GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: Len on 13 January 2014, 16:44
-
Cambelt pulley on end of crank is wrong!!!! :angry:
The diesel crank has a flat section whereas the 16v abf has a notch in it.
The diesel pulley has less teeth so the cam belt wont fit it!
Makes me wonder as if you read the forums ClubGti etc. many people say they have done the same engine conversion as me but they dont have the same problems!
They telling porkies or have kept quiet about the problems????
Anyway think I need and engineering shop with a milling machine!
-
abf crank pulley is 26 teeth and the diesel 22 (I don't know if that helps in any way?)
also abf timing belt has number of teeth 151 and width 25mm
-
Run a diesel cam belt?
-
diesels are 137 tooth belts
-
Run a diesel cam belt?
Cant!
Wont fit the camshaft pulley nor the secondary pulley that drives the oil pump!
-
abf crank pulley is 26 teeth and the diesel 22 (I don't know if that helps in any way?)
also abf timing belt has number of teeth 151 and width 25mm
No it doesnt help! :grin:
I just found that out today!
The real problem is how they fit onto the end of the crank itself.
I cant see any way round this other than getting the abf one machined to fit!
-
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 :wink:
-
Timing will be out wont it?
I would just get the right one
-
don't think there is a right one when you fit a diesel crank into an abf block.
-
abf crank pulley is 26 teeth and the diesel 22 (I don't know if that helps in any way?)
also abf timing belt has number of teeth 151 and width 25mm
No it doesnt help! :grin:
I just found that out today!
The real problem is how they fit onto the end of the crank itself.
I cant see any way round this other than getting the abf one machined to fit!
I would machine the crank as if you take any metal off the pulley it might weaken it.
-
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, 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 :wink:
Will take pics tonight. :afro:
-
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!
-
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?
-
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.
-
Thinking about this now (damn you BUSH! :grin:)
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.
-
Thinking about this now (damn you BUSH! :grin:)
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,
-
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!)
-
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.
-
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 :grin:
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.
-
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 :grin:
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.
Indeed :grin:
So in summary, it's no coincidence that the effective diameter and number of teeth on the ABF cam pulley is precisely double that of the crank pulley :nerd:
-
What the nipple said ^^^
-
I am replacing like for like! The crank gear off the diesel is wrong full stop!
The set up I will have (one spike has done his bit! :afro:) will be exactly the same as on a standard abf engine.
Except for the fancy/expensive verier cam pulley!! :whistle:
-
Once the belt is locked you could have a short belt or a 10 miles long belt, the belt is fixed so both pulleys spin at the same speed hence timing stays the same.
-
Was gonna say last night, while nipples has it its worth going up a thread size on the crank gear for the bolts which hold the pulley on.
Need to clear the holes on the pulley, but its well worth doing it as the 8mm bolts snap and strip the threads very easy.
-
There's no need for that really. The crank pulley is hard so as long as decent graded bolts are used there won't be a problem.
-
There's no need for that really. The crank pulley is hard so as long as decent graded bolts are used there won't be a problem.
That's not the reason, the tension on the belt pulley stretches the bolts and the first few threads.
Either the heads snap off when you go to undo them or the thread picks up and strips, pita when you want to do the timing belt and that happens.
I've had to do it a few times, I also stick a decent timing mark on the crank gear and pulley :smiley:
-
Not had a problem with those bolts! Only getting them undone!
The alllen key heads are a pain! That applies generally!
-
There is one big bolt that holds this gear pulley on and that has to be tightened to 90Nm then a quarter turn! So all the stress is on that.
The four bolts only hold on the two outer pulleys for the alternater/aircon and water pump/steering pump
-
There is one big bolt that holds this gear pulley on and that has to be tightened to 90Nm then a quarter turn! So all the stress is on that.
The four bolts only hold on the two outer pulleys for the alternater/aircon and water pump/steering pump
Not really, the cam belt is run with minimum tension as its a toothed drive not friction. It also is made more accurately and runs between the cam and crank which are very accurately guided in bearings with minimal run out, critical for engine function.
The Aux belts are friction drive and subject to more run out and other conditions which equal shock and vibration transmitted through the drive. This is why you have a flange joint and cast rubber damping in the pulley to ensure the crank does not take this loading.
I could blab along for ages on this subject round a number of situations, but essentially the four 8mm bolts take a lot of stress which makes them stretch and fail in one way or another.
Maybe I should have preceded my original post with the words "if they were buggers coming out or snapped off" and mentioned just running a carbide or coated tap down the threads instead I would have made more sense.
Me being me I just see a stronger bolt with a bigger allen key size and go blazing ahead :grin: (tampering with a deliberate weak spot without working out the full nature of my improvement, how proffesional :lipsrsealed:)
Your right about the big bolt, it stops the whole lot sliding off the crank and making a big mess of things, I would fit a new one if I could just to be sure :grin:
At risk of going on and boring you and our Mk3 chums, have you considered new pulleys for your engine to maximise smooth running and efficiency? dont make me bore you with pulley wear and belt slip :laugh:
-
I dont know that it is such a weakspot. I have never heard of them shearing off!