14-07-2021, 09:21 AM
Hedd, there are others here doubtless better qualified than I to answer, but the rules of thumb I have always followed are that piston to bore clearance on new parts should be 1.5 thou for split skirts and 4 thou for plain skirts; measured with a feeler gauge at the bottom of the bore.
I have a note of 6 thou here as the notional scrap limit (probably refers to split skirt types), and 10 thou when measured 3/4" from the top of the bore.
You would probably need an actual piston rather than specifications to check the above.
Only a partial reply I grant you but possibly of some help.
As a parting thought, it takes a long time to get an engine running quite so sweetly again, and most of them leak or have the cracks you describe... If it's starting to become troublesome or unreliable then yes, time to do something.
I have a note of 6 thou here as the notional scrap limit (probably refers to split skirt types), and 10 thou when measured 3/4" from the top of the bore.
You would probably need an actual piston rather than specifications to check the above.
Only a partial reply I grant you but possibly of some help.
As a parting thought, it takes a long time to get an engine running quite so sweetly again, and most of them leak or have the cracks you describe... If it's starting to become troublesome or unreliable then yes, time to do something.