Toyota Alternator in Race Car - Auto Electrician help needed!

[Art Racing]

Hi Guys. Am continually blowing the alternator in the race car - and am getting a bit sick of it. But because it is wired up a bit different etc and all aircraft wire (ie white) the local guys don't seem to want to touch it.

Am after an auto elec I can ring and discuss how it is wired, and what might be going wrong. Anyone who can help? And no its not as simple as 'sensor should go to this terminal, ignition to this one' as that is all correct. Alternator currently in the car is an early 4 cyl Camry one but only because that fits nicely, I also have a couple of 7MGE alternators with the same basic setup but slightly longer and they all go bang the same way.

Send me an SMS if you think you can help and want to chat! Yes popped another one today hence the post.

John

0414374244

[lexsmaz]

I won't be able to help but I'm curious as to what goes "bang" in the Alternator ..

[Art Racing]

I'm just a driver, bang is a very technical term to me!!!!

The internal regulator fails. Car original had a Bosch alternator with an external regulator so it could be more easily replaced if it failed during a race, but as it doesn't do 24 hour racing anymore we put a more easily available Toyota alternator in it about 6 years ago. Have had one fail since with the field winding shorted, and 4 now have done regulators. Thus I am assuming it is something to do with the way the alternator main supply to the battery is wired but don't quite understand why it would be causing the issues as, apart from the Signal wire the Toyota needs, the car has been wired the same way since 1985.

John

[dumbass]

maybe the local guys don't want to touch it because your not paying them enough hahaha

most of the time if the internal shield wiring gets shorted it means the alternator is spinning to fast
I had this problem with my fj20 over 8500 rpm
u can always put a bigger pulley to try slow it down but then u loose the charge rate at idle which on a race car doesn't really matter

u don't really need an auto electrician
u need a professional who builds top race cars day in day out
normal auto electricians don't really understand the difference between parts lasting for the road and then lasting for the track

[Art Racing]

Car has had an underdrive pulley for 31 years now on both water pump and alternator, 71% normal speed on the alternator. Considering I was only running the car today to test some cooling systems changes I never took it over 3k. Alternator was new, only installed after last race at Muscle Car Masters when the previous one did the same thing. Whole car has been rewired since with same result. It has nothing to do with the alternator speed, but thanks for your thoughts.

JA

[dumbass]

So how is the alternator plug wired up
Do u have three wires

Ign
Batt
And light wire

Also where is the thick wire going
I pressume if its a race car it has a red cut off switch
Does the engine stall once u turn off the red cut off switch
It's going to be incredibly hard to diagnose this fault if it only blows the reg once every few months
And 99% of auto elects will just say its Chinese made reg

[DX20VT]

I have fitted a few of them to race cars and never had an issue, but there are a few tips,
S/h genuine toyota regs are more reliable than the new aftermarket regs,
dont use a rotor that has had a repair or new slip rings fitted, again a s/h genuine rotor is better than one with replaced slip rings,
Make sure that there is battery power onto the B+ stud and the sense wire at all times, even with the ign switch off and master switch off,
as if these switch off while running it causes problems, but usually rectifier issues.

Also to check, does the alternator light glow at all with the 3 pin plug out of the alt?
as sometimes people wire things off the warning light wire to use as an "engine running feed" so that things only work while the engine is running,
and this can overload the warning light circuit in the reg depending on if it is a reg that will drive a choke or not.

What is the part number off the back of one the regs?

[Art Racing]

Alternator is wired through the battery master - current wiring is:

Alt b+ feed direct to starter. Main lead to starter obviously through FIA style battery master so is not always live.

Sense direct to FIA switch so it is on when master is on, not direct to battery although that would be easy to change.

Ignition - from ignition as per normal.

Light - straight from the bus bar (supplied when ignition is on) through ignition light to alternator.

