Henry Boler Posted January 19, 2017 Report Share Posted January 19, 2017 Hi All, I've been having a play with my rear shock absorbers lately. The car is a MK3 GT6 with Rotoflex. When I rebuilt the car I opted for the GAZ rotoflex conversion kit with the little brackets that bolt onto the chassis that the club sells. No good at all, two years down the line I've finally got round to dealing with the problem, that is when the car is sat stationary there is about an inch of play before bottoming out on the shock absorber internally. This isn't much of a problem if there is nothing in the car, that includes the driver. But otherwise, totally unusable, even with a new rear spring and a rear end that sits quite high up in my opinion the car is bottoming out ten times a dozen. I have had the dimensions of the shock absorbers checked and they are spot on. I have just done phase one of the new set up. Which was to install a different set of brackets that also bolt on the chassis, but instead, mimic the original correct rotoflex mount position, I'm still using the shock absorbers designed for the other bracket, but hey, it's a million times better now. Also thanks Mark Reed for the new brackets, as I only had to fettle them a little to make them work! I'm now trying to gauge exactly what the differences are between the shock absorbers for non-rotoflex, for rotoflex, and for rotoflex + conversion bracket. Namely the open and closed dimensions hole centre to hole centre top to bottom. This is for future proofing. I think I need to buy different shocks as mine are knackered already 2 years in anyway, but I want to know for example, if I buy a set of standard non-rotoflex shock absorbers, with the option to in the future change rotoflex to cv drive shafts, are they going to be the right length for my set up now? I tried measuring my old ones but they are too dead to be of any use! Hope that all makes sense. Cheers, Henry Link to comment Share on other sites More sharing options...
Clive Posted January 19, 2017 Report Share Posted January 19, 2017 If you go the CV conversion route, you can use the non-roto shocks onto the std chassis mountings. That is what I have on my spitfire (CV rotoflex setup, std spit rear shocks) Not a full answer, but partway. Re proper rotoflex shocks, I believe a beetle shock is the correct size (old aircooled beetle) but google for exact details. Link to comment Share on other sites More sharing options...
Henry Boler Posted January 19, 2017 Author Report Share Posted January 19, 2017 Thanks Clive, but do we know if the non-rotoflex shocks are the same dimensions as the rotoflex ones? I appreciate they have different bushes but its the lengths that are important. Also, I know I've asked this before (2 years ago on this forum), but does anyone else have a GT6 with the rotoflex conversion brackets and if so, what is it like? Mine was totally awful with a passenger, bad enough with just me weighing in at around 12 stone (76kg) and an empty car. Link to comment Share on other sites More sharing options...
Gary Flinn Posted January 19, 2017 Report Share Posted January 19, 2017 Henry This is a copy and paste from the Herald/Vitesse section of Club Triumph site from when I fitted Koni 80-1717 to the rear of my old Vitesse a few years ago? I've been having E-Mail correspondance with the Koni UK Distributors regarding the correct Telescopic Dampers for the Rear of the Vitesse.I was quering the Open & Closed lengths of the Koni 80-1389 Dampers which they specify for the rear of all models of Vitesse, against the recommended 80-1717 early Mini Dampers, see the reply below:- Hi GaryIndeed we do list them for all models of the Herald & Vitesse 1962 to 1971, checking the 1981 catalogue its seems this has always been the case.The damper specs are listed below.Part No Max Min bump force rebound force80-1389 316mm 246mm 910nm 450nm80-1717 296mm 218mm 700nm 200nmThese says to me that the forces on the Mini units are too soft to be used on the Vitesse, particularly the bump force which is less than half of what is required, it would make the back of the vehicle very soft.A better option may be a Morgan damper. It is slightly stiffer in rebound, but the bump is the same.Part No Max Min bump force rebound force80-2885 296mm 243mm 1050nm 450nmRegardsTrevorTrevor Leigh | Performance Parts Sales Manager____________________________________________Automotive Parts Solutions Unit 4Lockwood WayLeedsLS11 5TQ I Never had any trouble with bottoming out even with 4 people in the car? The only faf was the top bushes I had to buy some Separate Poly Bushes and shouldered bolts to get the top of the Dampers to fix to the Brackets? If you Search on the Club Triumph Site for Koni 80-1717 you can see how I fitted them? Cheers Gary Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 19, 2017 Report Share Posted January 19, 2017 On a different drift had this on a swing spring conversion on the Vit6 and to get any ride amounts of kit butchery ended with cut 25mm off the shocker dust can and removed 2 of the 3 rubber bump rings to get some travel. the whole thing was useless and removed to a courier spring set up. pete Link to comment Share on other sites More sharing options...
