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Dampers

Started by B.P.Bird, March 22, 2017, 17:16:34

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B.P.Bird

There have been several threads on this forum raising questions about dampers in general and Spax in particular, as applicable to the Ace and Aceca chassis. Having reinstalled the original 1954 Armstrong dampers on AE22 it was apparent that the original open length, both front and rear, gave rise to various problems:
   1) The front suspension is allowed to droop so that further travel is limited by the track rods contacting the wishbone inner mounting bracket. At this point the steering is obstructed.
   2) The rear suspension is similarly allowed to droop excessively allowing the drive shaft U.J. maximum angularity to be exceeded. This locks the driveshaft.
   3) The rear dampers have a clearance cut out in the rear carrier (B60061/2) but with excessive droop this clearance is insufficient and the damper body is forced against the carrier.
   Of course one might rightly point out that unless you launch your Ace in to the air over a hump backed bridge these problems will not arise. Not quite true as they can be a nuisance when jacked up for greasing and are unwelcome, not to say dangerous, when on the track, where hard cornering can allow the unloaded, inner wheels, to droop far enough to reach these limits.
   I do not know whether Thames Ditton ever addressed the issue, or even regarded it as significant - obviously they did not in the early days. In any event, as discussed in previous threads, Brian Eacott pioneered a shorter rear damper extension to restrict droop. Inspired by this I discussed with Spax a similar restricted extension damper for the front. They have now produced this. With the shorter type fitted, front and rear, to AE22, all clearance problems have been eliminated and I have decided to retire the original dampers to the shelf.
   Out of interest the open length of the original dampers far exceeds the maximum suspension unloaded travel - front 15.25" rear 16". The Spax shorter extension dampers reduce this - front 12.9" rear 15.25" measured eye centre to eye centre rear and eye centre to mid stem on the front.
   The Spax part numbers are:
   
   Front - G9442AS
   
   Rear - G623EA
   
   I should say that the reduced extension rears are well tested on a number of cars, but the fronts await road testing and that will be a while so far as AE22 is concerned. If any one tries them meantime please report back. I must say Spax have been very helpful and, unlike many other manufacturers, their products have increased in quality since I first used them on BEF 2535 back in the seventies.The set I have had on CSX 2033 for nearly thirty years are as good as new.
   
   Here is a rear on AE22.
   
   
   
   And a front, don't copy the brake lines - the Formula III style mounting on the spring only applied to AE 22 and 23
   

johngoose

I haven't got the part numbers but Spax have also been very co-operative and have built spring over damper assemblies for the Greyhound
   John

TTM

Hello,
   
   I installed a set of B.P.Bird/Spax updated dampers a few weeks ago.
   
   The reduced maximum open length of the new units allowed me to remove the wire cables that had been installed at the rear axle to avoid excessive travel.
   
   The dampers that came off were also Spax units, part numbers G403HL (Front) and G623HH (Rear). So far I have not been able to notice a big difference in terms of handling, though that could be due to the car being probably oversprung, as comparing the new dampers with the old ones off the car with various settings on the adjusting knobs revealed that the old ones were most likely past their best.
   Comparing both dampers side by side showed the net gains in loss (!) of open length.
   
   Sincere thanks to B.P.Bird for instigating these new dampers with Spax!