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#1074058 - 06/04/22 05:57 PM Re: Front sway bar project [Re: mmc427ss]  
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For those interested in times...

https://www.scca-susq.com/live/index.html#camt


Lance
1985 Monte Carlo SS Street Car
#1074059 - 06/04/22 09:04 PM Re: Front sway bar project [Re: mmc427ss]  
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Looks like they are starting PM runs now.


Lance
1985 Monte Carlo SS Street Car
#1074069 - 06/08/22 05:25 AM Re: Front sway bar project [Re: mmc427ss]  
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Ran the autox this past Sat with my son. On the drive home decided to take a couple days to think about what we learned before pounding the keyboard. Also wanted to do a close post inspection of the car before i made any mention of how the new bar effected the car.

So many things to note.
Not being a early riser the 4:45 am wake up Sat morning, stop for coffee, hoagies, top the gas tank off, $76, and arrival at 7am makes Bob a dull boy. Tech, walk the course, registration and find Bernie's cousin, SickSpeedMonte, who helps run this event, to say Hi. He actually was the course setup that day, COOL.
As luck of the draw it was good to us, 120 cars in the AM, we worked the 2nd and ran the 3rd run group, perfect. In the PM only 80 cars or so and worked 1st, ran 2nd, perfect. We got to watch a lot of car run the courser before us. Last two time there i was the 2nd car out in the AM, no good.
Couldn't be happier about the way that turned out, made the day a whole lot less stressful.

How did we do as drivers, my son good. As his seat time increases and he figures out rear wheel drive cars, especially this one he will be getting faster.
He's a FWD guy but that's another Saab story.

Me, I've slow, need to fix a couple things so I stop death gripping the wheel. Better securing me to the seat needs to be added. I'm using my arms to hold myself in the seat. As the car corners better the need to stick to the seat increases. And the worse result of that problem, death grip, is you find that core muscles to help hold you in the seat ain't working that well anymore. Think it may be to late for situps to fix that.
I need to become one with the seat so I can relax my arms.
The second benefit to relaxed arms is I believe i will be able to better run lines through a course instead of dodging cones in front of me. I'm slow because I'm a slow learner. Always takes me longer to figure things out.

The car, I'm very happy with it. First off this engine is getting near 15 years of some abuse. The T56 went in 20 years ago. I've owned the car for 30 years. I ask it to drive 75 miles on 4.11 gears at 70 mph, run 16 50+ second runs in 3rd gear, then drive it home 75 miles, with the A/C and cruise making the ride, nice.
I mention that as the owner and fixer of that car, getting home is always a priority. Not that i use that as an excuse but it's always in my mind as we get ready for another 50 sec pass. My co-driver doesn't have that excuse.

A note on the course setup, fast, 18 corners with 2 360s. My 2nd run in the AM the safety officer wanted to know why i spun out in the 2nd 360. It was a comical moment for both of us.
Neither my son or I had any DNF or hit a cone. i think that shows the car was very good through the slaloms.
For the most part we pulled out in 2nd and shifted 3rd before the first turn, ran the entire run in 3rd. This kinda helps and also hurt time i think. Reinstalling the 3.73s is a 10% change, would be able to pull off the start in 2nd and should be able to run the entire length in 2nd. That gear swap was on my Winter list but didn't get done, sway bar project used up all the blood and sweat.

Sway bar. Zero problems with the parts. A dozen times on Fri night, and Sat event you can just touch the end of the bar and feel the arm had not moved on the spline. Mon day morning in the shop raise the front end 2' in the air and did a thorough inspection of the chassis/drivetrain.
Arms did not move on splines, pinch bolts torque checked at 37, good, link 1/2" rod end still have the same relationship to the bolts, COOL, some grease has spewed out of the torsion bar mounts but i expected that, they were pump FULL so they would spew, the reason for a grease fitting in that 1 3/4" OD tube.
The damn brand new Moog lower ball joints also spewed grease on the inside of the wheel. Yes, i may have over filled them when they were install and off the car.
The left head gasket at the #7 left a trail of antifreeze going back to the muffler. Easy to clean up but just warning that someday you need to do head gaskets under those old AFR heads.

Tire touch:
Nothing on the left side front. On the right front the tire sidewall touched the top corner of the sway bar arm and took the powder coating to bare steel. I know when and who took that paint off, my boy while getting in line to run cranked the steering full left several times. The side wall of the tires doesn't even show a rub so i know it was that slow speed maneuver. On Mon I removed the spindle stop on the left side and added some steel to it with the MIG. After some fitting now have the tire an 1/8" away from the arm. If necessary can add more to that steering angle stop. Down side to less steering angle is turning radius gets bigger. A while ago after the new tires and wheels went on and adjustable steering arm stops were added a 100' tape and a big parking lot was found, turning radius was up, would need to look for that number but think it was 44'. Will measure that again soon, schools out.

