Re: Valve question....

Posted by JeromeSolberg On 2020/10/9 0:46:54

As I understand it, the question is about "flat tappets", e.g. whether the part that contacts the cam is a flat surface or a roller with bearings. The 51-54 288/327/359 engines all used flat tappets. The other possible distinction is whether they were "solid lifters",e.g. needing to be adjusted every so many miles, or had hydraulic lifters that automatically adjusted. I believe the '54 Patrician had hydraulic lifters, as did the Cavalier, whereas the lower-priced models had solid lifters, though I think they could be equipped with hydraulics as an option(?), see also the image attached grabbed from the parts manual. From what I can read the "Senior" 8 and V-12 from before WWII had roller lifters, but in a more complicated system than illustrated in the web page linked, where they operated on a pivot, as in the second image attached from the 1938-39 Service Manual.https://www.theengineblock.com/battle-of-the-lifters-flat-tappet-roller-solid-hydraulic/

Cheers. Sorry for writing so much, just been spending a lot of time thinking about this stuff recently.

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