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Alignment specs. conversion
Posted by: firevair66 ()
Date: December 02, 2021 12:28PM

need specs for the new machines inches to degrees for front end alignment

John Shoemaker,Riegelsville,PA.
1958 Impala Sport Cp. 348 ,pg/ac
61 Rampside full custom show truck
65 Monza 110/4 vert driver
65 Full Custom Monza 140 Cp
66 Monza 110/PG Vert
66 Corsa FITCH SPRINT Documented ( in Process,recondition)
66 CorV8 350 "firevair"Custom Show

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Re: Alignment specs. conversion
Posted by: MattNall ()
Date: December 02, 2021 01:57PM

We have a topic on the within the last year. iirc Just search for "alignment"

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Re: Alignment specs. conversion
Posted by: 66vairman ()
Date: December 02, 2021 03:24PM

Alignment discussion are somewhat like the "OIL" discussion. A LOT of different attitudes depending on if you want a good "street" setup, or a good "track setup".

Bigger rims, wider tires, wheel offsets that don't match the stock wheel all impact the alignment.

I had a terrible experience with the local "expert" alignment shop that supposedly set up custom cars. I warned them the Corvair front and rear suspension had been apart, but everything was clean and all the adjustments could be done "without getting out the torch". They "claimed" they knew Corvairs and gave me a good price, but rushed the job and wouldn't touch the caster. When I asked them about the caster I was told "It's fine no need to adjust".

I've talked to early Mustang owners who have a similar strut rod up front for caster and they say they get the same run around. The shops are reluctant to adjust caster as the adjustment nuts tend to be rusted in place and they don't want to deal with telling the customer those parts have to be replaced.

After a year of "fighting" the steering wheel in corners and wandering down the highway like a drunk, I did my own alignment with a bubble gauge alignment tool. The car now steers easy and tracks straight down the highway.

As they say -- "If you want it done correctly, do it yourself".

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Re: Alignment specs. conversion
Posted by: MattNall ()
Date: December 02, 2021 04:27PM

I searched!!!GG



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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Alignment specs. conversion
Posted by: firevair66 ()
Date: December 02, 2021 06:13PM

Thanks Matt;
Just what I was looking for

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Re: Alignment specs. conversion
Posted by: MattNall ()
Date: December 02, 2021 07:28PM

Glad to help

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Alignment specs. conversion
Posted by: JimBrandberg ()
Date: December 03, 2021 05:28AM

My local guy has been at it a long time but has a humble attitude. The best thing is they don't mind if I'm present to "help". I don't touch anything but can input on risk vs. reward decisions. It's a nice time to visit even though I have no interest in fishing and he has no interest in old cars. They deal in angles and conversion to inches is sort of loosey goosey off the top of the head, 1/16" is a few degrees, 1/8" is a few more.
I had an alignment done at a place where they knew all about everything and it was unsatisfactory. The guy doing all the talking wasn't the guy doing all the work.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Alignment specs. conversion
Posted by: RobertC ()
Date: December 03, 2021 08:13AM

JimBrandberg Wrote:
-------------------------------------------------------
> They deal in angles and conversion to inches is sort of loosey goosey off
> the top of the head, 1/16" is a few degrees, 1/8" is a few more.

This not true.

If you look at the alignment sheet above for Front Toe:

.04 / .05 degree

I believe it is an alignment sheet I posted. The front toe is 1/16".

> I had an alignment done at a place where they knew all about everything and
> it was unsatisfactory. The guy doing all the talking wasn't the guy doing all > the work.

True. The shop that I use took the time to do it right. Even though the alignment guys have come and gone over the years. I believe the rack has changed, also And, I am charged more than their standard alignment price.

But, I have been going there for tires / alignment for decades.

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Re: Alignment specs. conversion
Posted by: 66vairman ()
Date: December 03, 2021 08:50AM

Matt -- ONLY 1966 shop manual lists a front caster of 3 +/- 0.5 degrees. I think it's a mis-print as ALL the other model years are 2 +/- 0.5 degrees.

Since I have wider than stock tires on the front with a 7" vs. 5.5" wide rim I had to use a 1.5 degree caster to reduce the "self centering" effort to reasonable level. Just me.

