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EVO: Engine Mechanicals - Sub-01A
Timing Inspection Hole Plug Thread Repair
- The timing inspection hole plug (centered between the two cylinders on the right crankcase) can be troublesome to remove and even harder to install.
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- Once removed, check the threads on the plug and in the case for damage before trying to re-install the plug. These are straight (not tapered) threads. Inspect them closely for warp-age or damaged.
| 5/8“x18 plug has straight threads with Teflon tape around the neck. | Notice the plug doesn't go all the way into the end of the case threads |
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| Same drag on bore gauge, front to back. No taper |
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- In the case of warped or damaged threads, first try to 'chase' the threads, see also warped or damaged thread repair.
- When chasing these threads with a tap, you'll need a 5/8”x18 'bottoming' tap which is flat on the end.
- There is not enough room between the outside of the case and the crankshaft to use a tapered end tap. This could possibly end with you running in too far with the tap before you get good threads, pushing against the crankshaft (which will create back pressure as you continue turning) and crack the case.
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