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jyrostng's avatar
jyrostng
Explorer
Mar 29, 2017

Onan 5.5BGMFA26105H, adjusting lifters question

Anyone ever tried to adjust lifters in a gas onan rv generator. Mine has a click like a lifter loose, runs perfect, can't hear the click inside. I want to keep it running good. 800 hours on it.
  • Yes, it is easy to do. You need to take off the head rocker covers so I suggest picking up 2 rocker cover gaskets as the old ones will probably tear when removing rocker covers. The valve lash gap is .oo4" with engine at room temperature.
    See manual : https://www.manualslib.com/manual/822463/Onan-Hgjab.html
  • GREGORYJ wrote:
    Yes, it is easy to do. You need to take off the head rocker covers so I suggest picking up 2 rocker cover gaskets as the old ones will probably tear when removing rocker covers. The valve lash gap is .oo4" with engine at room temperature.
    See manual : https://www.manualslib.com/manual/822463/Onan-Hgjab.html


    Thank You
  • Since you have a 5.5BGM (older style Marquis set), adjusting valve lash is a bit trickier. You will need to remove intake and exhaust manifolds, then tappet chamber cover plates to access tappets. Valve lash is .005" intake and .013"ehhaust. You will need 2 intake manifold gaskets and 2 exhaust manifold gaskets, plus 2 or 3 tappet chamber gaskets. The valve lash is adjusted at the tappets on this "flathead" style engine. Your ticking noise is possibly caused by excessive valve lash, could also be excessive carbon build up in combustion chambers, in which case you will need to remove cylinder heads and clean carbon from heads and pistons. Sometimes a can of Sea-Foam aerosol sprayed into carb can remove some carbon, but is only temporary fix. Good luck