Anything special about I-6 engines? (Volvo,BMW...)

[Quattro Pete]

Originally Posted By: RobertISaar
this is the first time i've ever heard of this.... care to elaborate/link for more information? i've never heard of specific RPMs being problematic, especially since none of my 60V6s have ever had an issue at that speed.

I don't notice it on ours either.

 

[RobertISaar]

of the GM 60V6 i've had/have:

1990 GM 3.1(iron block, aluminum head, OHV/flat tappet)
1995 GM 3100(iron block, aluminum head, OHV/roller tappets)
1995 GM 3.4DOHC(iron block, aluminum head, DOHC, flat tappets)

none of these have balance shafts, both the 3.1/3100 have very badly worn motor mounts(especially the lower hydraulic mount) and the 3.4 has new, solid rubber everything.

i get "rumbles" from them at various RPMs, but it seems to be all intake/exhaust acoustics. i can make it change by using different intake tubing or resonators. 2100RPM is roughly 70MPH in 4th gear on all of them, that is where they all seem pretty well sorted out.