Starter motor throwing gear but no spin

[TurboRA28]

Hi all, to cut a long story short .. I've RWD'd a Toyota 1MZ engine using a 3vz 4runner v6 flywheel, bellhousing and starter motor. I've made mention of this problem in my members ride thread but wanted to open it up for all to see.

Now attempting to start it the starter motor throws out the pinion you can hear it banging away.. But it doesn't spin.

On the bench the starter motor works fine and spins.

I've tried bridging main batt wire to the solenoid but same problem occurs so i've eliminated wiring issues.

I suspect 2 problems, the gear isn't getting thrown out all the way so the starter doesn't spin, or bad starter (it is secondhand).

But i'm bit lost as to why it wouldn't throw out far enough seeing that i'm using the fly, bell & starter all from the same donor car. Same goes for any mesh problems.

There is around 2mm clearance between the pinion teeth and flywheel teeth at rest. Is this enough? I was concerned about this due to possibility that the 1mz crank may sit differently and the flywheel may be closer to the block than the 3vz was?

I took the starter to an auto elec and he reckons as it spins up fine on the bench it isn't a starter problem. I argued that under load could it be different but he didn't think so.

Ideas?

[oldcorollas]

if the gear is being prevented from throwing out enough, then the solenoid will not connect the switch at the back.

can you space it out with a washer or two, to give a little more engagement?
or accurately measure the gear position with solenoid engaged (but not spinning.. duh ) and the ring gear, and see if it can go all the way...

[airfireman1]

the starter rmotor will only spin when the pinion in fully thrown out. Bad contacts will stop it spining. It does sound like the pinion is not throwning out far enough to allow the contacts to close the circuit to activate the motor. How is the alignment? maybe the pinion is hitting the flywheel and not engaging the ring gear. Pity your gearbox is in otherwise it would be a little easier to check. If you have access to a spare starter and try that to eliminate the starter being the problem that would be easiest then if it still does not turn overit must be an alignment problem, One more point does the engine turn over easily by hand?

[TurboRA28]

Yeah engine turns over by hand ok.. It feels tighter than most engines i'm used to but then I am more use to the low compression turbo engines.. maybe that feels a bit different when turning over by hand?

[oldcorollas]

can you wedge the starter gear out, and try and insert into the hole/engage with the rong gear, and see if it goes in straight and fully in?

[TurboRA28]

Fixed! could have been two problems.. Firstly the contacts for the motor were terrible so cleaned these up.. Also the wire for the solenoid could have been shorting out so I fixed this..
We are not cranking..

[TurboRA28]

Fixed! could have been two problems.. Firstly the contacts for the motor were terrible so cleaned these up.. Also the wire for the solenoid could have been shorting out so I fixed this..
We are now cranking..

[airfireman1]

So is it fixed? or is it still not cranking.

[TurboRA28]

Oops I contradicted myself there.. It is indeed fixed.