Tire touch in the rear. What i saw on Mon surprised me. That course on Sat had a few turns, corners that asked a lot of the rear suspension. Under normal driving there is no touch of the tire to the frame on the left side and a generally no touch on the right rear tire to the frame in the back side. Last year autox the right rear had taken the paint off the frame and the left side had barely a touch.
Touching was down a lot this past Sat. The left side has barely a touch, the right side is very good, only a touch also, paint still on the frame. When these autox tires went on a few weeks ago those two areas the tires touch got a fresh coat of paint. So less rub indicates more control over the rear coming from less frontal roll? Hmmm
On the rear shocks shaft is a tie wrap, it's used to show shock max compression. There was plenty of compression left on the shock after a days event.

So at this point the new three piece sway bar is installed, survived it's first test of 300+ corners and isn't as ugly a ride as i thought it would be. My son noticed as soon as he got behind the wheel how little roll it was and the buckboard word came out of his mouth. I know it's harsher, but don't care anymore much about NVH.

Tires: Like the Falken RT660 tires, and need to have them last a few events. Autox tires in any size are hard to get right now. As a cold pressure I ran them at 32-32 in street trim. Every run i would touch the tread with my digital fingers/hand and get a feel for temp across the tread. I wasn't so concerned about how they performed on track as how they were wearing across the tread. nothing we would learn about tire temp would make us faster. We sprayed a couple times in the afternoon and bleed off most all afternoon after each run, 32-32 was my goal.
Looked at all four tire's sidewall arrows back in the shop and happy. Will need to rotate then and chalk the edges next time out to see whats going on there.

Got a lot of positive remarks about the car on Sat. Think there is still some more on the table for the car and know my son will take advantage of that. Me I need to figure out who to plant my butt in the seat so i can relax in the car.
Bob

#1074070 - 06/08/22 11:21 PM Re: Front sway bar project [Re: mmc427ss]  
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Restricted comment for now: I don't know how widespread this is with AFR heads, but the last set I had was way out-of-flat. Had to mill the entire head-gasket surface afresh to ensure a good seal with the block. I forget how much we shaved off: 7 mils? 10 mils? It was a lot.

Last edited by MAP; 06/08/22 11:23 PM.
#1074071 - 06/09/22 05:57 AM Re: Front sway bar project [Re: mmc427ss]  
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Those AFR 210s are over 15 years old with the same set of FelPro heads gaskets, heads never been off, 27K not the easiest miles. I know removing the heads is not only a lot of parts to remove first but also opens that whole can of worms. Just getting a set of heads refreshed today is an arm and leg, if you can find a machine shop to do it. So yes I procrastinate big time on that job.
There some dump in the coolant "restores head gasket" stuff but the radiator wouldn't like it.

Tonight had the car out again, maybe 20 miles of in town and some back roads. Bill was riding shogun and sometimes he doesn't like to be uncomfortable, so I was compliant. The primary reason for the trip was to drive over to my TIG guy's shop and show him what the final bar install looks like under the car. Reasonable impressed was he, liked everything he saw. Was impressed by the way the torsion bar snakes across the frame.

And the secondary reason to go see the TIG guy with the car was to talk about what his ideas were on putting a harness bar behind the front seats. Very soon that will be the new mod for the car, belts. Lots more on that later in a new thread.

Tonight, car still warm from the road trip and sitting at ride height in the shop got a few measurements related to ride height and sway bar.

Yes i run a little more ride height than most do, tonight;
RF 26 1/2" LF 26 7/16"
RR 26 3/4" LR 27 7/8"

Directly related to the ride height is the angle of the swaybar arm produced at ride height when the links are installed. Typically you would like to see the end of the sway bar that the link is attached to that section being parallel to the ground surface. It would show a 0 angle on a digital angle gauge. In the stages of arm and link design and how to make them fit in a confined area on the LCA you know then compromises were in order.

The sway bar arm's angle at ride height is 2.25 degrees up both sides, which it should be equal both sides. Two reasons for 2.25 degrees not 0.
Articulation of the front suspension is max 2" compression, most likely 1 1/2" when the bump stops are used. In rebound it is in the neighborhood of 3 3/4" travel.
When in full droop the lower 1/2" rod end is closest to being in bind. At full compression no bind problems at all with the lower rod end. Moving the arm height higher improves lower rod's clearance and doesn't hurt compression clearance.

