They will never bed in properly if not honed
ThomasLRNL
Active Member
Ok, clear on the honing. Anything regarding the slap/marks? am i correct, or are those due to something else.
Might be teaching you to suck eggs so apologies..
Slap (knock) is caused by excessive lateral movement when the fuel combusts.. the piston literally slaps straight the cylinder wall.
A far as I'm aware that doesn't cause the discreet scratch marks in the pics, more like a wear patch
Slap (knock) is caused by excessive lateral movement when the fuel combusts.. the piston literally slaps straight the cylinder wall.
A far as I'm aware that doesn't cause the discreet scratch marks in the pics, more like a wear patch
ThomasLRNL
Active Member
hm, yes. i agree. The thing i am mostly aiming for is that it laterally ticks the same spot every time? thus making that score. or is that a bit of a wishfull thinking kinda thing... Since maybe that means it should ALSO be on the other side.
Have a look at this link
I'm not sure but i would think it's going to be only one side
I'm not sure but i would think it's going to be only one side
ThomasLRNL
Active Member
The longitudional lines shown in the picture is exactly what i have...
ThomasLRNL
Active Member
I am using 15wxx (i think 50) oil. Is it worth rebuilding this and running it with a thicker oil? That seems to help solve a lot of issues for people experiencing piston slap. Especially since my PSI readings are all fine and dandy. Thoughts?
15w50 is fine for these engines, use a mineral oil rather than synthetic.
Personally i wouldn't think a thicker oil would make much difference, but.. if it does.. it's putting off the inevitable and you've already got it in bits. Do you want to do it now or take it apart again in another few 1000? miles..
Just my thought but others might have a different idea
Personally i wouldn't think a thicker oil would make much difference, but.. if it does.. it's putting off the inevitable and you've already got it in bits. Do you want to do it now or take it apart again in another few 1000? miles..
Just my thought but others might have a different idea
ThomasLRNL
Active Member
all, its been a while and i did some measurements of the bore.
calculated based on: 90,47 being the required bore.
left to right cil 1 to 4. minus means the bore is bigger than target.
top -08 -08 -09 -13
middle -07 -08 -08 -12
bottom -02 -02 -03 -02
top thrust -12 -11 -12 -18
middle thrust -06 -04 -04 -11
bottom thrust -01 -01 -02 -02
clearly, cilinder 4 is worn more heavily.
i measured the piston skirt as well. this is 90.305 - 90.47 is .165 in difference. this is (even with the perfect 90.47 bore) already way too much clearance is it not? the manual says 0.044 to 0.066…
i dont know what conclusion i should pull from these numbers. new std size pistons? new bore? anyone advice id like it thanks.
calculated based on: 90,47 being the required bore.
left to right cil 1 to 4. minus means the bore is bigger than target.
top -08 -08 -09 -13
middle -07 -08 -08 -12
bottom -02 -02 -03 -02
top thrust -12 -11 -12 -18
middle thrust -06 -04 -04 -11
bottom thrust -01 -01 -02 -02
clearly, cilinder 4 is worn more heavily.
i measured the piston skirt as well. this is 90.305 - 90.47 is .165 in difference. this is (even with the perfect 90.47 bore) already way too much clearance is it not? the manual says 0.044 to 0.066…
i dont know what conclusion i should pull from these numbers. new std size pistons? new bore? anyone advice id like it thanks.
ThomasLRNL
Active Member
all, its been a while and i did some measurements of the bore.
calculated based on: 90,47 being the required bore.
left to right cil 1 to 4. minus means the bore is bigger than target.
top -08 -08 -09 -13
middle -07 -08 -08 -12
bottom -02 -02 -03 -02
top thrust -12 -11 -12 -18
middle thrust -06 -04 -04 -11
bottom thrust -01 -01 -02 -02
clearly, cilinder 4 is worn more heavily.
i measured the piston skirt as well. this is 90.305 - 90.47 is .165 in difference. this is (even with the perfect 90.47 bore) already way too much clearance is it not? the manual says 0.044 to 0.066…
i dont know what conclusion i should pull from these numbers.
calculated based on: 90,47 being the required bore.
left to right cil 1 to 4. minus means the bore is bigger than target.
top -08 -08 -09 -13
middle -07 -08 -08 -12
bottom -02 -02 -03 -02
top thrust -12 -11 -12 -18
middle thrust -06 -04 -04 -11
bottom thrust -01 -01 -02 -02
clearly, cilinder 4 is worn more heavily.
i measured the piston skirt as well. this is 90.305 - 90.47 is .165 in difference. this is (even with the perfect 90.47 bore) already way too much clearance is it not? the manual says 0.044 to 0.066…
i dont know what conclusion i should pull from these numbers.
