Rebuild '97 LS1 w/ forged internals or new LS1/LS6 block
02-03-2012, 05:10 PM
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Rebuild '97 LS1 w/ forged internals or new LS1/LS6 block Sorry for the book, but I'm building an S13 240sx for a general fun street/autocross car, I have no intentions of FI or nitrous in my future (400 whp in 2700 lb car is enough).
A year ago, my less informed, naive self purchased a '97 LS1 longblock w/ lots of accessories from a vette w/ 130k for $650.
It is immaculate inside, clean bores, still had cross hatches, no spun bearings and a video of the engine running well before it was removed. It always was pampered with Mobil 1 and never saw boost or nitrous. I figured since I had the engine out to rebuild w/ new rings/bearings and do a ball hone. I also recently found complete 853 heads and pistons/rods from a '99 LS1 with 3k on them for a good price (no marks on pistons, all like new condition) and have arp rod bolts already.
After measuring my block, my piston to bore clearance seems ok (on high side), but there is a noticeable taper in the bore, basically more than the 0.0007" limit even though the cross hatches are still visible, but not that excessive.
My options:
1 - Torque plate hone current block to 3.903, get forged rods/pistons and a balance, roughly $1300-1500 and I will never really need the forged internals. Sell rods/pistons. Will have better internals, but poorer oiling, fatigued old block.
2 - New block from GMPP for 1100-1200 shipped, use like new pistons/rods and get new rings. Sell the old block for whatever its worth. Will have better oiling, less fatigue, but stock internals.
3 - Try to find a lower mileage block somewhere and hope for the best.
4 - Throw it together with new rings, pistons, rods, flex hone and hope the rings don't crap out in 25k miles (not really considering this option).
Weight is a fairly large concern, so I'd like to stick with an alloy block.
I have searched for a while here and other places and am familiar with what the different options are, but am at a loss which path to go. I have an all new valvetrain and it will be paired with a T56.
What would you all recommend for most reliability for the least money?
A year ago, my less informed, naive self purchased a '97 LS1 longblock w/ lots of accessories from a vette w/ 130k for $650.
It is immaculate inside, clean bores, still had cross hatches, no spun bearings and a video of the engine running well before it was removed. It always was pampered with Mobil 1 and never saw boost or nitrous. I figured since I had the engine out to rebuild w/ new rings/bearings and do a ball hone. I also recently found complete 853 heads and pistons/rods from a '99 LS1 with 3k on them for a good price (no marks on pistons, all like new condition) and have arp rod bolts already.
After measuring my block, my piston to bore clearance seems ok (on high side), but there is a noticeable taper in the bore, basically more than the 0.0007" limit even though the cross hatches are still visible, but not that excessive.
My options:
1 - Torque plate hone current block to 3.903, get forged rods/pistons and a balance, roughly $1300-1500 and I will never really need the forged internals. Sell rods/pistons. Will have better internals, but poorer oiling, fatigued old block.
2 - New block from GMPP for 1100-1200 shipped, use like new pistons/rods and get new rings. Sell the old block for whatever its worth. Will have better oiling, less fatigue, but stock internals.
3 - Try to find a lower mileage block somewhere and hope for the best.
4 - Throw it together with new rings, pistons, rods, flex hone and hope the rings don't crap out in 25k miles (not really considering this option).
Weight is a fairly large concern, so I'd like to stick with an alloy block.
I have searched for a while here and other places and am familiar with what the different options are, but am at a loss which path to go. I have an all new valvetrain and it will be paired with a T56.
What would you all recommend for most reliability for the least money?
Last edited by noskcaj; 02-03-2012 at 05:40 PM. Reason: typo in option 1
02-03-2012, 05:27 PM
#2
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I chose option 1, assuming that you use your existing block, there seems to be a typo in your post.
My theory is that a high mileage block that was well maintained will be absolutely no less reliable than a new block, assuming the bores are re-honed, surfaces machined, and you use new bearings/bolts/gaskets etc. The high mileage indicates that the block is proven and has no issues.
My theory is that a high mileage block that was well maintained will be absolutely no less reliable than a new block, assuming the bores are re-honed, surfaces machined, and you use new bearings/bolts/gaskets etc. The high mileage indicates that the block is proven and has no issues.
02-03-2012, 06:21 PM
#3
I chose option 1, assuming that you use your existing block, there seems to be a typo in your post.
My theory is that a high mileage block that was well maintained will be absolutely no less reliable than a new block, assuming the bores are re-honed, surfaces machined, and you use new bearings/bolts/gaskets etc. The high mileage indicates that the block is proven and has no issues.
My theory is that a high mileage block that was well maintained will be absolutely no less reliable than a new block, assuming the bores are re-honed, surfaces machined, and you use new bearings/bolts/gaskets etc. The high mileage indicates that the block is proven and has no issues.
02-03-2012, 08:19 PM
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Thanks for the advice so far! Looks like keeping my block and get it freshened up is the way to go.
Also just found some Probe forged pistons with a 3.902 bore and press fit pin,
http://www.summitracing.com/parts/PBP-P2600F-003/
Which seems to be the best option since I can keep my stock rods and these are about 200 cheaper than other forged, floating pin options.
Also just found some Probe forged pistons with a 3.902 bore and press fit pin,
http://www.summitracing.com/parts/PBP-P2600F-003/
Which seems to be the best option since I can keep my stock rods and these are about 200 cheaper than other forged, floating pin options.