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Re: Alignment specs. conversion
Posted by: Brizo ()
Date: December 03, 2021 09:18AM

66vairman Wrote:
-------------------------------------------------------
> Matt -- ONLY 1966 shop manual lists a front caster of 3 +/- 0.5 degrees. I think it's a mis-print as ALL the other model years are 2 +/- 0.5 degrees.
>
> Since I have wider than stock tires on the front with a 7" vs. 5.5" wide rim I had to use a 1.5 degree caster to reduce the "self centering" effort to reasonable level. Just me.

I did the same thing on my Greenbrier. It's been lowered and has 17X7 wheels and 7" wide tires and I set my front caster at 1.5 degrees to reduce steering effort in low speed and parking situations with a 14" Corvette steering wheel. Still self-centers fine. Our shop has a laser rack from the '90s?, that lists Corvair specs in degrees.

Dan Brizendine, Circle City Corvairs
'64 8 door Greenbrier, +.060, stroked 1/4", 188 ci, 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"



Edited 1 time(s). Last edit at 12/03/2021 09:19AM by Brizo.

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Re: Alignment specs. conversion
Posted by: 66vairman ()
Date: December 03, 2021 09:58AM

I'll add that the CAMBER MUST BE SET BEFORE THE CASTER if you use a bubble gauge.

If the camber is at, or near, 0 degrees, then caster reading is invalid.

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Re: Alignment specs. conversion
Posted by: joelsplace ()
Date: December 03, 2021 10:21AM

66vairman Wrote:
-------------------------------------------------------
> I'll add that the CAMBER MUST BE SET BEFORE THE CASTER if you use a bubble gauge.
>
> If the camber is at, or near, 0 degrees, then caster reading is invalid.

Camber should be close to 0 so how does that work?
If you had 0 KPI then the caster gauge wouldn't work on a bubble gauge or computer.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

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Re: Alignment specs. conversion
Posted by: gbullman ()
Date: December 03, 2021 01:09PM

I will need to get my car aligned eventually. Is one to ignore the red in the above diagram and just provide the numbers to the tech?

I'm expecting to stick with stock wheels and 185/80 R13 Tires, would these values still apply?

Is there a consensus on whether front Caster should be 2 or 3 +/- 0.5?

Thanks for posting this info.
Gary


Gary
1966 Corsa Convertible
Northern New Jersey


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Re: Alignment specs. conversion
Posted by: MattNall ()
Date: December 03, 2021 01:16PM

Correct! Print out the green portion of the pic and take it with you.

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Re: Alignment specs. conversion
Posted by: RobertC ()
Date: December 03, 2021 01:33PM

gbullman Wrote:
-------------------------------------------------------
> I will need to get my car aligned eventually. Is one to ignore the red in the above diagram and just provide the numbers to the tech?
>
> I'm expecting to stick with stock wheels and 185/80 R13 Tires, would these values still apply?
>
> Is there a consensus on whether front Caster should be 2 or 3 +/- 0.5?
>
> Thanks for posting this info.
> Gary

Yes.

They were how an expert suspension guy set up my Corvair in 1980 / 1981 - while rebuilding the suspension.

Caster setting is a matter of taste. Well, From all the opinions, you could state that alignment specs are a matter of taste.

+3 degree caster provides a "stronger" "return to center". Than +2 degrees.

You can "test" your car by going to an empty parking lot and do a left / right turn and take your hands off the wheel and see how the car (steering) responds.

The widest tire I have used is 205.

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Re: Alignment specs. conversion
Posted by: 66vairman ()
Date: December 03, 2021 01:34PM

joelsplace Wrote:
-------------------------------------------------------
> 66vairman Wrote:
> -------------------------------------------------------
> > I'll add that the CAMBER MUST BE SET BEFORE THE CASTER if you use a bubble gauge.
> >
> > If the camber is at, or near, 0 degrees, then caster reading is invalid.
>
> Camber should be close to 0 so how does that work?
> If you had 0 KPI then the caster gauge wouldn't work on a bubble gauge or computer.

