rvwp Posted July 9, 2020 Report Share Posted July 9, 2020 Hi Guys, Has anyone know of a simple (ish) method of checking the non-return valves fitted on the pipe outputs on a PI metering unit. I believe if these are not sound then fuel can drain down over time when car is not used and cause the common problem of difficult starting after a few weeks layup. I don't know for sure but I imagine that during Metering Unit refurbishment these valves are not rebuilt and will be original as NLA. A older local garage mechanic I know who used to work for a Triumph dealership tells me that starting was never a problem with PI cars left for months when new. Rich Quote Link to post Share on other sites
barkerwilliams Posted July 9, 2020 Report Share Posted July 9, 2020 Rich, Even if the valves are sound after so many years I expect ever increasing Ethanol will soon be the death of them. With so many PI's about we should all get together and get new seals manufactured, it is only a simple cone. Alan Quote Link to post Share on other sites
Richard Green 54 Posted July 9, 2020 Report Share Posted July 9, 2020 14 minutes ago, barkerwilliams said: Rich, Even if the valves are sound after so many years I expect ever increasing Ethanol will soon be the death of them. With so many PI's about we should all get together and get new seals manufactured, it is only a simple cone. Alan Alan, Rich was asking about the metering unit non return valves. I thought these were just plain spring loaded disks that seal against a flat face inside the MU connector. Richard Quote Link to post Share on other sites
astontr6 Posted July 9, 2020 Report Share Posted July 9, 2020 1 hour ago, Richard Green 54 said: Alan, Rich was asking about the metering unit non return valves. I thought these were just plain spring loaded disks that seal against a flat face inside the MU connector. Richard As far as I know new non return valves are obtainable from KMI including re-con ones on their part exchange system? I have had both types from them in the last 18 months. Bruce. Quote Link to post Share on other sites
barkerwilliams Posted July 9, 2020 Report Share Posted July 9, 2020 On my metering unit they are a rubber type material, a solid cone with the smaller end formed into a small peg that clips into the top of the spring. Are you suggesting that they should be metallic discs that are held in place by the spring? Are there different types of non-return valves, does mine just have something unusual fitted? Alan Quote Link to post Share on other sites
Richard Green 54 Posted July 9, 2020 Report Share Posted July 9, 2020 2 hours ago, barkerwilliams said: On my metering unit they are a rubber type material, a solid cone with the smaller end formed into a small peg that clips into the top of the spring. Are you suggesting that they should be metallic discs that are held in place by the spring? Are there different types of non-return valves, does mine just have something unusual fitted? Alan The TR6 manual shows the arrangement in the picture and there does not appear to be a cone. The banjo NRVs are like this on my MU because I had one in my hand the other day. Perhaps you have some sort of aftermarket 'improved' version. Richard Quote Link to post Share on other sites
John L Posted July 9, 2020 Report Share Posted July 9, 2020 I have taken the rubber puck like disc out and changed them round, there is a sort of cone that the rubber sits/seals on but its not that well machined. the rubber discs where marked a bit so turning them over did improve them. The ones closest to the engine 2 and 5 are not the same so didn't do those. I just used a small tool to unhook the spring and out it pops. John Quote Link to post Share on other sites
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