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Nice way out the box thinking there and a beautiful bit of cad work there . The shocks will be working in a different angle range with this bell crank style set up compared to the set up at the moment ( exaggerated the current set up the shock will partially swing through an arc instead of linear in and out motion )
Not too mention inboard shocks look amazing but will also give you more shock travel for less vertical axle travel depending on the lever ratio, plus allowing more fine bump and rebound control and no worry of bottoming out the shocks.
Ok we can't compare it to hyper cars but a lot of hyper cars run this style of inboard shocks and it works for them.
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Just read through the whole thread and this is one amazing car. Keep it coming!
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Dec 10, 2016 10:56:49 GMT
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I don't really understand why you have done this? You stated the angled 45deg shocks were a negative but you still have them, your bottom bolt is still in single shear. Don't get me wrong it's definitely cool and I appreciate the work involved, I'm just not sure what the benefits are of the added complexity? its not the specific angle they sit at which cause the issues but the wheel to damper movement ratio, with his new rocker linkage its much closer to 1-1, if not exactly that, which makes setting dampers and getting them to work without massively expensive units a lot easier. there's a few similar setups for peugeot rear axles, where the standard wheel to damper ratio is something like 2.5-1 with very minimal room for a bigger damper body so in competition use the dampers overheat very quickly, and you get that pogo effect which fires the cars off into the scenery.
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mrluke
Part of things
Posts: 239
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Dec 10, 2016 14:47:51 GMT
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With all that said it seems to me that fundamentally the same amount of load is still going through that bottom bolt mounted in single shear. Apologies if I have this the wrong way around but on the cortina isn't the spring mounted separately from the damper? Won't this fix your bolt shearing issue? BMWs also use a similar rear setup.
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Hey mrluke, your right on one count, the bottom bolt is still in single shear however there is a big advantage with the pushrod setup over the previous setup. With the previous setup I had to space the dampers away from the axle by around 30mm to make sure the springs cleared the axle, therefore there was a massive moment on the bolt just bending it. The pushrod setup is much slimmer so allows the lower joint to be bolted directly against the axle bracket,therefore there is very little moment on on the bolt (although still in single shear) and the added friction of the rose joint against the axle bracket will make it more secure.
The bellcrank geometry is set up so there is a 1:1 ratio between the axle movement and shock movement at ride height, this rate then increases during bump (as the axle goes up the rate at which the shock compresses relative to the axle movement increases), so is a definite improvement over the 45 degree mounted shocks!
Also it looks awesome.....
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mrluke
Part of things
Posts: 239
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Dec 11, 2016 13:22:46 GMT
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Thanks Chris one thing that surprised me is how much the rear axle can move in the forwards/backwards direction which will also load up your bolt, no doubt you have some kind of multi link setup that is yet to be revealed watching with interest.
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Dec 11, 2016 22:13:54 GMT
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The bottom of the pushrod is rose jointed now so any axle rotation isnt so much of a problem....I don't like it though so obviously some improvements will be made.....
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Dec 12, 2016 21:35:19 GMT
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OK so the next part of the plan was to make sure the whole plan was going to work, I refined the CAD and adjusted the geometry of the bell cranks, crank position, shock length and pushrod length until I had a geometry that gave me a 1:1 motion ratio at ride height and a rising rate during compression. Theres not alot of info about rising rates around on the web but luckily I have some contacts through work who said I was on the right track, so time to plough on. The CAD model was based of some basic measurements taken from the car so the next job was to make sure it was going to fit, I wasnt about to cut holes in a perfectly good car unless I was sure they would be in the right place! Modern technology comes to the rescue and luckily I have some access to it through my work, enter the Faro arm. Its a 3d measurement coordinate measurement system onto which you can attach a laser scanner, this generates a point cloud which can then be made into a surface and imported into CAD. The ping pong balls on the side are so when I take various scans I can align them all together using the spheres as reference. Works well but only to 50 microns or so, I sure I can manage with that. Heres the raw scan, this is then turned into a surface and imported into the CAD. You can see the rear quarters, and the rear beam in the middle. I scanned the beam in the boot, then the chassis rails on the underside, then used the rear quarters to align the scan and make sure the rear beam and chassis rails were in the right place. Unfortunately I haven't got any screenshots of just the CAD and he scan imported, it'll come later but it would ruin the surprise now! Some minor adjustments and it all lined up....ready to start cutting then....
