How to convert my 6.9 to coil springs with standard parts - whos done it?

[B13]

Hi everyone, I'm well aware of most peoples opinions on losing the hydro suspension from the 6.9 so please keep opinions to oneselves

I've failed a roadworthy now because of three leaking hydro struts, a leaking rear control valve, both front ball joints one upper control arm, some mornings the system doesn't pressurise (red-light doesn't go out unless I prime the pump), control valve leaks, etc. I'm over it because its now seriously impacting my enjoyment of the car.

Those that have converted a 6.9 to coil springs using standard parts please speak up and tell me what I need.

My list thus far reads:

4 coil springs
4 shock absorbers
2 spring cups for the front springs where they meet the swing arm
1 engine blank plate for there the hydro pump was

What else does one need?

I.

 

[Styria]

Hi Ian, you are really in the wars, aren't you ? In my opinion all these issues are not seriously impairing your enjoyment - you have no enjoyment. To the best of my knowledge, only one 6.9 owner that I have heard of has changed the 6.9 system to a conventionel one. Guy in Californioa, but I cannot recall his name. He has posted on all three forums, i.e. the M100 site, TK and the org. site. You should be able to find him.

Some matters should be considered. Firstly, even a steel sprung system feartures hydraulic self levelling at the rear - you also still have a hydraulic reservoir, a hydraulic pump, as well as two air cells (albeit smaller ones) at the rear. Your rear shockabsorbers also have hydraulic lines, and you have a self levelling valve at the rear. So, are you really that much better off by converting ? I have my doubts. Look, why not bite the bullet, and spend money on the car, because of whatever you do, money will be needed.

Regarding the conversion - you have a standard 450 - check the mounting points for the front shock absorbers - that's where you main problem area needs taken care of. I am not certain about shock absorber mounts at the rear. Sorry Ian, I am not that much help to you, am I ? Anyway, please feel free to contact me on my mobile, 0428-50-1800. Regards Styria

 

[motec 6.9]

Hi Ian it should be possible to convert to all coilspring suspension. I know I have heard of it being done for the rear use parts from a non self leveling suspension car as for the front contact Cam and see if he has the struts and springs left from his car as they were made for the weight of the m-100 motor . Or ask him the specs . Geoff

 

[Styria]

Ian, WGB's post may help a little, although I do think you have similar facilities on hand with your racecar. Regards Styria

http://www.topklasse.org/forums/newreply.php?do=newreply&p=4066

 

[john erbe]

I'm the guy from California. Did the conversion several years ago. Still running strong. Job can be done in one day. Quite simple using coil over struts. Had machinest make adapter for top connection as well as mount at base replacing the the ball valve on the hydraulic strut. You'll also need a spring compressor to insert the rear coil springs. Would be happy to forward more details and opinion. Have changed identity and moved as purists have contract out.

 

[john erbe]

Ian: In continuance, after reviewing your list, you need just two coil springs for the rear not four, two coilover shocks for the front, two standard shocks for the rear, the plate (as you mention) and four adapters for the front coilovers. Pay no attention to the 4,5 set-up. This conversion borrows nothing from the standard front suspension on the 4,5. You will simply replace the hydraulic struts in front with the coilovers. No muss no fuss. A machist will make a copy of cone shaped top two inches or so of the hydraulic strut with the 13mm tap on top and he will add a tap at the base to receive the threaded top of the coilover shock. Be prepared for a completely different ride. You will feel the road however handling will be far superior in my opinion, no rolls in corners, very tight and responsive. Huge future savings in maintenance. The shocks I used had lifetime warranty as they are rebuildable. I have not spent one dollar in the maintenance since they were installed years ago. Can send photos if interested.

 

[Helmet]

Very interesting conversion, can you post some pics here ?

 

[john erbe]

Tried in vain to post some pictures. All thumbs w/computers. If you go to the m-100 website and do the search for my posts or suspension conversion there are some pictures. Or email me: jerbe@sbcgloobal.net I can forward.

 

[WGB]

The coilover shocks solve the problem with the different front end sheet metal.

Bill

 

[Michel]

Tried in vain to post some pictures. All thumbs w/computers. If you go to the m-100 website and do the search for my posts or suspension conversion there are some pictures. Or email me: jerbe@sbcgloobal.net I can forward.

John,

PM sent

 

[Helmet]

The coilover shocks solve the problem with the different front end sheet metal.

Bill

Yes, makes sense to me

 

[john erbe]

Yes, and conversion is reversable. If you don't like, swap it back.

 

[Michel]

These are the pics that John meant to upload


The Upper Strut


Close up lower


Adapter, bottom view


Machined upper adapter


The Car

 

[john erbe]

Thanks Michel. I included the photo of the car as the conversion resulted in a lower profile with the front lower than the rear giving a more modern look.

 

[Oversize]

Looks like you've done a great job and the ride height is neat! Looks like you have alloy upper arms when I'm told the steel ones should be used. But to be honest I haven't seen a broken one yet.... BTW are they 15" Bundts??

 

[john erbe]

Yes, 15" deep dish Bundts.

 

[Oversize]

Nice!!! Can you post a larger pic of the wheels? I've never seen them up close...

 

[john erbe]

Send me a PM and I'll forward.

 

[Styria]

John,

PM sent

Thanks for helping out, Michel. Regards Styria

 

[Styria]

Yes, 15" deep dish Bundts.

John Erbe, when you say 'deep dish', are there different 15" designs ? I know that Fuchs made them back in '70s, but there was another company by the name of ARC that also manufactured them. I wonder if there is any difference in design between those two manufacturers ? Regards Styria