Guidance please - I keep cooking alternators

[Doug]

I have a problem which seems to be a bit repetitive and which I hope someone may be able to help shed some light on.

 

My 2.0 litre Raceline Zetec keeps cooking its alternator. The first one went 2000 miles ago, so I bought a new one, fitted the step down pully and fitted it to the car. I also took the opportunity to check/replace all earth straps and the four wires to the alternator. I did find that the centre one, of the three next to each other, was not in good shape so I put a new spade connector on and soldered it for luck! All seemed to go well until I was caught in heavy traffic on the A34 under the M4 3 weeks ago. Engine temp raised significantly and, once I got going again, I noticed that the ignition light was glowing gently. After a couple of miles it went out and I thought all was well.

 

After a further 35 miles, engine temp completely back to normal again, the engine started missing, popping and banging, particularly on the over-run. I managed to get to my destination, removed the battery and put it on charge. It was almost flat and took two days to recharge fully on an Oxford Oximiser.

 

On the return trip, realising I almost certainly had a charging problem, the car ran beautifully with a fully charged battery. The ignition light glowed gently again for a couple of miles before going out completely. Needless to say I had a somewhat eventful journey and the car finally cut out completely as I approached Oxford on the A40! Fortunately my wife was able to bring me a spare battery which got me home.

 

On a Zetec, the alternator is on the passenger side about 30cm ahead of the closest primary exhaust pipe. This problem seems to happen in warm weather so I wonder if the heat build up under the bonnet becomes so great that the regulator (on the rear of the alternator) cannot dump its own heat build up and fries.

 

I am considering wrapping the exhaust primaries and making a shield to go just behind the alternator, protecting it from exhaust heat. I am aware that an alternator gets quite hot when working with lights, wipers etc on so putting a wrap around the alternator, similar to that used on starter motors, is probably a mistake since the heat will then not be able to escape.

 

I would really appreciate some guidance from any one else's direct experiences, together with the best materials to use and where to get them from. Demon tweeks have a multitude of exhaust wraps and heat shield materials as do other sources... but which is best for this application?

 

 

 

'Have you any idea what it's like to have the wind rushing through your hair!' (Quote:Sq Cdr the Lord Flashheart)

[Myles]

Seeing as you have no other replies:

 

On a Zetec, the alternator is on the passenger side about 30cm ahead of the closest primary exhaust pipe.

 

Erm, it's less than that on a K...

 

I've cooked everything bar the alternator (actually, the plastic shield did melt once, but the alternator still seems to work reasonably-well).

 

I dunno -I'm no auto-electrician - but are you possibly under-doing it with the pulley? I think I might be marginal due to running my lights 100% of the time and frequently using fan-override (and a moderate battery)...

 

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[Doug]

Thanks Myles - you are possibly right about the distance, it is probably less than 30cm and I haven't had a chance to measure it 😳

 

The pulley is Raceline's own spec and the same as they use on Zetec (and I presume Duratec) installations. What diameter would you expect it to have and I'll check that it hasn't been changed?

 

'Have you any idea what it's like to have the wind rushing through your hair!' (Quote:Sq Cdr the Lord Flashheart)

[Big Brother]

Doug,

 

Raceline also do a mounting kit to site the alternator on the inlet side of the engine (just under the inlet manifold).

 

Also, was the "new" alternator new or a recon unit?

Only asking as I went through 5 alternators and changed a significant amount of wiring and connectors trying to resolve a charging problem on my old Crossflow.

It turned out that the company who was reconditioning the units were not soldering the diode packs properly.

I ended up getting an auto electrician to rebuild the fifth alternator.

It spent 2 years on my Crossflow, 6 months on my Zetec and now lives under the bonnet of my Land Rover In all that time it's not missed a beat

[Tom_C]

As Myles says, with my powerspeed system on the K there is about 30mm from No 1 primary to the alternator.

 

I've wrapped the primaries with the cheapest wrap product from Rally Design, about £20 for 50' of 2" wide. Under bonnet temps are now much lower, with a corresponding increase in the temp of the unguarded silencer.

 

 

Cheers

 

Tom

 

FH54WLX

 

see here - UPDATED again

[duffym]

My Zetec has the alternator on the drivers side under the carbs. I think its a Raceline bracket or a Dunnell one. No probs with overheating so far , fingers crossed and its been on 5 years.

[Doug]

Se7en-Up - Interested to hear about your experiences. I have wondered if the 'new' item I bought was reconditioned since it cost me £50 and didn't look entirely new! Perhaps investing in a genuinely new item (£125ish) would be worth the money after all...

 

I will speak to Pete at Raceline to find out how easy it would be to convert to the other side. I'll almost certainly go down the route of wrapping the primaries though.