Mild 6.0L Build Suggestions?
- Thread starter Matthew Jeschke
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Matthew Jeschke
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Now the annoying stuff really starts haha... So I'm getting mixed answers calling machine shops and none of them are telling me what I thought was the case for an LS motor.
Quick overview: I'm calling machine shops to get the heads cleaned up as well as, the rotating assembly double checked for balance.
The LS is internally balanced (the harmonic balancer and pressure plate or flywheel are balanced independently). One shop told me I had to bring in the pressure plate and harmonic balancer with the rest of the assembly as they are balanced together.
The next shop couldn't give me a straight answer. I said it's internally balanced which seemed to confuse them a bit, then they couldn't give me a straight answer either.
I think it's simple, the machine get's the crank on it w/o the pressure plate or harmonic balancer on it. Otherwise if they balance it with those items the motor needs rebuilt if the pressure plate or balancer break.
Lastly, the guy I bought the motor and rods from specialized in building LS motors. He said SPECIFICALLY keep to factory parts and no balancing is necessary. He said the rods and pistons are all within factory balancing tolerances and that he mixes, matches, and swaps parts all the time so long as they are factory LS parts.
Maybe my thinking is off? I really don't think so. Anybody had experiencing with balancing the rotating assembly of the LS motor? Is there somewhere I could read more about how they make these?
UPDATE: I went out and measured weight of a 5.3 piston and rod. Then the new 6.0 piston and rod. The new piston and rod are heavier (to be expected). So I think the old advise that you can put a 5.3 crank in a 6.0 motor w/o any modification is wrong. I think the whole assembly needs re balancing although I don't think you need the pressure plate or harmonic pulley to balancing it. I also found a shop that could better answer my questions.
Quick overview: I'm calling machine shops to get the heads cleaned up as well as, the rotating assembly double checked for balance.
The LS is internally balanced (the harmonic balancer and pressure plate or flywheel are balanced independently). One shop told me I had to bring in the pressure plate and harmonic balancer with the rest of the assembly as they are balanced together.
The next shop couldn't give me a straight answer. I said it's internally balanced which seemed to confuse them a bit, then they couldn't give me a straight answer either.
I think it's simple, the machine get's the crank on it w/o the pressure plate or harmonic balancer on it. Otherwise if they balance it with those items the motor needs rebuilt if the pressure plate or balancer break.
Lastly, the guy I bought the motor and rods from specialized in building LS motors. He said SPECIFICALLY keep to factory parts and no balancing is necessary. He said the rods and pistons are all within factory balancing tolerances and that he mixes, matches, and swaps parts all the time so long as they are factory LS parts.
Maybe my thinking is off? I really don't think so. Anybody had experiencing with balancing the rotating assembly of the LS motor? Is there somewhere I could read more about how they make these?
UPDATE: I went out and measured weight of a 5.3 piston and rod. Then the new 6.0 piston and rod. The new piston and rod are heavier (to be expected). So I think the old advise that you can put a 5.3 crank in a 6.0 motor w/o any modification is wrong. I think the whole assembly needs re balancing although I don't think you need the pressure plate or harmonic pulley to balancing it. I also found a shop that could better answer my questions.
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Matthew Jeschke
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I'm going to save these links here. This guy's stuff is SUPER helpful. It's a machine shop doing the whole process building a 5.3L
1. They balanced with only the internal components on the crankshaft (bob weights and crank).
2. He has a method here to set the thrust bearing so it's aligned with the crank. He basically lightly cranks down the main caps... then hits the crank front and back hard with a soft metal rod and hammer. This aligns the thrust main / bearing perfectly with the case so it doesn't drag excessively.
Next I found specs on LS crankshafts HERE and am measuring up my existing crankshaft as best as possible to make sure it's good enough for reusing before I spend the $$ at the machine shop.
FYI ~ Seems to be between $200 to $300 for a balancing. The shop I called that seemed to know their stuff wanted $275. The one that didn't answer any questions was $200.
