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lowering 68 GP

  
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lowering 68 GP

 
69GP_WGF 69GP_WGF
New User | Posts: 21 | Joined: 12/13
Posted: 12/05/13
06:35 PM

OK, I have a 69 GP.  It has about 90k miles - and engine has not been apart - second owner did basics to get it running, a cheap paint job, and some new interior parts.  As you can imagine - it sits lower now than it did 44 years ago.

I want to add new springs and shocks (and along with upgrades to brakes and steering, I should have a radically different driving car).  I like the look of the current stance, but assume it is sagging from the years.....  I'd hate to add new springs only to find that the car now sits so high that I am unhappy with it.

To lower this car, is it better to do it with drop spindles or with springs.  Now, I understand that you don't want to simply cut out coils (always amazes me that anyone would still do this).  It seems to me that modified springs would possible degrade the ride quality - if there is less spring, but stiffer spring, the car would have to have a stronger spring to deal with the decrease in travel, right? IF one goes with drop springs, should he add coil over shocks?

What are the pros and cons of using drop spindles v. drop springs?  

69GTOby 69GTOby
Guru | Posts: 1114 | Joined: 02/09
Posted: 12/05/13
07:04 PM

Well, drop spindles keep the ball joints out of unfavorable territory.  My understanding is that if you lower a car, the ball joints are exposed to more extreme angles when the stock height spindles are used.

Take a car lowered using shorter springs while everything else stock.  Picture the suspension when viewed from the front moving up and down as if over bumps.  Now, picture a totally stock suspension in the same way.  It is higher off the ground, the A arms are angled differently, the ball joints are moving around their normal location.  Take a ball joint in your hand.  The geometry of a stock suspension is designed for that ball joint to be oriented such that the threaded post with the ball on the end can move around in that socket and not come close to the edges of the socket.  The idea is that drop spindles on a lowered vehicle return the ball joints to their proper "happy" spot.  That's my understanding anyway.

Dude, I would just keep it simple.  Lower the front a couple inches with some slightly stiffer springs, use some quality shocks all around, replace some worn bushings, give it a good front end alignment, etc...  You're not racing the car, are you?  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

wayne712222 wayne712222
Moderator | Posts: 235 | Joined: 10/13
Posted: 12/05/13
07:23 PM

so this is a bad idea right Grin

Wxghnjv

there are several spring suppliers.. i think eaton detroit is one.. that has stock height springs.. but also..reduced height springs...

you will want to get the car weighed.. front wheels .. then back.. then corner weights.   those numbers might help the spring vendor select the proper spring for the proper height..  

69GP_WGF 69GP_WGF
New User | Posts: 21 | Joined: 12/13
Posted: 12/05/13
09:15 PM

69GTO - thanks for the input.  I also agree with you, keep it simple.  I want to spend as little as possible - I will never race the car - just want to enjoy it - and hopefully have some father/son experiences - if I can get the X-box control out of his hand and get him into the garage. So, from what I understand you to say - drop spindles keep the ball joints from being overly stressed due to the difference in the geometry caused by shorter/stiffer springs.  I have some experience, but a lot of this is new to me (I've done basic rebuilds and maintenance, but haven't lowered a car).  But, the car has 90k miles, and is in desperate need of new suspension, steering components - and I plan to upgrade the brakes slightly.  So, I think we are on the same page - I was planning on replacing the springs and shocks, rebuilding the steering/suspension parts (A-arm bushings, ball joints, and so on.  My only planned deviation from stock is to upgrade the bushings (front and back - trailing arms), and add a larger sway bar up front and one in rear (which means I have to add boxed lower trailing arms - and I will upgrade the bushings as well).

In other words, I will do a stock rebuild of the front and back (suspension and steering), but will upgrade bushings, possible add a larger sway bar in front and add one in back - thus the boxed lower arms.  All of this should not be much more than a purely stock rebuild - but should make a huge change in drivability.  But, while I am at it, I was considering lowering the car - and didn't know if I should use shorter/stiffer springs or drop spindles - I think a two inch drop is all I want.

