So- i am pretty sure the M106 rings are chromolly and use a micro-hatched cylinder wall (at least that is what the almighty internests is telling me) and there are different part #'s in real OEM, so there really is no doubt they are different... thats not the question.
Question is, has anyone ever used M30 rings in an M106 block? I have a boosted M30, so I know the rings will work under boost (as will any, really) and when i try to purchase from BavAuto- it is pulling the same part# as the M30 rings....
I know i can get them custom made as some folks do, but im a simple man and im not going crazy with this build- I have had everything measured, vatted and polished/ honed and would like the path of least resistance, if it will work.... I am aware that they are different for a reason- but so are the cutting rings and i have been using m30 exhaust gaskets with no problem at all.
Thank you for any input, places to puchase 745i rings (other than the stealership) or your experiences with M30 rings in your M106-
Phil in Atlanta-
M30 Piston Rings in M106....?
That is actually more what I was looking for... verification that the ring would actually fit the piston.Golosok wrote:Not exactly your case but I succefully run M30B35 with M106 pistons and M30 rings for more then 2 years now.
Looks like my work is done here- I'm going with M30 rings and will post my findings.
Thanks all.
9
Good thing then that we always check and manually file our rings to fit, right?!
You should certainly check the ring gap, even if they are "pre-gapped" they will most likely be pre-gapped for an NA application.
Typically ring gap is set to around 0.004" per inch of cylinder bore in an NA application. In a turbo app I will typically use 0.006"-0.007". In a turbo app with particularly thin top ring lands or that will see nitrous I will gap them to 0.008" per inch of bore.
Assuming both pistons are mahle and the same ring thicknesses are spec'd, they are probably fine.
I would double check ring side clearance (feeler gauge between the top of the ring and the ring land) and also confirm that the ring grooves are deep enough that the ring can actually fit completely into the groove of course.
If that all checks out, no problem.
If the M106 has chrome top rings you probably don't want them for a re-ring job Anyway. Regular cast rings are much easier to get seated on DIY re-ring jobs and will handle forced induction just fine.
You should certainly check the ring gap, even if they are "pre-gapped" they will most likely be pre-gapped for an NA application.
Typically ring gap is set to around 0.004" per inch of cylinder bore in an NA application. In a turbo app I will typically use 0.006"-0.007". In a turbo app with particularly thin top ring lands or that will see nitrous I will gap them to 0.008" per inch of bore.
Assuming both pistons are mahle and the same ring thicknesses are spec'd, they are probably fine.
I would double check ring side clearance (feeler gauge between the top of the ring and the ring land) and also confirm that the ring grooves are deep enough that the ring can actually fit completely into the groove of course.
If that all checks out, no problem.
If the M106 has chrome top rings you probably don't want them for a re-ring job Anyway. Regular cast rings are much easier to get seated on DIY re-ring jobs and will handle forced induction just fine.