LTX and LSXPutting LT1's, LS1's, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects, including repairs, swap info, and performance upgrades.
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Hey guys, well I was wondering if anyone here knows if the crank from a 4.8L Vortec engine would go into a LS1 or LS2...or hell any other 3rd or 4th Generation GM Smallblock engine? Is their a big difference in the crankshaft bearings? Because it seems to me (from what I was able to find) that a 4.8 and a 5.3 share a block and pistons, the only diff is the rods and crank (way to go GM). Is this true?
Ive been drooling over the idea of a high rpm LS engine sitting in between the wells of my GTA. This could be it, assuming I could do the shortblock for under $2500 before machine work. Who wouldnt love a 327 LS engine!?
Ideas?
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Okay well the answer is YES! According to the chart on this webpage, all GM Gen 3-4 blocks have identical bolt patterns and journal sizes. Sorry for wasting the space on the site.
It seems to me that the ability of the engine to rev and make power up top is going to be a function of the top-end components. With an adequately strong bottom end, the stroke difference between 4.8 and 5.3 cranks shouldnt affect the revving ability
I think your working in too many different directions.
You want it to spin up faster and get better fuel milage? One or the other
But honestly, your going to loose alot of power and the extra RPM wont make up for it. Besides, my 3.66stroke/3.8x bore 5.3l motor spins to the moon and back near instantly. No need to try spinning these motors and faster
Hey, I was just throwing it out there. I doubt the difference in weight between the two will make much difference in how snappy the motor is. You could always work the 5.3 crank to be lighter than the 4.8 crank, no?
You ever been behind the wheel of a V8 doing 7k+? It feels like the engine is pissed off and ready to kick your ***...if it wernt bolted down. So with this idea its not about making more horsepower, its about making the BEST horsepower. For the ride that is. More than 400 hp is pretty awsome however you put it. I dont need more than that...especially when its at 7 grand.
And the 5.3 crank is the same as a 6.0 crank ,they are both 3.66" Stroke.
You ever been behind the wheel of a V8 doing 7k+? It feels like the engine is pissed off and ready to kick your ***...if it wernt bolted down. So with this idea its not about making more horsepower, its about making the BEST horsepower. For the ride that is. More than 400 hp is pretty awsome however you put it. I dont need more than that...especially when its at 7 grand.
And the 5.3 crank is the same as a 6.0 crank ,they are both 3.66" Stroke.
Ive been in a roadrunner with a 426HEMI shifting at 7,600. Whats your obsession with no-torque short stroke engines?
* you're going to spend a fair bit more for valvetrain parts that will be reliable at over 7 grand;
* a shorter stroke is definitely not the most driveable way to make power;
* horsepower is horsepower, regardless of what the exhaust note sounds like;
and
* you have the money to spend, & don't mind doing so,
then I say go for it. I can't see a practical reason for doing it (it seems as though you're basically wanting 'a certain exhaust note' and 'to be able to brag that your engine revs to 7k'), but hell, it's not my car/my money/my dream, so who cares?
If it's your car & your money, make it your car...
(Just do the research first, so you know what you're getting into!)
I have driven a car that revs over 7K i shift it at 7200 RPMs and it eats a couple pushrods every year. Just be prepared to spend the time and money upgrading and replacing things that aren't your normal "wear items" this means valve springs too...its no fun if you drop a valve, seen it on an old 327 that was shifted through a muncie, wrecked the piston, and shoved the valve through the head.
F-body is looking into the idea the GM 302 design came from, is what im understanding. Basically it was a 327 block destroked with the 283 crank, and from what i have been told these motors would snap 7 and 8 grand easy and make great power all the way to that range. So if gm was able to produce a motor to handle this with the technology they had back in the 60's, why not try to do it now with a new generation of motors?
F-body is looking into the idea the GM 302 design came from, is what im understanding. Basically it was a 327 block destroked with the 283 crank, and from what i have been told these motors would snap 7 and 8 grand easy and make great power all the way to that range. So if gm was able to produce a motor to handle this with the technology they had back in the 60's, why not try to do it now with a new generation of motors?
.......(Excerpt from a review about the 1969 Chevrolet Camaro Z-28 302 Cross Ram) "The good news was that the car had greater flexibility near the top of each gear and a higher top speed; the bad news was that freight trains could accelerate from a stand still faster...and perhaps quieter."
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FWD FTL!!!
