Does the 126 V8 117 engine oil pump have one (1) or two (2) plastic rail tensioners? When changing oil pan gasket in 81 500 sel I found some small plastic rail pieces floating around; looking up to the oil pump chain I saw only one small plastic rail tensioner on the drivers side but no corresponding plastic rail tensioner for the passenger side? I visually confirmed that car has new timing chain and upper rails on the heads and the usual telltale previous chain scratches in the driver side valve cover. Car runs excellent, chain is tight, new chain tensioner etc. and beautifully clean engine internals.

Hello Carlo(s) The guide on right side of block is inside of chain towards center of engine sits above crank gear so you cant really see it from underneath.The drivers side rail is outside the chain so its visible from underneath. Tim

Thanks Benztech. Another ?; can scratches on camshaft be polished? no cam lobe wear at all just some scratches from past lack of lube. Engine oil pump screen and cranckshaft in beautifully clean condition after 141,000 miles.

The cam lobes have a very thin what I believe is called a 'case hardened' surface, which means that you cannot polish out the unscratched surface area without going through this thin outer layer of hardened metal. To do so would obviously remove the hardened surface and expose the lobe to greatly accelerated wear as the rocker (also hardened) bears against it.
Having said that, I once tried this on a former 450SE cam, which had ground a huge gouge in the rocker (tic tic as the lobe passed over the 2 edges of the gouge). I put a new rocker in and lots of aggressive moly break-in lube on the new rocker and worn cam lobe. It did solve the problem, but for how long I can't say as the car was sold not many miles after.....

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1986 560SL
2002 Toyota Camry
1993 Lexus