How does a pre engaged starter work?

[Steve P]

Reason i ask is that i`m trying to crank over a brand new 2.6 engine i have built,i assumed i could just stick a battery on the motor with jump leads and it would spin,it  doesn`t,nothing happens.It`s a brand new(today) 470 amp battery from Halfords.Also does pre engaged mean it should be in contact with the flywheel all the time as mine isn`t,its a lightened GT6 flywheel if that makes any difference.
Pardon my ignorance,advice appreciated.
Steve

[C Mallock]

There should be the large connection which the jump lead will go to then a smaller one next to it normally a spade connect that too and it should work

[CharlieB]

redoxideVit wrote:

does pre engaged mean it should be in contact with the flywheel all the time as mine isn`t,

No, it uses a solenoid to push the pinion into engagement with the flywheel before it starts the motor spinning.

[phil866]

Pre engaged starters prevent an awful lot of wear on the ring gear and Bendix gear. They were a big jump forwards in reliability. Non preengaged starters work by throwing a spinning cog at the ring gear on the flywheel to turn the engine. It will only disengage when the engine reaches sufficient speed to throw the cog out again, or the igntion key is turned back from 'start'.  A lot of wear as you can imagine.  Pre engaged have the cog already in place on the ring gear before the starter motor turns.  Once the ignition key is turned back to 'Ign' it disengages and waits until the ignition is turned off before re engaging with the ring gear.  Vauxhall's have suffered from faulty ignition switched which remained in the 'start' position thus burning out the poor starter motor as it could not disengage.