Now the Alternator

javelinadave

javelinadave

Administrator
Staff member
Between the back of the motor and the bulkhead is where the plugs is. I left a inch or so of the original wiring and I soldered, then slid on crimp fittings and heat shrinked over each splice. I then used heat resistant split loom and ran it where the old harness was installed.
 
pmatusov

pmatusov

Technical Excellence Contributor
Callsign: AK6PM
For whatever it's worth: I took a few AMR2747 alternators to a local shop in San Diego for rebuilding.
One of them was on my D1 and failed quickly.
Only recently I took time to take it apart, and found that the shop left in place the old voltage regulator unit with old and nearly worn out brushes that barely made contact with the collector rings.
So... if you _know_ your alternator was new, than it's bad luck; the rebuilds, however, are far more of crapshoot.
 
rocky

rocky

NAS-ROW Addict
And that plus the fact that new units have dropped rapidly in price is why I've ditched reconditioning old units or buying reconditioned units.
 
RBBailey

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Interesting. I’ve been wondering about this as well. I would guess that a trusted rebuilder might be worth it, but might as well buy new on Amazon and not have to make the hour long drive just to pay less.

after sitting for 24 hours after the charge last night, the battery still showed almost 12.8 volts. The truck started this time, and the alternator showed 14.5-15 volts charging at idle. At the battery this was more like 14.1-.5 volts, and it settles down when revved. Have not replicated the no charge in three test start cycles.
 
RDavisinVA

RDavisinVA

Technical Excellence Contributor
If you suspect an intermittent break in continuity, run a heavy gauge brown wire between the (+) post on the starter (where the (+) battery cable connects) and to the (+) post on the alternator.
This will carry the load from the alternator to the battery with ceteris paribus.
 
Last edited:
NPT90

NPT90

Well-known member
RBBailey said:
Interesting. I’ve been wondering about this as well. I would guess that a trusted rebuilder might be worth it, but might as well buy new on Amazon and not have to make the hour long drive just to pay less.

after sitting for 24 hours after the charge last night, the battery still showed almost 12.8 volts. The truck started this time, and the alternator showed 14.5-15 volts charging at idle. At the battery this was more like 14.1-.5 volts, and it settles down when revved. Have not replicated the no charge in three test start cycles.
Click to expand...

Check that starter lug, run an additional wire to the alternator in heavy gauge, see if your problem continues.

The harness for the Alternator to Positive lug runs right along the engine, could be melted, could be shorting on the block, could also be intermittent if that is the case, could cause alternator failure
 
pmatusov

pmatusov

Technical Excellence Contributor
Callsign: AK6PM
I am too lazy to make a write-up on the subject of LR alternators.
Rebuilding one at home is a good alternative to a pile of questionnable used or shop-rebuilt ones.
There are several parts that require attention, to different degrees.

Stator or rotor winding can go bad, but it is extremely rare, and it is easier to buy a new alternator than to fix that.

Diode units - easy to buy, a little cumbersome to replace, but rarely go bad (they do go bad).

Voltage regulator/brush holder units: the most-frequent failure, the easiest to replace, relatively inexpensive.

I suspect the 300TDi stock alternator is using IX128 voltage regulator/brushes unit; earlier Classics and probably 94-95 NAS D1s used the same.
95 Classics and 96-99 D1s had the 100A Magneti Marelli alternator, which used IX123 regulator (same as on 120A P38A alternators).

I have never seen a bearing, front or rear, going bad in a LR alternator - can't say it never happens, just it never happened to me.

The collector (slip) rings do wear out, but much slower than brushes - new brushes will wear in to the ring pattern and be okay for a long while.
Slip rings can also be purchased separately, although I need to take some measurements or time to cross-reference them. Look here, for example.

That's about it for wearables.

Serpentine belt pulleys:
RRC and D1 - 7-rib, 67mm diameter.
P38A (300TDi?) - 7-rib, 52mm diameter. Using a wrong pulley will result in wrong tachometer readings in vehicles that use alternator feed for tach.
I don't know if using a smaller pulley to get more charging current at idle has any real benefits. I have never done it, and never had issues even with using the winch extensively on a slow trail.
 
NPT90

NPT90

Well-known member
pmatusov said:
RRC and D1 - 7-rib, 67mm diameter.
P38A (300TDi?) - 7-rib, 52mm diameter. Using a wrong pulley will result in wrong tachometer readings in vehicles that use alternator feed for tach.
I don't know if using a smaller pulley to get more charging current at idle has any real benefits. I have never done it, and never had issues even with using the winch extensively on a slow trail.
Click to expand...

Agreed, I know there are the 2 variants but I don't know why, I presume low RPM draw reduction but can't speak to it.
 
Steve 110

Steve 110

Member
I may have stumbled into the mother lode of alternators for old rovers!
These are factory new with warranties and no core charges!
Massey Ferguson.......Who knew??
It’s amazing what you can find when you look around!

9281



9282



9280


SteveSevier
Sevier@comcast.net
615.210.8615
9278
9283
9279
 
Napalm00

Napalm00

Technical Excellence Contributor
These are great alternators but only for 200 TDI. You could also swap in 100 amp for a 200 TDI check the how to section
 
javelinadave

javelinadave

Administrator
Staff member
RBBailey said:
By the way: The alternator has been fine the last two days....
Click to expand...

If it went from not working to working you have some kind of short or loose connection. Any day now we will get the annual "My clutch pedal isn't working" threads from the new owners. As the weather gets cooler things will shrink. Fittings, O rings and nuts may become loose.

 
RDavisinVA

RDavisinVA

Technical Excellence Contributor
The ebay: NEW 12V 70A ALTERNATOR FITS MASSEY FERGUSON MF-4253 MF4255 MF-4270 LRA602 MG-212
Looks like it has a dual pulley, is this correct or a picture illusion?
 
Napalm00

Napalm00

Technical Excellence Contributor
Most of the messy Ferguson alternators come with the dual pulley. the same alternators that I had posted a few years ago 70 amp replacements for the 200TDI. The are bolt on
 
T

Tiktaalik

Founding Member
Ben, You never mentioned what charging voltage your deep cell battery requires. There should be a sticker on the battery. If the regulator voltage output doesn't match the deep cells minimum threshold then you're in for a whole lot of trouble. I'm starting to suspect that a lot of "quality" issues people are having with alternators aren't actually a quality issue at all.
 
You must log in or register to reply here.
Top