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Old 09-12-2011, 04:41 PM
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Default Need help with oem koni shocks for 427 cobra

If anyone has an original front Koni shock (82-1390 SPA1) for a 427 Cobra that is not on a car, I would truely appreciate it if you would take a measurement of the centerline from top bushing eye to bottom bushing eye at the maximum length and post it to me. I have had a NOS set of Koni's for 30 some years and now that I am installing them the front shock seems to be about 3/4" longer than it should be. You should not have to compress the spring/shock in order to install them. Have contacted Koni USA and all there specs on these are long gone. Any help would be truely appreciated. Regards.
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Old 09-12-2011, 04:52 PM
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Blue,
I have front Konis on my ERA but don't know the part #. Possibly if you contact Bob Putnam on the ERA forum he will have a record of the part they supplied and its length specs.
Just wondering-thirty year old shocks may have dried seals and be internally damaged from time..?
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Old 09-12-2011, 05:05 PM
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On the front of the 427 cars, ERA prefers the Spax G135 PAS 200 but, if you desire, they will also go with the Koni 8212-1126SPA1 (double external damping adjustment with aluminum body). I just happened to remember that off the top of my head.
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Old 09-12-2011, 08:06 PM
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Default Koni's

I have a couple of sets of original Koni's that I had on my Cobra, one set was purchased in 1966 from Shelby American. I will try and dig them out tomorrow and measure the extended length of a front shock.
I remember that the rebound forces were really high compared with the original Armstrongs, the Koni's were also adjustable by collapsing them all the way and turning the shaft after it engaged the shock valve, a real PITA since they had to come off the car to be adjusted!
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Old 09-13-2011, 06:44 AM
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ERA does not use original-spec dampers. We designed from scratch.
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Old 09-13-2011, 07:21 AM
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Hi Chas,
I am fairly certain that the Knoi shocks that would be fitted to an ERA Cobra is different to the ones that were installed on AC's back in the 60's. These shocks were one of the last sets that Koni had and they are still in new shape so I really wish to use them. Thanks so much for the help.
AJ
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Old 09-13-2011, 07:30 AM
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Hi Patrick,
I replied to Chas's post that I have Koni's for an AC and not an ERA, so the dimensions would be different. Thanks so much for the help regardless.
AJ
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Old 09-13-2011, 07:54 AM
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Hi 3170,
I have heard the same thing about the rebound forces from another who had Armstrong's on an AC Frua and then switched to Koni's. I always wondered about how these shocks were adjusted. I never got any of the owners lit from Koni when I bought them. If you locate your shocks and are able to measure them I would appreciate any help. Thanks so much.
AJ
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Old 09-13-2011, 09:16 AM
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Default Koni dimension

AJ - One of my fronts with the spring on it measures right about 16 1/2" cntr to cntr, the best that I can eyeball it with a tape measure.

What we really need is someone who has a sophisticated enough algorithm to model the car/suspension to come up with an ideal FV diagram that the shocks can be revalved to (as much as possible). I suspect substantial handling gains could be made as a result of such an exercise, while keeping original 60's components.
CompClassics likes this.
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Old 09-13-2011, 09:59 AM
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Another issue is finding spherical bearings to fit the original shocks.
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Old 09-13-2011, 04:50 PM
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Mike,
Thanks so much for the info. I don't think I will ever drive my car that hard that I need a suspension so tuned! Have a great day.
AJ
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Old 09-13-2011, 04:52 PM
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Nick,
I believe you can still get to original Rose bearings out of England.
AJ
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Old 09-13-2011, 06:34 PM
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Default try Pegasus or McMaster/Carr

Try Pegasus.

Replaced the "rose" bushings on my SPAX front shocks with spherical bearings from Pegasus racing supply. The replacements are PTFE, teflon lined and hopefully last longer the stock steels units which were badly corroded.

McMaster Carr probably also has spherical bearings.

Press the units out and get the measurements...pretty standard stuff I
would think.

Also, I have read that KONI will rebuild/revalve the shocks if you think they may have bad seals.