Wanting to have a long link length the ways to do that is several. Goal was 3 3/4" to 4" center to center of the 1/2" rod end holes. The links on the left side is now 3 5/8", the link on the right side is 1 1/2 turns shorter, .075", necessary to get the bolt into the bottom rod end. Will revisit the "cross setup" of the bar preload a little later. Now have a lot better understanding of how to setup the bar for no preload each side. Also had to wait until I knew the front coils springs were sitting back on their alum and rubber seats, that can take a little while.

So that 2.25 degree up angle helps the link clearance at full droop, and the link would need to be shorter if I woulds want to set 0 angle. Of course the take away from that is the arm should have that 0 degree section 1/2" higher, In design the frame was the reason for not going much higher.

Measured the twist of that 0 degree section of the arm, yes now actually the 2.25 degrees up section. When built in the arm jig the goal was 4-4.5 degree twist of that section. Measured tonight they were 4.2 - 4.5. perfect.

The angle of the rod end links is something to discuss. Not near perfect, as in perpendicular in two planes, as they move up and down. the goal was to try and manage the load on the bar/links when they would be at their highest rates, 1 1/2 C to 2" Droop. In that range of travel the link angles are OK. Referring too the link angles in the same concept as alignmnet specs the camber of the links on both sides. As with wheel camber gain the link also has a camber curve with gain. At near ride height near -1 degree and in full droop maybe -4 camber. With the position of the lower link's mount on the stockish LCA possible moving camber or caster is not possible in my install. If I wanted to get camber closer to 0 at ride height the arm at the link attachment point would need to be move closer to the frame. The links camber could be tweaked to get closer to zero but is actually very good.
Caster of the links is high, might be 9.5 degrees at ride height. And get worse as droop increases. But there is no load on the links at much over 2" droop, so angle isn't as critical, the rod ends should be in "free, dumb and happy mode" at that time. Being the position of the lower link's end to LCA is forward as far as possible the top rod end and sway bar arm length determines the angle of the link at ride height. That compromise was made to give up caster in the name of a higher bar rate per inch of travel. Only one hole is in the sway bar arms, 7 3/4" length, 8.75" as the crow flies, 36", 1.272'. .615" ID comes out to about 1158 rate.
If i wanted to improve that caster angle of the link closer to perpendicular increasing the sway bar arm's length to 8" or maybe 8.25" the angle would be better, But the negative is the rate of the bar decreases. Same 1158 at 7 3/4" becomes 1083 at 8", then at 8.25" becomes 1015 lb/in. Initial goal was to end up with 1200 rate, the reason for the 7.75" arm length. Two sets of 1/2"-20 holes drilled and tapped at the end of that arm requires real estate not available.
Will get exact angles from the links in the coming days both camber and caster at ride height.

Now having this new bar/arm in action for a lot of different driving conditions and looking at how the pieces now fit there would be just a slightly tweaked parts but no major redrawing. Very happy the way it all fits and seems to work. Time will tell if there is a fault now overlooked.

Fri will do a toe check and maybe dial the toe back to 0 toe as no IN or OUT. Want to see and feel if that toe change can be seen on the tread and felt on the wheel. Next up is a jaunt up the turnpike to Carlisle for the Chevy Nationals to see a few old car guys. The 17" come off and the old 16" wheels and tires go on for that trip.
Later
Bob

#1074072 - 06/09/22 04:34 PM Re: Front sway bar project [Re: mmc427ss]  
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I told you you'd love driving with that bar...under all circumstances... laugh

I had no doubts your initial tests would come back positive, super happy nothing fell off the car during your travels!!


Lance
1985 Monte Carlo SS Street Car
#1074081 - 06/10/22 08:58 PM Re: Front sway bar project [Re: mmc427ss]  
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Some pics of Bob's MCSS on course in this gallery. You'll need to have your pop up blocker turned off and do a bit of scrolling...he's in the third group of cars posted.

https://photosbychristophercross.instaproofs.com/gallery/#events/1889699/4318691

Some great pics of some cool arsed cars at this event for sure.


Lance
1985 Monte Carlo SS Street Car
#1074082 - 06/10/22 09:38 PM Re: Front sway bar project [Re: mmc427ss]  
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Hi Bob,

Once again, provided linkage angularity isn't inducing bind, you're fine. At nominal ride height, you should aim for:

1. Longitudinal: endlink top tilted toward rear of car. Something like 5 deg should be fine.
2. Transverse: endlink top tilted toward centerline of car. Something like 3 deg should be fine.

HTH,
MAP

#1074083 - 06/10/22 11:12 PM Re: Front sway bar project [Re: mmc427ss]  
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It looks like some fun, the car looks good too. I wish I could take time out for something like that, I'll just settle with a ride too the ice cream stand I guess. laugh


Enjoy life, family first!
#1074088 - 06/11/22 05:22 AM Re: Front sway bar project [Re: mmc427ss]  
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Thanks for finding that link to event pics Lance. There are like 32 pics of the car there if you have the patience to scroll through all of them. I spend a lot of time looking at them to get an idea of what the car is doing in those different places on the course. For our first event of the year I give the car a B+, my son a B with an A for effort and myself a D. Jason was 266, the old man 66.

