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Story and images by Chirag Asaravala, John Dinkel and Day Scovel.

Last month when we wrote our Feature Car piece on the Shelby Automotive American Club (SAAC), we concluded that the organization is full of enthusiasts who defy the clubs own admission that its' members are not interested in working on their cars, because they simply pay professionals to do so. In fact subsequent to publishing the story we've received a flood of email's from SAAC members nationwide who were eager to show us their cars, which they themselves proudly built, race and maintain. While we always knew that the regional and national clubs were full of members who own all sorts of Ford muscle cars, the least of which are genuine Shelby's, and we also suspected that many of these guys are not only wrenching on their own machines, but in fact leading the way in innovative modifications.


John Dinkel shows off his OpenTracker roller spring perches.
We had to look no further than own FordMuscle Forums to find John Dinkel, aka "OpenTracker". John, a member of the Northern California SAAC club, is known in the Mustang open-track community as a highly adept fabricator of suspension components -more on this in a bit. However it is not his engineering skills alone that impress us, but rather his genuine desire to help fellow enthusiasts out. As you'll see in this article and the others in this series in future issues, John is completely willing to share his secrets and designs so you can reap the benefits of his innovations. Of course John doesn't mind either if you choose to have his shop, Opentracker Racing Products, build the products for you.

Improving upon Stock, for Less
You might consider John's driving time around the circuits of Thunderhill, Laguna Seca and Sears Point a sort of R&D facility. His guinea pigs include the 65 coupe (pictured above, with his wife driving), and the stable of other vintage Fords that occupy his Carmel Valley ranch. When John noticed aggressively lowered Mustangs breaking their shocks under aggressive track driving he started analyzing the situation. He noticed that the stock factory spring perches on Mustangs and most Falcons utilized a high durometer rubber bushing, vulcanized to the outer bore and also the center shaft. The result is a perch that takes tremendous force to pivot, and while it may be suitable for stock ride heights, when combined with lowered front ends and altered upper A-arm locations, the result was suspension bind. Not content with having to pay big dollars for aftermarket Mustang suspensions, he decided to design his own.

While researching the perches of other coil-on-upper-arm models at the local Pick-n-Pulls, he came across some early Falcon perches (see side bar) which utilized a bronze bushing and Zerk fitting. The perch on these designs was free to rotate on the shaft, eliminating bind. However the visible downside to the bushing appeared to be accelerated wear on the shaft and bushing due to the very limited range (less than 20 degrees) that the perch and shaft rotate. We suspect this is why Ford converted over to the rubber bushing perch.

Of course Ford isn't designing spring perches any more so whose to say whether they could have, or would have, improved further on the design. In John's analysis, the next logical approach would have been to utilize a bearing; whereby the load of the shaft is spread evenly upon the balls or rollers, and allowing the perch to pivot with the motion of the of the a-arm.


John has produced over 50 sets of roller spring perches since 2003.

John drafted up the design and produced his first set several years ago. That set is still running strong in his families daily-driver '64 Falcon. He produced several other prototype sets for his open track car and to give out to fellow club members. Since then he's produced over 50 sets for customers, and an untold number have been made from his design which he freely distributes. So far not a single one has come back to him failed, and in many cases the perches have eliminated broken shocks and other front suspension ailments. Those who have tested them at the track have sung praises on how quick and responsive the steering has becomes as a result of the simple upgrade. Others have noticed improvements in the ability to hold a line through a turn, as it is likely the old rubber bushings allowed slight camber changes to occur on the inside wheel under load.

Making your Own
We told you that John's first and foremost concern is in sharing his knowledge and know-how with his fellow enthusiasts. He's more than happy to help a fellow racer build his own set of roller perches, and as you'll see on the next page, he's got many followers who have successfully followed his recipe.


(How to Make Roller Spring Perches)
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In This Article:
The first in a multi-part series, we take a look at a track-inspired suspension modifications designed by John Dinkel of Opentracker Racing Products. In Part I we show to make and install your own rollerized coil spring perches for early Mustang, Cougar, Falcon or Comets.


Typical factory and replacement Mustang spring perches were built with a with rubber bushing. The rubber is vulcanized to the center shaft and the bore. The shaft cannot be rotated by hand.
 

This spring perch, found on some early Falcons, utilizes a bronze bushing and grease fitting. The perch is able to pivot on the shaft. It's not clear why this design was deviated from on future factory vehicles.
 

Spring perch with the Opentracker Racing Products roller bearing modification. The center shaft spins with minimal resistance, eliminating bind.



 

 


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