LM7 5.3 reliability focused rebuild HELP
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LM7 5.3 reliability focused rebuild HELP First a little back story I'm very technically inclined but when it comes to invasive engine building I'm a novice but i have no reservations I can do it as I'm no stranger to building things to tight tolerances and in sequences. The issue im having right now is wrapping my head around the parts and machine work I should be looking for. I can find hundreds of post about "my 600 HP 5.3 build" etc. But that's not what I'm looking to do. This is being swapped onto a jeep so rubber burning performance isn't what I'm looking to do. I want to rebuild this engine to be reliable and streetable and will go another 150k miles plus for years to come. If there are upgrades along the way that makes sense I'm not opposed to that. I'm just trying to get a fresh as close to new engine as possible if I gain a few hp cool... if not I don't care. Even the rebuild kits I'm findings seem to be 400+ hp overkill kits. Can someone point me in the right direction on parts and machine work/head work you would have done? I've been kind of surprised how hard it's been to find just simple rebuild knowledge on these engines that aren't some dude dropping 10k into them. I live in a small town and I don't have the greatest machine shop resources around me so I want to gain as much knowledge as possible so I don't have someone **** up my block. Reccomendations welcome.
Last edited by Kyle Pittman; Dec 1, 2019 at 12:13 AM.
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From: Central Cal.
Stock LM7's go 300k miles with dull regularity. Stock is good! Rebuild to stock tolerances and use quality parts.
One thing you might want to do is boost the compression to about 10:1 from the 9.5:1 it is now, as many of the Gen IV 5.3's ran regular 87 octane on that compression. .020" milled from the heads and .040 head gaskets will do that.
Call WS6store about quality parts at very fair prices, plus they will advise on which parts to use for YOUR purposes. They sell everything from stock to full on high performance, so won't railroad you into something you do not want.
Edit- Just read about limited machine shop talent where you are. WS6store might be able to do it, or steer you to where it can be done.
How many miles on your engine? If under 200k it could well just need rings and honing, plus a valve job(do multi angle).
One thing you might want to do is boost the compression to about 10:1 from the 9.5:1 it is now, as many of the Gen IV 5.3's ran regular 87 octane on that compression. .020" milled from the heads and .040 head gaskets will do that.
Call WS6store about quality parts at very fair prices, plus they will advise on which parts to use for YOUR purposes. They sell everything from stock to full on high performance, so won't railroad you into something you do not want.
Edit- Just read about limited machine shop talent where you are. WS6store might be able to do it, or steer you to where it can be done.
How many miles on your engine? If under 200k it could well just need rings and honing, plus a valve job(do multi angle).
Thread Starter
Registered User
Joined: Nov 2019
Posts: 2
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Stock LM7's go 300k miles with dull regularity. Stock is good! Rebuild to stock tolerances and use quality parts.
One thing you might want to do is boost the compression to about 10:1 from the 9.5:1 it is now, as many of the Gen IV 5.3's ran regular 87 octane on that compression. .020" milled from the heads and .040 head gaskets will do that.
Call WS6store about quality parts at very fair prices, plus they will advise on which parts to use for YOUR purposes. They sell everything from stock to full on high performance, so won't railroad you into something you do not want.
Edit- Just read about limited machine shop talent where you are. WS6store might be able to do it, or steer you to where it can be done.
How many miles on your engine? If under 200k it could well just need rings and honing, plus a valve job(do multi angle).
One thing you might want to do is boost the compression to about 10:1 from the 9.5:1 it is now, as many of the Gen IV 5.3's ran regular 87 octane on that compression. .020" milled from the heads and .040 head gaskets will do that.
Call WS6store about quality parts at very fair prices, plus they will advise on which parts to use for YOUR purposes. They sell everything from stock to full on high performance, so won't railroad you into something you do not want.
Edit- Just read about limited machine shop talent where you are. WS6store might be able to do it, or steer you to where it can be done.
How many miles on your engine? If under 200k it could well just need rings and honing, plus a valve job(do multi angle).
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Joined: Jun 2016
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From: Central Cal.
If you're worried, pull the heads and check for cylinder ridge at the top. If very little or no ridge, slap it back together and run it. If a very noticeable ridge, might just need a good honing and rings. I now own a 2004 Tahoe with 5.3 and nearly 170K miles on it. It runs like a spring chicken with 35psi oil pressure, 55psi at 2K RPM running on the freeway. I think she'll go at least another 130K miles.
Last edited by G Atsma; Dec 2, 2019 at 03:48 PM.
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From: Bossier City, Louisiana
For my 5.3, I replaced the knock sensors and harness - easy to do with the engine out. I also checked the injectors for impedance (should be 12 ohms) and replaced one for being too high. I also high pressure cleaned all of the injectors with Brake Kleen to remove the ethanol fuel grunge and check for a good spray pattern. I also checked the oil pump screen for cleanliness. The 4L60E transmission needed a new vehicle speed sensor and the engine coolant temperature sensor was replaced shortly after first engine start. A new oil pressure sensor was needed because it got destroyed during the pull from the donor vehicle.
My engine had 150,000 miles but had good oil pressure (about 35 PSI) with the plugs removed vigorously cranking with a good battery. Compression on all cylinders was good at 165-170 PSI. Check these things on your engine and you might not have to rebuild it anytime soon.
Rick
My engine had 150,000 miles but had good oil pressure (about 35 PSI) with the plugs removed vigorously cranking with a good battery. Compression on all cylinders was good at 165-170 PSI. Check these things on your engine and you might not have to rebuild it anytime soon.
Rick