A road trip to Carslisle is two weeks from now, spent time on Thurs tuning the R12 A/C system for that ride. Saw some 40 degree and less temps from the vents yesterday. Over the next week will be able to verify ice cold A/C is done.

As I mentioned earlier spent most of this week dreaming up my next mod, Velcro seats and a velcro shirt. Looking at all the ways possible to glue my body to the seat without permanent changes to the interior of the car. New thread coming.

Mark no apparent bind on the links. In the trans angle is very good, in the longitudinal just the opposite of what is needed, but that was the compromise.
Bob

#1074089 - 06/11/22 01:07 PM Re: Front sway bar project [Re: mmc427ss]  
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The guy took some great pics for sure. The cars looks awesome.

Diagonal roll looks great, it appears the rear is rolling just a touch more than the front which is what we want. No pics with the front compressed in dive which is what I like to use to diagnose unfortunately though. Although I'm sure the front contact patch is good. I'd like to see the ride height an inch to inch and a half lower over all but I get why you have it where it is.

Any in car video available yet? laugh


Lance
1985 Monte Carlo SS Street Car
#1074091 - 06/11/22 09:41 PM Re: Front sway bar project [Re: mmc427ss]  
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I'm not understanding what you're saying. Rotation about x is roll; rotation about y is pitch, and rotation about z is yaw. So when you say "diagonal roll" (= diagonal rotation most generally,) I take it you mean a combination of roll and pitch? Also, for a rigid body, roll at the front and the rear have to be equal, otherwise, the car would be twisting (not that that's impossible with an MCSS.)

But even with this, I'm not getting what you're saying (??)

#1074092 - 06/11/22 11:22 PM Re: Front sway bar project [Re: mmc427ss]  
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We got a few GoPro videos, will have Jason sent you the best one.

As far as lowering the car it is not slammed but pics on course don't really show ride height. Checked it the other day and it was 26 1/2" up front and 26 3/4-7/8: in the rear. Ground clearance here in this area needs to be a tad higher than other flatlander's areas. Being 99% of the 2000 miles i put on the car each year is back roads here keeping the bottom side of the car scratch free is a primary goal.
Another one of my goals was not to destroy the front inner wells for the sake of slamming a car or having to run outrageous shock compression to control that.

For a ride height gauge a drywall Tee square with a 24" to 28" scale scribed on it, then held against the side of the fender, the vertical plane of the square dissects the hub, another square locates the bottom lip of the opening, = repeatable accurate ride height. When the first change in the original suspension was done 20+ years ago that gauge was made, been a fixture in the shop since. Must have used it a hundred times, more, since.

Will be starting a new post on a seat/harness tonight.
Bob

#1074100 - 06/12/22 01:23 PM Re: Front sway bar project [Re: MAP]  
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Originally Posted by MAP
I'm not understanding what you're saying. Rotation about x is roll; rotation about y is pitch, and rotation about z is yaw. So when you say "diagonal roll" (= diagonal rotation most generally,) I take it you mean a combination of roll and pitch? Also, for a rigid body, roll at the front and the rear have to be equal, otherwise, the car would be twisting (not that that's impossible with an MCSS.)

But even with this, I'm not getting what you're saying (??)


Think about suspension compression on the front and rear outside tires to help understand what I'm referring to. If the rear compresses more than the front under lateral load, the rear would roll more than the front. This would unload the inside front tire more than it would unload the inside rear and would cause understeer.

When the outside front compresses more than the outside rear, it releases the outside rear under extreme lateral roll and this helps the car to turn.

Springs, shocks sway bars and roll center heights all effect this but looking at pics of a car in mid corner under hard load can give you a pretty good indication of how the car is handling, just by showing which tires are getting the most load on them.


Lance
1985 Monte Carlo SS Street Car
#1074102 - 06/12/22 09:22 PM Re: Front sway bar project [Re: mmc427ss]  
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Thanks for trying to help. I think I can translate what you're saying into something of physical coherency.

#1074140 - 06/18/22 06:55 AM Re: Front sway bar project [Re: mmc427ss]  
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Need to do just a quick update.

Have put several miles on the car so far since finishing the three piece bar install. Today's drive, maybe 10 miles had a dual purpose but primarily to test the A/C vent temps on a 90 degree day. Two people in the car and a digital gauge, tweaked the R12 a little more when i got the car back to the shop. Enough said.
The second test drive reason was i softened up the suspension a good bit just by adjusting the shocks. Up front 6 - 6 on a 16 scale, in the rear triple adjustable everything zeroed out.

