Modifying alternator

[teabelly]

I have the supposedly uprated alternator on a 2 litre mk1 vitesse but the wipers are still prone to slow down if you have the indicators on and the fan on at the same time. I was wondering whether it would be possible or sensible to change the pulley slightly so that the alternator naturally ran just a slightly bit faster at idle?

[logicaluk]

Hi tea
changing the size of the pulley should work,but it will sap more power when running at speed.

a couple of other things to think about;

does it still do it if you have the head lights on instead of the fan?

how olds your battery?

are all the connections in good condition & check the earths are clean

do the wiper spindle boxes need to be cleaned out & re-greased, if it's still got the original grease in there it may be causing extra drag on the system.

hope that helps
Dan

[teabelly]

The more you switch on the slower the indicators etc run. Regreasing the wiper spindles is a good idea though as they are very lethargic! It might be that the wipers when on do sap the extra power because they are being slowed. The car also has an electric fan and electronic ignition so I think that is putting more load on the system too.

Battery is brand new.

I hadn't thought about extra engine power being sapped.

Normally I just put my foot on the throttle pedal a bit and that speeds them up  :)

[Nick Jones]

I think there are two sizes of crankshaft pulley.  My Vitesse has a large one, but the new engine I'm building up has a smaller one for some reason.  Don't really follow the logic as my car would have had a dynamo originally

Might also be worth eliminating a more general volt-drop problem by checking that all the various power connections are clean and secure.  Goes from battery to starter solenoid and from solenoid to regulator box and from there to the fuse box.  As the regulator has been removed and bypassed to allow the alternator to be fitted it's worth checking how the links were done - I know mine was very dodgy and getting rather warm as a result.  The fuse box can also be a source of troubles both on the spade connections to/from it and also the fuse clips themselves.  Check earth straps as well.

Cheers

Nick

[nang]

Try running an additional large gauge wire from the spare large terminal on the alternator direct to the positive battery terminal. Make sure all connections and earths are clean and tight.
Tony.

[teabelly]

I'll try and check those things, thanks.  :)