Archived Message
Alternator temperature

I checked the temperature of my alternator right after a 1 hour drive today. At one special point (see picture) the temperature is about 184F, at other points it's between 122F and 140F.

Anything wrong here? Ciao!
Marcus Schopen
29/07/2012 @  21:02
Under topic: V8
Archived Reply(ies) received for this Message
Alternator temperature
Nice clean engine and polished alloy bits, the chrome fan is too bling for my taste but I cant see anything obviously wrong.

I suppose you are concerned with the temperature. I have never bothered to measure the alternator temperature and Im not going to start now but the hot spot is possibly heat soak from the water pump. If the alternator works and has worked for 40 years or so I wouldnt (and dont) worry about it.

Just out of interest, what is the temperature of the alternator with the engine running and cooling air blowing around?
Geoff King
30/07/2012 @  16:43
Alternator temperature
I notice the hot spot you identify with the red dot is on the side of the rear case of the alternator just behind the bracket on the front case, so that area of the rear case will to some extent be sheltered from the cooling airstream rushing through the engine bay. Under the red spot inside the casing is the rotor and stator. The temperature shown on your photo is 86C which is not a great deal higher than the 82C rating of the normal thermostat, so it's likely the coolant temperature and the ambient temperature in the engine bay could be close to the temperature you have measured. The heat soak factor Geoff mentions is also there too.

BTW there is a useful website with information, photos and exploded diagrams of Delco Remy alternators at:
Victor Smith
30/07/2012 @  17:28
Alternator temperature
I would say that this is no cause for concern. The main cooling requirement of the alternator is keeping the windings and electronics temperature down when it is working its hardest, eg supplying headlights, windscreen wipers, heater motor, hi-fi system. Its own front mounted centrifugal fan draws air from the back of the alternator and expels it at the front so the input "cooling" air may well be at 80C. The insulating varnish on the windings and the rectifiers and regulators in the electronics will have 125C ratings so the alternator cooling must ensure that the internals don't rise above this under full load. So I would expect that the casing temperature could easily be legitimately above 100C under conditions of high loading with a hot engine.
Bob Owen
30/07/2012 @  18:19
Alternator temperature
Thank you for you great answers.

Geoff: the temperature of the alternator with the engine running is higher, over 194F at the shown point. And yes, I cleaned the engine bay a whole weekend, including the chrome fan, hehe. I bought a tornador gun, which is a great helpful tool for any type of cleaning.

Some more questions:

I marked one of the hoses on the above picture. Does anyone know where to get this hose with the original yellow stripe?

Also I'm looking for a throttle cable in the original green color (also marked).

And I'd like to repaint the valve covers, but not sure what's best practice to handle the unpainted parts (MG logo etc.).

Marcus Schopen
31/07/2012 @  07:01
Alternator temperature
I think you're likely to be on a hiding to nothing to source a green throttle cable. Having said that, you might be lucky... I sold mine last year on eBay - it went mental. Hammer price was something stupid like 40 quid! Your best bet would be to source a new one and use a suitable shade of spray paint to achieve the apropriate finish.

Rocker covers are easy.
- Strip the old paint off
- Prime with a suitable ally primer
- Apply a few coats of topcoat and allow to dry
- Fit some wet 'n dry (emery) paper to your sanding block and start to flat down the paint.
Eventually the wet 'n dry paper will cut right through the paint to the aluminium.
-Keep sanding. Eventually you'll polish up the exposed aluminium sections to a bright finish.

At this point you can either decide to spray the rocker covers with some clear laquer to prevent the exposed ally from dulling or accept that you're going to have to get them off every couple of years and buff them up with some wet 'n dry paper to renew the shine.
JC Moulds
31/07/2012 @  07:37
Alternator temperature
As far as the valve covers are concerned, I did mine by chipping off all the black paint then, once cleaned, I resprayed them with aerosol Black Gloss. When dry, use a Stanley or Exacto knife blade. Holding it flat over the grooves and scrape the paint off the high part including the MG logo. Very simple but really effective.
Graham Cornford
31/07/2012 @  07:42
Alternator temperature
Marcus, one other tip... When you refit the rocker covers don't bother with those fancy re-useable rubber things. I persevered with a set of these almost all of last season, fitting them carefully, being incredibly careful not to over tighten them etc etc and still just ended up with oil leaks all over the headers. I could care less about a bit of oil on the drive but it REALLY stinks when oil drips onto the exhaust. So, stick with the original cork gaskets... Clean up the mating surfaces and "glue" the new gaskets onto the rocker covers with some blue hylomar and let it go off for a couple of hours before you bolt them onto the engine and you'll be leak free.

Engine bay is coming on nicely though. Stick at it!

P.S get those 'orrible power robbing K+N things in the bin. There's a link somewhere on the website that went up quite recently to a suitable K+N element that fits in the lobster cans.
JC Moulds
31/07/2012 @  07:58
Alternator temperature
Barrie Jones reported in November 2011 that K&N have made a filter element that replaces the standard paper element. These filters are washable and reusable and are custom designed to fit into your existing Factory MGBGTV8 air box. You can see the NEWS report by typing the key words "K&N filters" into the Search box on the homepage of the V8 Website and it's the first link.
V8 Webmaster
31/07/2012 @  16:16
Alternator temperature
At 90degC the alternator is approximately the same as the engine temperature, as Bob says it could be higher under load nothing to worry about.

Ive never heard of a Tornador Gun but a Google search pulled up an advertisement showing it in use and a cleaning fluid being sprayed all over a dashboard including the radio and switches Im not sure how long our cars would survive that sort of attack, forcing liquid and dirt into electronic components and switches cant be a good idea. Looks like it would be useful to clean non sensitive mechanical components but I wouldnt use it anywhere else.

For the throttle cable you could try Speedy Cables or Cable Tec and a pot of yellow paint, a small paint brush and a steady hand for the hose.
Geoff King
31/07/2012 @  17:21
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