Should note here there is an adjustable Spohn rear sway bar on the car. Typically in the past the bar was set to the weakest setting for all but drag racing were it would be set at it's strongest setting. The bar is 7/8" diameter and 35 length with 6", 7", 8" arm length available. that calculates to 6" = 502, 7" 364 and 8" 275 lb per inch.
As part of the suspension "what happens when you do this project" playing with rear bar rate after doubling the front rate is something I'm entertaining. Wish there was a place to be able to just do fast circles. "What do they car that?."

Checked the ride height, tire pressures, toe out several times now. Car has 5/32" toe out currently. Have checked it several times and yep, it's toe out a little more than an 1/8. Will leave it there for now. The old BFG 16" Comp are going back on the car, next Sat is the Carlisle road trip. No need to use up some good rubber off those RT 660 tires. Those BFG Comps are a 255/50x16 and a very good tire for this car on the street. But they are near 6 years old now, not wearing out, just aging out, but still look good.
To bad most of the sizes of those Comps are discontinued now.

At full lock left the right tire was just touching the top corner of the sway bar arm over there. Yes it took the powder coating off that corner but touched it up with my favorite Rustoleum Black. Then added some steel to the spindle travel stop on the left side. Yes you adjust the right side front tire touch on the left side LCA spindle stop.
This should have fixed the touching , but no. The two bolts that now hold the stop to the LCA (previously riveted to the LCA) were slotted making the stops adjustable several years ago. Besides adding steel, weld, to the stops the slots were made a little longer. And the area where the paint was rub off of the arm was blacked out with a Sharpie. Today's inspection after the road trip showed no touching. Maybe now have that touch adjusted out of the steering linkage.
Next time on the alignmnet rack will check to see how many degrees of full lock turning angle I have left.

In process of working on butt seat stick. New sway bar requires an improvement in that area. Also have been working on my driving skills and why they get thrown out the window on course.

So, today's evaluation of the suspension just cruising around the countryside with really soft shock settings. Don't forget it's 90 degrees outside and 44 degree air coming out of the dash vents, it was comfortable in the cabin. The first thing you really notice is how flat the car is at near any corner and how you just drive the car around a corner, no thinking about it. Love the feel of that huge front bar, 98 % of the time. On nice flat roads you wouldn't know anything much is different, just very firm with the 700 lb front springs and 200 rears. As mentioned shocks are soft all the way around. Only on a couple intersections pulling up to a stop sign on an old back road when the payments is unequally rippled left and right does that jostling of the car side to side show up. And I can say it doesn't bother me much because you can see it as you approach it and feel it in the steering wheel. The passenger doesn't have that luxury of reacting to that motion as the driver does. My wife wouldn't like that at all.

The guy that welded the arm for me and I were talking about using a huge bar. For some drag racing chassis builds a super high rate, huge bars are used to help launch the car level, reduce the frame/car flex by loading both sides of the frame equally. He asked if I was concerned about running that very high rate bar constantly on my car. He said the general rule for a huge rear drag racing sway bar is to remove a link when/if that car is street driven, breakage of sway bar parts the issue. My thinking was the balance of the car would be more of a problem, oversteer extreme, snap oversteer, with a huge rear bar and small front bar on that drag race car setup with a huge rear bar.

Well more street driving coming, a couple long road trips and at least one more autox to get a feel for all this new found front sway bar rate.
Bob

#1074141 - 06/18/22 12:41 PM Re: Front sway bar project [Re: mmc427ss]  
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I believe I predicted that you'd love the new bar, even on the street. It's what these cars need for sure. Glad you are happy with the result...


Lance
1985 Monte Carlo SS Street Car
#1074143 - 06/19/22 08:33 PM Re: Front sway bar project [Re: mmc427ss]  
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A mostly credible statement but "need for sure" isn't proven.

Last edited by MAP; 06/19/22 08:33 PM.
#1074241 - 06/30/22 05:50 PM Re: Front sway bar project [Re: mmc427ss]  
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My cousin Robbie makes some fun courses, especially considering the confines of the lot that he has to work with. He also puts a lot of effort into making sure the events run smoothly, getting there the night before to set up the course unlike the other club more local to me that doesn't get a car off before 10:30.

I just picked up some RT660's myself. I'm excited to try them out.

I think you'd be fine running in 2nd gear (unless you are really worried about the engine). Most everyone runs 2nd. I have 4.10's and only a 5500 redline and I hardly ever use 3rd, and only for a couple seconds if I do.

