burning out alternators

[ACKER323]

[font=Arial][font=Arial][font=Arial] I have a 89 civic si and i keep burning out my alternators. When i was at nelsons last weekend during a session the charge light came on and my 6 month old bosch premium was toasted. I took it to the local autopart store and they bench tested it and said it was the diodes. Is there any quick solutions so i dont have to replace alternators twice a year. Some say i should underdrive it but will the pulleys actually underdrive it enough. Thanks guys i am really interested on how the endurance civics kept their alternators alive.

[zracre]

how r u wiring your cutoff switch?

[Racers10]

I have been having the same problem. Kill switch on 3 Civics are wired properly, I even have the drivers kill the electric fuel pump and igntion prior to turning off the kill switch.

I hve been told by my rebuilder (who is tired of warranty repairs) that the diodes are susepable to buning de to units running at high rpm and suddenly dropping to low rpm repeatedly.

I don't have and answer yet. He is working on producing a singe wire version that he thinks will do the trick. I hope so.

Any better answers????

Maurice

[JeffYoung]

Bigger pulley to slow it down some?

[Racers10]

Who did my proof reading??

[ACKER323]

At the moment i dont have a killswitch and i was explained the same thing reving to high an then its trying to charge at high revs and it blows. I am wondering if any of you guys have tried a pulley set to fix it about 200 bucks for the pulley set so i want some advice if underdriving it will work. It is right now a de only car. The local auto parts guys laugh about it but ehhhh although you can change them fast i want one that will last ,since last year at the 12 hours at nelsons the yellow civic went through 3 of them in 12 hours.

[joeg]

For a car used on the street, the big pulley may not be that great a solution because it may not put out a charge just tooling around--it will need revs.

The big pulley is helpful on the race track, but is not a cure-all. Heat and vibration also take their toll on alternators.

My non-Honda would go through alternators quite regularly (1 and a half race weekends on average) until I installed the big pulley. However, I still occassionally still suffer a case failure (broken or loose case bolts) or a gradual failure I beleive is internal. These seem to be limited to once or twice a season. Perhaps it also has to do with the quality of the rebuilt alternators, which can be all over the place.

[seckerich]

Your stock alternator puts out full charge at 800-1000 rpm and sees 3000 on a regular day. Now turn it 5000+ for extended periods and it will toast the diodes with the surges. Do the math and drop the rpm by 40% and you will be in the ballpark. Remember to figure %drop on the circumference and not the diameter of the pulley.

[ACKER323]

When we are talking big pulleys are we talking like unorthodox pulleys or really big pulleys that you guys got to work just by trial and error. Also, its a track only car barely any street usage.

[joeg]

Mine was fabricated to give a 1 to 1 ratio with the crank pulley. Some thought has to be given here as to available belts--you obviously cannot use the original belt.

[ACKER323]

Well thats when the good old sewing tape measure comes into use to measure. I am just wondering for endurance usage and for lightness but first off i want to fix the problem. Joeg since going to a 1 to 1 ratio has your alternators seemed to be living longer any other problems with running htat big of a pulley.

[JeffYoung]

Do some searching on the net. I was able to find my stock Delco alternator with a large "race" pulley they called it already installed. I suspect someone has done this with stock Honda alternators as well.

[joeg]

They indeed live longer with a big pulley, but scan up a few posts and you will see that you can still have problems.

Frankly, I put alternators in a "wear" category about the same as brake rotors.

Remeber that the IT rules do not allow one to use a race alternator; just an OEM with any kind of pulley.