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Discussion Starter #1
One of my projects I'm doing is replacing the air ride in the Mark VIII. The cheap solution is the direct swap to T bird stuff. Not happy with what's available, I decided to figure out something different.

Started with a set of junk stock T bird front shocks. Drilled them to remove the oil, and cut them open to remove the guts. Cut the stock lower shock mount off and media blasted it. Cut the length down to match the length of the Bilstein strut insert. It's a press fit into the T bird tube.



The insert is for a Mitz 3000 GT. Lots of interwebs searching came up with it. Length extended, collapsed, and vehicle weight made it the closest match. Cheapest price I found was $135 shipped.

Specs:
OD 45.8mm (1.8")
Extended Length 480mm (18.89")
Collapsed Length 380mm (14.96")
Body Length 266mm (10.47")

Insert pressed into the modified T bird shock tube. Even the Bilstein seal is a direct fit.



Welded on a ring to space the coil over sleeve to match the end of the insert/tube.



Machined the upper shock mount to fit flush with the insert.



All I need now is to pick up a T bird upper mount, remove the rubber from the steel mount, drill out the hole for the shock. Might need a small spacer too.



Afco 7 inch length coil over sleeve.

QA1 10" 650lb spring. I started here based on someone here at TCCOA who converted a Koni to coil overs and it worked out well for him.

Also bought a torrington bearing set for the lower spring mount.



Need to finish the second setup, paint and wait on warmer weather.
 

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You may be a life saver for all of us who want upgraded shocks! Its obviously not the easiest DIY. But its something, and people will know what works!

You are awesome!
 

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Thank you for this post!

This is a very good example of what we will need to move into the future. :)
 

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Discussion Starter #4
You're all welcome. Since it's not even on the car yet, no claims on how well it will work.

A cheaper solution would be to just remove the guts of a stock shock and use the insert along with the original upper and spring. I think the shaft is long enough to work that way, but it's not something I've checked. I'll know more once I procure the stock upper seats.
 

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The upper shock mount that you machined - that's just a partial view of one of these, isn't it? Or is it something else?

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1198672&parttype=7600

I'm curious because if it's just the same upper shock mount we'd buy to put non-ARC shock into a car, then I think the worst part is about done there.

One more question - if you were going to use factory springs, could you cut the TBird tubes down above the lower shock mount and reuse that avoiding the coil over specific parts?

RwP
 

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Saturn5:
Brilliant work here.
Q: What's your plan for the rears to match the new spring rate and ride height of the fronts?
-g
 

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What happened when you drilled the tube? I'm looking into rebuilding ARC shocks and that part concerns me (releasing the pressure).
 

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What happened when you drilled the tube? I'm looking into rebuilding ARC shocks and that part concerns me (releasing the pressure).
Drill with a small (1/16") drill bit, and cover the end with a rag before it goes thru. :)

Most older shocks won't have gas pressure; it will have leaked...
 

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Discussion Starter #10
Ralph, That's the upper seat that comes with the Alco coil over sleeve/seat kit. I just opened the hole to match and trimmed the top to make it flush on my lathe.

gunn, I already have Cobra Conv Bilsteins out back. Down and dirty is using the Cobra rear springs too, tho I am looking at having the shocks grooved for a clip and coil over them too.

Yup, small drill, rag and stand to one side... Cause she's gonna spray. Once drained, I drilled it out to 1/2" (center, bottom) to clear the threaded stud on the bottom of the insert.
 

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Saturn5, I wonder what would be needed to just use the insert with stock TBird springs/lower spring mount / upper spring mount.

It'd be worth checking out if the inserts were cheaper ... too rich for me to play with, however.

RwP
 

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SATURN5 said:
So I wanted coil overs in the front..
Nice!..Way to show off those Engineering chops.. :xpwink:

Looks like a good design..Not just something thrown together..Probably outside of the scope for most of us though..

I mean..Not very many of us have a machine shop at our disposal..Again though..I applaud your skills..Good job!




Rayo..
 

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Discussion Starter #13
I have yet to pick up the T bird original upper mount, once I do, I should be able to answer that. I think tho, it should be possible.
 

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Yup, small drill, rag and stand to one side... Cause she's gonna spray. Once drained, I drilled it out to 1/2" (center, bottom) to clear the threaded stud on the bottom of the insert.
I bought one set of koni inserts before they discontinued them. :(
 

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Not counting the cost of the gutted mn12 shock, how much did this set you back? Looks like you installed the insert, welded a ring for the threaded sleeve to rest on. What about that shock mount?
 

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Discussion Starter #17
Inserts are $135 shipped.

Sleeves, springs $195 shipped.

Tbird top mounts $50 shipped.

Used shocks $45 shipped.

$560 complete. Not cheap, but much cheaper then putting new Motorcraft air shocks back in it.

I don't have a "full" machine shop... lol Just a small mill, lathe, shop press, and a Mig....
 

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Nice fab skills. I am in the process of fabricating some brackets to use a bilstein coil-over shock on the front of my car. I was wondering if you knew how harsh of a ride the #650 springs are? I would like to go that much but am afraid to because my car is a daily driver.
 

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Discussion Starter #19
I ran a the numbers using this: http://www.ridetech.com/info/spring-rate-calculator/

http://www.markviii.org/info/specsmain.html

Curb weight: 3761lbs

Weight Dist: 67/37 2520/1241lbs

Front corner weight: 1260lbs

Length from pivot to shock: 10.375"

Length from pivot to balljoint: 16.5"

Unsprung weight: 85lbs (est)

Spring angle: 80* (est)

Shock stroke/Spring length: 4.1"/10"

Cruiser/DD: 650lbsin/1.01" preload, Performance: 700lbsin/.73" preload, Race: 750lbsin/.49" preload

Additionally, there is a thread here where the OP used this same spring and found it acceptable.

My only question is the valving. Something I won't know until I bolt them in and drive. Worst case, I press then inserts out and have them revalved to the specs Bilstein used when they offered a shock for the Birds.
 

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Discussion Starter #20
The stock upper mount didn't lend itself to my needs other then to get measurements from..... So..... I made my own from 3/8" aluminum plate. Milled a 1 1/2" hole and made a two piece bushing from 2" Delrin. I think it'll work out just fine....







Now to strip it down, measure everything and build the pieces for the second unit.... :)
 
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