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I purchased a Leece-Neville 230 amp alternator to replace the wimpy stock one. Installation was pretty easy, with upgraded cables as well, until I went to put the belt on the new alternator.
I found that I can't get the belt over the 3" pulley (OE size)-- it's about 1/4" shy of making it over the pulley, even with the tensioner fully extended. The difference in shaft height between the alternators must be no more than an inch. I didn't expect that to make a difference, but apparently there wasn't much slack in the belt.
Were there multiple belt sizes from the factory on these trucks? Is it just expected that with a case size upgrade comes a need for a larger serp belt, or did someone replace a belt at some point with the wrong size? Should I increase the belt size, or go with a 2.3" pulley and overdrive it while I'm at it?
Here ya go. 81265 is the normal size. This list should show you what you need
I think the first line is inches length. The second is mm's. There's a fairly big jump to go bigger. Might not work for you tho. Hope it helps. I've had to mess with this before from aftermarket hyd pumps that I've seen on trucks.
Thank you, I'm just concerned that replacing a belt of unknown length with an 81265 might end up being the same size, and thus too short. Is that the known size for the 6.0 with the factory large-case alt?
EDIT: I did find that most auto-parts stores show 81260 as the OEM belt for this, so I suspect that is why my belt is too short.
TooManyToys, when you say "close", do you mean that there's almost no additional room on the belt at all? I'm thinking my belt is not stock, then, and it needs replacing with 81265. What size is your pulley?
69cj-- I'd like to, but I'm concerned about excessive wear. Plus the higher output should already compensate for lower amps at idle.
I'll throw in another factor though as the belt was a replacement Motorcraft JK81267A at 126 7/8", which is what Amazon and RockAuto shows as the replacement for an '03. It's OE number is 3C3Z-8620-DB.
It's been in place for some time. I used the stock pulley and I remember the belt just making it over the outer ridge. I have the underside pulley they are mentioning and I'm going to play with it in a week. I'm making up videos about out electrical system and that's one of the variables I'm planing on testing. At home I have the calculations between the pulleys and the data from L-N about the output and rpm range this alternator is rated for.
With the stock pulley at idle this L-N puts out 150a while the GPs are still on and when they are commanded off the alternator output drops to around 65a (battery demand dependent) as that is all the batteries will take minus the 15a system requirement. It continues to come down as the batteries charge and at about 30-40 minutes of driving your output will be 15a, supplying the truck (that's with no accessories on).
You also need a 6ga wire minimum between the alternator and pass batt positive terminal in addition to the factory wire/fuse links as they are topped out at about 140-150a, and that wire should be protected with a 150a fuse. There's a battery thread recent where I show a marine fuse that's a good choice. You can go up in that wire size but it doesn't improve your conductivity/voltage drop that much. And if in the deep dark night things go south I can just replace that fuse with a 250a and be on my way rather then trying to get a replacement harness from a dealer the next morning. You should not initially use a 250a fuse as that will not protect the electrical system properly unless your deleting the OE harness.
Your next biggest improvement in your electrical system would be to install a 1/0 cable between the drivers frame ground and the motor. It doesn't do much if anything at all for the charging side of our trucks layout as thats adequate with this alternator (the exception being the output wire noted above), but under the starting load it gets both batteries to work evenly.
I have the same alternator, and a 2005 single alternator, and am using the stock belt. Put the belt all around everything, with the alternator unbolted, tip forward, put on the belt and tip back flat on the mount and put in the bolts, then release the idler pulley tensioner release. It works fine. My brother has an 2004, same alternator, stock belt, no problems. It's not too tight and it isn't going to wear more. Take your pulley off your old alternator and mount to the leech Neville. I had to it came without a pulley. I would recommend a new belt though, the 230 makes her work hard at idle in a cold morning.
I managed to get the belt over the pulley, with much grunting. Part of my issue was that my kickstand was missing, which I'm sure would have helped a great deal.
I used the factory harness and an additional 4ga starter cable with a 200 amp inline slow-blow fuse.
My first symptom of a failing alternator was white smoke at startup and loping. That's when I took a voltage measurement at idle-- 12.2v. With the truck off, I had 11.9v. I discovered the failed alternator on this used truck wasn't even the high-output one from the factory as the build sheet said, but a cheap aftermarket part. IMMEDIATE improvement. Charges at 13.9v now. FICMs really don't like low voltage.
The are self regulated internally and the pigtail plugs right in. You have to provide you own pulley as mentioned above and they give you longer mounting bolts due to the size of the alternator case. I show a stock, 140a and this 230a unit in my upcoming work.
They carry a Ford part number as I've been told as some commercial Ford dealers sell them for their larger weight class 6.0l applications. So does International as I believe other members have talked about here on this site. I've seen retail pricing up over like $700, XDP sells them for about $350, but they come up new on eBay now and again for as low as $250 from some commercial vendors.
I've seen L-N alternators on commercial and transit applications for decades during my career, really huge units. A know a couple of Ford FSEs, and one is a very good friend who deals with emergency services of a large city who swears by these when used on the 6.0L. My verbal info is that they use welded diodes and the unit has two fans internally, so they are building them for heat. For part of my video project I shot a temp scan of the unit after a 35-45 minute run and it only showed 135F. It was daytime with only A/C running prior so not a high load, and with A/C off it was only putting out 15a since the batteries were I believe fully charged. We could play with variables of temp vs amp all day to get different readings, but I'm just stating what I recorded under those conditions. If you go to their site they show a brochure of the the units, Ford part numbers, etc.
But ..... It is way overkill, IMO, for daily driving. I am only using it due to some occasional high load external vehicle connection, and, well, it was free.
Anyway, I'm pretty impressed with the unit coming up from a very reliable Bosch 140a unit. I wouldn't have had a problem getting it for a good price when it pops up on eBay. If I was running big amps, lights or a snow plow I could justify a higher cost. It's commercially designed and built. But Mike in post 9 sounds like he has more long term experience so may have a more informative input.
10-20-2015, 01:37 PM
