Image Image

Will a 4bd1 alternator fit a 4jg2 with minor mods?

Get help fixing your Isuzu from other club members
ronstory
Posts: 5
Joined: Tue Dec 23, 2014 11:03 pm

Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by ronstory »

Hi--

My 80amp alternator on my mid 90's 4JG2T is make the classic 'bad noise'... it's losing a bushing. Since I'm in the states... trying to find an 80A alternator for a 4JG2 is rather hard, but the 4BD1 version LR170-418 off a NPR truck in the same vintage "appears" be the same or very similar. The mounting holes are in the same spots, the vacuum pump looks the same... the output is slightly different at 70A.

Any one tried this? It's only $100ish on Amazon... and pics look pretty much identical.

The 4BD1 alternator off amazon:

http://www.amazon.com/Alternator-Isuzu-3-9L-Lr170-418-Lr170-418B/dp/B0081SB3GS/ref=sr_1_1?ie=UTF8&qid=1419292697&sr=8-1&keywords=LR170-418

The 4JG2 alternator off alibaba:

http://jdhco.en.alibaba.com/product/970189232-218337751/80_Amp_Alternator_for_3_1_d_isuzu_bighorn_trooper_with_4JG2_engine_USB69_.html

Thanks,
Ron Story
Portland, OR USA
User avatar
geeves
Posts: 1980
Joined: Mon May 11, 2009 1:56 am

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by geeves »

http://www.aliexpress.com/item/NEW-ISUZ ... 21569.html

At least here you dont need to buy 5 of them.

It looks like it should fit with the old pulley but wiring might be quite different in terms of the regulator etc
ronstory
Posts: 5
Joined: Tue Dec 23, 2014 11:03 pm

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by ronstory »

Thanks Geeves! I saw that one but it didn't have the vacuum pump on the back and picture didn't who whether it had the shaft sticking out the back.

I also found http://www.aliexpress.com/item-img/JFB1702-Alternator-AC12V-14V-75A-4JA1-engine-Parts/1234087669.html but it's a for a 4JA1 motor but it's look identical to the 4JG2 alternator with exception of the pigtail.

So is it worth the experiment of the 4BD1 alternator? If it physically will fit in the mount... I sure I can figure out the wiring. Of course it's at the bottom of the engine under the AC pump which always adds bit of extra fun to wiring a 'project'.

Thanks,
Ron
User avatar
geeves
Posts: 1980
Joined: Mon May 11, 2009 1:56 am

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by geeves »

4ja1 one is at most changing the plug over. I dont know if the 4bd1 uses an internal regulator or not. In the general questions section of this form you will find a list of manuals on mediafire. One of them is for N series trucks. This should answer that question
ronstory
Posts: 5
Joined: Tue Dec 23, 2014 11:03 pm

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by ronstory »

Ok, I decide to buy the new110 Amp alternator LR1110-501. I purchased it off Amazon for whopping $122.09 USD with shipping from DB Electrical. The alternator was brand new (from China) and not a refurbished one, it looked pretty. :) Since I needed a tach line added to the rectifier bridge, I had it tested as well... no issues.

Since this is alternator has the newer oval connector, I purchased one off fleabay for $10.95 and they called it a P10 connector.

The shaft on this new alternator was bigger than the stock 4JG2 80Amp alternator so the pulley hole needed to be enlarged about a 1/16”. The lower mounting feet were too tight for the original bracket and the rear leg needed about 1/8" clearance grind a bit to get it fit. The pulley lined up fine with front leg spacing.

I also needed to move the vacuum pump output fitting from the original since it had two connections, a large and a small where the LR1110-501 only had a blank in place. Replacing the round terminal with new oval 2 terminal connector was no drama. The S line I just connected to the BAT+ connection and L line connected to the factor harness for the Ignition +12V, no diode was needed on my range rover. YMMV.

I now have an 110A and not a measly 80A and my headlights are bright again. The 1995 Range Rover LWB has *lots* of electrical needs and now seems to ‘behave’ much better. As an example, the front windscreen heater is connected to a shared 60Amp fuse… these trucks like having juice.

I hope this note helps others and as far as alternator swaps, while not completely painless... it was drama free. ;^)

Thanks,
Ron
User avatar
geeves
Posts: 1980
Joined: Mon May 11, 2009 1:56 am

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by geeves »

exelent
ronstory
Posts: 5
Joined: Tue Dec 23, 2014 11:03 pm

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by ronstory »

Glad to help. Finding more common alternator options for the 2.8/3.1L motor is handy for us folks in the states, where these motors are rare occurrences for non-industrial applications.

Thanks,
Ron
Benihanas
Posts: 3
Joined: Thu Feb 17, 2022 4:04 pm

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by Benihanas »

hey Ron , im doing the same mod as you are now and ive reached the wiring stage... if im understanding this correctly I can take my new 2 pin plug and hook S to the main post of the alternator and L to the old IGN line ?

(the old plug has S, L , IGN )

I could really use some clarification on this ; im here in the US and super stumped on how to get an alternator that's realiable... im wondering if I need to chicken out and get something with a similar plug because every alternator shop is telling me not to try this , but it seems so simple , so any help is greatly appreciated!
Benihanas
Posts: 3
Joined: Thu Feb 17, 2022 4:04 pm

Re: Will a 4bd1 alternator fit a 4jg2 with minor mods?

Post by Benihanas »

I know this is wayyyy long ago but I figured it was worth a shot!
Post Reply