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Hi to all you vintage volvo drivers,
I am slowly restoring a 1970 122s B20B and i am slowly buying parts for it's restoration.
I took the cylinder head off from the engine and had an opportunity to examine the bores of the engine.
The idea behind this was to acertain the level of wear in the engine, hence decide what route to go when overhauling.
The block has never been machined and has the std b20b cylinder diameter on the top of each bore i.e. 88.90mm.
The bore diameter below the ridge is 89.03mm on all cylinders and this was measured using an internal micrometer.
Hence the wear is 0.13mm.
A 0.010" (10 thou) i.e. 0.254mm oversize bore would bring the diameter to 89.154mm, which would be the minimum oversize route to go.
This would necessitate machine work and the purchase of a new set of pistons complete with rings.
Now my question, when does one install new rings alone? In other words what maximum allowable wear in mm is acceptable for a re-ring job only?
I am almost sure that the crank will not need cutting as previous volvos that i owned required no cutting on the crank. Besides main and big end bearings are not as expensive as pistons.
I would appreciate any advice.
Regards
Blueb20 from SA.
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