| Also known as | B118B, E4008 |
| Diagram | Fig. 6 — CYLINDER BLOCK AND HEAD · ref 50 |
| Subsystem | engine top |
| Listed in parts books | 1964–1970, 1974 |
PUSH ROD-500 UNIT 4.85L
Pushrod for the unit-construction Triumph 500 twin engine, 4.85 inches long, also known as B118B or E4008.
70-4008 is a pushrod for the unit-construction Triumph 500 twin engine, the family that includes T100, 5TA, T100S, T100C, T100R, and T100T variants as shown across the cylinder block and head figures. It's part of the valve train that runs between the tappets and the rocker arms, transferring the lift from the camshaft up to open and close the valves. This part shows up under the older B118B and E4008 numbering too, so if your parts book or an old parts bag has one of those stamped on it, it's the same physical piece.
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The catalog spec calls it out as 4.85 inches long, which is the dimension that matters most when you're sorting pushrods on the bench — mixing up lengths between different engine variants is one of the more common ways a rebuild goes sideways before it even gets to the cams. These show up across a long production run in our catalog data, 1964 into 1974, spanning several of the twin-carb and single-carb head configurations for the 500 unit twins.
Worth ordering a full set rather than just the one if you're mid-rebuild, since pushrods take wear at the ends over the years and matching lengths keep valve timing even across cylinders.
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