Re: Delco alternator conversion for the 258

[Matt Haas <mhaas@xxxxxxx>]

Doug,

1) You need to have each end of the mounting bolt boss supported so the 
alternator doesn't wobble. Wobbling will cause problems ranging from very 
short belt life to very short bearing life in the alternator and/or water 
pump. If you don't want to mess with the alternator yourself, Kennedy 
American (http://www.kennedyamerican.com) carries high output Power Master 
alternators that are already machined to fit in the stock bracket (I'm 
pretty sure you can get one from anybody that sells Power Master). The 
Power Master alternator was pretty expensive (about $200 but I think you 
can shop around and find them cheaper) but I was in a bind (bad alternator 
bearings) and Kennedy was there. The "low output" one I have can provide 
about 50 or 60 amps at idle and slightly over 100 amps at higher RPM. A 
stock Delco 10si only produces 65 amps. The only real drawback to getting a 
rebuilt Delco 10si alternator is that it's been long enough since they were 
last made that a lot of the ones you get now aren't rebuilt very well. I 
went through a bunch of them on my El Camino before I finally got a good 
one. The good one was rebuilt by Delco but it had a bad pulley that chewed 
up a belt while I was on Power Tour (a cheap chrome fan fixed that issue).

2) On my American, I simply had to move the top mounting bracket up a 
little for clearance (and to get the upper mounting bolt to fit).

3) Delco 10si alternators are quite a bit bigger than Motorola alternators. 
When I was running a stock 10si, I had about a pencil width between the 
alternator and PS box and it never hit (my motor mounts are also pretty new 
so the engine doesn't move much). With the Power Master alternator, it did 
hit the box and I needed a 1/2" shorter belt to get everything to fit. 
Dayco belt #15360 fit the bill. I was able to get from Kenosha to 
Cincinnati, OH on the slightly too long stock belt but I'm sure it would 
have slipped a lot if it had rained.

One other thing you'll need to do with a Delco 10si is rotate the rear 
housing 90 degrees to make it easier to connect the plug in the side (the 
Power Master alternator is this way already). In the stock location, the 
plug is between the engine and the alternator. All you have to do to rotate 
it is remove the 4 through bolts and it will turn (it may take a bit of 
muscle to move it and you may need to slightly separate the end but don't 
move it back too far or you'll need to put the brushes back in place).

Matt

At 06:56 PM 3/12/2006 -0500, you wrote:
> Hi gang
>
> If the answers to these are on an FAQ or website somewhere, I apologize 
> for taking up the bandwidth. Please redirect me to wherever I need to go.
>
> 1. I bought a Delco alternator for my 1973 258 in the Matador and after 
> reading several websites which show people grinding away the alternator 
> case to make it fit, I am asking why I can't just put the mounting bracket 
> on backwards and use a really long bolt with spacers to give the proper 
> clearance? I did the math and a 7" bolt with two 2" spacers and about 5 
> washers give me the 2" I need on the bolt to mount the alternator. I would 
> have it on except:
>
> 2. My alternator mounting bracket will not clear the rotating fan blades 
> on the front of the alternator. It appears to be too small of a 
> circumference on the front of the bracket. Any ideas for me there? A 
> junkyard part, aftermarket part, or modification of my existing part?
>
> 3. Also, when I was trying to wedge my alternator into the bracket and 
> onto the bolt, there was not much clearance between the power steering box 
> and the alternator. Does anyone have experience with this that they would 
> like to share with me?
>
> Thanks in advance.
>
> Doug

mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1967 Rambler American wagon
1968 Rambler American sedan
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