SBF bendix not retracting w/o load.

[nvrstuk]

Never looked at it from this angle... normally when the engine rotates faster than the bendix drive the bendix will retract as the engine starts.

Question- With the engine hanging and the starter hooked up and if I hit the hot wire to the starter it cranks the engine but won't retract all the way after I disconnect the jumper. The flexplate teeth are not binding on the bendix dirve teeth. They only engage about 1/2 way.

I've just never cranked the engine over and not had the bendix retract completely. I've tried 3 different starters and all the same.

 

[nvrstuk]

... for those that know me there's more (always more) to the story!) lol

So on my test engine stand without heads on the block I connected everything up and the starter engaged/cranked and disengaged just fine.

Put the rest of the engine together and do the same test and the starter doesn't disengage.

Now is this because the engine hasn't fired and spun faster than the starter can spin the engine so the load is off the bendix gear teeth and off the flexplate ring teeth so w/o a load on the teeth the starter spring can retract the bendix assbly easily.

I have seven different starters on the floor, 5 new ones, 4 fit and NONE retract. The starters are yes- absolutely flat and at exactly 90deg to the flexplate and I already posted a pic but here's a couple more...

I have new starters with a new flexplate, old starter with my old flexplate, 5 different combinations.

As you can see the teeth actually could be engaged even more than they are but in the pic you can see that the teeth aren't binding from being too close to each other and probably should be meshed a little tighter but this same pattern shows on my past flexplate from the last 3 yrs of use


The last 3 pics just show the tooth pattern from 2 yrs of use on my old flexplate

 

[DirtDonk]

Your theory is along the lines of what I was thinking, too. Seems like all it would take would be a slight load.
When there were no cylinder heads, everything sort of flowed freely and there was no residual pressure applied to the flywheel.
Once the cylinder heads were in place and compression present, there might have been just a slight extra tension between the ring gear and the starter drive gear.

But of course, when I first started reading it, my thought process went straight to the gears being a little too tightly meshed, or the wrong flexplate offset, not giving it the room to fully retract.
And, of course, lending mystery to the whole thing, I’m assuming this is the custom adapter flex plate you’ve been discussing in other threads?

 

[Jdgephar]

What happens if you rotate the crank by hand a little bit?

Sent from my SM-G981U using Tapatalk

 

[Yeller]

I think we're all on the same page as far as it should work. My question is, and I know it would suck to pull it back apart.... but does it do it when it starts. The act of starting is supposed to help push it back, I'm with you I don't see why it is sticking other than when it stops turning it is on compression and it adds just enough pressure to hold it. all of the parts are new too so they also lack the polishing effect of used parts. I'd be really tempted to start it and see what happens.

 

[gnpenning]

Have you tried any of the starters by themselves not bolted up ?

Yes you have to really hang on to them or put them in a vise.

 

[nvrstuk]

Your theory is along the lines of what I was thinking, too. Seems like all it would take would be a slight load.
When there were no cylinder heads, everything sort of flowed freely and there was no residual pressure applied to the flywheel.
Once the cylinder heads were in place and compression present, there might have been just a slight extra tension between the ring gear and the starter drive gear.

But of course, when I first started reading it, my thought process went straight to the gears being a little too tightly meshed, or the wrong flexplate offset, not giving it the room to fully retract.
And, of course, lending mystery to the whole thing, I’m assuming this is the custom adapter flex plate you’ve been discussing in other threads?

yup.. exactly. I was of course thinking the worst but the gear mesh pattern is not causing the bendix to not return so I yanked it out and wanted to make sure it wasn't something I designed in then started doing a "million" searches and still nothing 100% definitive but there are lots of posts with the exact same symptoms- just that not many guys are under their rigs checking for this when the starter is not causing any problems.

 

[nvrstuk]

I think we're all on the same page as far as it should work. My question is, and I know it would suck to pull it back apart.... but does it do it when it starts. The act of starting is supposed to help push it back, I'm with you I don't see why it is sticking other than when it stops turning it is on compression and it adds just enough pressure to hold it. all of the parts are new too so they also lack the polishing effect of used parts. I'd be really tempted to start it and see what happens.

That's what I've decided even tho my next run of adapters are coming on Friday w/o any changes. Starting removes the load and the bendix retracts was my conclusion yesterday afternoon but I wanted to be as close to 100% sure before I installed it- again.