1. They balanced with only the internal components on the crankshaft (bob weights and crank).
2. He has a method here to set the thrust bearing so it's aligned with the crank. He basically lightly cranks down the main caps... then hits the crank front and back hard with a soft metal rod and hammer. This aligns the thrust main / bearing perfectly with the case so it doesn't drag excessively.
Next I found specs on LS crankshafts HERE and am measuring up my existing crankshaft as best as possible to make sure it's good enough for reusing before I spend the $$ at the machine shop.
FYI ~ Seems to be between $200 to $300 for a balancing. The shop I called that seemed to know their stuff wanted $275. The one that didn't answer any questions was $200.
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Matthew Jeschke
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So I called up my buddy retired from GM in 2004. He used to build these work trucks. His story was, they don't balance the crankshafts that most likely the 5.3 and 6.0 are the exact same crank even balance wise.
I explained the pistons for 6.0 are heavier than the 5.3 ones were. He said to definitely get the crank balanced despite what the factory does. He also recommended:
1. Knock down high spots on sides of rods. Use a flat surface and fine sand paper like 1000 gritt. Slide the sides of the rods on that surface to clean them up.
2. Take the floating wrist pins and polish them by hand with double odd steel wool (extra fine). - I kind of wanted to do the shoelace method but don't have a vice to hold the pins in.
3. Weight match all the connecting rods. I need to find a belt sander to do this. Not sure if my DA from painting the truck will work. He said down to a gram is fine. A lot of guys are doing it to 0.5g but I'm not sure where to find a scale that accurate.
4. Have a machine shop balance the crank for weight of piston assembly.
On heads, he said not to worry about getting valves and seats ground unless they are pitted. To just take them and clean them up with lapping compound. Then use gasoline (or solvent) to do a leak test. If they seal up then that's all you need.
I watched some videos and saw how to check the valve guides and valves themselves. You can use a telescoping bore gauge (if you have one small enough) to measure ID of guide. Then measure OD of valve.
Another trick I saw was to put the valve in backwards. Then see if you can wiggle it at all side to side. If it wiggles, then the guide is bad. I found a tool to remove the old valve guides but it costs almost as much as a valve job so I'll just hire a shop if any need replaced.
Would be nice if there were specs on all these valve dimensions and stuff. Not sure where I might find them?
I explained the pistons for 6.0 are heavier than the 5.3 ones were. He said to definitely get the crank balanced despite what the factory does. He also recommended:
1. Knock down high spots on sides of rods. Use a flat surface and fine sand paper like 1000 gritt. Slide the sides of the rods on that surface to clean them up.
2. Take the floating wrist pins and polish them by hand with double odd steel wool (extra fine). - I kind of wanted to do the shoelace method but don't have a vice to hold the pins in.
3. Weight match all the connecting rods. I need to find a belt sander to do this. Not sure if my DA from painting the truck will work. He said down to a gram is fine. A lot of guys are doing it to 0.5g but I'm not sure where to find a scale that accurate.
4. Have a machine shop balance the crank for weight of piston assembly.
On heads, he said not to worry about getting valves and seats ground unless they are pitted. To just take them and clean them up with lapping compound. Then use gasoline (or solvent) to do a leak test. If they seal up then that's all you need.
I watched some videos and saw how to check the valve guides and valves themselves. You can use a telescoping bore gauge (if you have one small enough) to measure ID of guide. Then measure OD of valve.
Another trick I saw was to put the valve in backwards. Then see if you can wiggle it at all side to side. If it wiggles, then the guide is bad. I found a tool to remove the old valve guides but it costs almost as much as a valve job so I'll just hire a shop if any need replaced.
Would be nice if there were specs on all these valve dimensions and stuff. Not sure where I might find them?
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Matthew Jeschke
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I'm on track to refurbish the parts, do some cleanup, and balancing. Worked for a long time on weighing the reciprocating mass (rods, pistons, etc). Chart with some figures thus far below.
Was amazed to see the factory rods spanned a weight range of 10 grams (granted they are not cleaned up). Gives and idea of tolerance on balancing.
I'm slowly but surely constructing a jig to measure the rod ends. Then I will remove material as necessary to balance the spread down to 1 gram or at least better than 4 grams.
