Vehicle: 2001 E-350 cutaway chassis - 7.3 PSD (dual alt option). -- **Both alts are 110A small-case 6G units

Judging by exterior appearances..primary alternator appears about 1-to-2 yrs. old. Secondary alternator looks even more recently replaced (6mo. maybe?). --- No apparent charging output from either however, metering shows ~ 12.5V at B+ with engine running.

Took both alts to nearest Carquest dealer for checking. Parts-house owner (knowledgeable & trusted) tells me he can't give definitive assessment because his machine's meter jumps all over the place, and advises his machine may not be adequate for checking these alternators properly. -- I'll be out today taking both alternators to other places for checking.

Assuming these alternators have both bitten the dust (either from abusive overload situation...or from excessive heat conditions) I'm now considering my options. I'd like to avoid having to do this job again anytime soon because I'm finding that dual-alternator replacement in the E-350 is not a particularly pleasant task.

I see that rebuild-kits are available from a variety of sources, and both all-new & remanuf units are also easy to find. Obviously the DIY rebuild option is the more economical route, and I have no qualms whatsoever about tackling the job myself. On the other hand, simply replacing both alts would save me time & energy...and that's worth at least something with everything else I've got going on.

A few essential questions arise:

1) What kind of luck have others experienced with their own DIY-rebuilds vs. just buying complete replacement units? --- Pricing for complete replacements appears to run from a low of around $100/ea. to as much as $369/ea. -- Now I realize there are differences relating to quality components worth considering here.... but that's a LOT of difference in pricing range in my view.(??) -- So I'm wondering what are the most important factors to be aware of (and how to differentiate them) should I eventually decide to just buy complete replacement units? - After all, one can't simply tell what quality of regulators, bearings, rectifiers, brush-holders etc. are used from external appearances... or for that matter, just based on some online vendor's polished sales hype.

2) If I should decided to rebuild these alternators myself... and assuming some kits may use cheaper quality components than others --> Does anyone have any advice or comments about what to look for when assessing the differences (in quality) between different kit offerings? --- Any recommendations on where to purchase these better quality kits?

3) Considerable searching reveals no indication that higher-amp/heavier-duty alternators might be available for replacing the 110amp units as originally equipped. I see that 135amp 6G units are listed for other yr/model vehicles (same mountings/frame)...but nowhere can I find anything suggesting these might pose a suitable or appropriate alternative choice for my application. -- Has anyone 'upgraded' their 110amp alternator(s) with heavier-duty units? -- If so..possible issues to consider??

Thanks!

dave r.

 

If the alternator served you well, consider taking it to a local starter/alternator repair/rebuilder. These guys are usually VERY good at what they do and can not afford to do a bad job. IF you need a larger output alternator, then go with a new unit.

 

My theory is some alternators have serious problems in the windings and such, and will always get installed, turned in, "rebuilt", installed, turned in, "rebuilt".

If you had a known good alternator, that just quit because it had a long life and a lot of miles, I would be more prone to rebuilding it. These alternators you have now are probably "rebuild" units, and they usually come with a warranty and you can keep changing them out till you get a good one, but as you mentioned if it's difficult to change them, that's not a very good way to fix it.

 

Franklin2 is right on the money as usual with solid advice. Rebuilding an alternator is not rocket science, but there are things the average guy does not have access to. A good rebuilding shop will test how much the windings will take without the insulation breaking down. A good shop that works on alternators, starters for semi's is a good place to start. Most of these guy's have to be good, or they won't stay in business long.

 

On an 05+ Superduty with dual alternators the alternators are triggered by the PCM.

Is that not the case with a 2001?

Josh

 

Thanks guys for the thoughts & feedback. I haven't had any time lately to work on the thing what with the holidays & back-to-school scramble and all...

--- I've pretty much decided to take both Alts down to our local rebuilder as recommended here. They're the only alt/starter service I've ever known to serve the Austin area. Haven't needed to use them since maybe the late 80's... and I know they've been around for at least 30-35 yrs (as best i can remember).

Re: the PCM alt-control...
--according to the 2001 E-series service manuals (need to re-read & verify this).. but for 2001 vehicles with the dual alt option ~ the primary alternator (top one) is not controlled by the PCM. --But the DC output current levels from the secondary alternator (bottom one) is! -- The 2001 manuals are all I have...so I really couldn't say as to how any other year/model charging systems might be set up.

Thanks again guys.

 

Thanks...

I also recommend using a local rebuilder if that is an option. There is one in Fort Collins, Colorado "Auto Electric" who has been in business forever.

He hates the Ford 6G alternator, and this is a guy who is in his late 80s and for the most part has seen it all.

I tend to agree with him, the 6G alternator is failure compared to the workhorse large case 3G.

Josh

 

Thanks for the tip Josh...

I was not aware that anything but the 6G alternator could be used on my 2001 E-350 7.3 PSD. -- I did do some digging around recently, but couldn't find any clues as to any possible alternatives. Also, it's my understanding the large case 135amp HD 6G (used on certain other yr/model trucks) wouldn't work because of the mount-spacing difference.

Are you saying that the large-case 3G's are something I might could consider as replacements then? -- If so, I'm all ears..

 

The 7.3 from 94-97 used a large case 130 amp 3G. Different connector which is no big deal and the bracket needs clearanced or run some washers for spacers to clear the large 3G case. Also swap the pulleys.

According to several Excursion members they have done the swap no problem. I was actually going to go pick up a 3G side mount Saturday to play around with, but the salvage yard was closed for the holiday.

14+ volts and 100 amps at idle versus 13.7 volts and 60 amps.


Josh

 

The main problem is you need to know what Voltage regulator is has in it. They make 4~5 types and you need to put the same color one in it. You need to remove the regulator and look at what color the back of it is. Gray, White, Blue, etc. You have to use the same color combo or you screw the PCM up.

The Stator can be checked with an ohm meter for grounding or shorts, the diodes gate needs to be check for back feeding, any shorts or back feeding means replace them as well. Clean the voltage regulator mounting screw area with sand fine paper till it's shiny and make sure you tighten the screws down tight. Then fill the plugs with dialectic grease. I would replace the bearings while its apart too.

 

Thank you Muffinman ~ excellent!

With sage advice from the moderator of this sub-forum section... I *had* previously determined to just have the local re-builders do the job. Unfortunately... I was treated in a rather "unsatisfactory" manner when I visited them recently. Seems they aren't the same folks that *used* to be running the previously reputable business anymore.

Ultimately decided I'd just go ahead and do the job myself after all. Just haven't quite gotten around to it yet.

Already done the research and perfectly well understand the point made about the regulators and the need for insuring appropriate PCM signal inputs. -- already on top of that!

The advice about stator shorts & gate-feedback while checking on the rectifiers is also well understood and right up my alley. You're speaking my language mi amigo..and I appreciate the reminder. Maybe I should build a EMF vs. freq-stress curve-logging testing jig (NOT!) ~ but.. I understand, so Thanks for that! (( in fact, the sound opinions proffered from Franklin2 speaks to that very idea and the concerns arising therefrom!))

ahh well... what else have I got to do anyway..?

It's now raining here in Central Texas! -- Whoah! -- yet another incredible (and extremely RARE) natural(?) occurrence.

Cheers!