How much room do you have until you hit the bump stops? You may be low enough that the bump stops are before the bottom of your normal suspension travel.

 

How much room do you have until you hit the bump stops? You may be low enough that the bump stops are before the bottom of your normal suspension travel.
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Good question. I have tons of pics of the stops but all while the suspension is hanging while on a two post lift. I’ll take a pic with it on the ground.

Check to make sure you are not riding on the bump stops I dont know if the springs you have would have lowered the car to that point, but it can't hurt to look. Shocks not the correct length?

The shocks came with the Hotchkis kit so I’m assuming they are correct.

 

Check to make sure you are not riding on the bump stops I dont know if the springs you have would have lowered the car to that point, but it can't hurt to look. Shocks not the correct length?

 

Remembering some of your earlier posts on this, how low is your car? Springs, spindles?

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I currently have 2” dropped spindles. The springs are 1” lowering but that turned out to be too low so I have spacers (from Hotchkis) in the bottom pocket so they are equals to stock height springs.
Hotchkis says the springs are rated 515 lbs. I’m running a featherweight V6 so the springs might be to still for the load they are supporting. Could the frame be flexing some where the springs are not?
I have no idea if this is possible, I’m just thinking out loud.

 

515 lb spring shouldn't be ridiculously harsh.

What about your shocks? Are they adjustable?

Are you able to remove the shocks without separating a ball joint?

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So, what ever distance your springs are compressed to at current ride hight is what it takes to hold your car at that hight.

If they were compressed two inches that would be 1030 pounds.If you put 350 lb springs compressed three inches would be 1050 pounds. So maybe stock length springs @350 lbs with the one inch sparer would be close.

If it were mine I would either test drive it without front shocks or buy some cheap Monroes. Same goes for the sway bar, its easy to disconnect and secure for a test drive.



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are you running poly body mounts?

 

BTW, I just this weekend changed my front springs from 750 lb (talk about hash) to 550 lb springs. With an LS, I was working in that same 1050 range at ride hight. It does ride firm but in no way would I call it harsh.

Let's be clear all of our Individual assessments are subjective.

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Springs hold the car up and shocks dampen the ride. You have a very light weight engine and maybe too much spring. The lowered spindles may not be helping either. If you have the standard spindles maybe reinstall those first and see if that helps, if not might have to change the springs.

 

Body mounts are rubber, not poly.
I do not have the stock spindles any more, plus I like it low.
If I got new springs, I would get t stock height and take the shapers out. The spacers are just 1/4” aluminum plates the lie flat under the springs bottom rubber seat. I could trim from there.
The shocks can easily be removed through the bottom of the control arm. Same for the sway bar. I’ll try different runs with/without these items in various combos.

 

Body mounts are rubber, not poly.
I do not have the stock spindles any more, plus I like it low.
If I got new springs, I would get t stock height and take the shapers out. The spacers are just 1/4” aluminum plates the lie flat under the springs bottom rubber seat. I could trim from there.
The shocks can easily be removed through the bottom of the control arm. Same for the sway bar. I’ll try different runs with/without these items in various combos.

AFIAC the best and most relevant question in this thread was asked by two different members here in post # 2 and #3 about the possibility of the rubber bump stops on the front upper and lower control arms possibly hitting the frame during suspension compression. I didn't see anywhere in this thread where you replied or answered that question. Did I miss it? You can always cut those rubber stops down with a sharp blade. They're usually double the height of what's needed anyway. That's a common trick that us drag racers use to gain a little more front suspension travel. But you don't have to be drag racing the car to benefit from that. Especially when the bump stops being so tall might be the reason you're experiencing what you have been.

Just remember, when you modify the car with aftermarket parts, although there are certain performance advantages to that, with those advantages often comes the domino effects of the modification in question. You have to become your own engineer at times to make the aftermarket parts work correctly, and/or make then play nice with the rest of the vehicle. And I can assure you that many aftermarket parts manufactures are NOT always going to make you aware of those domino effects. I've learned that the hard way in the past myself. The aftermarket parts places, ( distributors, retailers and manufactures) main priority is to sell you parts. That's it.

 

I‘ve mentioned in some earlier posts that I’m contemplating either lighter springs or a smaller sway bar. I’ve got to do something, it’s just to harsh. My frame is not boxed either. Would this help or hurt?

Since you asked this question, the general rule is that the stiffer the chassis is, the softer you can go on springs and shocks amd smaller on sway bars and get the same level of performance, with a much more agreeable ride. All that big stiff stuff is just a crutch for a chassis with too much give in it.

 

Can you press down on the fender and bounce the front end up and down or is it too stiff to do that?

 

I did mention the bump stops in my reply (post 4) but it’s kinda buried in the post. I’m going to look at them tomorrow.


