As mentioned in my previous Alternator post I called Nu Rex in the States and they were very friendly and helpful.
They advised that I’d have to split the Alternator to be able to tighten the belt pulley which in turn locks the fan pulley in place. It’s apparently very rare for one of the pulleys to come loose. I’m wondering if the clearly incorrect fan belt was part of the issue?
Nu Rex advised that the centre of the belt pulley should not be shiny if the belt is the correct item or not worn out, as you can see we were wide of the mark on both counts!
I was also advised that the standard Model A Fan Belt is the correct item, and also to re black the pulley with a marker, which once it becomes shiny again will indicate belt change time.
Popped up to Simon’s and both he and his Dad gave me a hand to tighten the pulley and also lent me a piece of welding rod to lock the brushes in place to allow reassembly of the unit.
Been hearing a bit of a metallic sound and whilst I was working on the carburetor and noticed that the fan pulley on the Nu Rex alternator was turning independently of the fan pulley, which I’m pretty sure that it shouldn’t!
Will give Nu Rex in the States a call to understand how it all hangs together!
Now have the bolts, spacer and washers and have managed to (bodge) fit the alternator into place.
Not the most asthetic piece of engineering I’m afraid, however the Spitfire alternator brackets or quite hard to source and as a result quite expensive!
Everything is nice and tight and the belt run is pretty straight
Could probably do with a slightly longer belt I think, had a look in Halford’s today and the only ones available were either the same length or the 1500mm (a bit too long). I’ll go with the original for the time being.
I now need to fashion a little piece of aluminum or steel into an extension for the fan belt adjusting bracket, and then I will then complete the wiring.
So it begins, out with the old and in with the new(er)
Started with removing the dynamo (strangely enough:-))
Please note that the dynamo may foul the distributor.
Got around this by loosening it off and turning it away from the dynamo.
Be sure to mark the position of the dynamo before loosening so as not too put the timing too far out.
I put a small felt tip pen mark on an HT lead to line up with the LT lead of the distributor.
The dynamo was then removed.
Tried a few test fits of the altenator with the various parts of the existing dynamo bracket.
It would appear the best way to do this is to remove all the existing bolts etc (including the large one in the alternator and dynamo picture above) and replace them with two different size bolts and a large amount of washers to ensure all the pulleys line up.
The Herald fan belt will also now be too short, I’ll pick up an new one when I get the bolts.
This is how I converted my Herald to negative earth.
1. Disconnect the battery
2. Remove the battery from the tray
3. Refit the battery around the “other” way
4. Connect the terminals in the correct
configuration for negative earth
5. Swop the LT connections on the ignition coil
to also reflect negative earth configuration
(you may have starting problems if you don’t)
Please go to this link where there is a basic
but very clever way of testing if the polarity
is correct. here is the test
6. Remove the large terminal from the dynamo
7. Take a piece of wire connected to the live
terminal of the battery and “flash” it on the
dynamo terminal a couple of times(it will spark)
The dynamo should now be repolarised
Refit the large terminal to the dynamo
8. Start the engine and check the charge rate
of the dynamo
In my case the dynamo charged prefectly first time, you may however need to flash it again if the charge rate is not sufficient.
My fuel gauge and wiper motor appear to work OK, I will therefore be leaving them alone!
The heater blower also appears OK, however I will swop the wiring over in the near future to see if there is any difference in the operation pos to neg.
Please don’t take this method as the same in all cases, follow these steps at your own risk 🙂