| Also known as | E1477 |
| Diagram | Fig. 4 — CYLINDER BLOCK AND HEAD, 6T AND TR6 · ref 5 |
| Subsystem | engine top |
| Listed in parts books | 1960–1962, 1964–1965 |
TAPPET BLOCK TRIUMPH TWIN 1937-65
Cast iron tappet guide block for pre-unit and early unit Triumph twins, pressed into the cylinder block to house the cam followers.
This is the tappet guide block for pre-unit and early unit Triumph twins, part number 70-1477, also known under its earlier E1477 designation. It's a cast iron piece that presses into the cylinder block on both the intake and exhaust sides, and it houses the tappets, or cam followers, guiding their movement so the pushrods land square on the radiused tappet stem ends.
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It shows up in the parts books under the CYLINDER BLOCK AND HEAD figure for the 6T and TR6, and our catalog references run through the mid-1960s. The catalog description covers the Triumph twin range broadly from 1937 to 1965, so this is an early-style guide block rather than the later unit-construction version.
Alignment matters here. If the block isn't seated square when pressed in, the tappets won't track true against the cam followers and you'll get uneven wear or noise. Worth having someone check the fit carefully during a rebuild rather than assuming it's a drop-in job.
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