I have a 2000 V6 F150 and replaced my alternator in about five minutes
and now have been trying to re-install the serpentine belt for
about 6 hours. How do you grab the tensioner pulley ?

Also I selected the 130 amp new manufactured alternator at Advanced
Auto thinking the 130 amp might be somewhat of an upgrade to my
original Motorcraft Alt and after several hours I also discovered the
pulley on the new alternator is about a quarter inch larger in diameter
than the original alternator. I wonder if I should compensate with
a half inch longer belt or try to get the same one on.

In any case I cannot find a way to grab and move the belt tensioner
to allow me to reinstall the belt around the alternator. How do
you guys do that ? ? ?

Are there any pictures anywhere on how to move the tensioner to create
slack when reinstalling the belt ?

 

Is their something special about the V6? I don't have one... but I did change the belt recently on my '97 4.6L. On it, you use a 1/2" drive square to engage the square hole in the tensioner arm. I can't get a good shot at it with my 1/2" breaker bar, so I use my Sears Craftsman #941831 Serpentine Belt Tool. It has a long handle, and an arm that can be attached to it at different angles via a splined hole in it. So it can reach into places that I can't get a straight shot at. It also has a bunch of fittings for different vehicles that can be put on it. But for the 4.6L V8, just the handle and the arm does it, as the arm has a 1/2" square drive on the working end of it.

If you can slip the belt on over a smooth pulley as the last step, that can help, as the alternator pulleys have the grooves, and trying to slip a tight belt onto a grooved pulley is real tough, can damage the underside of the belt, too. Yeah, a slightly longer belt would help, as long as it will still be in the tensioners proper pull range. Some tensioners have line marks on them by the twisting part, shows where to stay within for proper operation.

For tensioners without a square hole in the arm, then a socket that fits the pulley bolt on a breaker bar, or suitable fitting selected on a Serpentine belt tool as above, does it.

Expect to use a LOT of muscle! And watch those fingers!

 

Ok the suggestion of a breaker bar and socket on the pulley nut
was the magic solution. I jacked up the truck and cut a 1x2
piece of wood that had one end on the floor and and the other on
the handle of the breaker bar and as I lowered the jack the stick
pushed up on the breaker bar from below and I was able then
to thread the belt on the pulleys considering the slack that was
now created by pushing the tensioning arm up with the stick.
Thanks for the suggestion.

 

I noted you did not address the larger pulley on the replacement.
Should put the original one on the new alternator.
If not the new alternator will run slower and may cause an issue at idle with lights, Fan and A/C due to lower output from slower rotation speed.
Good luck..

 

I was thinking the same thing... The 1/4 inch smaller is probably about 10%.. If you are on the road most of the time, running 1400- 2000 RPM you should be OK. If you spend a lot of time at idle with the AC or BOOM BOX on, I would change it. Smaller pulley is more output

 

The larger pulley in this application largely defeats the benefit from a larger capacity alternator at idle and low speeds.
Good luck.

 

Nah. We/you cannot know that. There is a difference in 10 percent rotation
speed plus or minus a percent. We dont know definitively what the alternator
output curve of either the original or the replacement is .... further unless you
are using/drawing more current by use of electrical items, the voltage regulator
will place limit on output anyway. I just somehow thought that getting the
larger amp alternator (135 amps vs 95 amps) could result in a lower overall
load and hopefully it will last longer. It was only approx 15 bucks more etc.
Now assuming it takes more torque to spin a higher capacity alternator,
the 10 percent slower rotation speed would also equate to 10 percent less
torque to spin the alternator..... maybe a near swap to not lower engine
efficiency etc. Anyway I figured only an eighth of an inch in extra tensioner
travel to accomodate the new larger? cap alternator. I never new how
much the original Motorcraft alternator output was in the first place ? ? ?

Bottom Line is if the retailers sell this alternator with a quarter inch larger
diameter pulley by the thousands ..... for years.... it must be working out
all right. If I had a special need for large current draws during the idle state
( like if I had a ton of exterior lights or was running an 110v inverter for
construction work etc ) I would change out the pulley and maybe even seek
a slightly smaller than original pulley size.

