5.3 Using only 5.7 Pistons, not whole rotating assembly?
12-15-2011, 10:40 AM
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5.3 Using only 5.7 Pistons, not whole rotating assembly? I have a 5.3 motor that has been already been disassembled, heads cleaned, bearings ordered. it is a low mileage motor (23k miles) and it came out of a 2003 Tahoe. One of the cylinders has already had some honing done (looks like a home job that didn't come out bad I am just not ok with using it like that, more of a piece of mind than anything, I already checked the bore with a dial bore gauge and it is ok and almost perfect ). I was wondering since the 5.7 pistons are only a tad bit more than ten thousandths bigger, would it be ok to have my block bored to the diameter of the 5.7 pistons and only use the pistons with my stock 5.3 rotating assembly?
I have done some research but all the threads I come across everyone is using the whole rotating assembly to make it an actual 5.7.
I have done some research but all the threads I come across everyone is using the whole rotating assembly to make it an actual 5.7.
12-16-2011, 01:31 AM
#7
Yea i have seen that some machine shops wont even do it because they charge so much to do it since it is multiple passes, i have even seen some shops charging you the price of 3-5 times what it costs to get one 350 bored 30 over...ridiculous i figure once they have block mounted it cant be that much harder to bore in multiple steps....unless this somehow messes with the accuracy of bore from the multiple passes...im interested to see if any problems doing it really bc ls1 stock pistons are reaily available....
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12-16-2011, 02:11 AM
#9
Yes actually the cost justifies itself.
It's not as simple as boring hole after hole. I'm an ase certified machinest, and this is the process a machine shop will use.
Once the block is set up, and the cutter is measured, which takes about a half hour, one hole will be bored. Then checked for accurately. Once its verified, a different non adjacent hole has to be bored to prevent heat transfer. Most shops will do cylinders 1 and 5, flip and re level the block, then do 2 and 6. Flip and level it again and do 3 and 7, Flip and level yet again and do 4 and 8.
Repeat that process 2 more times while stopping to check the cutter and bore size and you can easily see why it would cost 3 times as much. Essentialy, it is 3 bore jobs so seeing a shop charge for 3 bore jobs is not hard to believe.
Most shops however I have seen will Only charge 1.5 or double as opposed to 3 times simply because you don't have to actually remove the block from the boring bar.
It's not as simple as boring hole after hole. I'm an ase certified machinest, and this is the process a machine shop will use.
Once the block is set up, and the cutter is measured, which takes about a half hour, one hole will be bored. Then checked for accurately. Once its verified, a different non adjacent hole has to be bored to prevent heat transfer. Most shops will do cylinders 1 and 5, flip and re level the block, then do 2 and 6. Flip and level it again and do 3 and 7, Flip and level yet again and do 4 and 8.
Repeat that process 2 more times while stopping to check the cutter and bore size and you can easily see why it would cost 3 times as much. Essentialy, it is 3 bore jobs so seeing a shop charge for 3 bore jobs is not hard to believe.
Most shops however I have seen will Only charge 1.5 or double as opposed to 3 times simply because you don't have to actually remove the block from the boring bar.
12-16-2011, 08:16 PM
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We have done the overbore on a 5.3 block. I have 2 different bit holders that I just swap out. I cut one side the first step and then swap to the other cutter and cut it again.
Our boring bar is heavy duty enough to do it in 2 cuts. Its kinda hard on the bits but it will do it. Still time consuming but not to bad.
As far as the heat transfer it really hasent been much of a problem because we try to leave .005 thousandths to hone and we use a torque plate when we finish hone it.
We have to charge a little extra but is is not enough to be out of the question.
Andy
Our boring bar is heavy duty enough to do it in 2 cuts. Its kinda hard on the bits but it will do it. Still time consuming but not to bad.
As far as the heat transfer it really hasent been much of a problem because we try to leave .005 thousandths to hone and we use a torque plate when we finish hone it.
We have to charge a little extra but is is not enough to be out of the question.
Andy
02-06-2012, 08:33 PM
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Sorry to bring up an old post, but I am interested to know how the 5.3 turned out. I want to rebuild my 198k LS1 and have considered a 5.3 block with my internals. My buddy owns machine shop so price should not be to bad. Motor will be N/A for now