Sorry for the lengthy post - I am new at this.  But, to make sure I understand your advice - you said - lower it a couple of inches, stiffer springs, quality shocks, replace worn bushings, align it and drive it.  You mean lower with drop spindles here, right?  I will replace the springs and shocks for sure, you just mean stiffer than stock, but normal length springs - and drop spindles to get the lowered stance, right?  

69GP_WGF 69GP_WGF
New User | Posts: 21 | Joined: 12/13
Posted: 12/05/13
09:22 PM

wayne - nice pic!  I don't know if that is better or worse than just cutting a coil or two off the end?  Was a coil removed in the middle?  And re-welded?  Wow.

Yeah, regarding my situation - the car has a lot of miles - and the suspension/steering components are tired.  I planned on replacing the springs and adding good shocks all around - which should make a huge difference.

On the steering, I planned on replacing ball joints, A-arm bushings, tie rods, etc., and center link, etc., if necessary - and these changes should make a huge difference in the way the car drives.  I am thinking about upgrading the sway bar to a larger one - and using better bushing everywhere.  On the rear, I want to add a sway bar, and this requires adding boxed lower trailing arms - and I would add the higher quality bushing here also.  Altogether, these changes should make a HUGE difference - and won't be that much more than a pure stock rebuild.  That is, I should get a heck of a bang for my buck with these changes.

Another person suggested drop spindles, since that doesn't affect ball joint angles, etc.

In any case, thanks for the reply - I appreciate it!  

69GP_WGF 69GP_WGF
New User | Posts: 21 | Joined: 12/13
Posted: 12/05/13
09:28 PM

wayne, I was just thinking - hell, I am not an engineer, what do I know.  After looking again at your pic, I guess this makes more sense than cutting coils off of one end - which I have seen done.  This will surely achieve a lowered stance - what effect this has on the spring rate, and how the car handles - I don't know.  I'd never have the guts to attempt such a mod.  But, I am assuming you posted this pic for everyone's amusement, right?  If you pulled this out of your ride - you have to let us all know what affect this had relative to stock springs.

Thanks again.  

idrivejunk idrivejunk
Addict | Posts: 5144 | Joined: 12/09
Posted: 12/05/13
11:32 PM

I wonder if Bill or Peter can change the title of this to 69 GP, 68s are full size. (Strike these sentences too, if you do)

Wayne is good with the jokes, of course that spring pic is a ha-ha. The guy with the welder that day is braver than me!

I touched on this subject in your other thread, 69GP. Spindles front, springs all around, stock type sway bars, proper shocks for the new stance would be my suggestions for mild modifications. Keeping a stock ride height is cool though, I like it because of ride quality and safety.  
idrivejunk

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 458 | Joined: 11/13
Posted: 12/06/13
06:25 AM

"so this is a bad idea right?"  


WOW, Wayne, just when I thought I had seen it all. I'm speechless, lol.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 458 | Joined: 11/13
Posted: 12/06/13
06:34 AM

DROP SPINDLES - If you want a slightly firmer, less boat like ride i am not aware of any stock length front springs that are significantly stiffer than stock. check out year one, ames, opg and eibach if no one here knows. if you can not get stiffer stock length springs then you might consider dropping the front with shorter high perf springs instead of drop spindles. the lowering springs will do both things you want. the spindles will only lower it. you also have the option of using spindles and lowering springs and adding optional spacers to the lowering springs which will raise the front back to oem travel amount but the spindles still lower it. if you use lowering springs only you loose travel equal to the amount you lower it. this is not terrible though because it is a very common thing to do. even though you have less travel lowering it with springs it really won't bottom out much more than it did before simply because you are using stiffer shocks and springs, confused yet?


SHOCKS - White kyb's not the grey ones, grey is for grandma.

You can also get adjustable bilsteins or konis for around 125.00 ea.


CUTTING SPRINGS - Yes you can actually do this on straight wound non honeycomb high perf lowering springs. done it around 100 times but not more than 1 complete coil and typically just 1/3 coil. the lowering springs have optional spacers avail for them in 3 different thickness so you can easily adjust the ride height, they were slightly long with no sapacer for the cars i used them on so we had to cut them.







hundcutting springs - yRES YOU CAN SACTUALLY DO THIS ON STRSAIGHT WOUND HIGH PERF



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