Pete
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Old 09-13-2011, 08:07 PM
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Good suggestions, both a couple of my favorite places to buy hardware. Trouble for us is the 1-1/8" OD we need uses a 1/2" ID on the newer ones. We need 5/8" ID. They are also very narrow on originals. I'm working on a solution for that as I heard someone scored the last of those bearings from France and they are NLA.
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Old 09-13-2011, 09:05 PM
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My question would be..."How long would you think it would take for those 30 year old seals to start puking?" Arn't those type of Konis non-rebuildable?
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Old 09-14-2011, 03:41 AM
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They are rebuildable.
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Old 09-14-2011, 07:25 AM
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Default Original Koni shocks

Quote:
Originally Posted by blue sky View Post
Hi 3170,
I have heard the same thing about the rebound forces from another who had Armstrong's on an AC Frua and then switched to Koni's. I always wondered about how these shocks were adjusted. I never got any of the owners lit from Koni when I bought them. If you locate your shocks and are able to measure them I would appreciate any help. Thanks so much.
AJ
The original Koni shocks measured 13.625" eye to eye in the front and 17.5" in the rear. The front shocks do not have spherical bearings, they are captured rubber eyelets using a through bolt like most any stock shock, the rears had a spherical lower joint and a standard rubber upper mount. To adjust them you had to unscrew the top eyelet, remove the bump rubber, reinstall the eyelet and then compress them all the way to engage the valve, adjust the valve and then reinstall the bump rubber and eyelet, a very time consuming process. Later versions of the Koni had an adjustment window incorporated in the top eyelet like a Penske. I have a set of these purchased sometime in the late 1980's or early 1990's but never liked them because of the hysteresis vs Penske's. I have three way Penske's now and like them very much.
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Old 09-14-2011, 08:42 AM
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Quote:
Originally Posted by Cobra #3170 View Post
The original Koni shocks measured 13.625" eye to eye in the front and 17.5" in the rear. The front shocks do not have spherical bearings, they are captured rubber eyelets using a through bolt like most any stock shock, the rears had a spherical lower joint and a standard rubber upper mount. To adjust them you had to unscrew the top eyelet, remove the bump rubber, reinstall the eyelet and then compress them all the way to engage the valve, adjust the valve and then reinstall the bump rubber and eyelet, a very time consuming process. Later versions of the Koni had an adjustment window incorporated in the top eyelet like a Penske. I have a set of these purchased sometime in the late 1980's or early 1990's but never liked them because of the hysteresis vs Penske's. I have three way Penske's now and like them very much.
Thanks so much for the info. My front shocks measure longer than your numbers and the rears are the same. I am assuming that your dimenions are the maximum lengths. What I have are the earlier version from what I know. I spoke with Koni and believe I will need to install an internal bump stop to shorten the overall length. Have to see what lengths these come in. All I need for it to be is 3/4" shorter. To unscrew the top eyelet on mine, you first have to knock out a roll pin which really makes you have to work to adjust them. Thanks again. Regards.
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Old 09-14-2011, 08:50 AM
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Quote:
Originally Posted by mickmate View Post
They are rebuildable.
You are right Nick. This series of shocks are fully rebuilbable. You just have to pay Koni's price. Fortunately my are still pristine which saves a lot of money.
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Old 09-14-2011, 11:05 AM
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Quote:
Originally Posted by blue sky View Post
You are right Nick. This series of shocks are fully rebuilbable. You just have to pay Koni's price. Fortunately my are still pristine which saves a lot of money.
The original 60's vintage Koni's do not have any seals around the piston and with the piston being immersed in lubricating fluid, the odds of significant wear with the amount of use these cars get is slim. So, the main reason for rebuilding is cosmetic or if the shaft seals start leaking. Although Koni's rebuilding shop will tell you the original seals are no longer available, I have found replacement seals on the shelf at a local hydraulics shop that look slightly different but seem to work fine. Koni's shop has been automatically replacing the pistons, shafts (which may be a different length) and the upper threaded in cap which houses the shaft seal when they rebuild them. They claim replacing the threaded cap is necessary to accomodate the new seal design they use. I've tried to discuss tuning details with them, but their engineers don't seem to have any knowledge of the shock details/parameters, as they just use settings that were apparently determined decades ago, with underlying rational/analysis long gone.
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