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Coil-Over Shock/Spring Conversions  Rating:  Rating
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 Posted: 12-02-2006 06:47 pm
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James Wilson
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I'm think of upgrading the suspension components by going to coil-over shocks with stiffer springs.

Has anyone done this, and how successful was it? What shocks and springs were used, and was there any additional fabrication or strengthening required?

Useful information I need: Spring Lengths with/without load. Shock length: maximum and minimum extension.

TIA

James

 

Last edited on 12-02-2006 06:48 pm by James Wilson

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 Posted: 12-02-2006 07:37 pm
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Judson Manning
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James,

There really isn't enough room for a typical coil-over set-up to fit inside the JH crossmember and lower arm without significant modification.  You can see the modifications I had to make on my E-prod car to adapt a set of coil-over Konis.

Judson

 

Attachment: 05Jul06-001.jpg (Downloaded 525 times)

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 Posted: 12-02-2006 08:10 pm
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James Wilson
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That's useful information.

The alternative then is to use something like the Spax or Bilstein shocks and have the springs modified. It seems the front hasn't enough clearance to be lower but would there be benefit to increasing the rate. The rear seems to offer a fair bit of room for lowering and increasing the rate.

I have a front anti-sway bar from a GT that I'll use and I'd think about fitting one to the rear, if I can find a UK supplier.

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 Posted: 12-03-2006 04:34 am
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Art DeKneef
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Judson,

Is that rotor attached to the normal healey spindle or is it something else. It would be nice to have a 5-bolt rotor on the car.

Thanks, Art

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 Posted: 12-03-2006 06:52 pm
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Judson Manning
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No such luck Art.  What you are looking at is all custom and by no means a bolt-on solution.  I'll reveal all my 'secrets' in a future series of articles Greg has invited me to write for the JHPS monthly. 

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 Posted: 12-05-2006 12:41 pm
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normv
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James

I have just measured a Set of Spax they are as follows

               Min                  Max

Fronts      218                 307

Rears        308                 494 ( from the center of the lower eye to the lower mounting washer)

I also measure the koni rears 303 to 472 (this is with the 15mm bumpstop installed)

Sorry I have just installed the Koni fronts but I will measure the next set when they arrive if you want.

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 Posted: 12-06-2006 01:35 am
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James Wilson
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Thanks Norm. That should help.

Now all I need are the spring lengths- particularly the rear since I a "spare" front sub-frame to play with.

 

 

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 Posted: 12-06-2006 09:11 am
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normv
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James

I have just measured a rear coil from a JH5 it is 265mm uninstalled excluding the insulator rubber, the wire diameter is 12.3 and it is 4.5 coils with 110 internal spacing. I don't have the spring rate but I will be getting a set of coils made in the new year so I will measure this beforehand to work out what I need. Don't forget if you decide to go coil over you have to factor in the fulcrum point of the original spring , you will also need to allow clearance around the shock for the spring to clear the body.

Also I am not sure if these were different to the early springs as the bumpers on these are quite heavy

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 Posted: 12-09-2006 04:51 pm
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Ron Earp
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I seriously looked at the coil over solution too, because that is legal for me in IT.  But, I didn't see how I could make it work with the existing A arms.

I did put on re-valved shocks and made a lot of springs for the front and rear. On the rear I went to a common 2.25" ID race spring because they are cheap and readily available. I'm running a pair of 250lb springs now and I think they will be about right.

Up front I had a few sets of specific springs made from:

http://www.coilsprings.com

They are good, and cheap. A set of custom front springs with 3.25" ID at 600lb rate was right at $150 a pair, think they were 11" overall length. I made some at 500lbs, 650lbs, and I think the last set was 450lb. All are slightly different lengths and the set on the car now gets the A arm about 1.5" off the bump stop, actually, there is no bump stop so 1.5" off the subframe. I think it is too close and I'll have to go to a slightly longer spring.

Morale of the story is if you need some spring made call those guys at coilsprings.com.  Much less expensive than any race spring places, they do good work, and as a family business are easy to work with.  No, I don't get kick backs just pleasantly suprised to find a good place like that to work with.

Ron

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 Posted: 12-13-2006 09:21 am
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James Wilson
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Thanks Ron.

So it sounds like you're running 250 Lb. springs on the rear and 450 Lb. on the front (presuming the last ones were the ones you settled on using).

What lengths are these? Do the rear springs lower it any?

Shipping can sometimes be a killer (along with import taxes- VAT at 17.5%).

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 Posted: 12-13-2006 01:50 pm
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Ron Earp
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The car is by no means dialed in. But, up front at the 650 lbs springs and they felt good with the limited track time it has had, which is under 20 laps unfortunately. I liked the "flatness" of the cornering and the front felt very good. The front shocks are some shocks off of a light truck that cost like $15 each, but they work in a pinch.  The front is quite low, so the standard Koni's and Blisteins I had were too long.  clearly shocks will have to be looked at, but they are typically the last thing to adjsut after dialing in the springs, settings, bump, etc.

