Long term reliability of GM 8.1 Liter
I'm curious to know what kind of experiences owners of GM's 8.1 liter have had regarding long term reliability/durability. I believe it had the piston slap issue in every year the engine was produced...
Forum Discussion
More silicon, but only up to some percentage (forgot, but around 10%) and makes
it stronger.
Key is that is more thermally stable than the other aluminum alloys. Meaning it
won't increase in size in an iron block as would a regular alu alloy...meaning
that the designers can size it with less tolerance
Silicon readily melts and is absorbed by the aluminum during the process, so it
allows the designer to play with the crystalline phases during processing. Meaning
harder and lower co-efficient of expansion to allow tighter tolerances
The piston slap does have to do with expansion, but not the aluminum alloy itself,
but the coating on the piston
Piston slap was worrisome because it sounds like a rod knock
The oil consumption has to do with the harder piston rings mentioned in another
thread. That is an extension from my Suburban forum a few years ago. Some have
found that it takes 20K or more before the 8.1L full seats the rings...a very good
indication of longevity...if taken care of
I have the 7.4L big block...gen before the 8.1L. I'd LOVE to have a GMT800 with
an 8.1L, but with the way things are going with new...will keep mine till the
wheels fall off, or won't fix it anymore...or if a 8.1L crosses my path and can't
pass up that deal
These are TRUCKS.
Designed for work and much more to them than a 'car'. To last much
longer 'working' than any or most any car.
If the OP does get a full sized SUV with a 8.1L...first thing is to replace
the OEM receiver with a traditional design
it stronger.
Key is that is more thermally stable than the other aluminum alloys. Meaning it
won't increase in size in an iron block as would a regular alu alloy...meaning
that the designers can size it with less tolerance
Silicon readily melts and is absorbed by the aluminum during the process, so it
allows the designer to play with the crystalline phases during processing. Meaning
harder and lower co-efficient of expansion to allow tighter tolerances
The piston slap does have to do with expansion, but not the aluminum alloy itself,
but the coating on the piston
Piston slap was worrisome because it sounds like a rod knock
The oil consumption has to do with the harder piston rings mentioned in another
thread. That is an extension from my Suburban forum a few years ago. Some have
found that it takes 20K or more before the 8.1L full seats the rings...a very good
indication of longevity...if taken care of
I have the 7.4L big block...gen before the 8.1L. I'd LOVE to have a GMT800 with
an 8.1L, but with the way things are going with new...will keep mine till the
wheels fall off, or won't fix it anymore...or if a 8.1L crosses my path and can't
pass up that deal
These are TRUCKS.
Designed for work and much more to them than a 'car'. To last much
longer 'working' than any or most any car.
If the OP does get a full sized SUV with a 8.1L...first thing is to replace
the OEM receiver with a traditional design
