Starter Motor Choices

http://i815.photobucket.com/albums/zz79/Ji...zps61408453.jpg

Mulling some pros and cons here...

The starter and flexplate on the right turn a gasoline 4.8L @ 9:1 compression.

The pair on the left turn a 6.2L diesel @ ~17.5:1 IIRC.

Both starters have 11 teeth, the diesel ring gear 138 and the gas 169.

Converter, crank, and starter bolt patterns are the same, so the swap in a bolt in.

The diesel piece has heavier teeth.

The diesel starter appears to be a reduction unit.

The diesel flexplate has balance mass which will have to be removed (The proper plate is neutral). Shouldn't be a problem to drill out the three 'weld pins' and any slight imbalance for doing so should be of no issue for an engine that'll never see 4100 RPM.

The diesel pieces were amazing current hogs which could kill a PIAR of fresh 750 CCA's in 45 seconds, the 292 would start on the last dregs of a decade old battery at minus 20. But I figure that's more to do with the load than the motor, and that the diesel motor turning the gasser wouldn't eat more (possibly less?) than the original piece.

Replacement prices are $200 bucks apart in favour of the gas piece, but it's also been out of production since 1990 and may become rare. The diesel bits were discontinued ~11 years ago.

Without knowing the reduction specs I can't say which will turn the crankshaft faster. I'd think faster is better though.

I think a gas engine likes to see about 450 RPM to fire up. Do IDI glow plug diesels typically require more or less, or about the same?

Another option, although I haven't thought too much about it - is that as the output shaft is the same diameter, the bendix (bendixes?) should swap between motors giving more than two choices.

Any thoughts on how you guys would put 'em all together?

I'd probably stay with the original setup.

Lower cost, easier repaired, fewer moving parts. And despite the difference in out-of-production dates, I'm guessing you can find replacement parts (or even a complete unit) in more places on a backwoods road trip.

My two cents.

Yeah, there's something to be said for the OEM devil you know, isn't there? Still, the thought of having an HD piece rated to do better than twice the work...

i agree with mac .
yeah , it would be nice for brag factor to have that brute starter/parts in there ... however ... economics and availability weigh heavily .

how long does the "regular" starter last in service ?

Oh, I think I put 5 starters and 1 solenoid in the old beast all together, but never an off the shelf ($650 What the...) OEM part. I suspect shoddy aftermarket parts more than the unit's design though.

now that I think about it, wonder if there was more than one spec'd as there were 3 CR's (7, 8.5, and 9) for these engines. The 9:1 flat top piston with D reliefs was a special order for the dual fuel (propane/gas) 1982-84 Canada Post livery, but they don't ping even on the cheapest pump swill. Dunno how much deck the machinist took, so can only guess where exactly I am now. Been meaning to recalculate displacement with the extra .030" too. Child's handful of cubes and a half of a point CR I guess.

Hell, I remember playing with timing (factory spec 4 BTDC) and going way back to 12 (static), gaining some noticeable balls but not a hint of knock. No idea why they made 'em way down at 7:1.

Interesting. Just opening up the 6.2 starter to find an O ring sealed 4 brush - twiceas long as typical - unit with an, uh... planetary reduction, but not quite - also sealed. And bearings where there are usually bushings. Brushes can be serviced without pulling the rotor case apart (separate end cap) Guess this is the extra cash?

So 4 poles - the motor (rotor) spins twice as fast but is then reduced. To what advantage?

Now these were the starters used on the civie H1, and the original US military Humvee used the same J code 6.2 engine - but they're surely not mil spec - wasn't all the army stuff 24V??

Helluva piece though, and doesn't show advanced age (lots of brush, little dust, and clean commutators). Going to clean it up, lube it, and make it pretty. If nothing else there's Kijiji.

I'd think to provide more power for the higher compression and fewer number of flywheel teeth...

, I meant advantage over a direct drive unit. A bit of a search revealed they did make a direct unit, but it was a monster by necessity. However it was probably the cost of copper and not weight savings that actually powered the decision.

I wish you'd re-re-re-build your website and document Beast progress more. Last I heard you kinda keep track of it but only on facebook now?

I've only cobbled together bits and pieces of what it'll have/do over the last 6 years

Whew, had me worried there for a minute...

Probably a combination of cost and size, though weight may have been a factor to some degree.

Damndest thing is, that I had been doing pretty regular pages on all kinds of stuff but never got around to publishing them - waiting for enough of a marathon of solitude to fix up a bit of the olderstuff and resize some of the older pics - and then my drive went south. I recovered about half in drafts, and do intend to get back to it one day.

Yeah, been doing a fbook page. Much as I hate the idea of 'it' as an entity, it is working out as a forum for me to do regular unedited muse and daily (if they occour) updates. Some times it's just a soap box, or a means to entertain through thinly veiled geek comedy. A blog really I guess - which I probably should actually do instead for reasons of more favorable search results by others.

Not doing all that friend me frig me stuff that the chicks seem to do - indeed althogh I certainly appreciate my readers. and with that I unashamedly plug myself .

In the middle of tearing down and cleaning up this little beastie. I am quite impressed by it's construction.

if you count the teeth on the sun, and on the ring, you can get the ratio off that. I think they're usually in the 3:1 neighbourhood, maybe 4:1.