Gary Flinn Posted January 19, 2017 Report Share Posted January 19, 2017 I reckon the closed length of the GAZ Dampers may be to much. Henry, can you measure the fully open and fully closed lengths of the dampers? Link to comment Share on other sites More sharing options...
Henry Boler Posted January 19, 2017 Author Report Share Posted January 19, 2017 All interesting stuff. This is taken from an email from Garth Jupp at the Club Shop 13-01-2015. GAZ units are made to Open 12.11” closed 8.6” plus or minus ¼” (Open 307.6mm, Closed 218.4mm) At the time I checked this against my ones and found it to be correct. Link to comment Share on other sites More sharing options...
Gary Flinn Posted January 19, 2017 Report Share Posted January 19, 2017 Henry The open and closed dimensions are not to dis-similar to the Koni 80-1717? Are you sure the Spring is a correct Rotoflex GT6 Spring? Also is the spring in good condition? The Rotoflex spring on the Vitesse is a different profile and dimensions to the earlier Swing Axle springs. Link to comment Share on other sites More sharing options...
Henry Boler Posted January 19, 2017 Author Report Share Posted January 19, 2017 The spring was new in February 2015 and was purchased from Owens Springs (the company that makes them). The new spring lifted the car a small amount but not enough, All appears fine to me. Even if it wasn't right it looks right... And it puts up a fight and a half when fitting it! Have to use those big old spring lifting bars. I was also very amused by Rimmers who sell these conversions, and also 1" lowering blocks!? How would that even work?? Link to comment Share on other sites More sharing options...
Henry Boler Posted January 19, 2017 Author Report Share Posted January 19, 2017 Just emailed Rimmer Bros for dimensions, they don't have GAZ in stock at the moment but sent me the Spax dimensions instead. Spax are 355mm end to end full extended and 290mm closed. Slightly unsure about these numbers... Link to comment Share on other sites More sharing options...
Clive Posted January 19, 2017 Report Share Posted January 19, 2017 Rotoflex and non-roto shocks not the same dimensions. And with the extension brackets the mini size are what is best to use (though the std non-troto ones are often sold, which are too big!) All very tricky to get right. Best solution, CV shafts and non-roto Koni's! Link to comment Share on other sites More sharing options...
Gary Flinn Posted January 19, 2017 Report Share Posted January 19, 2017 I'm baffled, the closed length of the GAZ Dampers are identical to the Koni's I had on my Vitesse so this shouldn't be the problem. Owen springs have a good reputation so this should have been manufactured to the original rate and dimensions but have you checked it against an original spring for eye to eye length when off the car? On the original set up for the top damper fixing this was on the wheel arch so you would expect the damper to be a longer open and closed length. Are you sure the car is bottoming out on the damper internal stop and not on the bump stop on the wheel arch? Link to comment Share on other sites More sharing options...
Henry Boler Posted January 19, 2017 Author Report Share Posted January 19, 2017 Gary - This is why I've been baffled for two years!! The new spring looked exactly the same as the old one, and fitted makes the car sit perfectly at the back end. That is correct about the wheel arch fixing. However it is the GAZ / Rotoflex Bracket conversion that is the problem. I don't have any bump stops any more as they were ditched at the same time all the wheel arch metalwork was ditched. My current set up is now using the same GAZ shocks that I had the problems with above, but I replaced the brackets with ones that simulate the original wheel arch mount position and so far they are great. The real question is why doesn't the conversion kit work? Henry Link to comment Share on other sites More sharing options...
Henry Boler Posted January 20, 2017 Author Report Share Posted January 20, 2017 On another note, does anyone know if it's possible to dismantle GAZ shocks for servicing? I've never looked. Henry Link to comment Share on other sites More sharing options...
