[455Grandville]

Originally Posted by hurryinhoosier62

Brad,

Technology doesn't matter. Humans are STILL involved. Humans are prone to error. Take the Duramax. Fantastic block and bottom end. They also have aluminum heads.
The heads are not the problem, other than the normal aluminum head flaws (i.e. work hardening). The problem is the engineers didn't require an MLS head gasket. As a result,
the owners that try to use "performance" products (i.e. tuners, bigger injectors, bigger turbos) blow head gaskets out because the standard head gaskets can't handle the higher cylinder pressures that "performance" products produce. Additionally, I've seen some Duramax blocks with deck surfaces so rough you could catch a fingernail in it. As a rule, you machine an iron block using aluminum head MUCH smoother than if you were using iron heads (Ra vs. Rz).

Don't know; seems to me there's alot more troubled engines. Then again, they keep bringing out new engines with a much shorter shelf life vs. making the same engine for decades.
IMO aluminum heads on a diesel are less than ideal. If they were all that big rigs would use 'em. Maybe that's why I prefer the older IDI & Powerstroke engines. Some of the 6.0 and 6.4s worked with aftermarket studs are showing tremendous power when the weak spots are addressed.

Originally Posted by hurryinhoosier62

bigunde,

The statement you highlighted was directed toward big hammer, not you. He was somewhat condescendingly trying to explain to lil' ol' me WHY inline engine produce more torque. I spent MANY YEARS tearing down, machining and assembling engines and
their components. I will defer to P-dude, Ace, Ken Crocie, Mr. P-body, Cliff, and the various other builders on this site ANYTIME, but having a long-on-horn neophyte trying to instruct me on engine theory WILL NOT be tolerated. An ASE certification is evidence that you know the BASICS of the automotive maintenance. An ASE Master certification (which I hold) is evidence that means you've spent enough time in the trenches to have learn a few things.BTW.....you were lucky!! I stopped by a buddy of mine's shop while I was back home. He had a set of '05 Duramax heads that were leaking coolant like a sieve. Upon inspection, it was discovered that BOTH head gaskets had failed. Additionally, the right head was severely cracked between the intake and exhuast valve in #6 cylinder. The vehicle which these heads were removed from had a BullyDog stage 3 tuner, uprated injectors and an MUCH larger turbo. The deck surfaces resembled a relief map of Colorado when a straight edge was put on them.

Inliners making more torque is BS ! Detroit 6-71 and 6V-71 post the same damn numbers. The aluminum heads on the Duramaxx I predicted would be an issue years ago; just seems to me aluminum is not up to the task. Long rods make more torque, yea, but they'll do it further up in the RPM range; that's why some of 'em use shorter rods for now torque !