15 replies to this topic

[perrin_07]

hi guys.
i just bought a reconditioned alternator for my datsun. well it seems like its got oil in it and the mechanic said that if it has oil these kinds of alternators wont work(i think its hitachi or something, unsure). So i emailed the guy i go the alternator off(off a datsun club site and very very reputable) to see what the go is but he believes the mechnic is bsing. the mechanic has being nothing but awesome with me and known him for awhile. the guy has all reciept for the alternator.

so does oil really affect alternators? its for an L28 engine.

[Captn_Awesome]

Oil isnt a good thing.

How much oil?

[Vyute]

do you mean has oil spilled on it?

[perrin_07]

he told me while i was travelling interstate with bad reception so it was a bit awkard to understand haha.

i think oil got onto the seals

[Big_Valven]

This is very confusing. Did oil get into the seals, or out of the seals? Was it spilt? Was the alternator dipped in it? Engine explode?

Which seals?

Clean the oil off and use it, I say. But there's very little context to know, so it's hard to say for sure.

[ubernoob]

The oil may get absorbed into the brushes slightly but I'd just hit the sucker with a bit of brake or electrical cleaner and run it, if you spray it let it dry as you could make a small fire if you start it up straight away.

But yeah, odd question.

[perrin_07]

yeah as i said i was in a poor reception place and still am so i cant give more details ill i see him on monday. i do believe he said on the seals, how tho im unsure. it was a reconditioned alt so it SHOULD have been fine when the guy got it back.

[perrin_07]

nevermind, the alternator turned out to be a dud!

[perrin_07]

so i might as well buy a new alternator for an L28 engine. Im looking to be running around 1500wrms in my datsun, with some oldish amps. What kind of alternator will i need?

[ubernoob]

So you installed it and it didn't charge? Have you checked the charge light globe in the dash?

This is a weird thread.

[Captn_Awesome]

Stab in the dark my guestimate calcs would be as follows
1500 / 12.8 = 118amps x say 30% duty cycle = 35ish amps*
So something around 80amps should be heaps to run car and stereo and shouldnt zap too much HP from the engine.
Provided you've got a good battery and good cabling you shouldnt have any issues. Unless your running the stereo at full tilt with your high beams on everywhere. Of course if your running electric thermo fans you're going to need bigger again.
What stock alternators are available?
I'd be talking to a good auto elec to see what they suggest too.

* IMO most people think the average draw on their systems is a lot bigger than it usually is - whilst you might peak 150amps with it cranked on a real bass heavy song your average I would think is going to be more like 35 amps even at moderate - loud levels.
I ran an MRV-T320 @ 2 x 4ohm at moderate listening levels for a few hours with the amp powered by the remote trigger (which is supposedly rated at less than 1 amp...) from the head unit (didnt have enough grunt to power the MRD-M1000 at the same time though) when I blew a fuse (too small a fuse, 30amp, on the main power) and shorted the trigger and the b+ terminals on the amp - I dont think it was an advisable undertaking and I dont for a minute think that the head unit would have liked it but it worked and the head unit and amp lived to tell the story (infact I still have the head unit and the amp is in my brothers car happily powering a set of 165ks)

[perrin_07]

yeah sorry its at the mechanics and im not the most mechanically abled person as it is.

The very first alternator in the car was dead. The second one i bought was also dead and was covered in oil all through the inside. I then found another one, but this was an externally regulated? alternator and the car has being updated somewhat to use internally regulated alternators. The car/engine are from 1975.

So basically, since i keep having issues with secondhand alternators, i figured i might as well buy a new one that will also be good enough to run my audio when i get it installed.

[perrin_07]

The wiring will have to be upgraded as its an old car. I was going to do the Big 3.

It wont be on full tilt naturally and i doubt i would drive it everyday. The engine will be stock until i want more powerrrr(as jeremy clarkson says). I havent looked into stock alternators yet, but i shall do so. The mechanic quoted me about $260 for a NEW one but didnt say what ampish.

I was always under the impression i would have needed a larger alternator, mainly cos i heard old amps like to draw more current?

[ubernoob]

If you are buying new you should be able to get an alternator with the same dimensions and mounts that outputs more current for a similar price.
I managed to find a 90 amp alternator that fit my old Mini as a direct bolt on and it was from a boat engine or a Range Rover, the sales guy couldn't remember which.

[perrin_07]

hmm, thats not a bad way to go!

I think im able to get another recon one for free so ill obviously pursue that first