bokko

Member
Can someone tell me if it is totally out of order to put a Mini alternator on a 200tdi engine? at the moment it has a Lucas B127, the mini one is a Lucas 115/45 and it fits but wasnt sure what problems this may cause.
Cheers.
 
Depends what you need to power.

If it is less than 45A you might find that it struggles a bit.

However, the 115/45 should be OK.

Check that you have 14.4V into the battery with the engine running.
 
Bokko, why would you consider an alternator off a smaller engine and thus downgrade. Always better to go the same or upgrade. You can get then cheap enough.
 
Only reason for trying a mini one is because it was Sunday morning, nowhere is open to get a proper one today and I had one lying around that I new worked so I thought I'd try it.
It does work , or at least the ignition light now goes out but it's only putting 12v to the battery so I guess it was the alternator at fault, although I would have thought it would still put out more than 12v. Can't think what else it would be, checked all wiring and earths etc.
 
Chunkymonkey, Which leads do you mean and how am I suppose to check them? I had convinced myself it was the alternator and intended getting a proper one tomorrow but youve made me think it ain't that now
 
Have you checked the out put of your alternator at source? Its not unknown for the lead from alternator to battery or the points either end to get so filthy they become inefficient.

On my 90 (when i had it) i changed the alternator and it was the battery. Upgrade to a 100 amp alt and battery and never looked back. Starts strongly. In the summer a landy won't have trouble. In the winter with a weak battery and alternator they can struggle. Don't take my word as there are more experienced people on here but just worth the thought before spending the money
 
So was the charge light on before the change?
Rev the engine and check the voltage from the replacement, tickover on diesel is usually less than a petrol motor, the alternator maybe fine for now when running at higher revs
 
Thanks fellas,
I'll check to wiring and connections tomorrow before rushing out and buying anything.
Yes the light was staying on before the change, after the change the light went off but the voltage reading at the battery was only 12 on tick over and also at higher revs which is why I'm a bit unsure of my diagnosis. One thing is didn't do is fully charge the half flat battery beforehand
 
The volts should be 12v i think. I think its the amperes that you need to check. Standard landy battery is 69amp but a good upgrade to ensure great winter starting and ability to stick "toys" on.

The standard landy alternator will be running at higher amp output ( assuming its healthy) than the mini one.

Although the mini one will charge your battery well enough, heavy drain by using lights, spots, stereo and heater may draw faster than the little mini alternator can top it up.
 
I always check a good charging alternator across the battery terminals as more than just 12volts, I like to see 13,5 `ish volts..


re chaning alternators,
I was desperate for one on my 200 some time ago, so bodged a volvo 740 to fit while I bought a new one...
new one still in box over a year later - still got good volts and amps going in my batteries ;)
 
As I said earlier, you should get 14.4V at the battery with your engine running.

However, it is still OK if you get 13.8V ... anything lower is not good!
 
Although the mini one will charge your battery well enough, heavy drain by using lights, spots, stereo and heater may draw faster than the little mini alternator can top it up.

main issue is replacing the power used by a big engine starting, combine that with a few short journeys and it will soon not have enough power to start
 
As I said earlier, you should get 14.4V at the battery with your engine running.

However, it is still OK if you get 13.8V ... anything lower is not good!

;)
after I recover from £79 worth of tescos shopping......:eek:

I will relieve my backside and legs from sitting, then place a volt metre across my terminals of battery...

a rather large cup of reviving tea first, to wash down 2 rather naughty scotch eggs sir......
 
As I said earlier, you should get 14.4V at the battery with your engine running.

However, it is still OK if you get 13.8V ... anything lower is not good!

OK, after my pained walk to my disco, multimetre connected on a warm engine/batteries, I got a reading of 12.6 at rest,
14.07 at tickover, and
14.08/14.09 at slow run - but it makes no difference when revved...

I use 2 linked batteries for 12 volts but oodles of cranking power/
lights used when not running...
 
Because the lowest condition battery will 'drain' the other down to it's level, hence you only getting 12.6 at rest and 14.04 on full charge.

Try taking one off at a time and compare the charge and static voltages.

You may be surprised at the results!
 
Because the lowest condition battery will 'drain' the other down to it's level, hence you only getting 12.6 at rest and 14.04 on full charge.

Try taking one off at a time and compare the charge and static voltages.

You may be surprised at the results!

yep, I`ll do that when I get a minuet...
got some little service jobs to do before I drive to the big boy scouts jamboree next month :rolleyes:


not had a working oil pressure gauge since, errr, well ages..
swivvle joints not been topped up since, err - see above..
and so on..
 

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