1977 Triumph T140v - Wet Sumping Q's

Discussion in 'Technical Help' started by Charles West, Apr 11, 2024.

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  1. Hi Everyone,

    I've recently picked up a 1977 T140v that has a wet sumping problem. Based on information found on this forum and others I have ordered a new Morgo oil pump for it, but I am curious as to the function of the oil pressure release valve and whether or not it could be causing or contributing to the wet sumping problem too? What is the purpose of the pressure release valve and should I check it? Very much appreciate your input and guidance.
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  2. joe mc donald


    Dec 26, 2014
    slough / burnham
    @Charles West
    Yes does good to clean up the release valve as if sat to long they seem to seize up a bit. And as you are fitting a superior oil pump you should get over any probs there. I take it you have checked it is a straight forward swap. Some you have to shave some metal of the inner cases just to fit them. But good luck and do keep us all informed on the progress. Joe
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  3. Hi Joe, I've taken you up on your good advice to check and clean-up the pressure release valve and much to my surprise the wet-sumping issue seems be either resolved or vastly improved. I did a video of the work which shows the bike running near the end. I am super happy but thinking perhaps it might have been a bit of 'crap' in the oil pump that dislodged while running as I am not sure the PRV could have made this much improvement. Either way, I am really happy with the result, so thank you so much! Here's the link to the video:
  4. Iron

    Iron Elite Member

    Dec 29, 2021
    Bob Ross Studios
    #4 Iron, Apr 13, 2024
    Last edited: Apr 14, 2024
    Wotcha Charles, welcome in.
    The pressure relief valve is basically a piston with a spring behind it. If the pressure within the delivery side (timing side) of the engine is greater than the strength of the spring then the piston will move allowing the oil to bypass the crank and enter directly into the sump.
    This mostly occurs when the engine is warming up when the oil is thick. The pump easily scavenges this temporary overflow of oil back into the oil tank as the return side of the pump has a greater capacity than the delivery side.
    Once the oil becomes hot and thins the pressure drops. the spring in the pressure relief valve is then capable of pushing the piston back to the closed position. All the oil then passes through the centre of the crankshaft and sludge trap and on through the big ends as normal.
    You can remove and dismantle the pressure relief valve to both clean and ensure that the spring is the correct length. A well aged shorter spring wont hold back enough oil pressure to prevent wet sumping.
    I've had PRVs that measure ok but do not operate correctly (probably due to the piston getting lodged sideways somehow) and have cured wetsumping by just replacing with a new one.
    A 1977 engine shouldn't require any work if you've ordered a normal two valve pump and not a 4 valve as fitted on later years or one of those Morgo rotary pumps. The rotary pumps are just not needed and IMO increase pressure to cause gasket problems.
    Wet sumping is usually cured by a pump clean/test andreplacement. Although there are lots of causes - I did a thing on here sometime ago, I'll see if I can find it.......

    Edit......yep here ya go


    Extra Edit.......I see you've already seen the thread. The checks listed there are worth running through if your new pump doesn't cure the issue.
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  5. Hi Iron, thanks for the info. I've ordered a standard two valve morgo pump from Shropshire Classics that it is supposed to fit this bike exactly, so fingers crossed :). Interestingly though after cleaning out the PRV the bike doesn't visibly wet sump any longer. I haven't drained the sump to check on the quantity of oil in there, but it visibly isn't blowing blue. I am frankly not convinced that cleaning out the PRV solved the issue as I suspect running the engine as I have been, may have loosened or dislodged something in the oil pump. That said, since I have the pump or order, I'll fit it anyways when it arrives ...at least that's my plan right now :) Really appreciate the info and the help!
  6. Iron

    Iron Elite Member

    Dec 29, 2021
    Bob Ross Studios
    #6 Iron, Apr 15, 2024
    Last edited: Apr 15, 2024
    A two valve Morgo from Shropshire Classics should slot straight in.
    Have a check of the two oil seals in the timing cover. The upper one is for the exhaust cam into the points. The lower one (which faces the other way towards the cover) and held in with a circlip can also cause wet sumping if it has been damaged or hard.
    Enjoy :)
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  7. Hi Guys, just circling back to let you know I completed the installation of the Morgo oil pump and lower seal, and it all worked out great the wet sumping issue appears to be fully resolved. Joe and Iron, I really appreciate your help!! Here's a video of the installation in case you're curious, and thanks again!
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