I cannot budge the fender with my 200 lbs.

Since you asked this question, the general rule is that the stiffer the chassis is, the softer you can go on springs and shocks amd smaller on sway bars and get the same level of performance, with a much more agreeable ride. All that big stiff stuff is just a crutch for a chassis with too much give in it.

Yes, I wished I had boxed the frame. If I could find another frame at a good price I would box it reinforce it and swap it in. I need the car for transportation so I can’t have it down to remove and box my current frame. I’d box this one after and resell it.

 

How does it act in the rear?

I have had several Chevelles with poly bushings in the upper rear control arms, and it created a very harsh ride... Doing nothing other then swapping out those upper bushings with rubber or arms with spherical bearings actually improved the feel and handling of the cars... The factory upper arms actually flex, along with the bushings. "boxed" uppers with still poly bushings are too stiff to flex when trying to articulate, and end up increasing the spring rate significantly by acting similar to "torsion" bars...

My latest project isn't set up to handle, but I did add Edelbrock adjustible upper arms with Spherical bearings at one end, and Currie Spherical bearings in the rearend housing uppers ears...

 

I've always subscribed to the less spring more swaybar theory for a street car. Too much spring just isn't pleasant for much street driving, plus it really depends on the quality of the roads in your area. In the NE you get all the freeze/thaw cycles that destroys the roads like I do here in Iowa. I've been to some of the southern states and always marveled at all the smooth blacktop roads, has to make for a nice driving experience.

 

I bounced on the fender just now and it moves but just barely.
I can’t get a tape measure on because my back went to shi t yesterday but it looks like about 4” from the rubber bump stop to the contact point on the frame.same with the uppers. No evidence of the lowers touching. It appears the uppers touch when I lift the car.
What I did notice is that the bottom of my sway bar has pretty good scrapes on it where it appears to have hit the outer tie rods. Static there is about 1” between the two.

 

Another thought, how much does the weight of the tire/wheel/brake combo factor into ride harshness.

 

If you're just using the car as a driver and not running tracks or autocross, you don't need that spring rate, especially with the aluminum v6 set back as far as you have it, there's no weight on the nose.

I'm running an iron block LS, have stock moog 6200 springs (290lbs), stock style gas a just shocks, and a huge sway bar up front. Couldn't be happier with the ride. It'll try and throw you out of the seat if you cross railroad tracks caddy corner, but normal driving you'd never know it was set up to corner. My bushings are pretty much solid with no cushion and only time I notice that is when I hit a sharp bump in the road.

 

Related to this, how much movement is there between the body and the frame? I have two points where the front valance (mounted on the body) is about 1/4” from a bumper support bracket (mounted to the frame). They were touching and making and awful noise until I found the problem and bent the valance edge up a little. Is a 1/4” enough?

Also, is anyone running rubber isolators on the top of the their front coil springs?

 

I'm unsure on a 67 about body movement, my 64 has 0 rubber between body and frame up front. If stock rubber I would assume some movement as our frames are not the most rigid around. I'd drove around for a bit without wheelwells and you could literally feel the front end squirming going around curves. Once I installed wheelwells it seemed to triangulate (stupid word to use) the sheetmetal and really stiffen the front up. I would love to get some down bars between the firewall and frame horns to better lock the front end in place.

Really glad you found your noise, you'd never think that would have been the case.

I removed all the isolators from my springs when I installed them. They were originals and in bad shape, wasn't worried about NVH getting into the cabin.

You can somewhat see how much body movement I have at the autocross. The runway was extremely gravely / harsh, really tore into the tires and my 500 treadwear tires didn't want to bite too much. Front end pushed, could throttle steer the rear but considering most of the cars were hondas/miatas I was trying not to be the drift idiot. I was still an idiot as I'd missed one corner of the track.

Here's my first run from the outside can better see how little body roll I have, completely missed a slalom on the backside and turned it into a dragstrip.. Had my daughters and her friends with me on the walkthru and was 100% distracted. Not my finest moment.

That's the stock spring rate, stock style shocks, and 1 5/16" front bar with unknown name brand rear bar tied to the lower control arms. Car rides like a stock 64 until you go into a turn and it stays flat. At some point I do want to go with a more aggressive spring but don't want to wear kidney belts driving it. That's the way my blazer was and didn't really enjoy driving it. My chevelle rides better than my 07 Yukon and wife's '14 terrain denali.

 

Those were pretty cool videos. I could see some body lean from the outside shots but not bad at all. That’s with 290 lbs springs? Stock height and stock spindles? Do you know your front axle weight?

