Realizing Mistakes Were Made - 2 Years Later

[armor64]

Hi All, have you ever done something, and realized after the fact you were ignoring all the signs, and then making excuses because "there's no way i messed up... right?".

Well, I've never been happy with the handling and suspension on my 68. Its all factory front end parts minus the torsion bars (pst bigger ones) but its always ridden like a fridge truck. Low front end, jaring over bumps, darting on uneven roads, ect.

Well, after having the car on tall jack stands in the back, and ramps in the front swapping to aluminium heads, and pulling the 727 for a rebuild, everything finally snapped in my head and i realized, potentially, what was wrong.

Ive had no suspension up front this whole time. the swerving towards the center line if the right tires go up on a bump, the thunk going over the little asphalt crack filler lines, the harshness, all of it. at first, i was like "its an older car design, it was never going to be as comfortable as new stuff..." I thought maybe the control arms were fubar'd, so decided to screw the adjusters all the way in, and it still sat at the same height (bumpstops).

as i was thinking i needed to pay 1000's to replace everything with tubular or the like, i decided to go to basics and take a look at each step of assembly, removing the adjusters completely with the nose in the air, and see that the torsion bar insert/cam stays well above the control arm at full droop...

I didnt install the torsion bars correctly... im 1 flat off on the hex indexing, i must not have had the adjuster cam fully down when i hammered them into place ... the only "suspension" i had up front was the sidewall flex on 17in tires (not alot...)

so now i get to build a torsion bar removal tool this week and hopefully the grease i put into the hexes saves me a tonne of hammering or damage as i try to fix my error for $20 in u-bolts and angle-iron.

 

[b5blue]

They should just wiggle back enough.  (I wrapped a rag and vise gripped.)

[Kern Dog]

You were on the bump stops the whole time?

[armor64]

basically ya, with the adjusters where i had them, there was just enough on the nose to not "crush" the stops, but very little to no lift. the compounding "dont worry about it" came around as, I needed to work on a vehicle for my sisters family last year instead of my stuff (95 yukon fix-up), it ran perfect, the stance looked great and it cornered level, plus the smooth roads where i was driving most of the time, could easily forget about issues while enjoying the rest of the ride. but ya, not a proud moment of realization

[Kern Dog]

Smooth roads?
You must not live in California....
The ride height of my car is low too, but I like it.



If my bumpstops were stock, I would be barely touching them.  I made my own using some cut down urethane units. These allow travel before contact.
I have 1.15" T bars with Bilstein shocks. Mine rides firm but not harsh. There is travel but the torsion bars are in play doing their job.

[Mike DC]

Wow, your T-bar rate & height must have been JUST RIGHT for you to ride around on the bumpstops for a long period without damage. 

I once rode on a totally broken T-bar for a few miles (limping home) and it was enough to bend the bumpstop strike plate on the subframe rail. 



Modern vehicle bumpstops have evolved for handling purposes.  It's one of those things the aftermarket muscle car stuff has not fully caught up on yet.  Those softer foam "jounce bumpers" on modern stuff basically work like progressive rate springs.  More like miniature airbags than blocks of rubber.  They also do some minor energy-absorbing (like shock absorbers rather than springs) if the impact is fast. 

[armor64]

i think it was luck for sure, with the lack of damage or anything, ill take it as a small victory that i hopefully wont have to replace anything and no damage was done (except Ego, naturally). bright side, i got the drivers side torsion bar out last night, but the pass side seems to be getting stuck at the outer edge of the rear hex housing. Ran out of garage time yesterday, so going to take a look after work today to see if there is a small dent from hammering it in back in the day, if so, light bit of finger belt sander for clearance and out it will come too (it slides from full depth to that spot easily with the greased ends at least)

[armor64]

Well 1 step closer to reassembly. Got the pass side out too, the cam/adjuster pivot was almost flat out compared to the lower arm being at the 4/8 o'clock position (not cammed down to the adjuster block) so im feeling better about the "1 flat off" on the hex. on the drivers side, with everything at full droop without disassembly, i could not get the torsion bar to go in with the cam sitting on the adjuster wedge nut, it has to cam up about 1/4in for it to align, even taking the brakes and lower ball joint off, it cannot get lower, so it must need to go in at that rotation of the Hex. Basically, the lower arm would need to be hanging straight down or something to get another of the hex flats rotation, so that cant work.

