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Falbelt Video: Crazy Times in the Engine Compartment
Posted by: aircooled ()
Date: September 08, 2021 10:18AM

I thought some here might find this interesting.

I have recently gotten more into practicing heal-toe downshifting, which leads to higher RPM downshifts, which, as many here may know, leads to fanbelt fun times.

I started smelling smoking belt after driving and thought, in my infinite wisdom, that loosening the guides a bit would help... fanbelt mayhem ensued. So, I decide to mount my GoPro in there and do some lighting (having reflective heat shielding on the engine cover helps)

https://youtu.be/ZLYbCYnqyjY

Some crazy stuff going on there. Keeping the idle guide pretty tight seems like a good idea, but I will probably play with some kind of guide for the belt coming off the crank pulley. I might try putting my spring loaded pulley back on just to see what it looks like (they do not help with belt retention BTW)

I find it kind of funny the Corsa Technical Guide (I think that is where it is) has a suggestion to add a guide to the other side of the pulley, which is clearly not where it's needed!

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: isucorvair ()
Date: September 08, 2021 10:24AM

I've taken some "During Autocross" videos of my engine too -its pretty wild. You should see how much an engine moves around with a bad motor mount! Or - Even with the Clarks "Heavy Duty" motor mount!


Eric P.
DeWitt, IA

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: Phil Dally ()
Date: September 08, 2021 10:33AM

Excellent Video...Thank You!!

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: 66vairman ()
Date: September 08, 2021 10:34AM

isucorvair Wrote:
-------------------------------------------------------
> I've taken some "During Autocross" videos of my engine too -its pretty wild. You should see how much an engine moves around with a bad motor mount! Or - Even with the Clarks "Heavy Duty" motor mount!
>
>
> Eric P.
> DeWitt, IA

That's why the LM shifter base slides in the floor, but the outer shift tube is anchored to the engine/transaxle support.

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: Seth Emerson ()
Date: September 08, 2021 12:42PM

Great footage! If anybody really wondered why belts can come off! I would be interested in seeing the same shots with steel (OEM) pullies in place. or with different types of fan belts. It is easy to see why you need the belt guides - - - or a 4000RPM redline! (grin) Again, Nice work.

Seth Emerson

Check my new Performance Corvair Web site: [www.perfvair.com]

Located in lovely San Jose, California

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: isucorvair ()
Date: September 08, 2021 12:54PM

66vairman Wrote:
-------------------------------------------------------
> isucorvair Wrote:
> -------------------------------------------------------
> > I've taken some "During Autocross" videos of my engine too -its pretty wild. You should see how much an engine moves around with a bad motor mount! Or - Even with the Clarks "Heavy Duty" motor mount!
> >
> >
> > Eric P.
> > DeWitt, IA
>
> That's why the LM shifter base slides in the floor, but the outer shift tube is anchored to the engine/transaxle support.

Correct - but my engine 'twisted' 4" or more...lots more than designed for.

Eric P.
DeWitt, IA

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: CoCoCo ()
Date: September 08, 2021 04:24PM

Seth Emerson Wrote:
-------------------------------------------------------
> I would be interested in seeing the same shots with steel (OEM) pullies in place. or with different types of fan belts.

And another one with a Nash Fan as well.
I've always wondered what the biggest influence on belt flap is. Engine pulses, fan changing speed at a different rate, or maybe alternator doing the same thing.

Loved seeing the video, especially with blow-by-blow commentary.

Paul

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: 63turbo ()
Date: September 08, 2021 04:37PM

All that wildness as it enters ( or trys to enter) the idler is what my "apparatus" will take care of... it will be obvious that if it doesnt entirely fix the problem in that one spot, adding another set elsewhere will. Heck of a video!!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: aircooled ()
Date: September 08, 2021 04:37PM

Yeah, it would be interesting to do some comparisons. I am tempted to mount up some of my older, more classic style belts. I even have a non-wrapped toothed one! The belts in the video BTW are all the thin style belts (like Clarks sells).

Has anyone else seen the jumping over the guide behavior? It has happened on this engine a few times recently (after loosening up the guides a bit). Historically the belt would just jump off, so no way of knowing where it was coming off but the idler guide area certainly seems like a prime candidate.

The belt in the first clip was WELL worn. I think it may have been thrown once. It is interesting that it had severe whip on the tension side, while it was much more limited on the second one.

I do suspect power pulses do play into the whipping.

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: jazzworkerbee ()
Date: September 08, 2021 04:48PM

Does anyone know if the Robson Spring loaded idler helps to take up slack on deceleration in any significant way?

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: cnicol ()
Date: September 08, 2021 05:39PM

Wow, that was cool to see. I wonder if the idler belt guide would have prevented the flip?

