5.3 rebuild question ???
GM designed the LS engines for 250K so pending proper maintenance your bore taper should be very minimal. You could micrometer the piston skirts (approx. 1/2 inch up from the bottom) and lock the mic to use to set the bore guage and then check each cylinder for taper or out of roundness. Unless you know the history of the engine...who owned it, what vehicle, oil changes...etc then just clean, ball hone, and install new rings. Use dexron ATF to wipe the cylinders clean after honing as well as a few drops to lube the rings on install.
Thread Starter
Staging Lane
Joined: Jun 2014
Posts: 82
Likes: 1
From: Detroit, Mi
my local machine shop says it's impossible & it's a must to get it bored over and new pistons..! I honestly don't believe him because I've seen it done before. plus I never read about such a thing. correct me if I'm wrong
Thread Starter
Staging Lane
Joined: Jun 2014
Posts: 82
Likes: 1
From: Detroit, Mi
GM designed the LS engines for 250K so pending proper maintenance your bore taper should be very minimal. You could micrometer the piston skirts (approx. 1/2 inch up from the bottom) and lock the mic to use to set the bore guage and then check each cylinder for taper or out of roundness. Unless you know the history of the engine...who owned it, what vehicle, oil changes...etc then just clean, ball hone, and install new rings. Use dexron ATF to wipe the cylinders clean after honing as well as a few drops to lube the rings on install.
TECH Fanatic
Joined: Jul 2007
Posts: 1,800
Likes: 326
From: Wilmington, De
I redid an aluminum 5.3 not too long ago and I reused the pistons, and the aluminum blocks are much, much more prone to ovaling out than the iron blocks.
Unless the bores are that out-of-round on your engine, you should be fine with a clean-up hone and cleaning of the pistons. It is all about measuring and checking for proper clearances. So, either the machine shop is saying that an overbore is necessary because things are out of spec, or they are trying to sell you on some new pistons.
Unless the bores are that out-of-round on your engine, you should be fine with a clean-up hone and cleaning of the pistons. It is all about measuring and checking for proper clearances. So, either the machine shop is saying that an overbore is necessary because things are out of spec, or they are trying to sell you on some new pistons.
Thread Starter
Staging Lane
Joined: Jun 2014
Posts: 82
Likes: 1
From: Detroit, Mi
I redid an aluminum 5.3 not too long ago and I reused the pistons, and the aluminum blocks are much, much more prone to ovaling out than the iron blocks.
Unless the bores are that out-of-round on your engine, you should be fine with a clean-up hone and cleaning of the pistons. It is all about measuring and checking for proper clearances. So, either the machine shop is saying that an overbore is necessary because things are out of spec, or they are trying to sell you on some new pistons.
Unless the bores are that out-of-round on your engine, you should be fine with a clean-up hone and cleaning of the pistons. It is all about measuring and checking for proper clearances. So, either the machine shop is saying that an overbore is necessary because things are out of spec, or they are trying to sell you on some new pistons.