doing front suspension on 56 olds 88,using gm parts with only minor frame mods. if yous guys are interested i will try to post a build thread. newbie from my custom shop
Cool, remembering the cost of rebuilding the stock front end from one I was involved in several years ago plus the hassles then on a couple of parts that looks pretty interesting.
Crowded is okay if you have AC and decent lighting. You have improved on the OG Olds front end, what about the steering box?
Please explain more about the mods you are making......the original intended application of the parts you are adapting.......don’t just tell us what time it is, tell us how to make the watch.... I have always liked Oldsmobiles.......that ‘56 is a beauty! Ray
glad theres interest. i have been doing a mild restomod on the 55 chev in the picture and when we sold the olds the customer wanted the car to be capable of a 20 mile drive every day. i started looking at front brake systems and as i was doing new parts on 55 i thought maybe those parts might be good as the frame system is similar. ive done a few jaguar swaps but the frame in this setup requires major frame rebuilding work [see older thread of 56 olds]. the a arms are tri five tubular from ebay and the price is stupid cheap. ive looked them over well and they seem to be pretty well made plus there offset for more caster[ on 55]. the arms bolt on the same as the 56 lower arms althought they are about 2" shorter. i am using the original 55 chev spindles and bolt on disc brake kit. cleaned off upper a arm mount and reset and lowered mount for corrected caster and camber curve. only real issue so far is rather large scrub radius. as the lower arms are shorter and move upwards as the mounting moves outward i have made a 1/2 inch bolted and welded spacer to help level lower arm at static ride hgt. and [hopefully] improve bump steer. cant really check this until final caster numbers are set. this setup could be done easily at home as very little fab work is needed and i have tried to keep it simple. roll ctr is about 4" with maybe 3 degrees camber gain at full droop 3-4 " travel. sway bar is original and needs to be moved forward about 1.5 " but width is very close to mounts on new arms. yes , shop is crazy crowded right now as i have 9 projects going. 356 porsche resto. norton p11 resto .cobra daytona coupe build. camaro restomod. three other porsches and the coolest, a restoration of a devin bodied tube frame ,hilborn injected bbc, tube frame a/msp drag car built in 64-65. one of three known to have had a roof fabbed on. out of 2000+ bodies built. we sell vintage parts and special interest vehicles.
thought you would like to see the 1955 chev idea car. there is no new paint on the body ,design was done by just smoothing out chips in five paint jobs!
thanks for the reminder about steering box! as im not so familiar with these 56s ,i THOUGHT at first glance the box had been changed as the motor is a chev w/th350 . looked like a later model box with a rag joint,WRONG,oh well. think i will try this box with new suspension first as it felt "ok" when i drove the car 2 blocks. cant be worse than my mopar p/s boxes. has4.5 turns L/L. CHANGED 55 CHEV TO NEW BOLT ON 500/600 cpp p/s box and chromed tilt column,[another stupid cheap decent part]
I'm curious as to a few things especially since the car retains the older style OEM instant centre with no anti-dive. However with a modified system as such increasing the front track and scrub on a large heavy car will make the steering heavier and compromise the handling, not so much an issue on a smaller and lighter car. There are more competent HAMBers with an in-depth knowledge of suspension design, fabrication and how these impact on handling characteristics. Hopefully they can chime in. Looking at new upper mounting bracket I envisage that it will be gusseted, what about bump steer in this configuration? I recall another HAMBer adapted Jaguar IFS & IRS to a big Olds some time ago, power R&P and disc brakes and smaller GM (Chev) bolt pattern. https://www.jalopyjournal.com/forum/threads/1957-oldsmobile-jaguar-xj6-ifs-irs.739171/
Your scrub radius problem is going to be difficult to overcome with those spindles. The King pin axis is probably 3-4” behind the spindle shaft by design and the rest of the bearing hubs or rotors push the center line of the wheel further outboard.. This is in part why most modern vehicles have positive offset wheels.. It brings the wheel back towards the king pin axis along with the ball joints being closer to the wheel and the rotor hats and bearing hubs are also way more shallow..
first question on roll center is that ive been working with getting a roll center approx 2" above ground . working on keeping the rc consistent with bump droop and roll. ive added anti dive, probably hard to see in pictures, more than i may need. there is a plate to lower inner lower control arm mount into a better position as the shorter lower control arms move up to high on the looped style crossmember. front track is about the same as original only the scrub is a little ugly. im setting initially caster at 5 degrees and camber at.5-1 degree. bump steer is not to much of issue so far as the angle in both x and y are very good to inner tie rod point and also 55 chev steering arms bolt on allowing some easy changes to length of outer shaft. ive done two xj jag conversions that worked good but the olds does not lend itself to that swap, might as well build a whole new frame. not that hard but a lot of work. im going to work with wheel offset but astetics are important also. many race cars run big scrub and have no real problem and as i have good caster camber adjustment and power steering i doubt steering effort will be an issue. thanks guys love the imput
more photos soon . installing air con, and new hanging power brake /master combo. lots of "fun" fab work.
I like what you’ve done and was considering something similar on my ‘57 Buick. I was going to use the ‘59-‘64 Impala control arms and 2” dropped spindles though. I had considered modifying the arms to keeps the geometry stock ‘57 Buick. But I am rethinking that approach now.
I am not to fond of most pre 90s front end geometry but I dont always like turning the project into a retirement job either.this is just such a inexpensive system of nice new parts compared to most set ups .i will post all my mods soon so you can make as good a decision as possible . it will be about 20 days till its driveable so will spec it as close as possible then. 3.5 " rollcnter with drop to 1" at 2degrees roll. using stock sway bar till i can test lean angles and customers tires are tall [235/75] so a little help with scrub.have 2" drop spindles on 55 chevy and it has same scrub problems and slightly poor geometry but picked up caster and better camber profile [ all just bolton goodies and using the arms off that car untill new ones arrive tues. ask anything you like to know and ill tell what i can. will be nice to test 55 chev against 56 olds for comparison!
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