Dont get mad if I call you and idiot i just call them like i see them, If you want to tell me im a jerk save it ive heard it all before....
no all power is up high thats y they had 4 speeds with big rear gears...and they were designed for the trans am races so power needed to be mid to high not down low...overall not good street engines....
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FWD FTL!!!
Dont get mad if I call you and idiot i just call them like i see them, If you want to tell me im a jerk save it ive heard it all before....
Also - the 5.3 -in stock form- comes out to right about 325 ci. I know you're primarily looking for the new engine to be a high-winding unit, but I figured that someone was going to note that anyway...
Also - the 5.3 -in stock form- comes out to right about 325 ci. I know you're primarily looking for the new engine to be a high-winding unit, but I figured that someone was going to note that anyway...
Well yes thats true...but the 327 I mentioned here would be a 3.27 X 4.006 unit, not a 3.66 x 3.78 like the 325 (5.3L). The shorter crank also has the great upgrade of a 1.92 Rod Ratio over the 5.3/6.0s 1.6 Rod Ratio. The longer rod ratio would help to crutch the loss of CIs and Stroke. And anyway this engine would only lose 5.5% of its CIs over a LS1 anyway...its a minimal loss IMO.
But after looking into it, it seems like the project will need custom pistons...which isnt something im very happy with. I like to stick to readily available parts (another one of Smokey's rules). Which has protected me from mistakes in the past. I'll keep looking but as far as it looks for me, this engine is just a set of pistons too far out into the exotic range for me.
Reviving an old thread but no customs pistons needed if you go this route and my calculations are correct. This is using an LS1 but the 6.0 is just a larger bore. All other dimensions are the same.
4.8 crankshaft is a 3.26" stroke.
4.8 rods are 6.278" long.
You would need a piston that had a compression height of 1.335 to 1.34 depending on how the block was decked. Stock LS1 pistons have a compression height of 1.34. So a short stroke LS1, LS2 or 6.0 can be done with stock parts.
Sorry to re-dig a dug up post. But wesilva your saying that the LS1 pistons are 1.34, does that burn down to the 6.0 as well? If I could get a 6.0 and a 4.8 I could make it work with minimal extra parts....just when I thought I had it figured out...man.
The short answer is yes. The 6.0 shares the same compression height of 1.325 - 1.336 because it shares the same crankshaft stroke of 3.622" and the same rod length of 6.098".
The formula is fairly simple. Compression height is measured by the following:
Crank stroke divided by two: 3.622 divided by two = 1.811
Add that to the rod length: 6.098 + 1.811 = 7.909
Subtract that from the deck height: 9.245 - 7.909 = 1.336 compression height.
Now remember that the decrease of stroke is going to decrease compression. You will either have to mill your heads to the appropriate combustion chamber size or purchase heads with the combustion chamber size.
Now lets use the same formula for the destroked 6.0.
4.8 crank stroke of 3.26 divided by 2 = 1.63
1.63 + the rod length of 6.278 = 7.908
Deck height of 9.245 - 7.908 = 1.337 compression deck height. Basically the same compression deck height.
I've been through this already because my son and I are building a LS1 for maximum gas mileage and the inherent anti friction capabilities of the short stroke/long rod LS1 engine will give us the goal we are after. Those anti friction capabilities being favorable rod angle to minimize piston thrust scrub, lower piston speed and narrow ring package.
I think we all knew it was possible, the point is, its a complete waste.
4" stroke LSx motors have been taken over 7k rpm safely.
To lay it simply, it hasnt been done, cause its not worth it, its a loose loose. You loose power, and you dont gain fuel milage.
If you've got an itch for a super high rpm motor, crotch rockets redline at like 18,000 rpm. Were talkin V8's here, and were workin with the newest technology.
The limiting factor to getting a LS1 to 7k rpm is primarily valvetrain.
If you have perfect valvetrain, you can throw in a forged 3.622 rotating assembly, then get a priority main oiling block if you want it to be a 100% safe 7k+ rpm redline motor.
Your thinking too hard for this, its simply not worth it. But a 6.0L and keep it as a 6.0L.
Buy an iron 4.8. They can be had for very cheap. Bore out the cylinders to the LS1 3.9 standard bore. The block will safely take that bore. Buy LS1 pistons. Modify the motor any way you choose like modified cylinder heads, cam, etc. If you don't like it...drop in an LS1 crank and rods and be done with it. All your out is your labor.