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eurogranada
Europe
To tinker or not to tinker, that is the question...
Posts: 2,552
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Impressive tool!
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mk2cossie
Club Retro Rides Member
Posts: 3,031
Club RR Member Number: 77
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Dec 13, 2016 13:34:40 GMT
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Thats quite a solution to get more space and a better leverage ratio on the coilovers at the back Is the assembly for the coilovers going to be bolted or welded in to the boot floor?
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Dec 13, 2016 20:20:01 GMT
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Bet that's the first time ever that a faro arm and a cortina have been seen together on the entire web , we have one in our inspection department ( we build and overhaul gas turbines ) and it's a very nice bit of kit. I dof my hat mate 👍
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PhoenixCapri
West Midlands
Posts: 2,685
Club RR Member Number: 91
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Dec 13, 2016 20:31:10 GMT
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Love a faro arm, fantastic bits of kit. Oddly I've known faro arms used on all sorts of retro tin. Engineers have a knack for finding reasons to use the fancy tools infact I need to get the port layout and manifolds measured up on my new motor Keep the updates coming, loving it.
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Dec 14, 2016 13:24:55 GMT
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Thats quite a solution to get more space and a better leverage ratio on the coilovers at the back Is the assembly for the coilovers going to be bolted or welded in to the boot floor? don't worry mk2cossie all will be revealed....! So gonna leave the rear suspension for a bit and move onto the steering. I installed power steering when i did the engine conversion and its been awesome, however as with everything Cortina you cant get performance parts for it,therefore no quick racks available. The steering was reasonable (4.2 turns lock to lock) but ideally I'd like it a bit quicker, my colleagues in dynamics tell me the best thing you can do to improve response and make a car feel more sporty is to increase the steering ratio. So if I want quicker steering theres a few options: Adapt another rack to fit - could work however finding another rack of roughly the same dimensions would be a pain and package space under the engine is pretty tight, most newer racks a re a fair bit larger. Shorten Steering arms - Not keen on cutting and welding the cast hubs and it would cock up my Ackerman angles Look to good ol USA and see what the NASCAR boys use - they put a gearbox in the steering shaft so they can change the steering ratio without changing the rack. As ever not one to take the usual route Option 3 looks like a good experiment....I also meant that if I did it right it could be a bolt in solution so if it didnt work I just bolt the original column back in. Start with another steering column and a 1.5:1 ratio "steering quickener" from 'Merica Take lots of measurements and section the steering column outer and inner I used the adapters supplied with the steering quickener to adapt to the cut steering column, I was planning to turn the shafts down if necessary but out of pure luck they were a perfect fit! Then I turned up another adaptor to fit the steering quickener into the end of the column outer. Then fit it all together and add an anti rotation tab to hold the gearbox in place (the adapter actually holds concentric and in the right position) And trial fit.... Looks good so far, theres a bit more play in the gearbox than I'd like but thats in the bearings so theres not a huge amount I can do about it, I'll see how it goes when driving, hopefully I wont even notice. Next up was the steering intermediate shaft, it connects the end of the steering column to the steering rack. The old one was fine but had a big rubbery canvas doughnut to provide some damping to the driver, it was pretty old and tired and also removed a fair bit of feedback from the wheel. The steering quickener is going to reduce the feel slightly due to the gear ratio so any other damping needed to be sorted. I bought another steering shaft of eBay and set to work Shaft cut down to a close length And welded So thats the steering column done, I had the column powder coated so it looks all smart now, just need to sort out a mount for the indicator stalk...Next stop 3D Printing...
