Morris Minor Owners Club

I have been trying to decide for a while if to go for an uprated torsion bar that will transfer the suspension loads as designed into the crossmember or a coil over setup that is more flexible in terms of spring rate choice but transfers the suspension loads into the cars bulkhead area. I am leaning towards the coil overs but i am concerned about increased bodyshell loadings. My worries about the shell are based on the impact a rear damper conversion had on the rear floor. Despite the structural strength of the car it must be inevitable that increased power and suspension loadings must have a detrimental effect on the bodyshell and action to allow for this must be taken as i have already done regarding my rear damper setup (ie reinforcememt of floor). Any thoughts?

I had uprated tortion bars on my ragtop so I could get the front end in the weeds.Unfortunatly the was no spring rate left so the front just blow through the rest of its travel.
On my traveller I desided to fit the coilover kit from JLH just for the flexabilaty of adjustable hight and rate.
The kit may look to be expencive but you get what you pay for.
The kit I got was really heavy duty and fitted a dream.
I have no conserns about the change of loading on the bodyshell....

GAS have you got pics of the coliover conversion?

Here are some pictures.









ha the memories....
hope this helps...

Now thats a lot better than the kits i have seen using the old mounts as location points. Thats really good (well designed jlh). Does the lower mount do away with the tie bar as well and is the camber fixed or adjustable ( it looks like the negative camber will increase as the ride height lowers just like a standard setup). When my project is past the planning stage i think i will call JLH

All adjustable Paul. Camber is adjustable

Tiebar is no longer needed.

But the standard torsion bars are perfectly satisfactory for a road-going car. They really don't need any 'upgrading' - for sane road use. Better damping is what's needed - the old Colin Chapman theorey - soft springing and excellent damping. It works.

I have already tried the soft spring heavily damped option. Overdamping reduced the suspensions complience to produce a kidney shattering ride!! When you lower the car you reduce the spring rate so you end up with a softer than standard spring rate. so the answer on a lowered car (in my case only 2" lower) has to be an uprated spring to restore the rate. The suspension has to be a balance of spring and damper not all of one and none of the other. Lotus designed the a frame suspension on the mk1 lotus cortina the one that fell apart so they went back to leaf springs no designer is god.

Agreed the torsion bars on a standard car are 'satisfactory' on a road going car. However, if a car has been fitted with the likes of a Fiat, Ford or K series, the dynamics of the car change. Not only by additional or less weight,in the case of the K series, but the demands made on the suspension when using the potential power of these motors. A standard replacement of the original lever arms with oil or gas dampers goes a long way to improving matters, but attention also needs to be directed to the spring weight, which in the minor is 220lbs for each side at the front. Adding weight will need the spring rate to be increased, this has in the past been done by fitting 1.8 Marina/Ital torsion bars. However this set up can unsettle the car leading to an uncomfortable 'pattery' ride quality.
The reason for the coil overs and wide section A arm is to one offer much better location on the bottom trunnion and allow for multi adjustable damper and spring rates, along with easy geometry changes to suit the style of driving. We have fitted these kits to many standard cars as well as heavily modded ones all of which are used on the road as well as heavy track use. I don't believe that any of my customers are 'insane' BM, but just delight in the new found perameters of the modded set up.You really should try it BM as those who have seem pretty happy.

When you lower the car you reduce the spring rate

How does this happen? The resistance within the torsion bar is the same and static preload is too because the weight of the car doesn't change.
Or do you mean that with any spring the rate increases as the suspension rises and that the lowered setup will exert a lesser rate at maximum top out?

Or do you mean that with any spring the rate increases as the suspension rises and that the lowered setup will exert a lesser rate at maximum top out?[/quote]

Yeah that one.
Anyway at the end of the day the suspension does'nt have so far to go to the top bumpstop so you need stiffer springs to make it harder to get there.
I see from GAZs photos there is just one thing wrong with that suspension set up. That mouldy old kingpin and trunnion setup looks all wrong. Anyone got plans to do away with it with a more modern setup. I do worry that some conversions may have all the new gear and then have the lower trunnion go.
Hopefully my neighbours son is fitting his coil overs this sunday so i can try that out and make plans based on that.

