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MicKPM
ClioSport Trader
Clio16v/Zoe Z.E.50
Fred is right so listen to what he's telling you and forget the sprockets key way (I believe its the same oil pump and sprocket used on the Megane F7R-714). Its purely bolt tension and clamping force that holds this entire assembly together which works just fine.
Till someone doesn't tighten it properly or it decides to come loose lol Aint going to slip if its running a keyed cog.
I'm going 225 meggy for slightly more peace of mind with this rebuild
Not sure why Renault didn't keyway it. I know Ford Zetecs in 2 litre form are
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Wont make a bit of difference, it won't stop the timing slipping or the oil pump for that case if the bolt loosens. The only benefit it has is on a supercharged engine where the pulley is being used to drive something non oem.
If the bolt comes loose it can't slip, thats the whole point of keyway. The lug of the cog slots into the crank preventing it ever being able to turn independent of the crank hence why they fit them on charged engines.
Yeah all it does is stop the crank aux pulley from spinning, there are three pieces that attach to the Clio F4r crank on the timing belt side, 4 if you include the bolt.
Oil pump gear, timing belt gear and then the auxiliary pulley which is the only one that will be stopped from spinning by the key way. The other two are still held by friction the same as without the meg pulley. Best to use a megane crank bolt too (thick washer) as its a non stretch bolt.
275 Trophy
The key won't last any length of time if the bolt comes loose anyway, believe me as a mechanical engineer. Also, if that does happen you'd be lucky if it didn't ruin the shaft as well.
I'm meaning the timing belt gear mate, the inner cog which the cambelt goes round. Thats definitely keyway'd on the Meggy 225 cog so can't slip.
The auxiliary pulley, i was led to believe the Clio 172 / 182's where the same as the Megane 225, held by the bolt not key'd?
My understanding is the opposite from yours as the 'inner cog' needs to move in order to time the engine with any accuracy (it does on the clio's anyway) The aux pulley is what you wanted keyed for a supercharger as that is what's driving it.
The power in an engine comes from the pistons through the crankshaft, I would agree a keyed 'inner cog' would be of be benefit if the power came from the camshafts which would then be putting power (drive) through the belt itself.
Edit: Just seen your pic post. Its definately keyed but I don't see the benefit of using it??
If thats a reply to my question mate then that only applys to a supercharged car with a keyed aux pulley and not a keyed crank pulley. The crank pulley pictured above should move in order to time the engine with any accuracy. Its not your usual crank pulley arrangement as said loads in this thread.
A keyed 'aux pulley' is what your wanting to stop it moving which would in turn stop the crank pulley from moving as its a friction arrangement. The superchargers fitted to these cars are ribbed belts driven from auxiliary belt pulley and not toothed belts driven from timing belt.
Never timed a Clio but the Ford Zetec engine has a keyway and all i did was put the cambelt round the bottom cog, slacken off the cam pulleys till the belt was in position then lock it up and tighten the bolts. Would imagine the Clio would be the same?
The Meggy 225 benefit is, the cog can't move if the crank bolt becomes slack, it can if its normal 172 / 182.
Is the Megane auxiliary pulley, the big outter one, keyway'd ?
and still, none of them key the oil pump sprocket
Yeah its similar but nothing is keyed on the Clio, its all done on bolt tension. Plus you need the cam locking tool as the cam pulley torque is so high that it bends all other tools if not used.
You really need it to move to time it right and without the oil pump spinning its game over anyway.
Yeah I have seen keyed pulleys and I'm pretty sure its from a Megane. The SC failures I have heard of is when the aux pulley spins due to drag from turning SC which then turns the timing that way. Someone with a supercharger would know best as most have failed at one point.
A Keyed crank pulley would not save the timing from slipping if the bolt came loose. The key ways are literally there as a locating tool.
I'm sure K-Tec have fitted and not fitted in some cases a keyed aux pulley for the boost brigade.
Whats the point in changing to a 225 cog when using a s/charger if it still spins? Its keyway'd thus can't slip independent of the crank, thats the whole point :S
No, it's so it's not got additional drag on the aux pulley that can undo the bolt.
You are misreading what people like Dan@SJM are saying.
There are two seperate issues:
1) Standard engine : Pulley bolt comes loose and pulley moves, in this situation it will just eat the keyway and spin anyway, which is why Dan is saying that if the bolt comes loose it wont save you
2) On a charged engine: even with the bolt still done up there is insuffienct inertia to stop the pulley from spinning, a keyway does help with this.
With regards to the oil pump, its only a small load and friction is sufficient, what will scare you even more the first time you do it though is the chain so loose its slopping around like a dick in a bucket and no tensioner on it, just seems wrong the first time you build one, lol.
Chip I still don't see how this has any affect on stopping a supercharged engine slip the timing when all the extra load is put through the aux pulley. If the aux pulley was keyed I would see a benefit, if the crank sprocket moves then its game over anyway as you have just said above with it having intertia to break the woodruf key.
Also if you think about it the engine turns clock wise from timing belt side (iirc) so it would actually be tightening the bolt when/if for any reason the charger had more drag put on it.
Also if you think about it the engine turns clock wise from timing belt side (iirc) so it would actually be tightening the bolt when/if for any reason the charger had more drag put on it.
275 Trophy
I tried telling him that and he got all shirty. Leave him to his own devices I reccon.
The engine turns clockwise, thus the drag is then anti clockwise.
Right enough