 

hey Scott, your 'assuming' an awful lot, then ...... telling me I can't know!
Have you saw how many times high performance smaller 'crank' pulleys have been installed in place of stock sizes and cause charging issues, all for vehicle performance gain without regard for side effects of all driven accessories?
The OEM sizing for pulley is done to meet the best overall conditions the vehicle has to operate over.
That includes all electrical power under the worst conditions of idle and electrical loads of night time lighting, A/C-heating and accessories that are normally supplied with a vehicle equipage.
Hence this means a certain minimum Alternator RPM at idle and starting and even battery sizing enters into the equation.
You may get away with the larger pulley but don't think for a minute it will have no effect.
First hint will be the headlights and other lighting brightening up when you raise off idle speed. That would tell you the alternator is not rotating fast enough regardless of the regulator performance.
Battery recharge after starting will take longer but you can't see that happening except the effects of it.
I fully understand how regulation works as well.
This is now a technical debate I happen to have expertise in.
You want to keep going on with your assumptions?
Do what's right and place the original size pulley and get the gain your after.
.
BTW, a 10% reduction in rpm at idle is .1 x about 750 rpm = 75 rpm or equivalent to an idle of 700 rpm.
It depends on where the particular alternator falls out of regulation and ability to output enough power to stay 'ahead' of the system to has to supply without falling back on the battery. This is where the issue comes from.
Good luck..

 

I am not saying you dont know how to add up numbers. I am saying you dont
have the numbers to add up so you CANT POSSIBLY know. Forget the goofiness
with assumptions and your PHD in the subject though I do appreciate your interest
and input. Sure your arguments as to how the electrical system "can" function are plausible but you DONT have the output curves and so your guesses are as good as mine. All I am saying is over the long haul with a large commercial organization if there were repeated problems and warranty issues I think they
would have corrected the problem by now. Dont you think any company with thousands
of stores and major volume could easily procure a pulley of identical size if it seemed
appropriate? No, I dont have the output curves either but I am betting on long term
experience of the retailer. Further the gain I am after is "reliabilty and longevity"
Ten percent less RPMs could mean ten percent longer wear life. I am after all
just replacing a 15 year old dead OEM alternator.
Since we are both "betting" here.... the argument would seem to be which circumstances
affect the "odds" the most and the the main goals. Success could be defined in different
ways .... maybe higher output alternators that are run slower last longer than lower output alternators that are run faster. Nearly everything since the industrial revolution
(all things being equal) lasts longer at a lower percentage of max power continuous operation. Yes Yes I concede too low a power could cause problems in other areas.....
I'll let you and everyone know if it that happens.

In hindsight, before I installed the new alternator, I wish I had them put the new
one on a testing bench to record output at various rpms so I could create my own
output curves. Then I would have to find a way to get a new Motorcraft OEM unit
with smaller pulley to test on the same testing equipment. Considering I dont anticipate
any long term idling situations where 700 rpms vs 770 rpms could make a difference...
the issue is pretty much moot except where others might similarly need to replace
their dead OEM alternator.... and then confronting you with a high and mighty "right"
thing to do.

 

Ya Ya.
Have a good day.

 

The problem I foresee is since you had to put so much force on the tensioner to get the belt on, either the tensioner (spring or bearings) will fail early, or the bearings in the alternator will fail early. It shouldn't take that much force to get a belt on. I usually use a regular size ratchet, and as mentioned, put the belt over the smooth idler pulley last. I only use a breaker bar in situations where I cant get enough leverage with a ratchet. Swapping the pulley would have been my first choice as soon as I noticed a difference, but I would have researched it first by asking a alternator/starter rebuilding shop. If it needed the bigger pulley, the next size up belt (usually 1/4" bigger) would be purchased. I bought the 200 amp alt for my 5.4 and had to use my old pulley because the new one didn't have one at all.

 

I agree 100% with all of this. The other thing to keep in mind is the tensioner will be putting more tension on the line as the spring is progressive the further it loads up. That will pull on the entire belt drive pulleys more then they were designed to take. Not saying they can't take it but I wouldn't want to find out with smoked water pump/pw steering/idler/crank bearings.

Instead of arguing about curves with assumptions why not just swap the freakin pulley and put the right one on it?