Differences Between Alternator Serpentine Pulley Kits

[jviss]

There seem to be two 'brands' available, the Balmar and the "PK." Are these the same thing, in different colors with different brand names? Are there any differences of note?

I'm looking at them for a Westerbeke 38B. The Balmar kit is part number 48-WSP-18, and goes for about $450. The PK is part number PK-38B and costs about the same.

Both come with three pulleys, bolts, Tef-Gel, Loctite, a belt and a spare.

Thanks,

jv

 

[Bob S]

I don't think there is any difference between them that should concern you. Either one will make a huge difference. I machined my own for an M25xp on my C30. I used a K6 belt (automotive) but these I believe are a J10 (10 grooves, industrial) which should run a bit smoother but more expensive to replace. Automotive belts are produced in a much higher volume. I was lucky enough to design it using a Honda belt that could be bought at any auto supply house for $8 - 9.
Are you using an Electromaax or a Balmar alternator? The only thing I would check before buying is the alternator shaft. The Leece Neville 8MR that I had had a shaft size of .627. If the sheave isn't the correct fit and aligned correctly it could fail. Don't ask me how I know this.

 

[jviss]

Thanks, Bob. Interesting. I don't know the shaft size on mine. It's an Amptech that the surveyor guessed was 125A. I haven't been able to find a shaft size so far via a cursory search of the 'net.

 

[Bob S]

Pain in the butt, but remove the existing pulley and use a micrometer.

 

[Gunni]

Both those serpentine belt kits are packaged for the particular alternator you are installing them on - Balmar or Electromaxx. I believe Amptech relies on the old twin v-belt technology.

 

[jviss]

Yes, Gunni, but the idea here is to replace the alternator pulley with a new one. They aren't specific to Balmar or Elecrtomaxx, should work with a universe of alternators, assuming, as Bob points out, the shaft diameter is correct, or can be sleeved, it too small, I imagine.

 

[Maine Sail]

Yes, Gunni, but the idea here is to replace the alternator pulley with a new one. They aren't specific to Balmar or Elecrtomaxx, should work with a universe of alternators, assuming, as Bob points out, the shaft diameter is correct, or can be sleeved, it too small, I imagine.

The "PK" is an Electromaax product and is technically in patent violation with the Balmar/AltMout patented product. Balmar and E-Maax partnered together for a short period of time but the bridge was burned and Balmar parted ways with E-Maax.

Balmar has tremendous customer service, google search for Electromaax customer service.. I would urge you to DO YOUR HOMEWORK before buying from them.

I have one article on my site that featured E-Maax products and I had so many customer service complaints that I had to issue a customer service warning at the beginning of the article.

I used to be an Electromaax dealer but I no longer sell their products. I won't say more than that on-line. John always treated me pretty fairly but I can't say so much for some of my readers and customers who bought direct from them.

Trying to fit an AltMount or E-Maax kit to an AmpTech may require some shimming, machining or alignment work. These kits are designed for the Balmar 6 series or AT series or E-Maax copies of the Balmar. They were not designed as a direct fit the old 10DN case Ample, Balmar or Amptech HO alts. The alt pulley will fit but may not be a complete "drop-in"... Keep in mind that these 10 groove kits are not standard off the shelf pulleys and even the alternator pulleys are a fully custom made product. I normally sell that Balmar kit for $449 so the price you are seeing is quite good.

 

[jviss]

Thanks MaineSail. I was attracted to the PK kit only because an online vendor, marinesmartenergy.com, has it on sale for $407, free shipping. The Balmar kit is $453, also free shipping. The $46 extra might be worth it for customer care, eh?

 

[jviss]

I just chatted with an Amp Tech customer support person, and their alternator shaft size is 17mm.

The Balmar installation docs say "The AltMount alternator pulley can be used on any alternator with a 17 mm rotor shaft. "

So, good!

 

[Maine Sail]

Thanks MaineSail. I was attracted to the PK kit only because an online vendor, marinesmartenergy.com, has it on sale for $407, free shipping. The Balmar kit is $453, also free shipping. The $46 extra might be worth it for customer care, eh?

E-maax has gotten such a bad reputation they simply created another storefront. It's the same company....

You could also click the signature link and help support the guy who just helped you out.. (wink)

 

[Maine Sail]

I just chatted with an Amp Tech customer support person, and their alternator shaft size is 17mm.

The Balmar installation docs say "The AltMount alternator pulley can be used on any alternator with a 17 mm rotor shaft. "

So, good!

Most of the small case Delco based alts are 17mm. This does not mean the offsets are the same, so some machining or alignment or spacers etc. may still be necessary. Balmar's old 91 series, also a 10DN frame, used a "dished fan" and the 10 groove pulleys still fit the old Balmar 91/10DN frame with very minimal to no fuss. The Amptech, depending upon year, may or may not use a dished fan. Most are a flat fan with a spacer behind it. The nub on the back of the E-Maax or AltMount pulley may need to be machined off and it is pretty difficult to tell until you have the pulley in hand...

 

[jviss]

Gotcha, thanks. I vaguely recall that, when I put a heavy-duty pulley on my old boat's alternator. I have a collection of fans, spacers, etc. Worst case, I have a lathe, and I'm not afraid to use it! It will just be a pain going back and forth to machine parts.

 

[jviss]

You could also click the signature link and help support the guy who just helped you out.. (wink)

The bed-it link doesn't work. Can you give me the link to the pulley kits, please?

 

[Maine Sail]

The bed-it link doesn't work. Can you give me the link to the pulley kits, please?

It's the store link on my web site; marinehowto.com

 

[Hayden Watson]

I don't think there is any difference between them that should concern you. Either one will make a huge difference. I machined my own for an M25xp on my C30. I used a K6 belt (automotive) but these I believe are a J10 (10 grooves, industrial) which should run a bit smoother but more expensive to replace. Automotive belts are produced in a much higher volume. I was lucky enough to design it using a Honda belt that could be bought at any auto supply house for $8 - 9.
Are you using an Electromaax or a Balmar alternator? The only thing I would check before buying is the alternator shaft. The Leece Neville 8MR that I had had a shaft size of .627. If the sheave isn't the correct fit and aligned correctly it could fail. Don't ask me how I know this.

Good day Bob. You wouldn't have drawings for the hardware that you created would you. I have a couple of machinists in the family.

 

[Bob S]

I'm not sure I have them anymore. They were in a binder that went with the boat when I sold her. All the info needed can be found in a machinist handbook. your alternator specs (max rpm and performance curves) will dictate diameters. The trick is in the alignments. I took the old pulleys and measured their ceterlines to their mounting faces and used that to machine the serpentine pulleys. Because the cast iron crankcase pulley on my boat was in bad shape I removed it and turned the OD to a diameter for a snug fit to the new pulley. Not only is the alignment critical but any runout / concentricity is very important too.
To be honest I will be buying a setup from Compass Marine on my new to me boat. The time it took me to do a one off wasn't worth the $450 and I had the 6061-T6 aluminum bar stock and had them anodized at no cost.