Quote:
Originally Posted by 88ls1blazer
Good luck doing that AND purchasing new cars in the future.
Aluminum is better for NVH, it is lighter to help shave weight, it is surperior in transferring heat, and is almost the same cost. Plus the durability is pretty darned good (some would argue better then Iron, I would be one of them), as good as 3800's were, Gen III and Gen IV LS motors are easily matching their reliability with none of the intake manifold issues seen in the 3800. IIRC the only V8 that GM makes that still uses an Iron block is the 6.0 in SOME of the trucks, and maybe the 4.8. The 5.3 DOD, 6.2, and some 6.0 have moved to aluminum foundations.
|
compact graphite iron is the choice material for diesel engine blocks...we'll see MORE of them!
cast iron is better for nvh! aluminum is a better conductor, but there's a thermal break at the IRON liner...which also complicates casting and limits bore size. ohv engines with cast iron blocks are still lighter than all aluminum dohc (ohv has a lower c of g). it's not a benefit in itself, but to offset a [weight] disadvantage in the heads. they don't use it
because it's more durable.
the LS1 block is $1500, while the 6L iron block is $500. 300% higher cost is not 'almost the same'. the C5R block is $6500 and can take 1000 hp. the LSX iron block is $1900 and can take 2500 hp. the 2JZ has a cast iron block, and street engines see north of 700 hp on stock parts.
marine engines are often ALL cast iron. you can get away with aluminum in cars if you don't overheat them for too long. not worrying about fasteners seizing, stripping and heli-coil tapping them is another good reason.
an aluminum block with nikasil or silicon liners matches piston expansion rate, thus you can reduce allowances, blowby, cold engine piston slap, hp, etc. they still coat the pistons with iron. the gt-r needs better coolant management to keep parts from warping.
high heat transfer also means you lose heat from combustion, so you need to increase compression ratio to compensate. ice are most mechanically efficient at 10.1:1. increasing compression raises thermal efficiency, and lowers mechanical efficiency past this point.
you can never go wrong using quality parts.
so is the lucerne the only car with an ohv v6? has anyone announced when the ohv v6 dies? if the ohv v8 can live on, the v6 should have an even stronger position in gm's lineup!