#1074246 - 07/01/22 05:10 AM Re: Front sway bar project [Re: mmc427ss]  
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Ran in that lot twice last year and setup was nearly the same each time. I was pleasantly surprised this last time, longer, a little faster, paddock was even much easier. He does a very good job and keeping everything moving. It helps that he has a great group that all work together well.

I have nothing bad to say about the RT660s. I do know there are no expectation of mileage, two years 4K was my goal. This past weekend I pulled them off the car and put the old Comp BFG on for the 220 mile Carlisle road trip. Two reason for that, no need to run those 200s up the turnpike at 70 mph, second reason is I'd rather get caught on a wet highway with the Comps. The Falkens are near slicks when push comes to shove, no hydroplaning please.

My second gear is 2.07, third 1.43. Running in second my son hit the rev limiter a couple times. 6K rpm in 2nd is 54 mph. I laid off the throttle and ran the course slower to respect the rpm. We found running in 3rd with the 4.11 at 4500 is 58 mph, right at max torque. Now with the 3rd ratio of 1.43 we kill a lot of that torque, for the better. Made the car easier to drive, and a little faster.

Now with over 500 miles on the new sway bar setup it was time to see what all those parts moving around looked like. The arm to torsion bar spline attachment was initially a problem on the left side, it had moved outboard after the first couple trips locally. That arm was removed from the bar, all splines cleaned and with no lube reinstalled dry. The pinch bolt and it's lock nut were then torqued to 37 lb. So that now after 500 miles hasn't moved.
But the right side was found moved outboard when inspected today.

So that made it necessary to do the process of adjusting the length of the links. Why?
Because when i put the last bolt of the 4 link bolts in it's home at the first final install of the bar links that right side link's length had to be shortened 1 1/2 turns to allow the bolt to get into place. On that bolt's 1/2-20 thread that would be .075".
Doesn't sound like much but curiously for some reason the ride height of the car left to right up front changed by + or - 1/16" side to side. What was 26 1/2" each side was now 26 7/16 on the right and 26 9/16 left. Hummmmmmmm.

When working with these three piece bars with everything mechanical solid it takes a while until you figure out how to jack each side of the front of the car to unload and reduce the load/ tension at the links. No easy feat And with my setup to access the link bolts the wheel/tires is removed. Then you set that right LCA down of some wood and put weight back on that corner by lower just that corner with a jack at the #2 body bushing. Then you put a scissors jack under the left LCA so you can apply force upward as necessary there. Yep it was a juggling act for an hour or so.

With tension off the right arm the pinch bolt was removed, a block of wood and a couple taps of a hammer and the arm was moved inboard now about .100" set back.
I had bought ARP 3/8-24 x 3" a little while ago, cut them down to correct length and installed that bolt, SAE .060" washers and Jetnuts, torqued to 45. Changed out the left side also so both are now ARP at 45 lb.

Next up is drive the car as much as possible, keeping an eye on the arms to see if they move again, and will keep an eye on the ride height to see if that .075" adjust to the right side really does influence the left side. I knew when I put that links in the first time i would be revisiting that again. Hoping now I won't need to do anything to that new 240 rolls of nickels sway bar. I do know it really changes the way the car drives, for the better. 90 % of the time you don't even know it's there.

Oh, have ran the S10 ZQ8 LCA bumpstops for many years now at their stock length. At my ride height the stops were just touching the frame. Anyone familiar with these bumpstops knows they are pretty trick, don't add much rate initially but really help when crushed at lot. I ran them through the bandsaw and disc sander and shortened then about 1/2" each. Now have about 3/8" clearance between them and the frame. They help and do there work on the back roads here when the car is using a lot more suspension travel.
These bumpstops leave their footprint on the frame where they contact it. Will need to make that area virgin again so I can monitor it.

The local car show is this Sat night, 500 cars or so but looks like rain late in the evening. I did wash the turnpike bugs off the car tonight.
The trip to Carlisle for the big show last weekend, didn't wash the car, no need to, it's a 50 footer.
Bob


Last edited by mmc427ss; 07/01/22 05:11 AM.
#1074248 - 07/01/22 01:35 PM Re: Front sway bar project [Re: mmc427ss]  
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Are you certain that when the bar twists in roll, its not shortening up enough to push the swing arms out?


Lance
1985 Monte Carlo SS Street Car
#1074249 - 07/01/22 09:23 PM Re: Front sway bar project [Re: mmc427ss]  
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A cylindrical rod lengthens slightly with twist, but its diameter shrinks slightly as well. If the arms are moving, the cause must be something else, like maybe the distortion of the frame.

About spline engagement, adding lubricant like anti-seize will not reduce the strength of the joint.

"I do know it really changes the way the car drives, for the better." Can you explain this in detail? How do you know it's better?