Polishing Exhaust Runners
The LT1 I built, I ported matched and polished the heads both on intake and exhaust side. It was pretty crappy job where I simply cleaned up castings and widened to match the gaskets.
I'm going to leave the intake side alone on these 317 heads but started working on polishing the exhaust ports. I'm not going to bother matching them via the gaskets either. I may cc the cylinder side though, that looks pretty simple.
However, I need to know how to really polish, get a mirror finish, on the exhaust ports. I'm currently VERY slowly removing sand casting finish with a 120 grit Dremel wheels. I need some sort of rubbing compound after that to clean up the grove the sanding wheel put in it. Any ideas?
Was amazed to see the factory rods spanned a weight range of 10 grams (granted they are not cleaned up). Gives and idea of tolerance on balancing.
I'm slowly but surely constructing a jig to measure the rod ends. Then I will remove material as necessary to balance the spread down to 1 gram or at least better than 4 grams.
Polishing Exhaust Runners
The LT1 I built, I ported matched and polished the heads both on intake and exhaust side. It was pretty crappy job where I simply cleaned up castings and widened to match the gaskets.
I'm going to leave the intake side alone on these 317 heads but started working on polishing the exhaust ports. I'm not going to bother matching them via the gaskets either. I may cc the cylinder side though, that looks pretty simple.
However, I need to know how to really polish, get a mirror finish, on the exhaust ports. I'm currently VERY slowly removing sand casting finish with a 120 grit Dremel wheels. I need some sort of rubbing compound after that to clean up the grove the sanding wheel put in it. Any ideas?
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Tonyrodz
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Years ago extrude honing was big. Not sure if they still do it.
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Matthew Jeschke
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Appears I'll have to either (1) buy a new crank or (2) get some serious balancing. After a LOT of measuring today, it seems the setup will be nearly 100 grams heavier per piston. Would have been a good idea to get a Gen IV crank as well.
Found this.
Found this.
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Matthew Jeschke
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Anybody have factory valve guide and valve stem dimentions for 317 heads?
I got everything torn down on the new heads I am rebuilding. I also got all the exhaust ports polished on one side... Will do other after I get them out of the hot bath. Am also considering polishing top of combustion chamber.
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I got everything torn down on the new heads I am rebuilding. I also got all the exhaust ports polished on one side... Will do other after I get them out of the hot bath. Am also considering polishing top of combustion chamber.
Sent from my SM-A505U using Tapatalk
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Matthew Jeschke
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Just arrived custom ground camshaft, springs and retainers:
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Matthew Jeschke
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I'm trying to get equal weight on my connecting rods. The older style have a place to cut weight on them (counterbalance area). These new ones do not. I see some people just cut the rod itself at the ends. I don't like that idea as the most stress is on the rod ends.
Long story short, I think I'm just going to buy a bunch of used rods. Clean them up and use the ones that have the closest weight. Then sell the extras on eBay. I need to understand the casting numbers though.
Questions:
Casting numbers Mine are all 3847 on one side, then the other side has a Txxx number. The *** changes, I don't know what the Txxx is about?
Crankshaft Journal mine all seem to have some sort of an oil relief on the upper part of the journal. When I search used connecting rods, I cannot find any pictures with that relief in it? What is that?
Lastly there's a printed number on the I beam. It's BARELY visible due to varnish and wear. Not sure what that number is or is about.
NOTES: 2003 seems to be first year for full floating pistons. Two part numbers 12649190, 12607475 (possibly more).
Long story short, I think I'm just going to buy a bunch of used rods. Clean them up and use the ones that have the closest weight. Then sell the extras on eBay. I need to understand the casting numbers though.
Questions:
Casting numbers Mine are all 3847 on one side, then the other side has a Txxx number. The *** changes, I don't know what the Txxx is about?
Crankshaft Journal mine all seem to have some sort of an oil relief on the upper part of the journal. When I search used connecting rods, I cannot find any pictures with that relief in it? What is that?
Lastly there's a printed number on the I beam. It's BARELY visible due to varnish and wear. Not sure what that number is or is about.
NOTES: 2003 seems to be first year for full floating pistons. Two part numbers 12649190, 12607475 (possibly more).
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