Triumph Spitfire MkIV Alternator problems

[Gnbickley]

Good morning everyone,

I'm hoping that the vast store of wisdom on here might be able to help me. I've gone through three alternators and an alternator rebuild in just under two years!

At first I thought it was the old alternator so rebuilt it. That died so I assumed it was my poor skills so bought a new one (relatively cheap). That lasted over a year then died so I assumed it was because I'd bought a cheap one so I then purchased an uprated one from Canley Classics. This lasted a few months then died on the way back from a weekend away. I had to call the RAC and the mechanic thought it might be a problem with the regulator. He also thought the mountings looked wrong.

I've compared the mountings I've got to photographs I can find and to the technical pictures I've got and I'm not sure if I've got the right fittings or not.

I've attached some photos and if be very grateful if people could let me know if this all looks correct.

As to why the Alternators keep blowing? I'm stumped. We've checked the electrical system and can't find any problems that might cause it.

[Paul H]

Hi , there’s a current discussion on alternators here . The conclusion seems to be the crap quality and quality branded alternators are the solution . I hope this is correct as just purchased a 12v 40A Alternator kit car racing race car 101211-1032 3Pin denso

Paul 

[Bfg]

I'm not familiar with the mountings on this particular car but the importance of them is only in respect to 1. holding the alternator secure enough to prevent the belt slipping (but no tighter as that wears bearings out),  and 2. to aligning the alternator pulley in the same plane as the other pulleys. 

However, I wonder about the alternator's fan.  The engine fan suggests that the engine turns anti-clockwise (as viewed from the rear) whereas the fan on the alternator looks to be for clockwise rotation.  If I'm correct, that may cause it to overheat and prematurely fail. 

Of course, a repeatedly heavily-discharged battery or even a wrong battery size would overwork the alternator.  To small a capacity and the alternator is working full wack to keep up with the winter needs of lighting, heater blower, and wipers etc.  Too large a battery capacity is again too much work to recharge, should the battery be left to go flat.  

I would also ensure the HT lead was well clear of the alternator case.  If that lead is shorting out through the alternator then I cannot imagine what that sort of high voltage would do to it .. possibly very similar to welding on the car while the alternator is connected.  What is the other wire resting on it ? ..the one that runs around the front of the engine. Again if grime on the outside of that cable's insulation can conduct electricity, then the HT lead may short through that to the alternator.  

Pete

[Colin Lindsay]

6 minutes ago, Bfg said:

However, I wonder about the alternator's fan.  The engine fan suggests that the engine turns anti-clockwise (as viewed from the rear) whereas the fan on the alternator looks to be for clockwise rotation.  If I'm correct, that may cause it to overheat and prematurely fail. 

I had to run out and check mine... but they're the same as those above, as are any I've checked online. 

As BFG says the mountings need to keep the belt taut and the pulleys in line, with the last mounting being a sliding mount to allow for expansion. That's a 1090 belt, many of the current suppliers sell an 1100 for the 1500 so that might allow more room. I'm assuming that when you say they fail, it's the electronics and not the bearings?

[NonMember]

45 minutes ago, Bfg said:

the fan on the alternator looks to be for clockwise rotation.

No, it's correct for a standard alternator. It's intended to blow hot air out, drawing cold air through from the back. Impellor type fans, like that, always operate that way - they're horrendously inefficient if you try to pull air inwards.

 

48 minutes ago, Bfg said:

What is the other wire resting on it ? ..the one that runs around the front of the engine.

Probably the coolant temperature (gauge feed).

 

59 minutes ago, Gnbickley said:

He also thought the mountings looked wrong.

He's an RAC mechanic so he can't be expected to know anything. That mounting is correct.

 

[Pete Lewis]

47 minutes ago, Bfg said:

welding on the car while the alternator is connected. 

its good parcatice to disconnect the battery and ground both terminals to the body/chassis when welding  on a car ( or anything similar ) 

we had welding problems on some 8 wheel trucks when the cassette front wheel bearings had the outer track burnt due to earthing via the tyres when serious chassis

modifications took place ....both front axes bearings on 6 trucks all very noisy , on strip down the arced marks were very obvious where each roller made contact 

cost someone a fortune but  not   warranty .  great to push the rejected button   ha 
Pete

[Gnbickley]

Thank you everyone for your answers.

