so the only difference btw the 4.8 and 5.3
07-13-2004, 04:51 AM
#23
Originally Posted by Juggernaut
Ahh yes, the ol' 327 block & 283 crank combo(DZ). The stuff dreams are made of.
Ryan
Ryan
Where we lived, Brandon Fla, a joining Seffner Fla where Don Garlits was reeking havoc at the time, He was never put down until it got tired. The machine ran real strong for almost a year. I rode with him in a couple of close races where I thought it was gonna blow. He said it was gonna blow up or win! One real close one was to a Hemi Cuda. We knew it had headers but couldn't tell if there was more. His head light was at the front wheel axle. Man! I haven't relived that in years.
07-13-2004, 08:16 AM
#24
TECH Senior Member
iTrader: (2)
Join Date: Nov 2001
Location: Tampa Bay
Posts: 9,970
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by GMCtrk
so crank and rods cost $800 extra? Looks like GM really pulled a fast one with this engine option...
go out and buy a set of rods and a crankshaft for a 5.3L motor. maybe you can do it cheaper
also the chevy 302 motor and this 5.3/4.8L have as much in common as the 426 hemi and the new 5.7L hemi.
07-13-2004, 08:59 AM
#25
Originally Posted by 02Silverado
The Difference in the 2 engines is the crank and rods. Pistons are the same.
325 = 3.780" x 3.622" ('99-later, Gen.III, "LM7" 5.3 Liter Vortec, 6.098" rod)
293 = 3.780" x 3.27" ('99-later, Gen.III, "LR4" 4.8 Liter Vortec, 6.278" rod)
Mor Tec
325 = 3.780" x 3.622" ('99-later, Gen.III, "LM7" 5.3 Liter Vortec, 6.098" rod)
293 = 3.780" x 3.27" ('99-later, Gen.III, "LR4" 4.8 Liter Vortec, 6.278" rod)
Mor Tec
So, the entire rotating assembly is different.
07-13-2004, 09:22 AM
#27
Wow, I'm sorry I missed this thread yesterday. Lets see....
Pushrods are part of the valvetrain and have nothing to do with the volume of the motor. Connecting Rods are part of the rotating assembly, connecting the piston to the crank. Connecting rods don't directly change the volume of the motor either.
Almost... The crank is different in the 4.8 which accounts for the difference in stroke. The stroke is the amount of up and down travel the piston moves, which is a direct relation to the crank. The 4.8 has a shorter stroke than the 5.3, which accounts for the .5 liter difference in the two motors.
Bore on both motors are the same as they are the same physical block.
No he's not.
You got it. Its a completely different setup. It would be possible to use a similar rod by adjusting the pin height on the piston. The 5.3 piston will travel 9mm further down the bore than the 4.8 will. The piston in the 5.3 has a dish to make the CR 9.5:1, but with the 4.8s shorter stroke, it doesn't need a dish to have a 9.5:1 CR.
As above: different crank, longer connecting rod, different pistons. GM used a longer rod with the shorter stroke to keep the piston at the proper deck height.
Yes (and rods) and Yes.
As stated earlier, the piston is different since it doesn't have a dish needed to achieve the correct compression ratio.
Originally Posted by GMCtrk
so the only difference btw the 4.8 and 5.3 is a different length pushrod????
Originally Posted by nekkid_hill_billy
i believe you both are wrong...the 5.3 has different piston rods resulting in a different stroke....and if i am not mistaking the crank is different
Originally Posted by vortec350
I beleive the only thing is the bore is smaller
Originally Posted by Deckhand
you are right.
Originally Posted by Hit Man X
Yes, shorter stroke results in different rotating assy...it could be the same rods (with shorter crank) just different pistons, but I doubt that.
Originally Posted by Tiburon
I was under the impression it was both, a different crank and shorter piston rods.
Originally Posted by O3GMC
just read on another thread that the 5.3 pistons are dished and 4.8's are flat......
so the differences are stroke, crank and pistons? bore is the same?
so the differences are stroke, crank and pistons? bore is the same?
Yes (and rods) and Yes.
Originally Posted by 02Silverado
The Difference in the 2 engines is the crank and rods. Pistons are the same. ...