75 Alternator Transplant

[MD]

Part 1

Had any problems with the alternator lately? Droopy lights,sagging B+ voltage rail, accessories working on and off? What you need is a high voltage injection from an updated alternator that can handle the current loads put on them from all the high tech electrical gizmos running in cars these days.

Ever tried to get a high capacity (moderately) alternator for an Alfa? Forget it. If you can get one the price will cost you your left nut and a box of postage stamps.

I decided to carry out this conversion using a VP Commodore Australian made Bosch alternator with a 20amp increase in output and replace the existing 65amp unit which is close to 20 years old. Now this is not a job for the faint hearted so if that's you, just look at the prutty pitches and move onto the next topic set.

On the other hand, if you want to have a crack at it, for under $100, you can do a worthwhile conversion.

OK, lets start. I got mine from a local wrecker and checked it had good bearings. I then took it to my auto elec. and got him to test its output and supply a set of new brushes for it. Report is good so we start the conversion.

Unfortunately, Iam going to have to make numerous posts as the website will not allow it seems a long post in one go.

[MD]

Part 2A

The first job is to trim off the the excess material on the bottom mount as it is too wide. It's not possible to change over the front covers as the clamping bolt holes do not line up so you have to use the original front mount. Unfortunately, to get the correct size of cut, you need the original mount on the engine for a test fit as you go so put this job aside for now and come back to it later.

Remove the regulator carefully and replace the brushes having purchased new ones in anticipation. This requires a soldering iron to heat the solder holding the original copper tails in place. Be careful to catch the spring that is inside the housing because as you heat the solder joint, it will release quickly and the spring that pushes the brushes out to make the connection will go west.

Resolder the brushes in reverse order. If you cant do it, either buy a new regulator assy and install that or take it to an auto elect and they will do it for you.

So now you have a checked unit with new brushes.

[MD]

Part 2B

Here's the photos of the combined voltage regulator and the brush set followed by a photo sequence of how to replace them.

[MD]

Part 3

Before you can install the new alternator, you need to take off the original one. Do this.

Disconnect the battery terminals and remove the battery.
Undo all the fixing bolts to the power steering pump, remove belt and move pump out of the way onto battery tray. Remove all bolts holding the alternator in position, loosen off the belt, remove wiring at rear and remove unit. This is easier said then done as the bottom bolt can give some grief. It pays to remove the triangular mount fixing nuts on the side of the sump and lift out the power steering pump rear mount all at the same time.

In the installation I prefer to install the bottom 12mm long bolt from the back of the engine and place the fixing nut in the front for ease of tensioning and refit. You will need to use the bottom mount for a test fit of the alternator modified bottom mount and bee sure it is a tight fit so do not cut off too much to start with and preferably file finish to get the fit.

You will need to install spacer washers between the power steering rear mount and the alternator mount so that there is sufficient clearance for the B+ alternator terminal and it will not short to ground. (See photo)

Once you have the bottom mount sorted, you will need to make a new belt tensioner bracket.

[MD]

Part 4

The Electrics.

The original connection is to the B+ terminal with a 6mm round flat connector and the green wire spade connector to the D+ post.

To convert it over, you will need to make a connection from the "S" terminal on the regulator to the B+ and connect the "L" terminal to the original green wire.

The original loom B+ connector needs to be replaced with one with a larger hole (7.5mm) so it will fit over the new larger terminal.

It is preferable to solder all these connections for minimal voltage drop and avoid loose crimp connections.

Once the modified wiring is complete, the transplant can be installed and everything placed back in reverse order.

A final check of the new alternator is the voltage output while the engine is idling and higher rpms. It should preduce around 14+volts at idle and around 14.2volts at revs.

Best of British Luck.

[OzMidnight]

Is this alternator lighter than the original?

[MD]

Only if you place a jack under it..

[Colin Byrne]

Nice instructions, just one point

It is preferable to solder all these connections for minimal voltage drop and avoid loose crimp connections

.

Whilst soldering produces a fantastic electrical connection it is generally not ideal in applications subjected to high levels of vibration, the solder can wick down the wire and cause a large stress point, a properly crimped connector is the go for automotive use.  By "properly" I don't mean the $5 crimping tool from supercheap!