Paul H thanks for the link I'll take a look 

BFG, the battery is the correct one and has never been discharged apart from when the alternator failed. I'll try and move the wires so they don't touch.

Colin, yes indeed it's the electrics failing not the bearings. I've got a 1300cc engine so not sure if the 1100 would be too big?

Non-member, thank you for confirming the mounting is correct. To be fair to the RAC guy he was very excited to be called out to the car as he was told it was a Herald (🙄) and he used to have a number of heralds.

 

[Pete Lewis]

as you have it mounted is fine its most important the tube /sleeve on the rear lug is midships in the lug as the case eaxpands a lot 

so a bit of tube each side of the lug is perfect 

 

what is the black wire from the alternator plug  

there is as far as i recall no earth tag on the 3 pins on the socket  

just two 30amp lucar positives and a warning lamp    No Black wires  !!!!!

are you earthing a main charge feed +ve  hence the repeat falures ????

Pete

[Gnbickley]

11 minutes ago, Pete Lewis said:

as you have it mounted is fine its most important the tube /sleeve on the rear lug is midships in the lug as the case eaxpands a lot 

so a bit of tube each side of the lug is perfect 

 

what is the black wire from the alternator plug  

there is as far as i recall no earth tag on the 3 pins on the socket  

just two 30amp lucar positives and a warning lamp    No Black wires  !!!!!

are you earthing a main charge feed +ve  hence the repeat falures ????

Pete

Thanks for the info Pete. As to the black wire Ive just checked and there are only two wires connected to the alternator a thick brown one and a thinner brown and yellow one. There is a green cable that comes from the same loom but goes over the top of the alternator. And a black wire that goes behind the alternator but neither are connected to it.

[NonMember]

1 hour ago, Gnbickley said:

And a black wire that goes behind the alternator

Is that even a wire? It's clipped to the fuel line all the way round what we can see, in exactly the way that the thin black plastic vacuum advance pipe should be.

[Colin Lindsay]

1 hour ago, NonMember said:

He's an RAC mechanic so he can't be expected to know anything. That mounting is correct.

I used to work for the RAC, as do a number of fellow Club members at present...

First thing I did when I bought my last Herald was remove the AA badges and cover up the holes....

[Pete Lewis]

well ive just collected some new   0-0¬`  from specsavers   

pete

[NonMember]

1 hour ago, Colin Lindsay said:

I used to work for the RAC

Yeah, in fairness, the mechanics are usually not bad. They can't really be expected to know about old cars, as they rarely see them, but they're usually competent and efficient. Unlike the dispatchers.

[rlubikey]

Yes, I've had problems with alternators, including a new higher capacity one from a reputable Triumph specialist. I took the high capacity one to a local alternator rebuilder in Burghfield Common (doesn't help you in Cumbria!) and he showed me how the nut holding the diode pack together wasn't tight. That's Chinese quality control for you! Vibration resulted in movement of the connections leading to failure after a year or two. By the way, the alternator would sometimes screech, which made me assume the bearings were dying, but I think this was the beginning of the intermittent connection in the diode pack.

Cheers, Richard

[daverclasper]

On 01/03/2022 at 12:25, Pete Lewis said:

its good parcatice to disconnect the battery and ground both terminals to the body/chassis when welding  on a car ( or anything similar ) 

Hi Pete. Not clear on this, I always disconnect battery terminals, when welding anyway, so the the battery is isolated out of the equation. Which cables?, are we grounding here?. Cant get my head around it?.

Cheers, Dave  

[Pete Lewis]

earth to the body both battery cables when youve  disconnected the battery

stops any welding voltage spikes blowing instruments and delicate stuff   this used to be common practice     

Pete

[Gnbickley]

On 03/03/2022 at 13:41, rlubikey said:

Yes, I've had problems with alternators, including a new higher capacity one from a reputable Triumph specialist. I took the high capacity one to a local alternator rebuilder in Burghfield Common (doesn't help you in Cumbria!) and he showed me how the nut holding the diode pack together wasn't tight. That's Chinese quality control for you! Vibration resulted in movement of the connections leading to failure after a year or two. By the way, the alternator would sometimes screech, which made me assume the bearings were dying, but I think this was the beginning of the intermittent connection in the diode pack.

Cheers, Richard

That's interesting, I'll have a look and see if my nut is loose. My current plan is to purchase a new regulator and rectifier and fit them to see if that makes a difference. If not I guess it's another new alternator! ☹️