Overboring stock block questions
Overboring stock block questions Hello,
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 1999 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 1999 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
Last edited by nytoy; Jun 29, 2006 at 10:35 PM.
Originally Posted by nytoy
Hello,
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 2001 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 2001 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
Don't know how to respond to this other than to say what I would do. Find an engine builder. Discuss the problems that you've had. Let the engine builder explain the best way to resolve the problem & how he's to do it w/a full warantee. Second choice is to buy a balanced & blue printed assembled block & have your current engine assembler (or you) mount the heads, accessory pullies, water pump, intake,.....etc..
I realize there is a huge labor savings in having the same guy re-build the engine. Personally, I'd move on. Best of luck.
Originally Posted by nytoy
Hello,
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 2001 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
1. How far can you overbore a stock 2001 ls1 block? .10? (what piston size do you then order?)
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Thanks for any help, I searched but didn't get an difinitive answers.
2. The oversize of the piston really has nothing do with the balance of the engine. It is buying a set of pistons that are manufactured the same weights (within tolerance). That being said.. I would have the rotating assembly balanced regardless. It is not that expensive.
3. See number 2
4. Yes there is a specific LS torque plate. If you engine builder has never bored or done a block before.. take it somewhere else, my $0.02
5. As for the "best" piston. This is a loaded question. Everyone had their own opinion. I prefer to use JE and their matched ringset. There are plenty of others out there that are probably ok. If you never plan on doing much to the engine, a set of stock pistons would probably also be fine, but why go through all of that and not put a set of good forged pistons in the engine.
One thing you did not mention.. head gaskets. STOCK GM MLS gaskets.. $30 a pair from Summit, end of story.
Just for the record I do all of my own work. I have done everything to my car except bore the block.
Good Luck.
I would definitely find someone who is familiar with LS1's. The iron sleeves are cast into the block which leaves very little room for error. I believe stock over bore tolerance is .005 on 97-98 blocks and .030 on 99+ (don't quote me on that). If you're going to be road racing, the engine will spend a lot of time at high rpm where balance issues will be at their worst. I would highly recommend finding a builder who is LS1-versed.
Originally Posted by nytoy
Hello,
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
Trying to rebuild my engine now, and I'm having a builder do it, but he is clueless with ls1's.
Originally Posted by nytoy
1. How far can you overbore a stock 2001 ls1 block? .10? (what piston size do you then order?)
Originally Posted by nytoy
2. What over sized pistons can I use without rebalancing the rotating assembly? 3.905?
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
Builder says use cast, because stock has cast, using forged would throw off the balance because they are heavier. I don't run nitrous, just road race.
Originally Posted by nytoy
3. Should I have everything rebalanced anyways since I'm changing the pistons from stock? OR only if they are heavier than the stock ones.
Originally Posted by nytoy
4. For the torq plate and honing, is there special plate I should get so the machine shop doesn't screw it up, do you fully tighten down the head bolts? If you are boring to 3.905 I assume you must use a torq plate while doing this correct?
Originally Posted by nytoy
5. What are the best N/A rings / pistons setup non-forged (not running nitrous)
Originally Posted by nytoy
Thanks for any help, I searched but didn't get an difinitive answers.
Yes, the search engine has had some problems recently. You might browse through the internal section and check out the sticky at the top.
Thanks for the responses. The cost of pistons and rings plus the machine work shouldn't be more than $800 I'm hoping. So I can't justify going somewhere else and spending $2700 for a sponsor shortblock or another builder. I'm basically out of money and spending $800 is about all I can afford. I'm usually the one preaching about not being cheap, but this time I have no choice.
I am going to call a machine shop that is local that supposedly has experience with LS1's, about boring the block out for me. Hopefully they have the torqplate.
I assume you put the torq plate on it and fully tighten all the head bolts correct? I have the ARP's so re-using them shouldn't be a problem.
It shouldn't take a rocket scientist to assemble the engine, it's just the pistons/ring/bore issue that I need to get figured out for myself.
