1964 Monza Sprint - A Bear of a Corvair

The Sprint by John Fitch
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UNSAFE
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1964 Monza Sprint - A Bear of a Corvair

Post by UNSAFE »

From Road & Track magazine July 1964
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Kevin Willson
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Ecklund
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by Ecklund »

Interesting article.

I wonder if those seat track extensions were custom or if someone still makes them today...
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Allan Lacki
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by Allan Lacki »

It's interesting to read about the suspension modifications that Fitch & Company made to early-series Corvairs, namely the removal of the front anti-roll bar and stiffening of the rear suspension. This is directly the opposite of the common cure for jacking in rear-engine swing-axle cars.

In other words, with a swing axle suspension, you generally want to increase roll stiffness at the front end and decrease it at the rear end. Take a look at the rear suspension of any Formula V car and you'll see - Many of them have a Z-bar at the rear to promote roll, rather than a conventional roll bar to prevent it.

The last of the swing axle Beetles had Z-bars, too.

The better Formula V's have a rear suspension setup that has zero roll resistance! In the photo, you'll see that it has one horizontal coil-over spring. It serves as the spring for both axles so that the axles work against each other instead of against the chassis. So, there is no resistance to body roll whatsoever. I've seen Formula V cars like this at the Duryea hillclimb. Very clever!

Overall, the premise of this is to let the front suspension provide roll resistance while letting the rear suspension roll around the U-joints, thus eliminating jacking. Personally, I drive a late-series Corvair, so I don't have any direct experience with this, but I thought it's interesting none the less.

Al ::-):
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Ecklund
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by Ecklund »

Allan Lacki wrote: Sat Mar 18, 2017 6:50 am It's interesting to read about the suspension modifications that Fitch & Company made to early-series Corvairs, namely the removal of the front anti-roll bar and stiffening of the rear suspension. This is directly the opposite of the common cure for jacking in rear-engine swing-axle cars.

In other words, with a swing axle suspension, you generally want to increase roll stiffness at the front end and decrease it at the rear end. Take a look at the rear suspension of any Formula V car and you'll see - Many of them have a Z-bar at the rear to promote roll, rather than a conventional roll bar to prevent it.

The last of the swing axle Beetles had Z-bars, too.

The better Formula V's have a rear suspension setup that has zero roll resistance! In the photo, you'll see that it has one horizontal coil-over spring. It serves as the spring for both axles so that the axles work against each other instead of against the chassis. So, there is no resistance to body roll whatsoever. I've seen Formula V cars like this at the Duryea hillclimb. Very clever!

Overall, the premise of this is to let the front suspension provide roll resistance while letting the rear suspension roll around the U-joints, thus eliminating jacking. Personally, I drive a late-series Corvair, so I don't have any direct experience with this, but I thought it's interesting none the less.

Al ::-):
Thank you Mr. Lacki,

I was second guessing myself about that exact topic.

I'd always thought/read/observed that stiffer springs, an anti-roll bar or a bigger anti-roll bar and/or stiffer shocks all add to the 'roll couple' of whichever end to which they are ADDED. An increased in the front roll couple would INCREASE understeer and if REDUCED/REMOVED from the front would DECREASE understeer.

And of course the inverse would be true of the rear of the car. ADDING roll coupling through an anti-sway bar or a larger one, stiffer springs, stiffer shocks or any other device that would limit roll, like a transverse spring, would INCREASE oversteer and a reduction of roll couple would DECREASE oversteer.

Tire size, compound and air pressure also have a large effect.

The article on the Sprint seems to make the opposite conclusion.

The lateral spring on a '64 isn't really an anti-roll bar. It clearly has impact on roll resistance and adds to the total rear spring rate for the car, but its primary role seems to be to keep the rear wheels from dropping under the body at too much of an angle which might lead to undesirable suspension action.

It looks like it would be difficult to add a rear anti-sway bar to the '64.

I wonder if the '64 Corvair really does oversteer that much. Or is it that at the edge of tire adhesion the rear engine pendulum effect exaggerates the snap when the rear end finally does come loose and becomes much like the so called 'widow maker' Porsche of the day

Oversteer and car behavior at the edge are not the same thing. A car can understeer horribly but can snap at the edge of adhesion and be a handful.

I look forward to actually driving my humble '64 four door with automatic. I suspect its classic GM understeer.

While the Sprint Corvair article may have been incorrect in explaining the suspension forces involved, the effect it achieved by increasing rear roll stiffness/couple with stiffer springs at the same time reducing front roll stiffness/couple buy removing the front anti-sway bar may well have countered some of the unwarranted understeer GM added to the car.

With massive understeer designed into the Corvair GM certainly kept typical drivers further away from the unfamiliar effect of having a rear weight bias and harsh reaction when tire adhesion is lost in an extreme cornering situation. But the '64 Sprint car shows that the stock Corvair's had significant understeer and removing some would make a much more sporting car that had still addressed the original Corvair suspension design limitations.
1964 Corvair 900 (969) four door with powerglide - new project
Luke Geis
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by Luke Geis »

I have recently thought about starting a new thread about this, but this topic seems to be inline with my query. I have a 1961 and I do have a late model front crossmember in it. I do not have the sway bar and the original spindles were retained to keep 4 lugs all the way around.

