new to site and ls engines
#1
new to site and ls engines
here's my story, bought a z71 silverado with a bad 5.3 didnt know history of truck so looked for a cheap donor engine to get it running to see what else could be wrong, found a 6.0 with rust on cyl walls, honed the **** out of it and threw it in, truck runs sweet but has a lil piston slap noise, so my question to the ls site is...what is the good 6.0 to get or should a find a good used 5.3 to put back in? any info would be great, im looking to pull a trailer so i was thinking the 6.0 would be a better option, so inform me ls peeps! thx
#2
TECH Apprentice
Being new to the LS platform piston slap might bother you but it's actually very common at least in the older GEN 3 SBC's. (original LS based motors) Not really sure about the newer GEN 4's (GM started introducing the GEN4's in 05 I believe) but my guess is that piston slap is probably common in them as well. You get use to it.
Many threads on here discussing piston slap but here is an old but very good thread explaining why these motors commonly experience piston slap and why it's generally not a big deal.
https://ls1tech.com/forums/generatio...-engineer.html
You need to be careful just throwing any motor into your truck. Vehicles desided to be run with a GEN 3 motor can't run the majority of GEN 4 motors and vise versa without doing some work. Mainly changing the crank. This is because most GEN 4 LS motors use a 58x tooth reluctor wheel on the crank vs the 24x tooth reluctor wheel on the GEN 3 and early GEN 4 motors. Your PCM will determine what crank you need. What year model is your truck? Also GEN 4 have a different location for the knock sensors and they may have things like VVT and other modern system that you would need to figure out. You GEN 3 LS 6 liter motors are the LQ4 and LQ9. If you just want to leave it a stock motor I would say the LQ9 is more diserable. It's still an iron block but uses things like aluminum heads and makes more power than a LQ4 which I think used iron heads and was produced in 99-00 and I think the LQ9 replaced it from 01-06. As far as 6 liter GEN 4 motors go I would say that a LS2 was the best performance, but some of the later 6 liter GEN 4's like the LY6 got LS3 heads which are rectangular heads flow better than the LS6 heads used on the LS2 but LS6 heads are still very good and the best factory cathedral heads GM made/makes. You just have to research and study and deside what you want. Most 6 liter motors are iron block motors. The LS2 and 1 or 2 of the later truck motors are aluminum block motors.
Still if you're getting a little piston slap when the motors cold that goes away when it comes up to operating temperature I think you're fine. I your motor seems to burn excessive oil when it's cold then switch to 10W30.
As far as the 5.3L goes they are good motors. With a good tune even otherwise stock they run pretty strong in my experience. The biggest advantage the 6.0L has over the 5.3L IMO is more head options and the ability to run better flowing heads do the the 4" bore where a 5.3L has a 3.78" bore. Still not really a concern unless you want to run LS3 heads or an aftermarket heads that requires a 4" bore. Both motors use a 3.622" stroke.
Hope this helps but there are people with much more experience and knowledge of the LS platform on here than me. Hopefully some of them will find this and help advise you.
Many threads on here discussing piston slap but here is an old but very good thread explaining why these motors commonly experience piston slap and why it's generally not a big deal.
https://ls1tech.com/forums/generatio...-engineer.html
You need to be careful just throwing any motor into your truck. Vehicles desided to be run with a GEN 3 motor can't run the majority of GEN 4 motors and vise versa without doing some work. Mainly changing the crank. This is because most GEN 4 LS motors use a 58x tooth reluctor wheel on the crank vs the 24x tooth reluctor wheel on the GEN 3 and early GEN 4 motors. Your PCM will determine what crank you need. What year model is your truck? Also GEN 4 have a different location for the knock sensors and they may have things like VVT and other modern system that you would need to figure out. You GEN 3 LS 6 liter motors are the LQ4 and LQ9. If you just want to leave it a stock motor I would say the LQ9 is more diserable. It's still an iron block but uses things like aluminum heads and makes more power than a LQ4 which I think used iron heads and was produced in 99-00 and I think the LQ9 replaced it from 01-06. As far as 6 liter GEN 4 motors go I would say that a LS2 was the best performance, but some of the later 6 liter GEN 4's like the LY6 got LS3 heads which are rectangular heads flow better than the LS6 heads used on the LS2 but LS6 heads are still very good and the best factory cathedral heads GM made/makes. You just have to research and study and deside what you want. Most 6 liter motors are iron block motors. The LS2 and 1 or 2 of the later truck motors are aluminum block motors.
Still if you're getting a little piston slap when the motors cold that goes away when it comes up to operating temperature I think you're fine. I your motor seems to burn excessive oil when it's cold then switch to 10W30.
As far as the 5.3L goes they are good motors. With a good tune even otherwise stock they run pretty strong in my experience. The biggest advantage the 6.0L has over the 5.3L IMO is more head options and the ability to run better flowing heads do the the 4" bore where a 5.3L has a 3.78" bore. Still not really a concern unless you want to run LS3 heads or an aftermarket heads that requires a 4" bore. Both motors use a 3.622" stroke.
Hope this helps but there are people with much more experience and knowledge of the LS platform on here than me. Hopefully some of them will find this and help advise you.