This strap is used to give support and strengthen the centre main bearing cap on large-bore engines (1275cc-plus). It helps counter the problems caused at higher rpm where crankshaft flex (‘whip’) causes the standard cap to move (‘shuffle’) leading to bearing failure and possible breakage of the main bearing caps. In particular, where higher rpm than standard will be the norm – i.e. in excess of 6,000rpm. Especially where this is for extended periods.
The standard centre main cap needs to be machined by a competent engineer or engineering shop, as the finished surface needs to be absolutely flat. The final finish being ground where practical.
The cap should be milled/machined down to the original bolt head surface. If the finish is not smooth and flat, this MUST be finish-ground.
When finally assembling the engine, ensure strap is fitted with adjusted chamfer edges to cap, fit new bolts supplied and torque down to standard setting (threads clean and dry, 65lb ft.). Higher torque settings are not necessary.