Going in this morning.

 

[nvrstuk]

Not on the engine or on the test stand w/o rods/pistons or heads the starters all work perfect.

On the long block now the starters when power is removed all try to retract a little, then if I move the engine in a CW direction like it's starting by only one tooth the bendix"s all immediately snap back like they are supposed to. THat's why I'm installing again today and see how it all goes.

Of course I'll report back

 

[Broncobowsher]

What happens if you rotate the crank by hand a little bit?

Sent from my SM-G981U using Tapatalk

Thinking the same thing. You just don't have enough rotating inertia to spin past the starter inertia. Put a wrench on the crank bolt, make the engine over-run the starter. Just bar the engine forward a quarter turn. If it kicks out, nothing to worry about.

I have a Y-block and the starter bendix on that one will never kick out unless the engine starts. It is a weird reverse bendix. If you can't get the engine to start, then need to remove the starter, it is a super pain to do. Learned a lot about hanging bendix working on those. What you are showing I don't think is a real problem. Just appears to be since the engine isn't actually starting to fully kick out the bendix.

 

[ssray]

I‘ve run acros starters in the past that would stick because of a dirty bendix mostly from farm use with all the dust and dirt. Shouldn’t be the case with new other than possibly one that was really tight tolerance when built. Jdgephar mentioned turning the crank. If you bump it up just a hair and the bendix snaps back that might be a dead giveaway. Just my thoughts.

Ive heard people talk about getting parts 3 times before getting a good one. With the luck you had on this engine maybe you set a new record with 5.

 

[ba123]

And so you're doing this just to see if the patterns work and then you found this potential issue? Sorry, I missed the other threads mentioned.

I agree on the turn by hand to see if it comes out, if it does, I'd bet no prob. You could also try some feeler gauge. I've never found any reason to, but:

This is from a starter sheet...not like it's adjustable, but so you can rule it out that way if you wanna try:


From your pics, it does look like there is plenty of space though and even too much space won't make it stick.

You could always try a little light lube that you could wipe off after you see it works, but prob unnecessary.

 

[nvrstuk]

I posted earlier quote here"(..., then if I move the engine in a CW direction like it's starting by only one tooth the bendix"s all immediately")...
retract immediately.


I was doing the paperclip insert yesterday. And it's (updated) .035" for the old PA adapter and .023" for the Meziere with my old mini starter.

Now I'll measure root to tooth gap for the '92-96 351w mini starter (haven't tried this one yet)

 

[nvrstuk]

So what Ford "mini-starter" fits our early blocks and 164 tooth flywheels?

I have been running one for 12+yrs but bought it from TBP.

Wouldn't mind knowing what I could get as a quick replacement at a parts store.

I am dumbfounded at the # of starter options Ford has for the SAME block-what a joke...

 

[DirtDonk]

Don’t use passenger car listings at all. Different beast.
Same for Explorer, although in some cases those do work.
Choose one for a truck or a Bronco with a 302 or 351.
Just be sure to choose one for your transmission type.

That .045 seems a bit excessive, but that’s just for a reliable engagement and wouldn’t hang anything up.
I wonder though, if the gear won’t retract fully with the engine not starting, is it still able to reliably repeat engagement when you turn the key to start again each time?
In other words, did you make multiple cranking attempts before manually releasing the gear?

 

[nvrstuk]

Yes, multiple starting repetitions and no issue with the starting turning since the gears are already engaged.

I think Ive tried all the options and now its time to prove another theory!

 

[nvrstuk]

Paul- what trucks had mini-starters tho? I am clueless on those offerings.

 

[DirtDonk]

I’ll have to look at an application guide, or you can look on rockauto. But I would say any V-8 from 92 to 96 would get the job done.
There are two part numbers that are common. One for manual, and one for auto.
I just don’t remember what the four digit numbers are at the moment.

 

[nvrstuk]

Thanks!

I bought a mini for a '92 Mustang 5.0 with auto and its not even
c l o s e to aligning!

 

[DirtDonk]

Is this version of your bronco an automatic or manual? I assume this is the automatic you’re working on?
If so, then it’s probably not aligning because the mustang probably used the manual transmission version for both manuals and automatics that year. Or vice versa.
That’s why mustang applications are generally to be avoided when choosing a starter.
Except for a Mustang, that is!