The rear is using 250 lbers and they are much shorter than stock thus lowering the rear considerably, but not as much as the front. The rear felt great on track, it has a panhard rod and as welded axle, very planted. I don't plan to change anthing back there right now.

I can measure the lengths of the springs and post them if you like.

You can get an idea of what it looks like in this thread:

http://www.jensenhealey.com/forums/view_topic.php?id=679&forum_id=2


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 Posted: 12-15-2006 12:33 pm
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James Wilson
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It would be useful to know the lengths of the springs too, and how much the rear has been lowered.

I believe Judson Manning in another posting mention you were using 250 Lb. 8 inch springs on the rear, and he recommended 175-200 for a street car. I'll be using mine on the street and not racing it... its being re-built as what the British call a "fast road car"....

I'm doing the engine and hope to get 180-190 hp or thereabouts from it, going to the Toyota 5-speed and want an uprated suspension to suit it.

I've thought about going to 15 in. wheels, mainly to improve the tire selection; but that's pretty expensive (I reckon on £1000 for a full set of 5 wheels & tires ~ $2k) and the money can be spent more effectively elsewhere and I can live with the limited range of tires available.

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 Posted: 12-15-2006 03:51 pm
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Ron Earp
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I'll check them for you, but, if you don't lower the front you'll have an odd looking car.  The stock fronts are quite tall and certainly jack the car up.  I have a number of rear sets, I want to say I have the 6" springs on now, but it might be 8". I'll figure it out.

R

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 Posted: 12-19-2006 11:24 pm
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Tom Thomson
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Guys

  Twice in this thread I have seen mention of Koni Shocks.  The Koni importer says no listing exists for the JH.  What application are you using?

                                                     Tom 13753

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 Posted: 12-20-2006 11:24 am
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normv
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Tom

Your importer is correct the Jensen Konis have not been available for some time and there is no direct replacement, the valving is always way out if the length is correct, I have had a couple of sets made up recently however this is a little expensive as they have to revalve and rebush some others and they know how to charge for this, unfortunately the hardest part was finding someone with the original specs for the Jensen so I cannot shop around. I am looking at a few options to reduce this including doing the modifications myself as I do have access to koni spares and have revalved my race shocks for years, I just need to find the correct valving My supplier wont tell me but I do have a set they have done. They currently work out to be a to be a little more expensive than the Bilsteins

I am in Australia but if you really want Koni’s I can get them done and post them to you. ( I consider they are the best, although I do also like my Spax but they cannot be rebuilt).

Norm

Last edited on 12-20-2006 11:25 am by normv

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 Posted: 12-20-2006 05:06 pm
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Greg Fletcher
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I had Konis on my JH for years and always thought they were too stiff for a road car, so I suppose it depends what you're after. BTW, Koni will be happy to rebuild an old set of JH shocks for $140 per shock. No idea what the valving is on those. Despite the cost of the Bilsteins, you get a lot of shock for your money.

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 Posted: 12-21-2006 11:54 pm
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Tom Thomson
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Greg

  Do you still have the old Koni's around and if so would you sell them?

                                       Tom 13753

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 Posted: 12-23-2006 04:32 pm
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Pat Connor
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Ron great info about custom springs from http://www.coilsprings.com .  What is their turnaround time on custom springs?

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 Posted: 12-24-2006 02:10 am
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Ron Earp
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Pretty quick in my experience. About 3-4 weeks tops, just make sure you phone back about 5 days after order to make sure it sticks. I had four good experiences, and one bad experience when my order was lost. It is a small family company and things happen, but I am pleased with them.  Out of KS if I remember right.

I've got a couple of sets of Konis that have rebuilt by TrueChoice. I might sell a pair, let me locate them.  The thing about shocks is to get your spring rate dialed in first - they are the primary spring in the equation and must be right. Shocks are dampeners, and they do just that - dampen the primary spring with respect to the suspension system.

Smart money goes to getting the springs right first, shocks second. I'm running a set of $15 truck shocks at the moment and they seem quite good.  I'll definitely change them out for something else once I know the springs are right, or re-valve my Blistens to match the springs once settled.

Ron

Last edited on 12-24-2006 02:14 am by Ron Earp

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 Posted: 01-02-2007 04:06 am
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Art DeKneef
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Since we were talking about shocks and springs, is there away to tell in what shape a shock might be when it isn't installed on a car?

I have some shocks that I can can compress and uncompress by hand. That kind of tells me the shock is worn. But by not havingany new shocks, I can't tell if that is correct. Checking around didn't offer any help other than testing with the shocks on the car with the old bumper bounce test orsome other test.

The shocks aren't leaking but the bushings look old. I'm just trying to decide whether to use these for a while or buy some new shocks.

 

Thanks, Art

 

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