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hi sages- the answers to my questions on whether a volvo ohc engine should use current 10-30 oil rated sn or zddp rich oil and whether the engine is flat tappet are somewhat inconclusive. the 92 245 engine does not have valve lifters which used tobe called flat tappets. nor does it have roller bearings on the valve stems to reduce wear. rather it has a round disc on top of the valve stem which seems similar to the surface of the old valve lifter. however word is that the valve spring tension is reduced in this engine. true the old push rod and valve lifter in ohv engines had more tension and pressure apparently necessitating the zddp oil. since present wisdom is to avoid zinc rich oil in cat equipped cars which since 74 has been all cars ,since it ruins the cat , there isnt a choice. my shaky conclusion is to continue to use 10-30 sn oil unless sages here warn me to use zinc rich oil(rotella). strange thing my cars with cats in the 70s right up did not have this warning about zinc. in fact never heard of it until the volvo days(2011). most of those were slant sixes and 318 v8s, all flat tappet ohv engines. looking forward to your comments. thanks tons again oldduke
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