The BallSS

iTrader: (9)

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!

JoeNova

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.

The BallSS

iTrader: (9)

Pump gas for the street tune and probably 101 or 105 race fuel for the hero tune lol.
So .030 top and .026 bottom? I thought the bottom was wider than the top for some reason.
So a torque wrench with an angle gauge correct?

JoeNova

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.

FormulaBoat

iTrader: (1)

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.....

The BallSS

iTrader: (9)

Good info Joe, thank you.
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?

Thank you the input FormulaBoat, I've read recently that King makes a good bearing and that with stock cranks, stock bearings are also recommended and used so I'll have to see where price falls.
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.

gjestico

iTrader: (5)

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.

1FastBrick

iTrader: (16)

The second part of that statement is false. The 2004 corvette, 04 GTO and the 04-05 Cadillac LS1's had floating pin rods and pistons.

G Atsma

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.

1FastBrick

iTrader: (16)

LQ9 got them first in 2003

G Atsma

Yeah, I saw that while looking up all the Gen III engines on Summit's site. Pretty cool!

The BallSS

iTrader: (9)

It's the same P/N crank for each application so I figured I was good and with the floaters in the LS1's as stated.
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.

psicko

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

The BallSS

iTrader: (9)

I have some of these and some of these I won't need but thank you for the info!

psicko

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.

gjestico

iTrader: (5)

So the rumour goes; But that's why I said LS1. The GTO and caddy versions were LS6 were they not ? So that would make a floating pin Ls1 a one year only, Vette only, engine which would be fairly unlikely that's what the crank the OP has came from.

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.

G Atsma

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….