BlueTR3A-5EKT Posted November 13, 2023 Report Share Posted November 13, 2023 (edited) Here is a sketch of a genuine Triumph oprv plunger and spring that I took from a new factory cylinder block when they were available as a spare part for £50.00. They included the oil pressure valve and the distributor drive bush. These items are similar to the samples Cox & Buckles used to remake the items in the 1980’s. i am surprised at the length of the spring when reading earlier posts. Edited November 13, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
Mike C Posted November 13, 2023 Report Share Posted November 13, 2023 I fitted a NOS oil PRV plunger and spring in 2016 in an attempt to reduce high cold starting oil pressure. The NOS parts made it worse so I reinstalled the old components. My engine is not stock and I have no idea how some PO sourced the PRV spring and plunger but I would not be surprised at finding many variations in spring length and spring constant floating about in the parts supply chain. Quote Link to post Share on other sites
stuart Posted November 14, 2023 Report Share Posted November 14, 2023 As long as you dont do what I found some DPO had done to one 6 engine, fitted a washer under the spring, on startup oil pressure shot off the clock and burst the oil cooler Stuart. Quote Link to post Share on other sites
PodOne Posted November 14, 2023 Report Share Posted November 14, 2023 Hi Stuart I always thought that adding a washer was a legitimate way of increasing oil pressure as long as you don't go daft or just a way of dealing with a short/weak spring. 40mm seems to be the suggested length in the Brown Book. So far had two new ones from separate suppliers ranging from 38 - 38.5mm no different to the one I took out at 38mm which is back in the block with the original plunger as I reasoned it would be a better fit having bedded in over the years. OP is good. Andy Quote Link to post Share on other sites
Mike C Posted November 14, 2023 Report Share Posted November 14, 2023 With my car the previous owners seemed to know what they were doing , implementing changes in ways typical of 1970's back yard mechanics. I installed the NOS oil plunger and spring hoping to cure a problem with filters blowing off a poorly built Mocal adapter. I don't know where the original PRV parts came from but I decided to leave sleeping dogs lie. Quote Link to post Share on other sites
Mk2 Chopper Posted November 14, 2023 Report Share Posted November 14, 2023 When I was finding erratic oil pressure figures, and the gauge lost that 'rev counter' movement, I looked at the PVR and spring and they looked worn, so I fitted a washer as the spring was less than the 40mm I'd read about. The oil pressure went back up, so I decided to get a new PRV the new spring still wasn't 40mm, but it restored the free movement on the gauge and increased the pressure. Gareth Quote Link to post Share on other sites
InfinityJon Posted January 7 Author Report Share Posted January 7 AN10 oil cooler pipe work made up running through thermostat. Going to change the red fittings to black but try they will do for testing. Now onto trigger wheel sensor mounting and readying for electronic ignition. anyone installed and using a mega jolt system? Strangely, I’ve got a few questions lol. Quote Link to post Share on other sites
john.r.davies Posted January 7 Report Share Posted January 7 I did, Jon, it ran but I could not program it, and reverted to distributor. The problem was later found to be a duff laptop - the USB port did not work! But I've never got around to trying again. JOhn Quote Link to post Share on other sites
roughground Posted January 7 Report Share Posted January 7 Your car reminds me of mine when if came from Jacksonville 30 years ago. I'm just getting around to changing the steering over, so no rush . If you live near the south coast it's great to tour in France. Quote Link to post Share on other sites
PodOne Posted January 7 Report Share Posted January 7 Hi Jon Unless you intend using mega boost pressure from a Turbo EFI set up to counter spark blow out it's a waste of money. Better to have your distributor rebuilt to counter scatter along with a flame thrower coil, electronic ignition and some decent HT leads. Just my opinion having being there and finding it made no difference running 2 Bar of boost over normal COPs. Your brass! Andy Quote Link to post Share on other sites
InfinityJon Posted January 28 Author Report Share Posted January 28 radiator mounted and electric fan mounted to radiator with custom aluminium brackets and Resin printed clamps. Also fabricated a mount for the coil pack to be mounted to the same mount points as the existing coil. Quote Link to post Share on other sites
InfinityJon Posted February 11 Author Report Share Posted February 11 Probably an obvious question. how can I be sure that all surfaces of the moving parts in the engine are getting oil? I have good oil pressure but how do I know for instance that the front bearing surface of the cam is lubricating? rear is easy, if I have oil at the rocker, then the rear surface of the cam is lubricating. But what about the front? Quote Link to post Share on other sites
john.r.davies Posted February 11 Report Share Posted February 11 "The front surface of the cam"? The cam bearings are lubricated via oilways drilled from the main oil gallery. Clean them out (and pass a drill through them if you like) when rebuilding. Without pressure/flow sensors you can't know for sure. But you mentioned the rocker. Between the two, the cams themselves and their followers are splash lubricated and by drip down from the rocker shaft, as are the pushrods and the rocker to valve stem contacts. Rocker bearings, of course have 'metered' flow from the rear camshaft bearing into the hollow rocker shaft. That comes in at the back, so did you mean the front rocker bearings? Seeing a drip, drip from them all is the best assurance you can hope for! PS When I rebuild, I pass a long drill right through that main oil gallery. I had always assumed that it was made by drilling the raw block casting, but my drill catches so many projections and imperfections that you just wouldn't see in a drilled bore that I wonder if it is made in the casting? Quote Link to post Share on other sites
Jonny TR6 Posted February 13 Report Share Posted February 13 You can of course run the engine with the rocker cover off and see what oil’s getting to the front rockers. I thought oil would be flying all over the shop, but it’s not an issue. Gives some peace of mind that you’re getting oil in the right places. Quote Link to post Share on other sites
stuart Posted February 13 Report Share Posted February 13 1 hour ago, Jonny TR6 said: You can of course run the engine with the rocker cover off and see what oil’s getting to the front rockers. I thought oil would be flying all over the shop, but it’s not an issue. Gives some peace of mind that you’re getting oil in the right places. Unless theres an additional oil feed up to the rockers in which case you`ll be drowned in it! Stuart. Quote Link to post Share on other sites
Jonny TR6 Posted February 13 Report Share Posted February 13 (edited) 48 minutes ago, stuart said: Unless theres an additional oil feed up to the rockers in which case you`ll be drowned in it! Stuart. Ah yes - forgot about that mod. From memory it’s not seen as worth doing ? Edited February 13 by Jonny TR6 Quote Link to post Share on other sites
stuart Posted February 13 Report Share Posted February 13 19 minutes ago, Jonny TR6 said: Ah yes - forgot about that mod. From memory it’s not seen as worth doing ? Definitely not, spawn of the devil. Stuart. Quote Link to post Share on other sites
InfinityJon Posted February 13 Author Report Share Posted February 13 No, not doing the additional oil feed. Rockers are getting oil ( stripped the rocker assembly off and checked oil emerging from the feed hole). All good! Fingers crossed on the front cam bearing. Weber rebuild x3 next. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.