Belts - Cogged or Not

It does work but in reality it was a great marketing gimmick, and I worked for them, but it really was great marketing with a proven advantage you could look at.   

Bottom cog belts allow for flexing around small pulleys while building less heat so bottom cogging is a good thing also.

 TOP CORDING is another subject, you put the cording at the top because it is the widest point so you get the most cording and the most strength in the belt.  Without the cording a belt will just stretch forever till it breaks.  A Top Cord belt is strong enough to lift your entire engine without stretching.

Now for a mind blower, some modern cars are built with no belt adjustment at all.  This is to save weight.  To allow this Belt Manufacturers invented a Stretch to fit belt so the new cording is flexible and will stretch and you tweak the belt over the pulleys and it snaps into place.  Goes against everything I was taught 40 years ago but there you have it.  Constant change.

Their numbers were Dayco 15405 (industry standard number 11A1030) for the alternator belt (40.5 inches .44 top width and 5/16 depth)

And Dayco 15460 (industry standard number 11A1170) for the raw water pump belt. (46 inches .44 top width and 5/16 depth)

They're both top cog belts and work just fine.

You can use those industry standard numbers to find equivalent size belts from all kinds of belt outfits in about any price range you want.

Here's a picture of a Dayco 15405 in a Mando alternator pulley

Height in the pulley is just right.

It might even cross reference to your numbers for Gates and NAPA

One thing to know, if you look at the fan belt and the main cording is in the middle of the belt buy another type.  Quality belts all have the cording on the Top of the belt.   Running that cording at the top is the widest point so the belt is the strongest.   The cheap fan belts all have cording in the center of the belt because it cost less to produce them.  Even Dayco, Gates and Goodyear or Napa can sell you the cheap center cord belt also as the price line but quality belts will have top cording.

Sorry the picture is sideways, not sure why.   Note:   A:  shows the cording,  B: is where the belt should be virgin rubber for friction.  C: is where thin cording is usually woven into the rubber to help the belt slip quietly when under loads, like when your AC kicks on, the belt allows slip while the AC gets up to speed with the engine.   If the Cording is in the B section it is a junk belt.  They build them that way to cut price, it is a inferior design but they are out there and cheap to buy.  They just do not last.   Buy a Premium Belt with Top Cord support and you are done for the life of your boat, OK, good for a long time.

I want to have a spare in the boat anyway so whichever I use, the other will be a spare.  It was $24.29 at a local Napa store.  Looking this morning I'm not as sure the 15/32" won't ride a bit too high, the 13/32" is flush, not riding too low.

In another thread when a guy asked about what he could get for belts to get him through the weekend, the suggestion was get an auto parts store belt and run it, order the Nautique specific set later and install but he'd be able to "get by" for the weekend.  I'm not so sure I'll buy any more of the Nautique belts, am wondering if a set of properly sized Gates cog belts are not a better option.

Well adding to the story, my battery is on the way out, alternator working harder than it should, I was getting chirping at every startup for the first 4-5 seconds.  New battery going in tomorrow, and I know exactly what you mean about riding lower in the groove so I'll grab a 15/32 and give it a try.

Humorous side note - I was at Autozone this evening.  I know what people think about Autozone but my local one has treated me well and the counter people are friendly and helpful, plus their rewards add up over time.  I asked for a belt to match the Napa one, she tried to cross reference but it didn't come up on their system.  So she brought me back to the "wall of belts" and said she was shorthanded and couldn't spend the time herself, but if I wanted to search the bins and use their belt measuring tool I was welcome to do so.  I spent about 23 seconds looking before realizing it would be a monumental task with the hundreds of belts they had there and I gave up.

Thanks Mark, very helpful as always!  So if I go with 15/32, go another inch longer?  Or not quite that much?

I kind of think the load on the raw water pump belt is actually significant given it's constant.  I'm just making that judgement by the effort needed to turn it by hand, not sure if I'm right.

On my '98 GT-40 I've always used a set of belts from one of the Nautique parts suppliers.  I found this last time that the alternator belt was difficult to get on even with the alternator at the limit of it's travel.  I was able to get it on barely but tightened it too much, it shredded.  My mistake.  I had the old belt for a spare and put it on so we were able to stay on the water, nice to have spare parts and a few tools to not ruin time on the water.

I picked up a belt with same profile and about 3/4" longer so it would mount easier, it was a cogged belt from Napa, a 7400 which is 13/32" x 40 5/8" OC (10mm x 1031mm OC).  It cross references to a Gates that is just 6mm longer, basically the same belt.  Both are cogged.

I see no reason not to run a cogged belt, but then again the OEM replacements are solid.  Anyone have an opinion on this?  The slightly longer belt fit perfectly, easy to mount and tightened with plenty of clearance to the fuel filter housing.