Ensuring proper connecting rod to camshaft clearance.
Due to the long stroke and confined packaging of the MGB engine, connecting rod to camshaft clearance is at a premium. The following are some observations and hints towards insuring that any new engine you might be building won't go "clunk" when you try to rotate it after assembly.
For proper clearance to the cam, the heads of rod bolts must be aligned with the rod as shown in the picture above. ARP rod bolts (not shown) have even larger heads which most engine builders grind for proper clearance.
Failure to align the rod bolt (as seen above) may cause it to contact the camshaft as it swings by on rotation.
The camshaft shown is a new stock replacement cam, currently available from most parts suppliers. The diameter of the shaft between the lobes was larger than any stock cam we had available to measure and we subsequently turned it down to provide ample clearance (as shown by the shiny area between the lobes). While the rods would have just squeaked by the cam as it was, this modification insured that there would be an abundance of room, which helps us to breathe easier in knowing that it won't fail.
With everything assembled, clearance is checked with a strand of .080" safety wire (not much room but it clears!) It is advisable to check this clearance point carefully before the engine is fully assembled in order to save the trouble of disassembly in the event it's not enough.
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