So 3-4x the torque..! But you're starting with a smaller motor, so not exactly... and spinning it faster, so burning more brush, I suppose.

(had to look it up. ratio is [sun/ring + 1] to 1)

if you ask me, the one with the reduction type gearset is the one to go for.

Chuffin' heck - that diesel starter motor could be a straight swap for the ENGINE in most Japanese cars!

dodge was (in)famous for reduction type starters , you could always tell when one was turning over if you were within earshot .
they had a very distinct sound .
most of the problems i seen with them were brushes , bushings and the solenoid/contactor .

man , i sure liked the starter motors with the external contactor .
of course , this meant more wear on a spin-out bendix .

somewhere in the back of my mind it seems that GM made a series of starters that did not last very long compared to others .
my dad had a 69 impala ... the starter was replaced on it twice :
once under warranty during the first year and then again by the GM dealership a couple of years after that (out of his own pocket) .
i replaced it for him the third time ... i think the car was about four years old and had about 40K miles on it .

Much of GM's starter issues were results of improper installation (not checking for proper meas depth, and shimming to correct), where they'd work for awhile and then start to skip off the ring gear teeth. Amazingly the ring gears tended to survive, and a new starter (tighter nose bushing and extra couple of thou on the teeth) would work again for awhile. How long obviously depending on how bad.

I've known wrenches who were at it years without knowing that GM starters were shim adjusted. Adding to the inner (towards crankshaft) bolt increased nose depth (axial), the outer brought the tooth mesh (radial) tighter.

I admit to once also not knowing this. And after 2 starters on a Chevy 'failed' in quick sucession, I changed a flexplate that was fine. Meh, wrenching experience two ways in hindsight.

Anyway, The Remy's tend to be beefy enough electromagnetically speaking, but the enclosures and connecting bits (end bushings, brushes, etc.) were chreaped out.

GM's definitely tended to take more starter motors in the car's life than Chrysler did though.

Hmmm... not sure I knew any mechanics that weren't aware (to my knowledge anyway), but plenty of owners certainly were. Not sure how they explained falling shim(s) as they removed the starter. Extra parts?

IIRC, GM new/rebuilt starters came with a small assortment back in the '70s.

Yep! Like most things have extra screws.

When you're fixing them, your job is to remove all those hazardous extra parts that were just sitting there on the device waiting to cause trouble. You can't always find all the extras on the first attempt, but if you're good you'll usually find some of them.

Nothing seems to have more extra screws than dashes, and other interior stuff.

The chryslers whined because they just had two spur gears, IIRC. most modern stuff uses a planetary setup, which is quieter, straight through instead of offset, and I'd imagine it gives more reduction. (unless the big gear on mopar stuff was pretty big, or the pinion teensy).

COPIERS!

Jeez, some 40 odd 4mm JIS to access the hard drive in a B-600. I thing it has to do with FCC part 15 - not like the panel is going to fly off and bean some receptionist. I generally put 4 back in, and theow the rest in the 'extra' bin - which weighs about 25 pounds atm.

Soo, this is interesting. Was cleaning up the 6.2 starter:

http://i815.photobucket.com/albums/zz79/Ji...zps680cf14c.jpg

As mentioned before, everything looked alright at a glance. This was a working starter motor that gave no problems.

But look at the commutator bars. Clearly quite a few shorted together. I picked at them lightly to see if it wasn't just a bit of dust from the wipe off with a scrubby pad - and no, the material is in there.

http://i815.photobucket.com/albums/zz79/Ji...zps817b2e2f.jpg

So why the heck was it working last time the key was turned?

BTW, I've pretty well made my 'decision'. There's a local guy who's always done me solid and is more than just a dude throwing parts together. If the loaded RPM spec of this unit is equal or greater than the 4.8, and if I can get it rebuilt at a decent price, then I'm going to go with the beast unit. The 4.8 is in poor condition upon inspection anyway, so if I have to have one built...

a hot pink starter casing !

you say that the copper was wedged in between the segments ... just about like it had been peened into position ?
weird man ... maybe because of the heavy current draw and better conductivity of the actual segment and associated windings ...
the lions share of the current went where it was supposed to ?

or ... just one more turn of the key would have let out all kinds of factory installed smoke .

Did ya do a continuity test? I've seen buildup like this before on working starters.

yep mac ... i have seen that too ... but not quite that extreme .

something i have noticed ...
long ago (gawd , i hate to be able to say that) the commutators had mica between the segments that had to be cut down slightly if the segments wore too much or after turning the commutator on a lathe .
the depth was not real critical .
the stuff i have seen in recent years does not seem to have this (or something like it) except "way down there" .

Now that's interesting. I guess I always thought it was some kind of polyphenol(sp?) or something, but had been under the impression for mechanical reasons that it had to be flush with the surface and wore with it - and that picking at it would ruin the rotor by letting material in between that would quickly short it, tear brushes up, etc.

So I could actually clean this crud out with an appropriate sharp stick?

Wonder if there's an epoxy that could be applied between segments and then just ghetto 'lathed' flush?

Nah, didn't bother to. A run over possum may still have a heartbeat, but it's still run over.