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Dec 14, 2016 13:28:27 GMT
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You could turn the bottom pushrod rose joints through 90 degrees and double shear them easily that way, more in line with axle movement then as well.
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Dec 16, 2016 18:36:22 GMT
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Hi, just read the whole thing, great project! I´m buildin a 2dor sedan taunus-73 same colour! I have a 2.3l Dohc from a Scorpio and automagic gearbox from a early granada that I'm fitting to my taunus. just the original 150hp for now but next winter i plan to break the 200hp limit. Struggling right now with fitting the EEC-V.. Was wondering about the rear coilovers, i to have planned coilovers too and i made som plans, i suspected that the rear has to be reinforced, so i made a 3D model. I was not going as extrem as your plan, was searhing for a easier and faster solution. I would appreciate your comments on this one. Pics: the structure pipe at the top would be welded (don't look at the boltholes..) to the subframe and go all the way to the other side replacing the existing fastening points. Some extra holes for the upper fastening of the coilovers (just playing around). I think this would make the angle closer to 25-30 degrees. The bottom would just be reinforced so that int would not shear. I have not taken any measurments so this model is not accurate.
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Dec 16, 2016 22:49:25 GMT
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Hi, just read the whole thing, great project! I´m buildin a 2dor sedan taunus-73 same colour! I have a 2.3l Dohc from a Scorpio and automagic gearbox from a early granada that I'm fitting to my taunus. just the original 150hp for now but next winter i plan to break the 200hp limit. Struggling right now with fitting the EEC-V.. Was wondering about the rear coilovers, i to have planned coilovers too and i made som plans, i suspected that the rear has to be reinforced, so i made a 3D model. I was not going as extrem as your plan, was searhing for a easier and faster solution. I would appreciate your comments on this one. Pics: the structure pipe at the top would be welded (don't look at the boltholes..) to the subframe and go all the way to the other side replacing the existing fastening points. Some extra holes for the upper fastening of the coilovers (just playing around). I think this would make the angle closer to 25-30 degrees. The bottom would just be reinforced so that int would not shear. I have not taken any measurments so this model is not accurate. Hey roba90, don't see why it wouldnt work like that too, if you created a new crossmember that linked the chassis rails and shock mounts on each side then it would be very stiff especially if you boxed it back in to the original crossmember and the floorpan. Ideally the shocks want to be vertical but 20 degrees or so should be fine. The main issue I had with the shocks going straight onto the axle was the clearance neeed for the springs and hence the distance the bottom shock mount needed to be from the axle, your bracket looks like it would work fine as long as there was enough clearance and its strong enough to take the load!
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Dec 17, 2016 10:02:17 GMT
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Thanks for the comments, Yes the plan was to connect the crossmember to chassis rails. I added 30mm to the bottom mount after i read your thread. Is the rose joints on the "upper arms" creating more vibrations ti the chassis than polybushings? I´ve not read anything about them other than they are stiff and easy installation. I want a stiffer rear on my car but as it is going to be a daily driver I want it to be as quiet as possible.
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Dec 17, 2016 11:59:28 GMT
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You can definitely hear the rose joints but mine was set up stiff so you wouldn't notice any extra vibrations and noise that much. There's inherent issues with the suspension which the rose joints definitely improve so I'd say they are definitely worth it.
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Dec 17, 2016 15:35:05 GMT
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You can definitely hear the rose joints but mine was set up stiff so you wouldn't notice any extra vibrations and noise that much. There's inherent issues with the suspension which the rose joints definitely improve so I'd say they are definitely worth it. Ok thanks, will give them a try!
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I would be careful about using too stiff bushes or joints in the "K-link" rear axle on these cars. Be very careful to check for binding, I advise to articulate the axle through the suspension movement (both bump/rebound and roll) with no springs to see that it doesn't bind.
Generally speaking, a K-link needs rather soft bushes and/or trailing arms that can flex, since the design usually has inherent binding issues. A read-up on the Fox body Mustang rear suspension (same design) may be helpful.
Gustaf
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