LM7 5.3 Assembly
#1
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Good morning gents,
I've got a LM7 5.3 that is currently in pieces and in need of assembly but there's a catch....
The block is an LM7 iron block, LS1 crank, L33 pistons and LM7 con rods, all are gen IV items.
From the research I've done these engines are assembled on a zero balance system so mixing and matching shouldn't cause issue within the correct generation of engine...I think lol.
Looking for a little guidance on assembly as I don't want to dump hundreds of dollars into this thing since its an SBE.
Application is turbo application, 20-24 lbs. max, 7K-7,500 rpm max, 800whp max so pretty pedestrian.
I'd like to install new rings and bearings after getting the block cleaned up, thinking .026/.028 on the rings and open to suggestions on the bearings.
Also open to any assembly recommendations, any special tools required like a rod bolt stretch gauge?
Thanks in advance for any input guys.
Cheers!
I've got a LM7 5.3 that is currently in pieces and in need of assembly but there's a catch....
The block is an LM7 iron block, LS1 crank, L33 pistons and LM7 con rods, all are gen IV items.
From the research I've done these engines are assembled on a zero balance system so mixing and matching shouldn't cause issue within the correct generation of engine...I think lol.
Looking for a little guidance on assembly as I don't want to dump hundreds of dollars into this thing since its an SBE.
Application is turbo application, 20-24 lbs. max, 7K-7,500 rpm max, 800whp max so pretty pedestrian.
I'd like to install new rings and bearings after getting the block cleaned up, thinking .026/.028 on the rings and open to suggestions on the bearings.
Also open to any assembly recommendations, any special tools required like a rod bolt stretch gauge?
Thanks in advance for any input guys.
Cheers!
#2
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What fuel? I usually go .030/.026 on gasoline and .026/.026 on E85 for a 5.3.
Gen 4 rod bolts are not Torque-To-Yield from my understanding. I wouldn't worry about stretch. Just install to spec (angle).
Stock GM bearings.
Gen 4 rod bolts are not Torque-To-Yield from my understanding. I wouldn't worry about stretch. Just install to spec (angle).
Stock GM bearings.
#4
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The problem is that the top ring sees a majority of the heat and will expand more, making it smaller than the 2nd ring under high load.
The 2nd ring will not see as much thermal expansion. Its gap will remain closer to the cold measurement as it sees a wider temperature swing.
I go just a touch wider than typically recommended on the top ring for safety. 2 to 4 thousandths extra might be what saves you in a major lean condition.
I try to prepare for the unexpected.
Others will recommend different ring gaps. As long as you stay on the safe side of a recommendation, you're far less likely to see failure.
#5
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I've never had bearing failure on any engines builds, they are a pretty simple, non-moving part. But, for the past several engine builds, my machine shop has recommended King bearings. I have ran them, and also had zero issues. Made in Israel, very nice fit and finish on product, measure at what they are supposed to, lots of info on their website, etc.....
#6
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The idea is for the 2nd ring to be wider than the top right so that it doesn't trap any compression that makes it through the top ring.
The problem is that the top ring sees a majority of the heat and will expand more, making it smaller than the 2nd ring under high load.
The 2nd ring will not see as much thermal expansion. Its gap will remain closer to the cold measurement as it sees a wider temperature swing.
I go just a touch wider than typically recommended on the top ring for safety. 2 to 4 thousandths extra might be what saves you in a major lean condition.
I try to prepare for the unexpected.
Others will recommend different ring gaps. As long as you stay on the safe side of a recommendation, you're far less likely to see failure.
The problem is that the top ring sees a majority of the heat and will expand more, making it smaller than the 2nd ring under high load.
The 2nd ring will not see as much thermal expansion. Its gap will remain closer to the cold measurement as it sees a wider temperature swing.
I go just a touch wider than typically recommended on the top ring for safety. 2 to 4 thousandths extra might be what saves you in a major lean condition.
I try to prepare for the unexpected.
Others will recommend different ring gaps. As long as you stay on the safe side of a recommendation, you're far less likely to see failure.
With this being a pump gas street car I certainly want to air on the side of caution since not all pump fuels are created equal I find.