Thus the b+ and sense wire connections are through the battery master not direct. Can be changed, I think the original thinking was that once the external cutoff was pulled there would only be one length of 'live' wire, the battery feed to the master. The original Bosch alternator was actually wired such that the field windings were routed through the battery master through an internal mod. Car shuts off properly when external switch is pulled and that doesn't seem to affect its operation.

Thus no ignition light when the plug is pulled. Regulator type (the round plug style) doesn't seem to affect it; it has blown second hand Toyota and aftermarket with equal effect.

My thoughts on it were: sense wire not direct to battery as per original Toyota design could be an issue; and ignition light direct to alternator with no other loads on that circuit also seems counter to the Toyota design, although the Bosch was wired that way for 25 years with no issues. Alternator wired to starter rather than straight to battery - all my Group C and A cars have been wired exactly the same way, but yes not knowing exactly how Toyota alternators/rectifiers/regulators work that could be causing issues as the starter tries to pull a gazillion amps on starting; again the Bosch didn't seem to care.

So why did I change from the Bosch? the physical layout wasn't available in Australia, its from a car that was never sold here and when it finally died after 20 years it seemed like a smart idea to replace it with something I had a few of already.

JA

[DX20VT]

Do you ever switch the master switch off with the car running?

[oldcorollas]

all alternators have a rev range they like to be in. different styles, different revs.
the old chunky style like lower revs than the new compact style (at least in bosch alts)
can't find the pdf I used to have, but whatsisname mentions the ratios here http://www.autospeed.com/cms/article...nator&A=112916

Toyota wiring stuff here http://www.autoshop101.com/forms/h8.pdf

could also be the solder of the field diodes cracking from revs? have had that happen before and can kill regs too

[Art Racing]

Nothing to do with revs or anything, as I noted this alternator that just failed hasn't been over 3k which with the underdrive is 2100. I limit the race car to 6,700 as I don't have unlimited funding to build engines, which is only 4,800 equiv at the alternator. And no I don't turn the engine off with the master unless I am upside down, hasn't happened lately. I have all the Toyota wiring stuff, every factory manual, even the factory training notes on Toyota alternators. Unfortunately this isn't a simple issue but I think it has something to do with the way it is wired; just can't work out what it is.

JA

[DX20VT]

what does it do when it fails?
I presume it does actually stop charging.
Does it also bring on the alt light?
Does it just stop and once the light is on it stays on,
or does the light flash on/off a bit then stay on?

[Art Racing]

Light comes on, and yes it isn't charging, battery voltage only. Am now suspecting it has something to do with the fact that the Toyotas have a diode before/after/both sides of the ignition light; the car doesn't have one as the Bosch alternator didn't require it, but perhaps the regulator in the Denso alternator does. Will put one in and see what that does. 19 days till next race......

John

[dumbass]

the diodes before and after the charge light is due to the charge light brings on other lights in the dash so the diodes
are there to stop feedback from the other lights

anyway its wired up ok and u have to be a dick to wire it wrong anyway especially with 3 wires to wire

so in the end it is going to be poor alternators
if u r crying about money then get out of racing
shit happens and your lucky its not a motor blowing up every few months cause ive seen that many times

I would goto afew auto elctricians and ask them what can they supply for you and will they give warranty
if they wont give warranty then go elsewhere

u r probably buying 2nd hand alternators each time so if this is the case then its hard to judge why they are failing but its not the wiring

if they are lasting longer than a month then its not wiring and most probably either shit parts or used parts or pure bad luck
I don't think anyone on here can help you with your problem because the wiring is fine
maybe u can try the new style alternators with one way clutch but to buy a new one is very expensive


also what type of racing is it so we know what type of person u r hehehe

[DX20VT]

I have run a denso alternator in y race car for years and it is wired with no extra diodes in the warning light circuit.
Have done probably 10 seasons of racing and never had an alternator fail,
but have probably 3 different alt's over the years as we modified the car and reduced weight etc so downsized the alt for a few KG's saved.

It is definitely a weird problem as I am an auto electrician and would say that they are probably one of the most reliable alternators out there.