NO I DIDN'T SAY CAMBER SHOULD BE ZERO. On a CORVAIR - If the camber is at, or near, 0 degrees, then the caster reading is invalid (as I posted). This is with the bubble gauge. Computer system depends on the type of equipment used. Some of the Jeeps had an axle pad you installed a tool on to set the caster so camber or toe had no impact on the caster reading.

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Re: Alignment specs. conversion
Posted by: 66vairman ()
Date: December 03, 2021 01:43PM

gbullman Wrote:
-------------------------------------------------------
> I will need to get my car aligned eventually. Is one to ignore the red in the above diagram and just provide the numbers to the tech?
>
> I'm expecting to stick with stock wheels and 185/80 R13 Tires, would these values still apply?
>
> Is there a consensus on whether front Caster should be 2 or 3 +/- 0.5?
>
> Thanks for posting this info.
> Gary

Robert C summed it up, but keep in mind ONLY THE 1966 SHOP MANUAL SUPPLEMENT LISTS CASTER AS POSITIVE 3 +/- 0.5 DEGREES. The 1965, 67, 68, 69 Shop manuals (or supplements state POSITIVE 2 +/- 0.5 degrees. This suggests the 1966 caster specification may have been an error.

Your choice. With a wider tire I set caster at POSITIVE 1.5 and the steering wheel return to center force is more than adequate.

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Re: Alignment specs. conversion
Posted by: Jonathan Knapp ()
Date: December 03, 2021 08:44PM

On a performance set-up, the point of caster is not just returning the steering wheel to center after turning.

Caster helps to keep the tire tread in full contact with the road surface in corners. This is particularly important the wider and lower profile you go with your tires. Modern, low-profile tires have little sidewall flex compared to standard or near standard profile tires, so it is important to keep them in full contact with the road.

If you start with 0 degrees caster and 0 degrees camber, the spindle will always be parallel to the ground and the tire will always be always flat on the ground at every possible steering input on an unmoving car. Why aren't these specs called for? Because you are not setting up your car to never move. The factor that is missing is body roll.

In order for the tire to stay flat on the ground under cornering as the body rolls, you need the outside tire to develop negative camber and the inside tire to develop positive camber in a turn. The more caster you add, the more this happens. With negative caster, the turn-in tire develops negative camber (the spindle start to point more upward). With negative caster, the turn-out tire develops positive camber (the spindle starts to point more downward).

The answer to how much is the "right" amount of caster is a function of how much body roll the car has, how wide and low-profile the tires are, and what you want the car to do.

Jonathan Knapp
Wheeling, WV
'66 Corsa Autocrosser

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Re: Alignment specs. conversion
Posted by: gbullman ()
Date: December 04, 2021 05:29AM

MattNall Wrote:
-------------------------------------------------------
> Correct! Print out the green portion of the pic and take it with you.

Am I misunderstanding? I was interpreting values at top, which are mostly red to be settings for front and those at bottom which are green to be for the rear.

My interpretation is in all cases the numbers are what the car was aligned to but the red values are because they were not programmed into the machine as the target values.

This info is great since radials require different alignment than bias plies and the factory had no reason to publish values for radials.


Gary
1966 Corsa Convertible
Northern New Jersey


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Re: Alignment specs. conversion
Posted by: joelsplace ()
Date: December 04, 2021 07:33AM

> NO I DIDN'T SAY CAMBER SHOULD BE ZERO. On a CORVAIR - If the camber is at, or near, 0 degrees, then the caster reading is invalid (as I posted). This is with the bubble gauge. Computer system depends on the type of equipment used. Some of the Jeeps had an axle pad you installed a tool on to set the caster so camber or toe had no impact on the caster reading.

No I said it should be near 0. I have a bubble gauge and it works fine setting caster when camber is zero. You might want to study front end geometry. Do you even know what KPI is?

> If you start with 0 degrees caster and 0 degrees camber, the spindle will always be parallel to the ground and the tire will always be always flat on the ground at every possible steering input on an unmoving car.

This would be correct if you had 0 KPI but that isn't the case. I can't remember what Corvairs have but it is nowhere near zero.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

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