Cutting rear coils on Mark VIII conversion kit - TCCoA Forums
 
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post #1 of 13 (permalink) Old 12-14-2015, 09:59 PM Thread Starter
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Cutting rear coils on Mark VIII conversion kit

The rear of my Mark sits waaaay too high for my liking. It has a dumb raked look, which maybe belongs on a pickup or old muscle car, but not the Mark. The rear is really soft and floaty, almost bouncy. Feels like a bowl of jello back there.

I bought the car with the coil spring kit already installed, so I have no idea what brand it is, but from my research, it appears to be the Monroe kit.

It has rear lower spring cups that bolt through the center of the LCA, all the coils are black, and the shocks all say made in Mexico, with spanish warning stickers. Strutmasters have red springs, Arnott's seem to sit nicely, and I haven't heard of any others, so Monroe?

I'm going to try cutting the rear springs. What I'm unsure of is how much I should cut the coils in the rear to make the car sit level, or just a lot less raked.

I'm thinking 1/2 a coil might not be enough or even noticeable, but 1 full coil could be overkill. I don't wanna do this twice, so if anyone has any experience here and could chime in, that'd be great.

See the pic below showing the stance.
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post #2 of 13 (permalink) Old 12-14-2015, 11:01 PM
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Half to three quarters I'd say. Safest way to be sure is to cut in quarter coil increments. It's time consuming that way but sure fire way to get it exact

-Matt
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post #3 of 13 (permalink) Old 12-15-2015, 06:41 AM Thread Starter
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Since these are progressive springs, would the rate technically increase when cutting them?

The rear is so soft that I'm worried it might bottom out with less height.
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post #4 of 13 (permalink) Old 12-15-2015, 08:19 AM
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Cut from the side where the springs are closer together, that will increase the spring rate more for the same amount of drop. Also as Matt said, start with a half a coil, and go up from there in 1/4 coil increments. I know it sucks to take it apart multiple times, but not as much as it sucks to have to buy new rear springs cause you went too far.

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post #5 of 13 (permalink) Old 12-15-2015, 03:34 PM
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My mark rode like that but sat to low in the rear. That bouncy lousy over steering conversion kit on my car was crap. I put some motorcraft shocks for a t-bird on the back, Monroe sensatracs on the front, some springs from a 97 sport (jjjj code) and she drives and rides good now. Also the conversion springs were already rusting.

1997 Mark 8 LSC

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1996 Thunderbird lx 4.6
1994 Thunderbird lx 4.6
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post #6 of 13 (permalink) Old 12-15-2015, 10:02 PM Thread Starter
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Quote:
Originally Posted by steamer471 View Post
My mark rode like that but sat to low in the rear. That bouncy lousy over steering conversion kit on my car was crap. I put some motorcraft shocks for a t-bird on the back, Monroe sensatracs on the front, some springs from a 97 sport (jjjj code) and she drives and rides good now. Also the conversion springs were already rusting.
Strange that it rode low in the rear. Do you know which kit it was? I don't find that mine has much of a tendency to oversteer, and the damping/ride height up front is...tolerable, but the rear is atrocious - jacked up and bouncing all over the place. The shocks aren't blown out, they're just not matched to the springs at all. I can only guess that a higher rate spring with more rebound damping would help sort this out. Some Tokicos from an SC would be a nice improvement.

Sigh. My springs are rusted too, and pretty much the only rust on the whole car is on the springs.

Can sport springs and Tokicos be bought new anymore? Probably ebay only I'm guessing.
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post #7 of 13 (permalink) Old 12-16-2015, 02:40 AM
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Sport springs are long out of production, but I believe you can still buy the tokico's new. For what it's worth, I used a set of eibach 1.5" lowering springs with tokico blues to convert my Mark, but I also cut the spring perches out of a couple junk tbirds, so I'm not sure if the tbird springs will work with the perches that came with the conversion kit.

-91 Cougar LS, coming soon, complete overhaul with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
-"Your buddy Mike is INSANE!" -ClintD's dad
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post #8 of 13 (permalink) Old 12-16-2015, 06:39 AM
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[QUOTE=96beaterbird;1800497]Strange that it rode low in the rear. Do you know which kit it was?

I think it was Arnott's kit but am not sure. It had sensatrac struts on the front and chinese shocks on the rear. I had to put Prothane spring isolators in the rear. It brought it up but still rode bad. What I researched online is the conversion springs tend to sag over time.

I got my springs off a junker with 180k miles. No rust on them but but made the "bouncy-bouncy" go away. Eventually I'm going with the 1" lowering springs from Vogtland and blues. From what I researched about $500.

1997 Mark 8 LSC

Former owner:
1996 Thunderbird lx 4.6
1994 Thunderbird lx 4.6
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post #9 of 13 (permalink) Old 12-16-2015, 10:36 AM Thread Starter
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This has me thinking... I've got a leftover set of Koni's from my 2006 Mustang...I wonder if the rears would fit...
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post #10 of 13 (permalink) Old 12-16-2015, 11:04 AM
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No. The mustang shocks that fit the rear are for the 99-04 Cobras.

-91 Cougar LS, coming soon, complete overhaul with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
-"Your buddy Mike is INSANE!" -ClintD's dad
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post #11 of 13 (permalink) Old 12-16-2015, 11:06 AM Thread Starter
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Still, I'm gonna take some measurements of the Konis. The lower bushing is a bit different, but if the body is the same length/diameter and the rod the same diameter, there's no reason I couldn't do a lower bushing swap on the shock to make it work.

A simple bolt on it will not be however.
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post #12 of 13 (permalink) Old 01-13-2016, 09:35 PM Thread Starter
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Quote:
Originally Posted by steamer471 View Post
I got my springs off a junker with 180k miles. No rust on them but but made the "bouncy-bouncy" go away. Eventually I'm going with the 1" lowering springs from Vogtland and blues. From what I researched about $500.
Do the sport springs fit the conversion kit's rear LCA spring cups and perches or did you have to buy custom ones?
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post #13 of 13 (permalink) Old 01-13-2016, 10:03 PM
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Used the same ones that were on it.

1997 Mark 8 LSC

Former owner:
1996 Thunderbird lx 4.6
1994 Thunderbird lx 4.6
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