Any recommendations for rings?
I've never had bearing failure on any engines builds, they are a pretty simple, non-moving part. But, for the past several engine builds, my machine shop has recommended King bearings. I have ran them, and also had zero issues. Made in Israel, very nice fit and finish on product, measure at what they are supposed to, lots of info on their website, etc.....
I'm only into this short block $200 at this point so I want to keep the cost low being essentially a JY SBE build.
#7
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Ls1 crank is not Gen4 and never came with floating pin rods (~30G heavier). Is it a 'real' LS1 crank (not a truck crank) ?. Im not sure how much the balance would affect things real world.
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#9
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Right. Even 05 on up truck engines have floaters in them, along with just about all other LS based engines that didn't have them before that.
#11
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#12
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I need to knock a very small amount if surface rust off the cylinders walls and am looking at bottle hones, anyone have any different suggestions?
I will of course select the correct one for the rings I purchase, just not a big fan of them but less a fan of spending $400 to have the block done up.
#13
On The Tree
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Ring compressor - self explanatory, adjustable sucks, tapered are awesome
Piston ring install pliers - self explanatory
Dial indicator w/ magnetic base and deck bridge - check thrust clearance, degree cam, check PTV, find TDC
Granite block or glass plate and sandpaper - adjust thrust clearance
Plastigauge or OD micrometers and dial bore gauge - check bearing clearance, housing bores, journal taper and out of round
Ring grinder, feeler gauges, & fine metal file - check ring gap and grind/deburr rings
Degree wheel and checking springs - degree cam, check PTV
Adjustable pushrods - check lifter preload
Valve spring installed height micrometer - check installed height
Valve spring compressor - remove and install springs
Engine Brush Kit - clean out internal passages of block and crank
#14
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What engine assembly tools do you already have? If you want to build it right, you need a lot more than just your basic Craftsman tools set and an angle gauge:
Ring compressor - self explanatory, adjustable sucks, tapered are awesome
Piston ring install pliers - self explanatory
Dial indicator w/ magnetic base and deck bridge - check thrust clearance, degree cam, check PTV, find TDC
Granite block or glass plate and sandpaper - adjust thrust clearance
Plastigauge or OD micrometers and dial bore gauge - check bearing clearance, housing bores, journal taper and out of round
Ring grinder, feeler gauges, & fine metal file - check ring gap and grind/deburr rings
Degree wheel and checking springs - degree cam, check PTV
Adjustable pushrods - check lifter preload
Valve spring installed height micrometer - check installed height
Valve spring compressor - remove and install springs
Engine Brush Kit - clean out internal passages of block and crank
Ring compressor - self explanatory, adjustable sucks, tapered are awesome
Piston ring install pliers - self explanatory
Dial indicator w/ magnetic base and deck bridge - check thrust clearance, degree cam, check PTV, find TDC
Granite block or glass plate and sandpaper - adjust thrust clearance
Plastigauge or OD micrometers and dial bore gauge - check bearing clearance, housing bores, journal taper and out of round
Ring grinder, feeler gauges, & fine metal file - check ring gap and grind/deburr rings
Degree wheel and checking springs - degree cam, check PTV
Adjustable pushrods - check lifter preload
Valve spring installed height micrometer - check installed height
Valve spring compressor - remove and install springs
Engine Brush Kit - clean out internal passages of block and crank
#15
On The Tree
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No problem. Like I said, those are just things to "do it right" so to speak. Most people get away without checking things like installed height or thrust even, but a bunch of people blow their engines up too and don't know why because they didn't check everything out. Either way, best of luck.
#16
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Anyways, The casting number on the crank is the same yes, But the balancing holes drilled in the crank are different between the various engines (eg 5.3 and 6.0), Presumably to account for the different piston, and rod weights. Also, around 2006 the crank casting itself changed shape subtly but used the same casting number.
#17
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04 GTO's had LS1's, along with 97-04 Vettes and 98-up Gen 4 F-bodies,
01-04 Vettes and 04-05 CTS-V had LS6's
Just to clarify….
01-04 Vettes and 04-05 CTS-V had LS6's
Just to clarify….