I need a FULL suspension rebuild front and back like it's nobody's business!!!! After lots of reading and research, I have come the conclusion I would almost be as well off just splicing a Mustang II IFS model into the car available from many vendors in order to A) get the suspension performance I desire. B) It would be about the same level of headache as trying to improve the current front end.

With the rear of the car I have concluded that I will have to go to FC axles and make the needed spacers to accommodate the extra length and deal with the late model Saginaw that is currently in the car ( roughly 1.5" extra per side as best as I can tell ). Needless to say, I have work to do either way. I do not wish to graft in a late model rear suspension on my car, but instead would like to improve upon it. My understanding thus far is that the wider stance in the rear which will bring it closer to the wider aftermarket front end will help a little, and the wider stance in the rear will reduce camber change and jacking. However it doesn't stop it and it doesn't make it go from snap oversteer to a neutral handling car.

So my next thought was a Z Bar to reduce roll stiffness and make the rear resistant to jacking. The issue I see is that with a lowered car, jacking is reduced any way and how does a Z Bar work around what happens when the suspension does go significantly negative camber? I get the feeling that keeping the rear suspension to never be able to go positive camber would really solve the majority of issues. I am not privy to how much body roll there really is in the car and how much rear lift there is under braking and turning? If you don't trail brake, this might be less of an issue?

Has anyone done linked suspension from front to rear? To me it seems that a sway bar attached from the front to the rear would address the body roll seen at the rear and make jacking a pretty hard task. You go into the turn, you are on the brakes, the front collapses and in turn pulls the rear down with it. The front sway bar tries to also pull the inside tire up and therefore along with it the inside rear tire. There is now zero body roll resistance from the rear of the car and the rear inside tire will not try and push its way down hence the body up? Perhaps that is a pipe dream?

If in fact, a linked front & rear suspension did work to reduce jacking, then you could utilize a standard sway bar in the rear to have a fully linked suspension that would resist body roll all together and in essence keep the rear tires in a negative camber state at pretty much all times? Or is teh Z bar really just the best way to go?
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by JerryM »

"Has anyone done linked suspension from front to rear?"
Luke,
Try looking up "interdependent" suspension. I think Packard had a patent on that in the mid-'50's.

As far as the "Z" bar, or any type of "de-stabilizer", for the early Corvair rear, can be set up to be very effective.
Jerry - Placerville California

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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by 66vairguy »

I didn't read the article, but keep in mind the "desk racing" car magazine writers were often just "writers" not automotive engineers. Basically I've read a lot of stuff over the decades in car magazines that simply was WRONG.

Fitch often stated he varied his build of a car to suit the owner/driver and the type of driving that would be done.

Yes a stiffer front suspension with a sway bar will promote understeer. This was done for the simple reason that a rear weight biased car tends to loose traction in the rear during an aggressive turn before the front resulting in oversteer. The scheme is to promote maximum rear tire traction and reduce front tire traction with a front sway bar (or low tire pressure) to "balance" the front and rear traction in a turn. It is a lot more complicated to actually implement. While a sway bar helps reduce roll it also unloads the inside tire in a turn effectively reducing that tire,s traction.

Then you throw in the swing axle issue and the Corvair's generous rear suspension travel and you have a jacking issue. The stock 64 suspension was a great design to promote stability for the AVERAGE driver on everyday roads. If you are going racing, and are skilled, you can change the suspension to suit the track and your abilities.
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Re: 1964 Monza Sprint - A Bear of a Corvair

Post by bbodie52 »

Ecklund wrote: Sat Mar 18, 2017 3:44 am

Interesting article.

I wonder if those seat track extensions were custom or if someone still makes them today...
bbodie52 wrote: Mon Mar 18, 2013 2:11 pm

One of our Corvair Forum members, Norm Witte, fabricated some Corvair seat extender mounts, which he documented on his website http://www.wittelaw.com/personal/extender/index.htm If you purchase a Corvair and decide that you wish to try to reposition the standard seats, his description and photographs may give you some useful ideas. The standard Corvair has no provision for repositioning the seat mounts further to the rear, so a custom modification such as the one described on Norm's website, or refitting and adapting some used seats – or some custom aftermarket seats, such as those manufactured by Recaro, might be deemed necessary to accommodate your tall size.
Seat Track Extender Project
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I believe that Norm Witte no longer has any of these extenders remaining that he fabricated, but Clark's Corvair Parts does carry a variation of them...

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:link: http://www.corvair.com/user-cgi/catalog ... N&page=266
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Part number C8256: SEAT EXTENDERS FOR TALL DRIVERS*ONLY FIT *62-69-NOT FC! 1=1 BUCKET OR 1 BENCH-ADDS 3"

Weight: 7 lbs 0 oz
Catalog Pages(s): 266
Price: $ 84.95


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Brad Bodie
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