I've also heard the way you file the rings, you have use a less course sandpaper because the newer style rings aren't like the older ones that require a more heavy grit compound.
So for what I'm reading JE pistons seem to be a starting spot, hopefully they come with matched ring sets so this isn't too hard. If I'm boring it .010 over then I should order the 3.905 pistons correct?
I am going to call a machine shop that is local that supposedly has experience with LS1's, about boring the block out for me. Hopefully they have the torqplate.
I assume you put the torq plate on it and fully tighten all the head bolts correct? I have the ARP's so re-using them shouldn't be a problem.
It shouldn't take a rocket scientist to assemble the engine, it's just the pistons/ring/bore issue that I need to get figured out for myself.
I've also heard the way you file the rings, you have use a less course sandpaper because the newer style rings aren't like the older ones that require a more heavy grit compound.
So for what I'm reading JE pistons seem to be a starting spot, hopefully they come with matched ring sets so this isn't too hard. If I'm boring it .010 over then I should order the 3.905 pistons correct?
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Brett Foote thanks for the answers, I found a shop that DOES have experience with them. My only remaining questions are:
As far as pistons go, should I be looking at something special for pistons and rings? I want something that seals tight and has a good oil control ring.
Head gaskets, does felpro make ones that are for oversized bores? Thank.
As far as pistons go, should I be looking at something special for pistons and rings? I want something that seals tight and has a good oil control ring.
Head gaskets, does felpro make ones that are for oversized bores? Thank.
The stock pistons are not cast, they are hypereutectic, so this guy has no clue what is in the motor to start with. when i put forged rods and pistons in my new motor, the shop had to take weight out of the crank to balance the rotating assembly b/c my forged rods and pistons were lighter than the stock stuff. I used Callies Compstar 6.125" Rods and Mahle 3.908 piston pack.
Originally Posted by moeZ28
The stock pistons are not cast, they are hypereutectic, so this guy has no clue what is in the motor to start with. when i put forged rods and pistons in my new motor, the shop had to take weight out of the crank to balance the rotating assembly b/c my forged rods and pistons were lighter than the stock stuff. I used Callies Compstar 6.125" Rods and Mahle 3.908 piston pack.
Last edited by 67Firebird455; Jun 28, 2006 at 11:09 AM.
i would first of all find someone who knows LS1's even someone who has done what u want before for that matter. and to have your block bored is going to be expensive cause they have to re sleeve it cause its an alum. block. not cheap. IMO
My block was bored .010" over without changing the sleeves. If you go bigger than that you need to resleeve, but i would just go iron block in that case. the weight difference isnt enough to worry about it.
The pistons come from Mahle with a coating on them to reduce friction. Its a greenish-grey color and yeah it looks dark and kinda funky but its a great idea. Mahle makes a very nice, excellent quality piece!!
The pistons come from Mahle with a coating on them to reduce friction. Its a greenish-grey color and yeah it looks dark and kinda funky but its a great idea. Mahle makes a very nice, excellent quality piece!!
Originally Posted by 67Firebird455
Dude, the GM MLS gasket is probably one of the best, along with the Cometics (but pricey). For $30/pair, that is dirt, and they do an excellent job sealing.
Originally Posted by moeZ28
My block was bored .010" over without changing the sleeves. If you go bigger than that you need to resleeve, but i would just go iron block in that case. the weight difference isnt enough to worry about it.
The pistons come from Mahle with a coating on them to reduce friction. Its a greenish-grey color and yeah it looks dark and kinda funky but its a great idea. Mahle makes a very nice, excellent quality piece!!
The pistons come from Mahle with a coating on them to reduce friction. Its a greenish-grey color and yeah it looks dark and kinda funky but its a great idea. Mahle makes a very nice, excellent quality piece!!
Originally Posted by nytoy
thank you for the response, I have a 1999 block, so I should be okay with a .010 over.
