pappaecho
Well-Known Member
Anybody fitted a second alternator and if so how?
Perkins 4108
- Thread starter pappaecho
- Start date
Piddy
Well-Known Member
I made a special bracket to hold the second alternator above the initial one as I was restricted for space at the sides.
Even though the crankshaft pulley had only a single groove I fitted double pulleys to each alternator so that the main belt drove alternator 1 and the water pump as standard and a small belt between alternators drove the second which charged the starting battery. Worked OK but was a bit fiddly to adjust initially.
Even though the crankshaft pulley had only a single groove I fitted double pulleys to each alternator so that the main belt drove alternator 1 and the water pump as standard and a small belt between alternators drove the second which charged the starting battery. Worked OK but was a bit fiddly to adjust initially.
Norman_E
Well-Known Member
Always remember when adding new belt drives that the longer the belt run, the easier it is to get sufficient belt tension. If you can mount the two alternators on opposite sides of the engine, a double pulley on the original driving the new one is a good arrangement. Belt drives absorb power, and so do alternators. To minimise power loss do not use very small diameter pulleys, or very thick belts. "M" section belt (about 3/8 inch wide) is sufficient and will transmit enough power between two pulleys of 3.5 inch or 4" diameter, whilst wasting less power than 1/2" wide belt.
LeytonC
Well-Known Member
why do you want a 2nd alternator? would a split charger be easier (cheaper?) solution?
Just a thought.
Just a thought.
Bejasus
Well-Known Member
Same thought occurred to me. I upgraded to a 75 amp alternator with Adverc smart charging system and 2 x 110 Ah domestic batteries and 1 x 110 Ah starting battery.
pappaecho
Well-Known Member
The original alternator was build shortly before mr Noah launched his ARC - hence it only produces 25 amps.
I have 400 amp hours of battery, 200 engine and 200 service, and would prefer to charge the service batteries with a separate alternator, which will also give me some flexibility, if the old one fails... which I wont get with a splitter
Oh I also have a few old Lucas/Bosch alternators, which I could put to good use, if the pulleys are the right size and the rotation direction is correct
I have 400 amp hours of battery, 200 engine and 200 service, and would prefer to charge the service batteries with a separate alternator, which will also give me some flexibility, if the old one fails... which I wont get with a splitter
Oh I also have a few old Lucas/Bosch alternators, which I could put to good use, if the pulleys are the right size and the rotation direction is correct
Roberto
Well-Known Member
Similar situation: a 500Ah battery bank (400+100engine), looking aft towards the engine, the second alternator (90A) is fitted just below the original one, on the left side
the belt is driven from a single pulley fitted to the main crankshaft pulley
the belt is driven from a single pulley fitted to the main crankshaft pulley
Bejasus
Well-Known Member
ah, can understand the reason for requiring more amps when using a 25 amp alternator to charge 400 Ah of batteries. Can also see that if you have a supply of old alternators, it would make economic sense, at the cost of a belt and bracket and maybe a pulley, to use what you already have, than to spend a couple of hundred pounds to go another route.
Not my personal choice, as I would just carry a spare alternator or brushes and regulator if I was cruising long distances. A spare belt I always carry anyhow.
Not my personal choice, as I would just carry a spare alternator or brushes and regulator if I was cruising long distances. A spare belt I always carry anyhow.
neale
Well-Known Member
Sorry to take this slightly off topic, but what HP is a 4108 and was it available as a turbo and non turbo version?
Cheers
Cheers
Roberto
Well-Known Member
AFAIK there is no turbo version (maybe retrofitted ?)
model 4.108M gives 49hp at 3600rpm, 41hp at 3000rpm
model 4.108M gives 49hp at 3600rpm, 41hp at 3000rpm
neale
Well-Known Member
My reason for asking is that I didn't think there was a turbocharged version and then saw an original Perkins spec sheet for a T4.108M which is Turbocharged and produces 65hp at 3800rpm. Is this a different engine or a version that was launched and didn't sell?
andrewjake3
New Member
turbo T4.108
I have also heard of the T4.107 and 8 but it does not seem to have gone into production. I can not locate any engines with the turbo or the turbo kits.
There is a man on the cruisers forum that is in the process of putting a turbo on his. (larson2032)
I am also in the process of doing the same.
I have collected all of the parts to do the job but I have ran out of time because I'm flying to mexico for the winter.
I'll fit it in march when I come back.
Some of us snailboaters have motorhead roots.
Mine is going in a 41 foot trimaran.
I talked to King Diesel and they don't see a problem, no computer or censors.
I talked to an injector pump calibrating company and they told me to just turn up the injector pump till it smokes then back it down.
It would probably add 20 or so hp.
It may not seem like much but 55hp at 4k rpm and adding 20 is 36% more hp.
I'm using an adjustable wastegate with a vacuum boost control and gauge.
That is big.
These motors are so bullet proof I've never heard of a crank failure.
That is where the turbo would add the pressure and I'm not worried.
I have 2 of these motors locally for $2k so if I blow it up I don't care.
Up grading to a yanmar is $13k.
I have also heard of the T4.107 and 8 but it does not seem to have gone into production. I can not locate any engines with the turbo or the turbo kits.
There is a man on the cruisers forum that is in the process of putting a turbo on his. (larson2032)
I am also in the process of doing the same.
I have collected all of the parts to do the job but I have ran out of time because I'm flying to mexico for the winter.
I'll fit it in march when I come back.
Some of us snailboaters have motorhead roots.
Mine is going in a 41 foot trimaran.
I talked to King Diesel and they don't see a problem, no computer or censors.
I talked to an injector pump calibrating company and they told me to just turn up the injector pump till it smokes then back it down.
It would probably add 20 or so hp.
It may not seem like much but 55hp at 4k rpm and adding 20 is 36% more hp.
I'm using an adjustable wastegate with a vacuum boost control and gauge.
That is big.
These motors are so bullet proof I've never heard of a crank failure.
That is where the turbo would add the pressure and I'm not worried.
I have 2 of these motors locally for $2k so if I blow it up I don't care.
Up grading to a yanmar is $13k.