26-10-2022, 03:38 PM
Realise this thread has drifted away from engine knocking to heavy deposits on pistons but as it all part of trying to get answers….
I purchased an internal bore gauge with a DTI and having checked numerous times now the bores have no more than 0.0015” deviation anywhere within the bores with all four being 2.198” max.
The pistons are all 2.188” in the area of the three top rings and on the split skirt there is a slight step up where they are all 2.196”.
The 2 upper rings have 0.001” gap in their grooves in which the ring sits and are all free to move.
The 2 lower rings (scrapper?) have a gap of 0.002” within their grooves in which they sit again are all free to move.
The ring gaps taken with the rings set 1” down from the top of the bores show a gap of 0.009” for the top two plain rings and 0.010” and 0.014” for the two lower rings.
The bores are all polished (glazed?) with no sign of any honing marks anywhere in the bores, even in areas where the rings would not contact the bores.
Would any of these dimensions be a concern and likely to be the cause of the oily carbon deposits?
If so what remedial work would be considered necessary?
With regards honing what is considered to be the best way to achieve the a satisfactory result, the three legged type honing tool or the Flex-hone type?
Answers on a post card please to the Balls Pond Road Care Home for Austineers
Cheers Denis S
I purchased an internal bore gauge with a DTI and having checked numerous times now the bores have no more than 0.0015” deviation anywhere within the bores with all four being 2.198” max.
The pistons are all 2.188” in the area of the three top rings and on the split skirt there is a slight step up where they are all 2.196”.
The 2 upper rings have 0.001” gap in their grooves in which the ring sits and are all free to move.
The 2 lower rings (scrapper?) have a gap of 0.002” within their grooves in which they sit again are all free to move.
The ring gaps taken with the rings set 1” down from the top of the bores show a gap of 0.009” for the top two plain rings and 0.010” and 0.014” for the two lower rings.
The bores are all polished (glazed?) with no sign of any honing marks anywhere in the bores, even in areas where the rings would not contact the bores.
Would any of these dimensions be a concern and likely to be the cause of the oily carbon deposits?
If so what remedial work would be considered necessary?
With regards honing what is considered to be the best way to achieve the a satisfactory result, the three legged type honing tool or the Flex-hone type?
Answers on a post card please to the Balls Pond Road Care Home for Austineers
Cheers Denis S