rod bearings check

[BAConaway]

I have Mazda 626. It was knocking. Took off heads. No noticed knicks or marks on piston or valve noticed. Through oil pan the main bearings have some movement side to side not up and down. One made a little different sound Going side to side maybe it is where the rod and piston connect. any ideas on how to check it out more without pulling the heads. there was no metal particals in the oil pan. it seemed to be that the knock quited down when the RPMS where up to normal driving. any ideas. I don't want to pull the heads if good as not to spend money on new rings and bearings.

[shorod]

Did you check oil pressure before disassembling the engine? Does the engine have hydraulic lifters?

-Rod

[chevy2808]

maybe a higher octane fuel is needed or maybe something is wrong in your cooling system