Slotted Belts?

[riversidevair]

I've had the '65 Sport Sedan for a couple of years now, but I'm still a novice! Only prior Corvair experience was occasionally driving a pristine '63 Monza sedan (102hp) that my dad had purchased from an elderly neighbor in the mid-60s. Styling of the '63 was elegant, clean and functional. The roof line was a good downsizing of the big GM cars ("Honey, I just shrank the Invicta"). I liked that car so much that when I was finally about to finish grad school in '68, I visited a big Chevy dealership in Glendale, CA, asked to see and perhaps drive a new Monza. I was quickly sent away with an armload of unwanted Chevy Nova literature. This '65 was located through an online dealership in North Carolina, has been a real pleasure to own and drive. Even my wife approves. The forum, corvaircorsa.com and the great vendors have helped a lot.

The car has fewer than 20k miles. Along with the chrome air cleaner cover (purely vanity) and the Dutch-made 7.00-13 radials, one of the relatively few non-original bits and pieces is (not surprisingly) the fan belt. From the forum, I find that the tension is about right (using the alternator "slip" test). Everything works and sounds as it should. But the belt is the slotted or notched type. It's noticeably wider than the spare that just arrived from Clark's. It doesn't seem to be seated completely in apex of the V-grooves in the alternator and crankshaft pulleys, so that it lies just about flush with the outer edges of those pulleys. On the other hand, I've read that slotted belts flex more freely than other belts, might run cooler and longer.

Any compelling reason to swap out the slotted belt ASAP? Or is it OK to run it a while longer, since there isn't obvious slipping or worse?

Thanks.

[cad-kid]

Great photos!
-Like anything else there are several opinions about belts. I personally run the Clarks type of belt. From what I have learned, the wider belts are not a good choice and could toss easier. I run my belt a bit on the loose side but it tightens up when the engine gets hot. 7 thousand miles and no issues yet.

[bbodie52]

It has been several years since you last posted on the Corvair Forum. Are you still driving the Studebaker President Speedster, Golden Hawk, and Avanti R2????



The two belts Gates lists for the Corvair includes a notched heavy-duty belt for an air conditioner unit. Clark's offers both styles. If your notched belt is in good condition, does not slip and you are carrying a spare belt and tools to replace it if it ever flips or breaks, why worry about it? If the shoe fits...

The 1964 and later Corvairs were fitted with a lightweight magnesium fan and a pair of belt guides. The light fan greatly reduced stress on the belt because it tracked engine speed changes much better. The older, heavier steel fans stored more kinetic energy (like a heavy flywheel) and the belt had to do more work to control the fan as the engine crankshaft speed changed rapidly (as in accelerating/decelerating and shifting gears).

These are the specifications for the belt recommended by the Gates website...

Part # 6597

Product Description
6597 SPECIAL APPL BELT

Product Features
Belt / Sprocket Specifications
Angle: 38

Outside Circumference (in): 57.00

Outside Circumference (mm): 1450

Top Width (in): .44

Top Width (mm): 11

Product Attributes
Application Type: Passenger Cars and Light Trucks

Category: Classical Section Wrapped V-Belts

Notched: No

Section: HC47

Clark's offers both belt types...

[Jerry Whitt]

The real test is in the v groove of the alternator and crank pulley and the pulley on the fan. The width of the belt tends to wear over the miles and this in turn causes the belt
to become more narrow, and then fitting lower in the groove, and then loose friction. Ideally, the top of the belt should be near the top of the alternator groove, and top of the fan pulley groove and crank pulley groove. These 3 are usually about the same, but the adjuster pulley is quite often a little wider, and the belt will ride a bit lower.

I have had good luck with slotted and non slotted. Most of the brand name belts are better quality now, than in the 60s.

There is a tool, called a "fan belt tension tool" that can be used to check tension if you have doubts about your guesstimates. Some parts houses have the tool, as do some
of the traveling parts trucks.

[riversidevair]

Thanks for all this technical information.

Yup, the other cars remain part of the family. I've had the Golden Hawk for over 47 years.