Hopefully Saturday i'll get it all together, get that 1 extra flat (instead of the attempted 2 i was just trying) and will see the nose stay up when its on the ground again!

[matrout76]

Chris Birdsong just put out this video https://www.youtube.com/watch?v=5CX0Wq2pFp8&t=6700s

At 1:51 he shows a bracket that he designed and made to lower the front end and maintain correct geometry, while keeping the LCA off the bumpstop. 

[Mike DC]

Chris Birdsong just put out this video https://www.youtube.com/watch?v=5CX0Wq2pFp8&t=6700s

At 1:51 he shows a bracket that he designed and made to lower the front end and maintain correct geometry, while keeping the LCA off the bumpstop. 

He will definitely get added bumpstop clearance and negative camber from that plate setup.  That's an interesting way to get sort of a taller spindle effect.

But I wouldn't want the roll center change that it brings.  These cars had front RCs pretty high from the factory.  I would rather be lowering it (in moderation) than raising it.  Just my opinion. 


The tight front bumpstop clearance on these cars can be a problem when it comes to handling.  Both for lowering the front end, and for fitting modern bumpstops in there.

But increasing the up-travel of the front wheels can get you in trouble if you bottom out hard.  The factory designed it so you can have a blown tire, and bottom-out the suspension on that corner, and it still won't quite dig the chassis into the ground.  Creating more bumpstop clearance is eating into that safety margin. 

Modern wheels are a mitigating factor though.  Bigger diameter rims give you more room because blowing a tire doesn't drop that corner down quite as far (the rim hits the pavement sooner.)

[armor64]

thanks for that link as well, I've only seen Birdsong when he was referenced in a roadkill episode where he got their General Mayhem back into shape, or a few years back with his window regulator setup/parts view, interesting stuff.

I was able to get suspension properly this weekend, as a test, i decided to take apart the driver's side brakes(also measured the spindle from the CPP brake kit, so i now know its 1 3/8in rear bearings, if i want to upgrade brakes later), and lower balljoint to drop the LCA all the way down on the pivot to see about getting "another 2 flats" on the hex bar from where i was, but to get it, the bar would literally be pointed straight down, no way to get it back into play from there. So reassembly of brakes and balljoint, i hammered in the torsion bars with the adjuster all the way out, and the cam 1/8-1/4in above the threaded blocks, and everything went in OK.

As a test, i ran the adjusters all the way up, leaving about 1/8in from the bolt face, and putting the car down, it was at full height, looking almost like a Gasser with all the weight in the trunk (temp storage). running the bolts down about 1/4-1/2 way in their threads instead, and its sitting nice and in the middle of travel, for the first time in my ownership of it.

my only remaining issue is that the drivers side LCA wants to walk off the bushing slightly backwards. While seating it into the crossmember, it bounces back past the wire clip. I had to lightly ratchet strap the LCA to the sway bar, and then pop in the clip. Ill be testing the rebuilt trans around the block this week and will recheck the clip is seated every loop, just in case.

[armor64]

Last-ish update on this, it looks like a success. I returned the adjusters to a more reasonable 1/2 way in and the front of the car is up a bit still but looks good, i will adjust a bit more this weekend. Took the car for a test loop of a couple miles to make sure everything felt good and was amazed at how different it is. total changes from the last winter drive before parking were: Properly Adjusted Torsion Bars,New Bilstein B-Body specific shocks, Rebuilt 727, Edelbrock Aluminum Heads, Doug's Headers, Hyperspark Dizzy/coil.

Its practically a new car. Shifts are crazy fast, easily chirps second, road bumps no longer send me into oncoming traffic, exhaust Drone from 75-85km/h is gone. I have to readjust the shift rod (have to shift past D slightly and back to get into D) and doesn't downshift from 3-2 on a acceleration test, but i also dont think i went above 50% throttle so may not be enough to get it to, its WAY faster to accelerate with a working trans and better timing setup. even without it wanting to downshift, in 3rd, going from 30ish kmh to 100 was amazing.

now i have to get the pestering thought of upgrading the disc brakes out of my head, now that i confirmed my front spindles are the 1 3/8 73+ size bearings...

[b5blue]

Be careful kick down linkage type and adjustment for the 727 is critical. You can roast that 727 pretty quick if wrong.