New starter motor sometimes not engaging to NEW flywheel

[v8dave]

They both get power at the same time so how can it engage first ?
Its the same coil that engages the gear that connects the live to the starter brushes

The power from the ignition switch causes the plunger to be drawn into the solenoid coil.
Not until the plunger is most of the way in does it trigger the contacts that apply battery power to the motor.

Here is an explanation with pictures for those interested.
https://www.youtube.com/watch?v=8WD5Q_PF3pM

[supadik]

Thanks for the replies. The explanation of how a pre-engaged starter actually does it's thing has cleared it up in my mind I refitted the original starter motor yesterday as I still had it as I'd fitted it to a 2.4 ldv and it had been working fine although a ton of metal filings fell out of it as I removed it but it's only been on there for a couple of weeks and after I gave it a bang on the floor and a shake it looked free of metal filings. Although it did seem better than the new starter it still missed engagement a few times when I tested it out. As the bendix was stiff to move be hand I'm going to whip it back off and clean it up before I go any further to rule that out. The trouble of course is that this starter is the one that chewed up the old solid flywheel so it to could also be iffy.

My Transit is a 51 plate 75ps fwd so it's one of the Transits that were recalled by Ford to have the DMF replaced with a solid flywheel so I'm wondering if these had a different starter to other transits as it seems to me that the starter's teeth aren't sitting deep enough down into the ring gear teeth. The reason for me thinking that is because at 1st I thought the opposite...the new starter was sat too low and the bendix was hitting the back face of the flywheel and needed lifting a bit. So I packed the side of the stater between the mounting bolts and flywheel with a 2mm spacer but this made the problem much worse, most times the starter would fail to engage or just spin freely without seeming to touch the ring gear at all. If it did manage to engage it would make a horrid sound and usually slip off and start spinning freely again.

I do think that the fit of both starters looks crap around the gearbox section of the starter nose but that might be how they all look? What I could do with is for somebody at Ford to run the reg, chassis and engine numbers to see what starter motor part numbers they produce. While they're at it they could cross those numbers to the part numbers of Mondeo starters to see if they are the same or not.

V8Dave mentioned that some starters sold are generic, the listing for the one I boughthttps://www.ebay.co.uk/itm/FORD-TRANSIT ... 2749.l2649 doesn't mention the Mondeo but I guess that doesn't mean they don't list the same item again as a Mondeo starter. It's stopped raining so I'll pop out now and measure things up and report back here.

[supadik]

To conclude the starter saga I ended up stripping and refitting the old starter as it's teeth looked ok. Turns out the new starter was only moving the bendix about 70% of the way across while the old one moved it the full 100%. They both measured up the same in all respects. I got a replacement sent from the supplier but it had exactly the same issue with limited movement so it's going on the LDV

[Harry_Viderci]

I have the same problem with my Mk5. I have found that the ringgear is worn in two places, 180 degrees apart. These two positions correspond to the crankshaft commencing a compression stroke, for a four-cylinder/four-stroke engine. Logically these two places are where the starter-motor "always" engages with the flywheel as the "slowing" crankshaft encounters the braking effect of a compression stroke, when the engine was last switched off. If I manually turn the crankshaft (forward) ~10 degrees, the starter engages and the engine starts first try.
Having said all that, I believe that the teeth of the starter-motor pinion do not fully engage with the ringgear teeth , applying excessive pressure to the reduced surface area shared by the driving and driven teeth. I plan to remove the flywheel and repair the damaged teeth, possibly applying hard-facing to the driven side. I may also machine the face of the starter-motor that seats against the spacer/bellhousing/engine block, to gain another 3mm of engagement.

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