Wish I could say the same for the white '63 Monza mentioned above. After a couple of years, the car flipped its first fan belt and began to drizzle oil on the rear grille, all in the same month, probably early '68.. It was gone quickly. My dad was not a patient man. I liked to polish the '63 sedan with something called Classic Car Wax, rather liked the soft sheen of the old DuPont acrylic lacquer. The Regal Red '65 was repainted by prior owner about 15 years back. It's obviously clear coat... beautiful, but not quite the same, As far as I know, the older paint formulations are long extinct. Believe the mag-style accessory wheel covers were added about same time as the repaint.

It has been several years since you last posted on the Corvair Forum. Are you still driving the Studebaker President Speedster, Golden Hawk, and Avanti R2????

[riversidevair]

Using Brad's helpful data regarding the recommended Gates #6597 belt, I find that the specified 0.44" top width is at least as wide as the belt currently on the car. It's the Clark's C5790 that's noticeably narrower than either. I obviously worry too much! The new Clark's belt will take its place as a spare alongside their modified wrench.

Thanks all.

Gil

[davemotohead]

6597 is the wrong belt, too wide and will ride up the pulley's, 3v-560 is the correct belt.

[riversidevair]

Thanks, Jerry.

The chassis shop manual specifies a belt tension of 75lbs +/- 5lbs for a new belt, 55lbs +/- 5lbs for reinstalling a used one. Sound about right? I've never used a tension gauge, so I'm not sure how this translates into typical back yard methods. The manual implies a fairly significant change in tension as the belt wears.

I shopped on Amazon for one of those tension tools last week, before I realized that it's likely one more gadget I might acquire, use once, file away.

Gil

The real test is in the v groove of the alternator and crank pulley and the pulley on the fan. The width of the belt tends to wear over the miles and this in turn causes the belt
to become more narrow, and then fitting lower in the groove, and then loose friction. Ideally, the top of the belt should be near the top of the alternator groove, and top of the fan pulley groove and crank pulley groove. These 3 are usually about the same, but the adjuster pulley is quite often a little wider, and the belt will ride a bit lower.

I have had good luck with slotted and non slotted. Most of the brand name belts are better quality now, than in the 60s.

There is a tool, called a "fan belt tension tool" that can be used to check tension if you have doubts about your guesstimates. Some parts houses have the tool, as do some
of the traveling parts trucks.

[riversidevair]

I seem attracted to machines with funky and somewhat demanding belt drives. Packard Hawks were factory-equipped with the McCulloch VS57 supercharger. The blower is driven by a really stout slotted V-belt. The idler spring tension setup is rather obvious. After I purchased the Hawk in early eighties, a mechanic (and friend) well versed in Packards and Studebakers tuned it. He found little boost from the supercharger, even after completely dismantlng it a couple of times. Both of us had failed to notice that the V-belt looked right, but it wasn't.

Notice how deep the belt lies in the groove for the blower pulley? The VS57 featured a rather clever variable ratio pulley. At low engine speeds the groove is quite wide, reducing the effective diameter and increasing speed of the blower for better response. At cruising speeds, the groove narrows markedly, the belt moves near the top of the pulley for decreased boost and very good economy. But a moderate push on the accelerator triggers a solenoid, quickly opening the v-groove and reverting to a ratio maximizing blower speed. Boost was limited to only about 5psi, but it made a heck of a difference if that variable ratio feature wasn't functioning (like the time I accidentally unplugged that tiny wire for the solenoid). If the belt doesn't have just the right dimensions and side angles, the system is defeated.

Car is one of 588 built, found it almost 35 years ago in a Hemmings listing which led to a consignment lot in Venice, CA. Seller was somebody named Donny York, long a member of a singing group called Sha Na Na..

[funvairs]

I have seen the 75# belt tension spec before in a service manual. The 1961 service manual calls for 3/8 deflection between the blower and idler pulley at 15#. It works for me and passes the drag test. That is in chapter 7-4 section 6

[mart]

I wish I had kept my Studebaker, completely trouble free....unlike something I could mention