Early 1600-2 Blower Motor

[Captain_Keram]

So this blower motor came out of my 68 1600-2. It was not working even with power applied to it directly. I decided to do a resistance test at the tabs where power and ground connect. I got like 31 Mega Ohms. So like 31 million ohms. Meaning this thing is getting like no power to any part of it. My question is it possible to repair this and get it to work again? As I can’t find another one of these anywhere to replace my current one

[calw]

31 megohms is an open circuit.  You may be able to "close it" by cleaning the crusty mess in the photo and finding something that can be repaired. (not a dig at your fan motor, it's over half a century old and lived out in the weather!)  You also may find out that if it does run, the bearings are past their date or the fan blades are cracked or out of balance. 

 

There are FAQ posts about non-BMW replacement fan motors(made by Bosch just like yours) that are still available, less expensive, and will fit in as a replacement.  There's also a scheme where you use a newer tech. fan by SPAL which was originally meant as a motorcycle oil cooler IIRC.  It requires you to remove the plastic cage structure of the heater box "top" that sits above the fan, but those are sometimes cracked and weather beaten beyond repair anyway.  I went that way and found it to be an excellent choice.  Less power draw and what seemed to be equivalent airflow.  Of course, you'll never win originality points at Pebble Beach without the original fan with the correct paper label.

[Mike Self]

And count your blessings it's 12 volts, not 6.  

 

IF you want to try and save the original motor, clean it carefully--be sure and don't use anything that will take the varnish insulation off the armature or field coil windings.  Then clean the commutator on the armature with fine emery cloth or sandpaper.  Next, make sure the brushes are not only clean, but have good tension against the commutator, and have continuity between the brushes themselves and the two power terminals.  Finally lubricate the armature bushings (they're brass so shouldn't be rusted) and try turning the fan by hand, then connect to power (try it either forwards or backwards--a DC motor doesn't care) and see if you can get it to move--help it along with your finger if it's trying to move.  Once you have it turning by itself, even slowly, let it run (make sure it doesn't overheat); oil the front and rear bushings and keep it going until it's operating normally.  Just don't let it over heat.  Worth a try, at least.

 

mike 

[Son of Marty]

Like Mike said, also take a small (dental) pick and scrape between the commutators.