Engine and Transmission Tech

I've been having some hot start issues with the 5.0L. Tried a starter blanket, but no joy. Finally, last weekend at British Car Day in Boston the Bendix wouldn't engage and I had to roll it downhill and bump start it. I heard some noise coming from the bellhousing on the ride home. When I removed the starter, this is what I found:



It's a PMGR mini-starter, with about 100 starts on it. It comes with a solenoid attached and I wired it through the Lucas solenoid on the Healey. I did some research after the failure and seems that if there is not a diode in the solenoid not on the starter, the starter will run as a generator and energize the solenoid so the Bendix doesn't fully disengage. I suspect that's what happened here.

I bought the mini-starter because I wasn't sure I'd have enough room for a full size one when I made the engine swap. Turns out I have plenty of room for a full-size starter so I replaced the mini with a full-size at about half the cost. So far it seems to be working fine.

Any other theories about the malfunction? (PS, no damage to my aluminum flywheel, thank God).



Edited 1 time(s). Last edit at 06/30/2014 08:59AM by HealeyRick.

No further theories, but I've had my PMGR starter for 8 years, wired through a start solenoid, without a single issue - just replaced it over the Winter just for preventive maintenance sake....here's the latest:
[www.ebay.com]

Rick,

Do you have a link to a discussion about needing a diode? Off hand, I can't think of a reason for needing one, but
I'd like to look into it further.

I lost a starter on the Roadmaster when I had it due to the ignition switch sticking in the "start" position, giving the same type of results. Luckily Carquest replaced it for free.

Here you go, Dan: [forums.vintage-mustang.com]

Rick,

Well, that was an interesting search! A lot of confusing info on the internet, and a lot of it is wrong.

Is a diode needed? Evidently it depends on how it is wired. If it is wired as shown on the left below, run-on could be a problem requiring a diode; if wired as on the right, it should not be a problem. Of course, I could be one of the internet sources that is wrong as well. Most sources say wire it as shown on the left.

What I don't understand is why the solenoid would stay energized for only a couple of seconds. If the starter is acting as a generator and driving the solenoid, I don't know why the solenoid wouldn't stay energized as long as the engine is running. Whether I understand it or not, that seems to be the general consensus on the 'net.

Hope this is of some help.




Edited 1 time(s). Last edit at 06/30/2014 09:54PM by danmas.

Or you could eliminate the Ford solenoid, wire it like a GM and not have a problem like the 1000's that have done it with no problem. Why would you want 2 solenoids?



Edited 1 time(s). Last edit at 06/30/2014 11:14PM by JWD.

Dan,

"What I don't understand is why the solenoid would stay energized for only a couple of seconds. If the starter is acting as a generator and driving the solenoid, I don't know why the solenoid wouldn't stay energized as long as the engine is running. Whether I understand it or not, that seems to be the general consensus on the 'net."

When I look at my starter, I wonder how it got that hot to melt the white nylon part unless the starter had been running continuously. I note the diagram you posted has a "Ford solenoid" The Ford solenoid for the Fox Mustangs has a diode installed in the solenoid, already. I don't know if any of the other Fords come with the diode.

As for me, I replaced the mini starter with a Bosch that does not have the solenoid built in. I hope it will solve the issue. So far, it's starting fine, but I haven't taken it on any long runs.

I had an automobile electrical shop for years and have never seen a starter with a diode. If the starter stays engaged in the flywheel, and you drive the car, the armature windings will totally explode due to the tremendous rpm. The only reason for this is power to the solenoid terminal. A starter will not generate power at any rpm due to the nature of the windings. The windings are far too large and not enough turns to generate power.

Admittedly I'm no automotive electrical genius so I'm a little confused. I've owned Fords, Mopar, most GM, and a few homemade cars, but never with two solenoids and was wondering what the purpose is? I ask because I have a ProComp Mini Reduction Gear starter and would prefer to stave off any unforeseeable problems. As Jim suggested, it's wired like a GM. Thanks,


Paul



Edited 1 time(s). Last edit at 07/02/2014 04:26PM by pspeaks.

The Ford solenoid is actually just a heavy duty relay. You can use it to handle all of the starter current, therefore you have no power at the starter except while cranking. This can be a safety feature, especially with situations like headers close to starters and starter cables.

My headers are through the fender and I've insured all cables or wire bundles are well clear. For added protection they run through Cool Tube Extreme heat resistant covers from Summit. However, after looking at Dan's schematic again, I get it and might want to consider the added safety feature you described. Thanks Larry!


Paul



Edited 4 time(s). Last edit at 07/03/2014 08:48PM by pspeaks.

Okay, so here's my two bits.
Rick if you look at the drive pinion on the bendix it has wear on both the leading and trailing faces of the teeth.
So clearly it was being overdriven.
One problem I see a lot of in PGMR (and most Chinese knock offs for that matter) starters is broken bendix forks. This may well be what happened here, jamming the bendix into the ring gear.
The wiring could also be a causal factor.
Per Dan's diagrams, the one on the left will keep the starter solenoid powered as the starter spins down causing the starter to "hang" for a second or so. Possibly enough to damage it over time.
The diagram on the right can cause it's own problems as well. The genuine Ford relays have the S, B and I terminals isolated from each other. The offshore ones don't. This causes the same problem as the left diagram with the added benefit of a backfeed from the ignition system!
For me, the "A" terminal on the starter should get power directly from the battery. Period. If you want to retain the fender solenoid, then run it's "B" terminal to the "S" terminal on the starter and live happily ever after.
But honestly, if your running a quality starter, the fender solenoid is just another failure point so get rid of it.
And live happily ever after, even more.
Cheers
Fred