#1074251 - 07/02/22 09:24 PM Re: Front sway bar project [Re: mmc427ss]  
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Follow-up: I know the two comments I made above may be unintuitive. About the rod lengthening under twist, even the US gov't engineers had doubts and commissioned a study roughly a century ago. The theory behind it is surprisingly complex; online searches will guide you to papers available behind a paywall. Just in case there are any MEs out there, basically twisting causes much of the interior of the rod to see radial compressive stress, constricting diameter. The length thus grows as a Poisson effect consequence of this diametric constriction.

About anti-seize not reducing the strength of the spline engagement, I'll give you a close, if not exact, analogy. If you use a factory SBC-1 block, you know that the head bolts live in coolant. To prevent leaks, you use some kind of high viscosity sealant that acts, for better or for worse, as a lubricant. That is, under torque, the fastener is easier to tighten, rather than harder to tighten, without the sealant being present. And yet, we have no fear that we will sacrifice the strength of attachment of the head to the block despite this fact.

About the claim that the car handles better with the extra-heavy front bar, I'm maintaining an agnostic opinion about this until and unless I see numbers proving that we can go around a circle at constant speed faster rather than slower. Provided we're not compensating for a serious camber problem, I contend the heavier front bar will increase understeer and make it go slower, but the bar may provide a net benefit for a front-heavy car that needs all the traction it can get from a lightly-loaded rear in a regime where we're accelerating to the maximum in every direction at one time or another (e.g., auto-crossing.)

But I'll say it yet again: the best solution to this problem is to shift the car's COM rearwardly. And we can at least take baby steps in this direction by lightening the front of the car, like substituting aluminum for iron wherever possible, getting rid of the AC, and moving the battery to the trunk. By doing this on my '78 Malibu, I got weight distribution to 53%/47% (F/R); you guys seem to be closer to 57%/43%.

Futzing with the front bar is really just a bandaid fix. There's also the transient versus steady-state response thing which is confoundedly easy to confound (!) There is absolutely no question that if we increase the car's stiffness in roll, we quicken its steering transient response, no matter how poor the car's weight distribution may be.

Last edited by MAP; 07/02/22 10:03 PM.
#1074259 - 07/04/22 06:03 AM Re: Front sway bar project [Re: mmc427ss]  
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Mark I'm not smart enough or desire to tackle the question of is the bar shorter or longer under max stress. I did look for an answer to that question and what I found was no one at the internet level could give a definitive, YES. The guys at Eng-tips, Physics forum the question was beat upon, helices, poisson, FE, and a bunch of formulas but no simple, yep, a bar this long at this thickness and this degree of twist will do this grow or shorten this much.

Lance had mentioned his bar got shorter and suggested allowing 1/8" in the mounts to compensate.
My mounts are 1 3/4" DOM tube, 3 1/2" long, with a shouldered Delrin bushing on each end of that tube. That mount is duplicated on each side of the frame. On the inner bushing a stainless steel collar, clamped to the torsion bar, rests against the inner bushings on both sides. This allows near zero movement of the torsion bar side to side.
On the opposite side of those mounts, outboard side, the arms are mounted via 1 1/4"-49 splines and pinch bolts. A clearance between the arm and outer mount bushings, 1/8" per side, was built into the locating of that mount/outer bushing to provide that 1/8" clearance per side. Also the arms are set back from the ends of the torsion bar/splines about .100".
Now have the ARP 3/8-24 bolts and locknuts, increases the torque-crush i can apply to 45, up from 37 to see if that pinches the arm to the torsion bar.
It is pretty easy to see if the torsion bar is growing or shrinking once the bar is worked hard enough to cause it to stress. Just monitor the surfaces of the delrin bushings and the collars for the shine.

As far as a mechanical reason for the arms to be working off the splines, I'm sure alignment of the torsion bar relevant to frame and LCA is possible. When the mounts were cut into and then attached to the bottom of the frame rails you find there is no good way to make the torsion bar exactly in the correct position, there is nothing to measure off of, square to. You end up doing a 5 3/4" setback on each side from the original sway bar location and hope you are good to go. Tape measures, squares, and eye balls got that job done, but you are still guessing.

I get the head bolt comparison. My SBC block has all blind head bolt holes, it a Dart block. I Neversez a lot of bolts, rotors, drums, wheels, spacer, just don't see the point to using it on the bar splines. Both steels being less susceptible to rust and the arms easily being able to use a puller on if necessary, and the car seeing very little water, dry will be the plan for now.

I've seen pics of the arms being welded to the torsion bar at the ends, I've seen two pinch bolts per arm, even square bar ends. Over the next year of driving this bar should, will be able to get to the point of just being something you just don't need to worry about anymore.

