| Also known as | E3743 |
| Diagram | Fig. 5 — CYLINDER BLOCK AND HEAD, T90 · ref 25 |
| Subsystem | engine top |
| Listed in parts books | 1964–1969 |
Joint washer
Joint washer for the cylinder block and head assembly on 3TA, 5TA, T90, and T100 family engines.
This is a joint washer that appears in the cylinder block and head figures for the 3TA, 5TA, T90, and T100 family engines, including the single and twin-carburetor T100 variants, across catalog listings running from 1964 into 1969. It seats between mating surfaces in the top end to keep things sealed where the cylinder block meets the head or a related joint face in that assembly.
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The part number 70-3743 also shows up under the earlier E3743 form, so if your parts book lists the E-prefix number, it's the same physical washer. Triumph later carried this joint forward under a new number, 70-9511E, so if you're working from a more recent listing or a rebuild kit that references that number, you're still looking at the same washer.
This is a small, unglamorous piece, but it's the kind of thing worth replacing any time the top end comes apart rather than reusing the old one. Since it turns up across several different engine variants in the catalog, double check which cylinder block and head figure matches your engine before ordering.
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