 

There is a little lean due to the "soft" springs but the sway bar kicks in pretty quick and keeps it flat. Those videos were with Moog 6200 front and Moog 6197 rear springs, stock gas a just shocks. The car rides like stock going down the road. I have cut coils out of the rear to bring it down some. Abrupt bumps are a little harsher due to little to 0 bushing deflection, but you'd never know it can pull curves. I have had so many passengers scared sh!t less grabbing for anything they can when I take a corner because it rides so unassumingly well.

CPP 2" dropped spindle, 0.5" lower ball joint, chinese lower tubular a-arm (global west knock off) with aluminum/delrin bushings, and SPC adjustable upper with sliver thin rubber bushing. Hellwig 1 5/16" solid front sway bar, Cooper Zeon RS3-G1 255/40/17 500 treadwear tires, LS1 brakes. No idea what my front axle weight is. I have the iron block 6.0L (LQ4, 364cuin) engine set back to the firewall, internet is saying it weighs 520lbs while SBC with iron heads weight 575lbs. Battery is in the trunk and running 2000 Z28 electric fans up front.

As stated before I do want to go with a stiffer spring to get a little more bite out of the tires, but not to the extreme that I can tell what side the penny is on when I run it over. Also when I drive the car to work everyone wants to ride with me at lunch. Work with some big boys and the tires do scrub sometimes.. Other than that, 0 drama. Have been on multiple long hour journeys with no complaints other than exhaust being too loud.

 

To simply answer your original question; no. The suspension is designed to flex (if it does not, it is not doing its job); the frame is not (but it does 'deflect' ever so slightly under load). The suspension can be too stiff (relatively) for the application/owner's desires.

Parts can also be installed wrong. For example; a sway bar should be installed at 'ride height'. No wheels hanging down. One can 'lock' the suspension from flexing with improper installation.

Also, mis-matched parts, modified parts, etc, can cause problems. For example; a spring has a 'installed height' (along with load, compression rate, and other specs). Install a spring with shocks that are too 'long', and the spring can not compress as it was designed.

Simply more examples of possibilities. When one deviates from the GM 'design'. They become the 'engineer'. NOT being critical in any way, but some folks are not qualified. AND after market vendors simply want to sell parts and make money. The 'good' ones are helpful (if asked).

Just trying to be helpful.

Pete

 

I’ve had mismatched parts before and I know that can be an issue. That’s why I bought everything, front and rear in one kit. Including shocks and sway bars. All matched.
They do offer small block and big block kits so I went with small block kit and that might have been the mismatch. My engine is a lot lighter than a small block, I’ve got a pretty small aluminum radiator, manual brakes and a minuscule battery.
I think my front end weight (1760 lbs) might be too light for 515 lb rated springs.

 

I had 500 # Eibach springs in my 65 when I first built it 20 yrs ago. Hated it, super stiff and harsh. I went back to a 350# spring that I cut to get the ride height I wanted and installed 1-3/8" swaybar in the front and a Helwig Pro Touring swaybar in the back. I think the rear springs are 150#. On smooth roads it rides like a stocker but hardly rolls over much on the on and off ramps!

Less spring more swaybar.

 

Thanks Jeff. I think I’m going to go to a lighter spring too. I know it breaks up my suspension “package“ but it’s just to stiff.
I’m thinking of the Moog 5244 which are stock height and 315 lbs rated. A little lighter than your 350 lbs springs but my engines lighter too.

 

I ran a pair of 5244's in a '67. They're listed for SBs with A/C or standard BBs. You may not be satisfied with the ride height with your lightweight V6.

 

You'll likely have to cut the 5244 some to get the ride height you want which will increase the spring rate some since there are less active coils....

The Math Behind Cutting Coil Springs - EATON Detroit Spring

Does cutting a coil change the spring rate?

www.eatondetroitspring.com

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The Hotchkis springs I had in there were 1” lowering springs but I had two Hotchkis plate spacers under them so they were back to stock height. This is because I also have 2” dropped spindles and it was just to low for a daily driver

5244 springs (315 lbs/rated) with my front end weight of 1760 lbs should be:

1760/315=5.59”. Free height of 17.75-5.59=12.16”. The stock installed spring height is listed as being 12.59” so if anything I thought I might still need to use a spacer.

If I use an estimate for just the unsprung weight of 1560 lbs, it works out as follows:
1560/315=4.95 - 17.75-4.95=12.8”. This would be about a 1/2” taller than stock.

Am I looking at this correctly?

 

Well apparently there is something wrong with my math. The new springs raised the front about 2”.
Were my math formulas off?
Did I miss a step in the calculation?

 

Doesn't surprise me. Those springs gave me a pretty high stance, (probably 1 1/2" higher than stock) on my '67 (in my avatar) with a big block. I would post a pic, but photobucket nuked the web & all the pics of that car are on my old laptop. I'll try to dig something up.