What I've been looking for years now are always the bandaids and have known since i bought my A-Body new in 1972 that it's about polishing these turds.
There is a corner locally that falls into that "belongs on a race course", have driven around it a thousand times, whether on the way with the family for ice cream or pushing one of my cars. Way back in like 72 in my new Chevelle SS, near state of the art Polyglass GT of the day, F41 suspension and only a SBC, found the limits of that front suspension, knew 55 mph was the max.

Last night an old friend came to our downtown car show. The weatherman's promise of downpours cut attendance in half, only maybe 200 cars, and of course it never rained. Autox related, the glued to the nose of the car bug count I took care of before I went to the show. Having to compound the nose to remove the bugs you realized they were possibly a year of more old, last years couple trips up the T/P to autox. As I mentioned it doesn't bother me the car has a ton of patina, and birthing marks. Don't get me started on the paint penitentiary, heard another horror story last night.

Quote:
"There is absolutely no question that if we increase the car's stiffness in roll, we quicken its steering transient response, no matter how poor the car's weight distribution may be."

Absolutely. After the car show that friend and I went for a long ride in my car. He wanted to see where some of the HotRod TV episodes were shot on the PHILLY builds with Tony Angelo. The Chevy G8 cop car 1000 hp build was hub dynoed less than 1/8 mile from sitting here. Their Philly Shop not far away, the 2nd gen Nova with the 4th gen G front clip and the 05 Impala SS with a turbo 3.8 up front, and an identical engine/transaxle setup installed in the rear. A true all wheel drive ridiculously fast 6th gen almost Monte. Kinda neat to have a Motor trend/hot Rod TV show car builds built in your back yard.
Anyways that corner the 72 SS plowed way back in 72 last night got an "oh wow" last night at a little more mph from the guy in the shotgun seat. The car just instills more confidence, is way more responsive to any movement of the wheel, just point and shoot,. All the shocks are backed off, the front DA are 6C, 6R, the rear TA shocks are full soft on all three setting, 1-1-1. front springs 700, the rear springs 200-100. The ride quality at those setting is noticeable very good for a relatively well connected frame/body and all solid suspension bushings. It's surprising at slower speeds and even when running the back roads at higher speeds and navigating all the quick rising and dropping section of highway that test fast near full droop to near full compression of the suspension in a second.

When i was a kid we had some toys we made. Being into control line airplanes with sometime iddy-biddy ICE engines we built a few tethered cars just for S&G, of course all prop driven. We learned pretty quick speed kills,they were destroyed pretty quickly. The drag racing, straight ahead didn't make one run, crashed. The next time it was see what they did if you tried to run them in a circle. The problem then was with only the little league baseball diamond to run them on dirt was the only option, and another FAIL. May have been 12 years old at the time.
The same problem I have today. Finding the 200 + foot circle in a parking lot some where that's 400 foot for runoff, has good or better blacktop, or concrete, is near perfect level, AND the big problem, being allowed to use it to run my car in circles for hopefully high speeds and not get arrested. Believe me I've looked for that happy place. I had to find a place just to be able to check the car's turning radius. People look at you funny when you have a 50' tap measure laying in a parking lot. Since adjusting the turning stops recently i will need to revisit turning radius again, more looks of curiosity coming.

July 16th autox not going to happen. Next is 8/20 which i intent to do everything necessary to attend that Sat with my son and I driving. The following Sat is UMI KOTM event, 8/27. So autox, with a 175 mile round trip drive and the next weekend do the 550 mile drive to the KOTM. The will put some miles on the new bar setup.
Ran into my guy that TIGed the arms together at the show last night, "did they break yet?" Nope.
Bob

#1074262 - 07/04/22 09:28 PM Re: Front sway bar project [Re: mmc427ss]  
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Hi Bob,

The rod lengthening under twist was suspected but not proven in 1920. But today, it's an established fact.

I believe something else is causing the arm(s) to move longitudinally on the torsion rod. For example, If I estimate how the frame grows with the heat radiated by the engine, I get about 0.030" across the frame rails. That's a small, but still significant fraction of your clearance. The Delrin itself grows a lot too with exposure to heat.

Who knows what other interference factors may be at play here.

Maybe you should measure your arm clearance with everything nice and hot; I suspect you may get a surprise.

Just curious, how fast is your SS going through that racetrack corner where your '72 maxxed-out at 55mph?

The matter of quickening steering transient response and the additional confidence it inspires in the driver to push the car harder should not be underestimated. It may be responsible for a significant improvement in auto-x times, even if a steady-state circle test would top out at a lower speed. But what would be ideal would be a higher, not lower, maximum lateral acceleration and all the positive attributes you claim for your stiff front-bar configuration. That will not happen without shifting the car's COM rearwardly - IOW, you need lots less weight on the front axle and more on the rear.

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