleys. The tooth pitch & diameter are calculated to give an exact rotational amount on both the crank and the cam pulley.

[VW BUSH]

You can have a belt 2 miles long but as long as it stays on the pulleys the ratio won't change one bit.
The important part is the relationship between the diameters of the pulleys. The tooth pitch & diameter are calculated to give an exact rotational amount on both the crank and the cam pulley.

Been focusing on why 300k's worth of Robot wont work, so trying to recall drive train calculations is a bit hard all I could think was driver over driven, driven over driver
Basically you need the right diameter crank gear with the correct amount of teeth, anything else will throw the cams out to the bottom end.