@LeMans850i posted:What is the size of the outside of the sleeve and the restriction hole on the Wydendorf kit… anyone knows??
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Roland I am sorry to read of your discovery.
The bushings have nominal dimensions of 1.002 inch OD, 0.875 inch ID, and 1.500 inch length. Bunting CB141612, cast bronze, SAE 660 plain sleeve bearings (i.e. bushings) are one possible source. If you purchase oilite bushings from Dennis Wydendorf I believe he machines them to 1.0025 inch OD.
The orifices (restriction holes) should be ¹⁄₁₆ inch for solid tappets, up to ³⁄₃₂ inch for hydraulic tappets. Ford's bushings had 0.060 inch orifices' (¹⁄₁₆ inch). Frankly, 0.060 is overkill for solid tappets, when you purchase restrictor push rods they have 0.040 inch orifices. But there is a concern for small orifices plugging-up with debris. I originally installed solid tappets in my first 351C engine (circa 1978) and later swapped them for hydraulic tappets; the 0.060 orifices worked fine with Johnson hydraulic tappets. But ³⁄₃₂ inch is a good "general" recommendation that should take care of hydraulic tappets with high demand for oil.
The tappet bores should be enlarged to 1.000 inch, therefore there shall be an 0.002 inch interference fit with the bushings. IF the tappet bores are enlarged beyond 1.000 inch, then the larger OD bushings shall protrude too far into the oil passages, and restrict the flow of oil. Thus, if the tappet bores have been enlarged greater than 1.000 inch the block has been ruined.
The 351C is tough on bearings. Installation of thin wall bushings in all 16 tappet bores is actually beneficial for any 351C, in any application, including mundane low rpm transportation duty. They are not just for high rpm, or race engine applications.
However, installation of only 8 bushings only seals up 50% of the leakage issues, the amount of oil delivered to the main bearings is not maximized. 8 bushings only fix tappet compatibility issues on one side of the block, and they only meter oil to the valve train on one side of the block. It makes no sense.
When only 8 bushings are installed a restrictor is also installed back at the no. 5 main journal, to restrict the amount of oil flowing to the entire left side of the engine. The result is left side hydraulic tappets randomly collapsing.
The whole idea of doing this at home was started by Ford, as they sold the original kit back in 1974. By the mid 1980s I had done several engines, never any problem. The Wydendorf kit is a much more thorough kit than Ford's was, with better tools.
-G