whats good clearances in rod bearings and mains?
08-14-2013, 10:51 PM
#3
Staging Lane
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What about rod bearing clearances? I was wondering the same.
08-15-2013, 12:06 AM
#4
depends on your application. n/a? boost? spray?
If n/a - 0.0017 - 0.002" is good for mains. at a certain point though how the crank feels with the caps torqued down is more important than a few tenths here or there. You want nice and easy rotation with no binding. Mine had less than 20 in-lbs resistance with engine oil as a lubricant. 0.0018" - 0.0022" is good for rods. you can run on the tight side if you're confident that all your bores are round, run on the looser side if you're not as confident and / or it's a high output build.
what's right isn't set in stone, you and/or your machinist will have to sit down and figure out whats ideal for your setup. my 0.02.
If n/a - 0.0017 - 0.002" is good for mains. at a certain point though how the crank feels with the caps torqued down is more important than a few tenths here or there. You want nice and easy rotation with no binding. Mine had less than 20 in-lbs resistance with engine oil as a lubricant. 0.0018" - 0.0022" is good for rods. you can run on the tight side if you're confident that all your bores are round, run on the looser side if you're not as confident and / or it's a high output build.
what's right isn't set in stone, you and/or your machinist will have to sit down and figure out whats ideal for your setup. my 0.02.
08-15-2013, 04:59 AM
#7
TECH Fanatic
if aluminum block, go with what ckpitt said. if iron block, you can go up to 0.0030 on the mains.
For the rods (doesn't matter what block material), I'm running up to 0.0028". Most people use less clearance, however I still have excellent oil pressure (50-60 at hot idle).
For the rods (doesn't matter what block material), I'm running up to 0.0028". Most people use less clearance, however I still have excellent oil pressure (50-60 at hot idle).
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08-15-2013, 09:54 AM
#8
On The Tree
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King bearings are pretty much top of the line by the way, I put the tri-metal ones in mine. Ive been also been told that they are made so that if you do ever spin a bearing, your crank wont get chewed up.
08-16-2013, 10:02 AM
#14
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You should get the book on how to rebuild LS1 engines, it goes over lots of little details that you could easily miss. And it expains how bearing clearances correlate to oil viscosity, i.e. tighter bearings equals thinner oil. And make sure you get a oil pump primer and dont listen to all the BS about cranking the engine with the coils unplugged until you see pressure, worst thing to do since it still is wearing on your brand new bearings. Plus you can see how your oil pressure is before your install the engine and identify problems before its too late.
08-16-2013, 03:00 PM
#15
Lots of good info in this thread guys, I'm in the same process with my motor and was about to ask these questions. Is there a specific book you'd recommend over others. I'm always willing to drop some cash on valuable knowledge.
08-16-2013, 03:04 PM
#16
Camshaft too. You should be measuring the OD of the main, rod, and cam journals and compare with the ID of the bearing install and fasteners torqued to spec. You should also measure the main and rod bores without bearings to verify they are round and within spec. Too big, and you lose the critical bearing crush that keeps the bearings from spinning in the bores.