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: Seth Emerson ()
Date: September 08, 2021 06:50PM

Wasn't the idler guide in place, Craig? I thought I saw it, at least in some portion.

Seth Emerson

Check my new Performance Corvair Web site: [www.perfvair.com]

Located in lovely San Jose, California

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: 63turbo ()
Date: September 08, 2021 06:56PM

cnicol Wrote:
-------------------------------------------------------
> Wow, that was cool to see. I wonder if the idler belt guide would have prevented the flip?


His idler guide was in place for all the trials... watch closely and you will see the belt get out from under the guide during the flip and then begin running on the outside, and seemingly reduces a lot of the chaos elsewhere in the system.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: jjohnsonjo ()
Date: September 08, 2021 07:20PM

I had a riding lawn tractor that liked to through belts. I changed the belt guides to double wide ball bearings that were in full contact all the time. That stopped it.

Nice video though, thanks.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: 63turbo ()
Date: September 09, 2021 07:59AM

aircooled Wrote:
-------------------------------------------------------
> Yeah, it would be interesting to do some comparisons. I am tempted to mount up some of my older, more classic style belts. I even have a non-wrapped toothed one! The belts in the video BTW are all the thin style belts (like Clarks sells).
>
> Has anyone else seen the jumping over the guide behavior? It has happened on this engine a few times recently (after loosening up the guides a bit). Historically the belt would just jump off, so no way of knowing where it was coming off but the idler guide area certainly seems like a prime candidate.
>
> The belt in the first clip was WELL worn. I think it may have been thrown once. It is interesting that it had severe whip on the tension side, while it was much more limited on the second one.
>
> I do suspect power pulses do play into the whipping.

It would be real interesting to see what happens at tighter belt tensions- It sure looks like the belt has to be slipping alot for the alternator side to be as slack as it gets at high rpms. The other one is to perhaps adjust the fan pulley guide in as close as the idler guide. Heck of a job!!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: aircooled ()
Date: September 09, 2021 05:38PM

63turbo Wrote:
-------------------------------------------------------
> aircooled Wrote:
> -------------------------------------------------------
> >
>
> It would be real interesting to see what happens at tighter belt tensions- It sure looks like the belt has to be slipping alot for the alternator side to be as slack as it gets at high rpms. The other one is to perhaps adjust the fan pulley guide in as close as the idler guide. Heck of a job!!


That is probably my next step since it is easy. See what a tighter belt or guide would do (although I don't think a tighter guide would have helped in the above video)

Running it even looser and greasing it up with silicone to see if that actually lets the belt slip would be interesting also.

The belt was the sort of common spec tightness BTW. Tight enough so that I could move the alternator pully with one finger. I should come up with a more measurable standard though. Deflection on one of the long legs (like the factory did) is probably the best measure.

I am looking at possibly adding another guide near the pulley and or add some Teflon blocks to the stock guides to help with the burning rubber from rubbing.

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: 63turbo ()
Date: September 09, 2021 08:36PM

>
> That is probably my next step since it is easy. See what a tighter belt or guide would do (although I don't think a tighter guide would have helped in the above video)
>
> Running it even looser and greasing it up with silicone to see if that actually lets the belt slip would be interesting also.
>
> The belt was the sort of common spec tightness BTW. Tight enough so that I could move the alternator pully with one finger. I should come up with a more measurable standard though. Deflection on one of the long legs (like the factory did) is probably the best measure.
>
That "common" tightness isnt a "factory spec", but is one that will garrantee the belt will slip at some rpm short of redline. I tried a tension like that(mag fan) and found the belt would slip around 4k in steady state. I measured the torque required to slip the fan belt on the fan pulley and it was approximately 8-9ft-lbs. The shop manual tensions are quite a bit tighter than what we know works well for high rpms, but does often result in better belt control right up to the point where it pops offspinning smiley sticking its tongue out

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: TheRealHip ()
Date: September 10, 2021 08:50AM

Has anyone done something else with this design. Instead of making the belt do the 90 degree turn?

66 crown v8

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: TheRealHip ()
Date: September 10, 2021 09:12AM

There has to be a better way to make that 90 turn.

66 crown v8

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Re: Falbelt Video: Crazy Times in the Engine Compartment
Posted by: aircooled ()
Date: September 10, 2021 09:50AM

The real solution is to just do a 911 style vertical fan and doghouse.

To be clear, this is only really a problem at the more extreme end of driving and like only with modified engines. Even as I had it setup, it required a very aggressive downshift to throw the belt, likely more than I would ever normally do.

I am not attempting to address a serious concern, just investigating the edges of the envelope and see if there can be improvements. And, just to see what is really going on in there.

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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