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Discussion Starter · #1 ·
My build is not yet road legal but been for some test drives and many engine starts, often get start grind (load whirring/grinding) = start pinion misalignment.
When it ground, got it to start by putting in gear and giving car a shove to move the flywheel.

Finally got around to taking the tranny and bellhousing out (pain in arse) and find the start pinion has zero clearance (vs .030-.035 thou its meant to) and will only engage if a flywheel gear valley is opposite the starter pinion.

Plenty of advice on net for GM starts and alignment. Ford modular starters are aligned to the bellhousing backplate and in theory should not need radial adjustment.

Flywheel is supposed to be a M-6375-R00A 164 tooth 8-bolt manual. Quicktime bellhousing. Starter is a powermaster XS high torque. Apparently aftermarket parts increase likelihood of misalignment.

Anyway, the starter motor has a circular boss on its mounting plate to align with the bellhousing backplate.
I figure I can align the starter if I machine the mount plate boss so the pinion can be moved 0.032 thou away from the flywheel.

The only other possibility was to somehow get a new flywheel that had a slightly smaller OD, if such a thing exists, however they aren't cheap and I'm in New Zealand so shipping also not cheap and if its wrong shipping it back and forth several times is really really expensive and takes 6 months. So don't really want to do that.

Picture below. Can't get a .015 thou wire into the valley there and the pinion sticks. Will only engage if can get a flywheel gear valley between the red lines.

The flywheel is true, bellhousing indexes within factory tolerance. Can see the aluminium circular boss on the starter mount that aligns the starter to the backplate.

Engagement depth is perfect (ie z axis, we have a radial x-axis problem, shims exists to fix depth issues, not radial clearence).

362572


Here is what I'm about to do to the starter mounting plate - machine 0.8mm (= 0.032 thou) off the outer edge of the alignment boss so can move the starter away from the pinion.

362573


Anybody have a a better idea or know what I've done wrong?

The flywheel came with the engine, the twits that sent the engine cocked that up and sent the wrong part number with an unflashed ECM - flooded on first start. Had to mail the ECM back to edelbrock to flash. Wouldn't surprise me if they also sent me a wrong flywheel. Have no idea if there are variations in flywheel diameter that could cause this misalignment.
 

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Discussion Starter · #2 ·
Nobody had a better idea so went ahead with above fix, pinion meshes just fine now.

Did find a few other posts around the internet about quicktime backplates not being accurately punched/machined.

The flywheel diameter is exactly same as stock flywheel which I found in a corner so is not the flywheel.

Backplate cutout locates the starter, inaccurate placement of the starter cutout in the backplate would therefore be likely cause.
Machining that would have needed removal of clutch and flywheel, couldn't face doing that.
 

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Discussion Starter · #5 ·
Update from OP - problem is definitely fixed. No idea how many starts - 20 or 30 at least no problems.

Problem was quicktime bellhousing backplate innaccurately punched, machining the starter cutout locator hole to allow correct alignment would have been the most correct solution, what I did above was to avoid further disassembly.

The mount bolts have 1mm or so of wiggle, don't need do anything to those.

Somewhere on net there is a good list of starter malfunction causes and how to work through them, youtube has videos you can hear the various noises that indicate possible issue.

For anybody who thinks they have the same problem: -
Google "jalopy journal starter grind", "starter gear to flexplate clearance" and "youtube starter grind noise".
Note that ford modular engines do not have ability to adjust starter engagement in x-axis, other engine families do.
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