Flipped my first belt

[mcgasman]

My belt came off today. and I'm not even on the road yet. bummer. I guess i need a lighter fan.

[bbodie52]

You did not mention the year of your Corvair. Prior to 1964, Corvairs utilized a blower fan that was manufactured from steel components and were somewhat heavy. In 1964, Chevrolet replaced the heavy steel fan with a magnesium blower that was much lighter. One of the primary causes of fan belt damage was a "flywheel effect", in which the rotating fan "fought" changes in engine speed. As the engine increased or decreased the speed of the crankshaft pulley, the blower fan behaved something like a flywheel, and resisted momentarily the speed changes of the engine crankshaft pulley. This placed excessive stress on the fan belt and sometimes caused it to flip over the edge of the pulley. In later models, fan belt pulley guides were installed next to the main fan pulley and on the idler pulley. The combination of the lighter magnesium fan and the pulley guides help to reduce occurrences of flipped fan belts.

If a belt does flip, you should not reuse it. Fan belts contain internal wire strands to provide the belt with additional strength and restrict the amount of stretch. If the belt flips, some of those internal steel strands may be damaged. The belt may appear fine when examined, but it is likely that it was weekened internally when it flipped over the edge of the pulley. Reusing a fan belt that has flipped will likely result in another failure fairly quickly. Most Corvair owners carry one or two spare fan belts and the necessary tools to change the belt. If you have an early Corvair with a steel blower fan, you may want to consider purchasing a used magnesium blower to upgrade your car and reduce the possibility of fan belt damage.

Also, when you replace a fan belt you should rotate the idler pulley and blower pulley by hand to try to detect any roughness or excessive resistance that might indicate a worn blower bearing or idler bearing. Finally, when you adjust the belt tension, a belt that is too tight can be as bad as a belt that is too loose. Excessively tight belts can cause premature wear of the bearings that support the idler pulley and the blower fan. It is actually desirable for the belt to be able to slip slightly as engine speeds change. The belt is tightened correctly when you can press on the alternator cooling fan blade with one finger and obtain a slight amount of slippage by the pulley against the fan belt. I have attached some additional tips for fan belts from the Clarks Corvair Parts online catalog.



The pictures below illustrate the difference between Corvair cooling fans that were utilized in different model years:

1960 Steel Corvair Blower (Fan)

1961-1963 Steel Corvair Blower (Fan) 2

1961-1963 Steel Corvair Blower (Fan) 2.jpg (60.34 KiB) Viewed 4900 times

1964-1969 Magnesium Corvair Blower (Fan)

1964-1969 Magnesium Corvair Blower (Fan).jpg (6.05 KiB) Viewed 4900 times

[cad-kid]

Bummer about your belt - was it a new belt from a Corvair vender? or a belt that came with the car? At least you can be thankfull the belt didn't decide to come off while on the road.

Here's a helpfull tip - create a signature and put your first name (or what ever you want folks to call you) in your signature - along with your car info. That way when we respond to your posts we don't have to go digging in earlier posts for basic stuff.

[UNSAFE]

Welcome to the club -- next we'll teach you the secret hand-shake

Lotsa stuff already written about belts but in a nutshell --

The belt must be exactly the correct length or it will alter the approach angle at the idler pully.

A thin belt that rides farther down in the groove is favored by me.

The grooves should be smooth without rust or corrosion .

The belt guides must be adjusted properly and the belt should not be overly tight.

Most important IMHO is to coat the belt and pulley grooves with silicone spray and give a new belt a little time to wear in before revving it too much.

[mcgasman]

Thanks Guys, cad-kid,Brad, That was funny unsafe. The belt looks short. i did pickup a LM fan. What else will I have to change out. I figure I'll grab a new bearing and belt from Clarks. Hey unsafe, thanks for all videos, there great.

[bbodie52]

The magnesium blower is probably the most-significant improvement to help reduce excessive fan belt stress and to increase belt life. A high-quality belt like those offered by Clark's on page 14 of their online catalog is also very helpful, as are blower and idler bearings that are in good condition. A properly adjusted belt with correct tension will prolong the life of the belt and the blower and idler bearings. The belt guides are also available on page 14. The idler guide is easy to install and will help prevent belts from flipping over the idler pulley. It is more difficult to install the belt guide that sits next to the blower pulley, because the older top shroud lacks the mounting points for that belt guide. I'm not sure if adding that guide would be worth the effort. The cumulative improvements realized by all of the other steps mentioned is likely enough to provide you with reliable belt performance. The last common enhancement -- the addition of the blower belt guide -- may be subject to the law of diminishing returns, in that the difficulty of properly mounting it on a shroud that lacks proper mounting points, or the added cost of buying the correct top shroud with the belt guide, may just not be worth the expense.

http://www.corvair.com/user-cgi/catalog ... IN&page=14

Clark's offers a spring-loaded Otto Parts custom idler pulley that supposedly helps reduce thrown belts (Page 15), and Corvair Underground http://www.corvairunderground.com recently reintroduced a newer design spring-loaded belt guide and pulley that was out of production for a while due to the death of the designer/machinist. I don't have personal experience with either of these, and have not read any customer feedback about their effectiveness.

