rvwp Posted January 5, 2021 Report Share Posted January 5, 2021 Hi Guys, As the oil in my Armstrong shock absorbers is of unknown vintage, I thought I would drain and refill. But what oil? The original Armstrong oil is NCA. I have heard that motorcyle Fork oil is suitable, but what grade? Also hydraulic Jack oil? Presumably the stiffness of the shock absorber will be affected by the SAE number. Any recommendations appreciated. Thanks Rich Quote Link to post Share on other sites
RogerH Posted January 5, 2021 Report Share Posted January 5, 2021 Hi Rich, this is what Moss have to offer Shock oil Roger Quote Link to post Share on other sites
rvwp Posted January 5, 2021 Author Report Share Posted January 5, 2021 Thanks Roger, yes I know Moss have it, but I don't like paying Moss delivery cost when E-Bay have lots of suppliers of probably suitable oil for less price with postage included. Interestingly, the Moss description states also suitable for motor cycle forks. Just need to know the best viscosity for the Armstrong Shocks. Regards Rich Quote Link to post Share on other sites
Charlie D Posted January 5, 2021 Report Share Posted January 5, 2021 (edited) Rich, Curious about this myself I did a Google search and found this: “It is a common practice in the construction and mining industries to use engine oil SAE 10, SAE 20 or SAE 30 with the lowest API rating as a substitute for hydraulic oil ISO 32, ISO 46 or ISO 68, respectively for hydraulic systems of heavy equipment. Is it a problem to use these? What integrity or lack of it does it give to the machine and to the people working around the site?" BUT… The ISO oils seem to be specific for use in hydraulic systems (Like the dampers). SAE 30 might be the same weight as ISO 68, but it is not the same chemically. (Anti frothing aditives etc.) For the sake of a few quid more I’d go with the correct oil for the purpose. Maybe search eBay for ISO 68 oil. Charlie Edited January 5, 2021 by Charlie D Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 5, 2021 Report Share Posted January 5, 2021 Bit of reading for you https://mgaguru.com/mgtech/suspensn/fs110.htm https://mgaguru.com/mgtech/suspensn/fs110a.htm discussed here http://www.mg-cars.net/triumph-tr6-bbs/rear-shocks-which-oil-200405200306322519.htm Peter W Quote Link to post Share on other sites
ed_h Posted January 5, 2021 Report Share Posted January 5, 2021 (edited) It's a hydraulic application, so a hydraulic oil is appropriate. Jack oils and fork oils are hydraulic oils. I think ISO 46 is around 20 weight, and close to stock. Ed Edited January 5, 2021 by ed_h Quote Link to post Share on other sites
Hamish Posted January 5, 2021 Report Share Posted January 5, 2021 I’m sure that Alec P suggested 30wt oil to me when he was talking me through competition improvements. motorcycle fork oil was the right stuff and I think specifically Harley Davidson dealers were a source as they need a heavier oil to deal with the weight. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 5, 2021 Report Share Posted January 5, 2021 2 minutes ago, Hamish said: I’m sure that Alec P suggested 30wt oil to me when he was talking me through competition improvements. motorcycle fork oil was the right stuff and I think specifically Harley Davidson dealers were a source as they need a heavier oil to deal with the weight. Are you saying Harley riders are fat? Quote Link to post Share on other sites
Hamish Posted January 5, 2021 Report Share Posted January 5, 2021 1 minute ago, BlueTR3A-5EKT said: Are you saying Harley riders are fat? no no no the bikes are just big boned I mean heavy Quote Link to post Share on other sites
TriumphV8 Posted January 5, 2021 Report Share Posted January 5, 2021 (edited) It is common to use thicker oil for the levers. For racing purpose it is a good idea, for street use not in my opinion. The reason is that race track often is flat but street has bumps. I found out that levers have very small valves that make car jump and uncomfortable on bumps and uneven roads. The thicker oil makes car stiffer in good roads but bad on bumpy roads. Swapping to modern sports shocks showed to me what comfort ist possible with big valves, opening on bumps. You get smooth riding comfort and good roadholding. So my recommendation for street use ist to use very thin fork oil for levers and beware of SAE30. Edited January 5, 2021 by TriumphV8 Quote Link to post Share on other sites
Z320 Posted January 5, 2021 Report Share Posted January 5, 2021 What ever was in, I top them up with "Bel-Ray MC10" motorcycle fork oil SAE 10 from time to time, which I have in my oil storage container from my BMW motorcycles. This works lovely, me and my wife like comfortable driving. Quote Link to post Share on other sites
TR4Tony VC Posted January 5, 2021 Report Share Posted January 5, 2021 Hi all My experience has been that thicker oil also can make the seals in lever shocks fail very quickly. Essentially the shock heats up inside as a result of continuous actuation of the piston, so the heat is transferred across the body, oil gets very hot and thin and the seals fail. Worse still the piston seizes. This is why a so called ‘upgrade’ with thicker oil Is only a partial solution and there is obviously a limit to the thickness of oil you can use and how long you can use the shocks for with thick oil in them. You can revalve shocks, change the springs in the valves or shim the existing valves out a little, but you need to be able to test the effect, which is why you need someone who knows what they are doing or learn how you do it properly yourself. I have destroyed a pair of NOS adjustable DAS9’s on the back on my TR4 as a result of trial and error so not recommended .... they worked beautifully until the pistons seized chewed a hole in the body. Once one side goes, the other rapidly follows. Beware. Regards Tony Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 5, 2021 Report Share Posted January 5, 2021 52 minutes ago, TR4Tony VC said: Hi all My experience has been that thicker oil also can make the seals in lever shocks fail very quickly. Essentially the shock heats up inside as a result of continuous actuation of the piston, so the heat is transferred across the body, oil gets very hot and thin and the seals fail. Worse still the piston seizes. This is why a so called ‘upgrade’ with thicker oil Is only a partial solution and there is obviously a limit to the thickness of oil you can use and how long you can use the shocks for with thick oil in them. You can revalve shocks, change the springs in the valves or shim the existing valves out a little, but you need to be able to test the effect, which is why you need someone who knows what they are doing or learn how you do it properly yourself. I have destroyed a pair of NOS adjustable DAS9’s on the back on my TR4 as a result of trial and error so not recommended .... they worked beautifully until the pistons seized chewed a hole in the body. Once one side goes, the other rapidly follows. Beware. Regards Tony Good trick here http://www.sebringsprite.com/shockabsorbers.html Did you ever try the twin valve units that the racers of the 1960s and 70s favoured? cheers Peter W Quote Link to post Share on other sites
TR4Tony VC Posted January 5, 2021 Report Share Posted January 5, 2021 Hi Peter Yes got a variety of solutions now, with changes to kit depending on regulations. FIA are stricter than others but most rally events I can run whatever I like as long as it was available in period or ‘free’. regards Tony Quote Link to post Share on other sites
rvwp Posted January 6, 2021 Author Report Share Posted January 6, 2021 OK Guys, Gone off topic now, so I will just buy from Moss and pay the £5.45 postage Rich Quote Link to post Share on other sites
stillp Posted January 6, 2021 Report Share Posted January 6, 2021 Last time I bought oil from Moss, the postage was free if I ordered from their ebay shop. Pete Quote Link to post Share on other sites
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