Paul, we do have designs for a full double wishbone set up but the cost of production and R and D would mean that the cost would be prohibitive to many, so we decided not to continue with it. We have had track cars covering over 3000 miles at full chat and not yet had any undue wear or failure with them. The design is excellent even if dated by todays standards.. Which coil kit does your friend have. I'd be interested if its the bolt on OB kit as the spring rate is only 120 or 180 lbs, which in effect will proove useless as the torsion bar is 220lbs, so in effect you are only adding a damper.

Just out of interest Jonathon, do you use a different spring rate on Fiat, ford and k series to take account of the different engine weights or is that dealt with by the shocks?

Ta

We do both Darren.

Lowering a torsion bar car does NOT increase the spring rate !! It stays exactly the same. What can happen is that the supension travel is obviously reduced and the car then smashes into the bump stops - this could be your hard ride - and is obviously not a good idea. My car has excellent damping and a beautifully compliant smooth ride with absolutely NO bounce - and almost never touches the bump stops - except perhaps at the bottom of a severe dip in the road taken at very high speed! The Lotus A frame Cortina rear suspension was for racing use - only fitted on the early cars for homologation purposes. It was expensive - and not robust enough for special stage rallying - that's why they changed back to the leaf springs. For racing use it was ideal! Suspenion should not give a 'kidney shattering ride' due to damping - unless the dampers were absolutely solid!! Long travel and good firm damping in both directions gives a very smooth ride which soaks up normal road shocks without any drama. Uprated torsion bars WILL give a much harder ride - is that what you really want ?

Compared to a modern car a minor has a very short suspension travel. So for us criminals who wish to modify (i won't say improve we are talking personal taste here) our suspension settings we will have to compromise. I wish to reduce body roll and increase my cornering speed. So I have to lower the rear using 1.5" lowering blocks and the front by unwinding the torsion bars. I have now reduced the distance to the bump stops the rear is easy use traveller springs and just enough damping to optimise traction. The front is a disaster you CANNOT make up for the reduced suspension travel with increased damping you HAVE to uprate the spring or raise the suspension again (i raised the suspension). I did fit an anti roll bar which made an improvement (most likely because it affects the spring rate-clue?). I am really looking toward to fitting the coil overs to my neighbours (i used to own it) minor. One of the reasons i sold it was because i did'nt have time to develop it to its full potential. I have no idea what the roads are like in bmcecosses area but down here in kent they are bloody awful and suspension settings will always be a compromise to allow for this.

I wouldn't lower the car much. I know the roads of Kent all too well. Better damping certainly helps and will reduce body roll. I had the top of my inner wing smashed to bits when the car was lowered, well it had the suspension set too low.

As i have been trying to explain the Minor is pretty well optimised for our local roads. The rear is fine with very good traction even without additional location. The front with its anti roll bar and adjustable dampers is still soft and produces slightly too much body roll into corners. We are talking fine tuning here i was fairly happy when i owned it and my neighbour is also happy but we can get more from the car. So in his case we will try the OB kit coil overs and hope Jonathon is wrong about the springs being too soft. If he is right (i suspect he will be) we will play with the spring rate and damping until we come up with a good compromise. However I am thinking on to MY next project which will use the best kits i can find with a bit of home fabrication on the way to reduce costs. As i see it and from what i have listened to this is a turreted damper and properly located rear axle (ford) and a wishbone based coil over front setup.

The secret of good traction with a live axle is as much travel as possible and as soft as possible. It`s a compromise between hitting the bumpstops and travel and spring rates.

I found Traveller springs with the bottom 2 leaves dropped off always worked well. Standard 7 leaves were too stiff.

Paul, are you keeping the torsion bars with the OB kit. If you do not then you will find that the car will sink onto the stops or worse the wheel.
We have been working with Koni to develop a new coil over unit with a bit more flexability and increased damping, to help bring down the spring rate. Were not far off now, just need to fit a new set onto a drone.