My opinion these motors are solid both the M42 and M44.
Both have a aluminum head and when you over heat an aluminum head it expands at a much higher rate then the cast iron block and cause big issues it's metallurgy at work here. The head gasket goes or cracks the head at extream cases.
I never over heat my stuff and never have issues with head gaskets and cracked heads and I boost these motors on stock castings and stock gaskets.
Now I run a BWM stock gasket for a diesel application up to 20psi never over heated but beat it very bad with no issues.
I've run 173K on a boosted stock motor M44 with no issues ever, but never ovr heated it.
Always take care of the cooling system on a BMW M42/M44 motor with aluminum heads and you won't have issues with head gaskets or cracked heads. You will burn exhaust valves if you have a lean condition but not a cracked head or head gasket issue, they are 99% of the time related to a over-heat issue.
Just my 2 cents...These motors are almost bullet proof, very well built, but prone to head damage if over haeted. Keep them cool boys and girls.
JohnBoy |