[Richard1]

Why re-invent the wheel. I've never thrown a belt on my 60.
Right belt (length and width)
Only so tight as to still be able to turn the generator or alternator fan by hand
Right pulleys that come up high enough over the belt
Right alternator or generator mount
Nothing rubbing

[UNSAFE]

Some people just get lucky with belts

Problems with belts are documented in many magazine articles in the media section starting back in 1959.

It was so bad in the earliest models that guides were added and the finally went to the lighter fan but it still happens.

The inertia and momentum of the heavy fan is too much for the belt to keep up with . I never had an early but I ran into the
problem when using one of those silly incremental fan pulleys some years back. I could count on loosing a belt everytime I
wound it out and shifted.

When I loose a belt it is usually at over 6500 rpm . Last year my belt made it thru multiple drivers at the track during the convention and then lotsa
around town rodding and then thru most of the Iowa fire & Ice track event with 3 drivers and then it finally came off . I put a new one on and it quickly flipped off as did the next two.
These were the same Otto belts each time and I was using silicone. I strongly believe that the belt needs to be broken in to create a bit of a glaze before too much revving.
Next time I hope to pre-run a few belts ahead of time.

If you haven't watched any of the Bob Benzinger videos that I put on youtube you might find them interesting . Bob was a Corvair engineer and talks about some of the belt problems
at the Flagstaff convention back around 2002 . Some interesting and humorous stuff . Here's part 1 of 4.

http://www.youtube.com/watch?v=7usPZtP97PM" onclick="window.open(this.href);return false;

[bbodie52]

Why re-invent the wheel. I've never thrown a belt on my 60.

1960 Caveman Corvair owners spend a great deal of time defending their 1960 Corvairs. They often discount any engineering changes made after 1960 as non-essential, and inconsequential, in an effort to defend their favorite, and in many ways unique model year. But the changes designed by Corvair engineers to increase fan belt reliability were real and valid. A good-quality belt that is adjusted properly will help a lot. A lightweight magnesium blower will add more reliability, as will the belt guides. You will have to decide if the cost and effort needed to upgrade to the later design is worth it to you.

[flat6_musik]

Flipped my first belt.

Sounds like a rite of passage for owning a corvair!!

[Richard1]

Racing is one thing, but normal use is another.
But in any event, I always like to start with the basics.

[jennirw]

I flipped my 1st and only belt in the early to mid 70's on a low milege 66. I broke my 1st belt 2 weeks ago. I have been driving Corvairs since 1962 and the is the extent of my belt problems. The one I broke was a used belt I got with the car in 2009, I drove that car 13,000 miles last year. I am thinking that the repatation the Corvair has for throwing belts is overblown.

[mcgasman]

I agree with you jennirw about belt flipping being over blown, but some times, with the wrong belt, sh!t happens. Heck i laught when it happened. Clark it sending me 2 belts with my new interior. After i get done with the springtime yard work, i will tackel the fan job. I just wonder if it well fit under the EM shroud? Thanks for all the input guys, happy motoring

[cad-kid]

I strongly believe that the belt needs to be broken in to create a bit of a glaze before too much revving.
Next time I hope to pre-run a few belts ahead of time.

Great tip! Since I have two new belts I will give breaking them both in a shot. Besides it's always good to practice changing a belt.

[bbodie52]

I agree with you jennirw about belt flipping being over blown, but some times, with the wrong belt, sh!t happens. Heck i laught when it happened. Clark it sending me 2 belts with my new interior. After i get done with the springtime yard work, i will tackel the fan job. I just wonder if it well fit under the EM shroud? Thanks for all the input guys, happy motoring

The feedback from customers and dealerships drove the cooling system redesign by GM engineers. The changes were implemented for a reason -- driven by feedback from thousands of owners and mechanics in the field. I would have some confidence in the validity of these engineering design changes. GM did not go to the expense of making the changes without cause. Fan belt design also improved over the years. The cumulative effect of the engineering design changes and improvements, and in belt technology, led to increased reliability -- even on the early cars that did not receive the later fan designs and belt guides. They did receive improved fan belts.

The top shroud was not changed to accommodate the new magnesium blower, so fan clearance should not be an issue. The only change to the later shrouds was the addition of mounting points for the newly added belt guide.

[jennirw]

One of the reasons I may not have had much belt trouble is that I have only owned three Corvairs with manual transmissions - 61 Corvan, 63 Spyder Coupe & a 64 Rampside - I have driven 10 different Corvairs as daily drivers - seven with powerglides.
I owned nine more Corvairs, four were parts cars and four I fixed & sold and one is being restored.