Hope you guys can help on this one. It's a farm truck, not a machine I've had for a while, so I don't have a huge amount of history with it. They generally take care of their stuff here, but this thing also lives a hard life.

The truck's a 77 F350 with a 460 and a 4 speed (super low, non-synchro first gear). It was originally a box truck, cut down to a flat bed some time ago.

They tell me it's eaten almost a starter a year for a long time. I know the guy who was mechanic here before me sometimes... didn't do quite the right thing by the machines. I came in this morning and they said yesterday it started making a horrendous noise when trying to start. I tried to start it, it sounds like there's a big chunk of metal in the bellhousing or something--loud, smashing, nasty noise. Shut it off, tried again, it started fine. Tried again, fine. Tried again, loud WACK, then engine won't spin. Ugh.

Tow it into the shop, pop the starter out, and the entire end of the starter--the cast bit with the needle bearing that supports the starter shaft and gear--is snapped right off. The shaft is intact, and the gear is still there, though its shoulders are a little chewed up. I fished the snapped off cast bit out, in mostly one piece about the size of a golf ball shell, out of the hole in the bellhousing, along with the grenaded remains of the needle bearing from its tip. I also found some much thicker rollers from a roller bearing somewhere sometime, which I'm hoping came from inside the starter. The truck has the kind of non-inspection cover, so I'd have to split the trans/engine to see in there, which is something they can't really afford to spend the time on right now on a veggie farm. I pried a bit of space in the cover at the bottom of the bell housing and nothing additional came out.

They say this is the first time it's actually cracked like this. The starter bolts were nice and tight, everything seemed straight. I believe Fords don't have shims, right? I also could see the funk inside the bellhousing rubbed clean where the starter shaft would have hit, but I have no way to know if that happened during/after the thing grenaded, or was itself part of the cause. The ring gear looks alright, from what I can see of it.

What the heck? I've got a rebuild on the last starter that came out that they had in the shop. Rebuilt by a guy down the road they say does good work--made me wonder, since it eats starters?! I have to go ahead and throw that starter in because they need the truck back in service, but it drives me nuts to ignore the CAUSE. Why would it blow up like this?

Thanks for any guidance.

Luke in NY

 

Since the truck eats starters on a regular basis I'd guess it's something to do with the flywheel/flexplate being worn or not aligning properly with the starter gear. But that's just a guess.

Does the engine backfire at all? Is the truck hard to start - meaning the starter is turning over very slowly before the truck actually lights off? My point being, if there is a carburetor issue and/or timing issue that causes a backfire the engine will kick back and can break off the nose of the starter.

 

The truck doesn't backfire at all. It does turn over a bit sluggish, but I just wrote that off to being kind of old and having to turn over that big 460.

Can you give me some pointers on how to check the alignment of the flywheel/flexplate? I'm working with a Haynes which is next to useless I'm finding.

It's frustrating to not know the mechanical history of the thing, but they've had a handful of different mechanics in the last so many years, and the previous guy just moved halfway across the country on not such great terms (so I can't really call him up and grill him about what he did or didn't do). The boss says a previous-previous mechanic swapped a new flywheel onto it, which the previous guy suspected may be misaligned and tried to realign/install. I'm new to these trucks, in case it's not totally obvious.

In searching I turned up references to a .100" shim some people have needed, even though I understand the factory didn't use them. I have no idea if this engine/trans combo are original or who in its past might have done the swapping. My understanding is that so long as the farm's had the truck it's been the 460/4 spd combo.

Luke

 

Make sure all the flywheel bolts are tight. Just a thought sounds like something is definitely loose or out of alignment.

 

Can ya verify that the last guy has installed the correct flywheel/ring gear for that year? There were 2 different tooth counts for early & later models, & they are def not interchangeable.

 

Two different tooth counts on the starter drives too.

 

Of course - forgot 'bout that detail.
The plot thus thickens .........