68vitesse Posted February 13, 2017 Report Share Posted February 13, 2017 Been looking at this with a thought to getting new shocks for the rear of my Mk1 2L Vitesse it has the swing axle rear suspension with a half inch lowering block on the diff. The current shocks are 223mm compressed between mounting centres and 270mm at ride hight, I put a carboard collar on the main body of the shock and went for a 50 mile run of mixed country roads and dual carriageway, just myself in the car and the usual rubbish in the boot. The collar was moved about 25mm down the shock so one with a compressed length of 248mm would still be to long as extra people and or luggage would cause it to bottom out. Regards Paul Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted June 2, 2017 Report Share Posted June 2, 2017 Like the OP I have a Mk3 Rotoflex GT6 with the rear telescopic shock absorbers bottoming out on the slightest imperfection in the road. Unfortunately I don't know the provenance of the shockers and brackets but the shockers appear far too long. The extended length is 14" (355mm) and closed length 11"" (280mm). I have probably added to the problem by recently fitting a 3/4" spring spacer. Can anyone recommend a shorter replacement shocker that can be fitted without modifying bushes or brackets please ? Link to comment Share on other sites More sharing options...
Gully Posted June 2, 2017 Report Share Posted June 2, 2017 Like the OP I have a Mk3 Rotoflex GT6 with the rear telescopic shock absorbers bottoming out on the slightest imperfection in the road. Unfortunately I don't know the provenance of the shockers and brackets but the shockers appear far too long. The extended length is 14" (355mm) and closed length 11"" (280mm). I have probably added to the problem by recently fitting a 3/4" spring spacer. Can anyone recommend a shorter replacement shocker that can be fitted without modifying bushes or brackets please ? Nick, Are your's mounted on the wheel arches, or do you have the chassis bracket conversion? If they are still on the arches, then you'll struggle to find 'simple' rotoflex shocks - you're looking at Gaz, Koni etc adjustables. The main parts dealers generally stock them, although I bought mine second hand via a Courier advert. I've a half inch lowering block on mine and there's plenty of travel on them. Gully 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 2, 2017 Report Share Posted June 2, 2017 we had gaz made up some to the length we specified for the Vit 6 with the lowered swing spring , as the spring was hopeless the shorter shockers just made things lower thats when we found the rings inside the top can were actually bottomed out and the spring wasnt able to spring gives hard direct cornering and the ride of a skateboard. why not try yours with the shockers removed as a test 1 Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted June 3, 2017 Report Share Posted June 3, 2017 Nick, Are your's mounted on the wheel arches, or do you have the chassis bracket conversion? If they are still on the arches, then you'll struggle to find 'simple' rotoflex shocks - you're looking at Gaz, Koni etc adjustables. The main parts dealers generally stock them, although I bought mine second hand via a Courier advert. I've a half inch lowering block on mine and there's plenty of travel on them. Gully Gully, My rear shocks are mounted off a chassis bracket. The attached photo shows the detail. The measurement between fixing centres is 11" (280mm) which is almost identical to the compressed length of the shock absorber so I am currently enjoying Pete's "skateboard effect". I guess I really need to find a suitable s/a with a compressed length of 8.5" or so? Nick Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 4, 2017 Report Share Posted June 4, 2017 I Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 4, 2017 Report Share Posted June 4, 2017 Koni 80-1717 as above work? Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted June 6, 2017 Report Share Posted June 6, 2017 Koni 80-1717 as above work? Ideally looking for some to bolt on without having to modify. Have now got some Spax on order from Moss which I hope will suit a lowered Rotaflex GT6. Many thanks to all for the suggestions. Link to comment Share on other sites More sharing options...
Qu1ckn1ck Posted June 8, 2017 Report Share Posted June 8, 2017 Spax adjustables for lowered Rotaflex cars fitted today and appear to have solved the bottoming out problem. 2 Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 9, 2017 Report Share Posted June 9, 2017 Good news, glad its all sorted 1 Link to comment Share on other sites More sharing options...
Henry Boler Posted June 9, 2017 Author Report Share Posted June 9, 2017 So you now have a completely bump free ride on your car with the Spax units fitted? Have you driven with the car loaded? Passengers and luggage and gone over any dips on the road yet? Henry Link to comment Share on other sites More sharing options...
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