pontiacjeff

Who makes pistons and rods for the 5.3? Has anyone built one yet?

Haulin_Ls4_GxP

iTrader: (1)

Any lsx 6.125 stock length rod should work just fine.

fieroguru

iTrader: (1)

Its probably a better questions for the Forced Induction side. I am sure someone has built a forged 5.3L over there.

supercatxr7

iTrader: (5)

Forged JE pistons in mine and CompStar rods. Pistons had to be custom made.

Haulin_Ls4_GxP

iTrader: (1)

Is there somthing different about the ls4 vs the iron 5.3 or other aluminum 5.3's or was it because you wanted a lower compression piston?

supercatxr7

iTrader: (5)

I remember the builder saying the off the shelf units would bump compression up to high when he did the research. Went with a custom set of 9:1 on the JE pistons. They are 1500hp capable

08 pimpala ss

How Does a set of those bad boys go for?

Haulin_Ls4_GxP

iTrader: (1)

Got ya. Must be something to do with combustion chamber size. Our heads have have a 58cc chamber IIRC vs the trucks having somthing like a 62cc chamber?

supercatxr7

iTrader: (5)

They were around $1000 total.

08 pimpala ss

Sweet Im gonna look into that as something to do along with my cam swap figure why pull the motor just for a cam mis-well go all out

85-308

just saw this looking for info on piston failures (looking like an unsourced rumour at the moment..)

per: https://ls1tech.com/forums/generatio...243-heads.html
combustion chamber volume of the 243 head is 65cc;

the rods for most of these LS engines are NOT 6.25", they are 6.098" per various rod suppliers websites.
Same for LS1, LS2, LS4, LS6, LS7, LS9 and maybe others.
Here is one page: https://www.lunatipower.com/Category.aspx?id=14

Hope you did your research before ordering! I'm investigating all this stuff myself at the moment... too much 'opinion without actual knowledge'.... as is the way on the internet..

85-308

In case this is any help.... formatting went off despite trying to fix! you get the idea....
would be nice if it had the big and small end diameters too!
From Lunati's website (credit to them)

CHEVROLET V-8 CONNECTING ROD LENGTHS
Displacement CI Liters Rod Length(inches)
302 4.9 5.700
305 5.0 5.700
327 5.4 5.700
350 5.7 5.700
350(LT5) 5.7 5.700
350(LS1) 5.7 6.098
383 6.3 6.000
400 6.6 5.565
396 6.5 6.135
402 6.6 6.135
427 7.0 6.135
454 7.4 6.135
502 8.2 6.135
377 6.2 6.135

05GXPjake

Not trying to be a dick, but how much credit can be given to a company that calls the 346 cid LS1 a 350?...

Ill_Born_ss

these numbers/specs above are not for the newer generation LS motors. Try checking the GM Performance Parts catalogue for almost all your needs... powder metal, forged, titanium rods. Lifters, camshafts, buckets, heads, ... SPECS.

Note. some posters keep saying "use /order/install LS7 lifters"
ALL the non DoD/AFM lifters are the same model/part# HL-128 lifters in all the LS motors and yes there is a high performance version available for these motors that are actually cheaper in price than the stock hl-128 ones.

85-308

This is getting more interesting; I have now found what might be considered 'reliable sources' (?) putting the combustion chamber volume for the 243 at anywhere from 61.5 to 66 cc.
Makes a bit of difference when trying to determine what pistons to get!

So I have ordered a burette (last one didn't survive the move) and will cc several combustion chambers since I have the engine apart. Will post my findings.

Also found one article that commented on yet 'another' connecting rod length for (I believe) the LS6 or at any rate one of the popular ones; which again throws a wrench into the works (pun intended!) I'll see if I can find any more on that! It was a small fraction of an inch but was definitely different.

Still haven't found any one or group or example of the pistons exploding due to a (rumoured?) weak spot near the wrist pin. So for now I'm sticking with stock... Engine is going to be a guinea pig.

Ill_Born_ss

To give you some EXACT info go here: http://www.chevrolet.com/performance...moboptout=true
DOWNLOAD the 2015 catalogue , THEN

Start on page 174... look at and read every detail! Then you can read the whole book, recommended.

91parkave

iTrader: (4)

We have small cc. 243 heads due to our small bore size (3.9ish)

85-308

went and looked and am assuming you mean the 2015 Chev performance catalog for 2015; I'm guessing it is now about pg 225 or so for LS parts; won't download for some reason, so can only see the index so far. Will try with a different browser later.
Anyway I didn't see the LS4 anywhere else on the site. If you have something really specific, send it along.

85-308

yeah; I'm going to be getting a cam quote and they need something specific on the combustion chamber volume. In the past I have seen from about 57cc, right up to 76cc in the dirty emissions years... for the SBC.

The burette and clamp should arrive tomorrow so I can start setting up a new cc'ing stand.
Will post what I find out as actual.

Ill_Born_ss

yes the 2015 catalog, there are different versions (zip,pdf )simply look around that page (drop downs) for other versions.
The whole idea is to educate you of the newer ls engines and parts available and inter- changeable components.
there is not a lot of stuff on the actual ls4 but the internals are the same, rods, cranks(shaved on both ends for the ls4), there are many lists/charts to show what works with what. Sometimes there is just a phrase in somewhere to get you an idea of what/ where to look. Like I stated more of an education of the new so you are not mislead with the old.
If/ when I have time I will post up most/all the ls4 engine specs/torques so you have accurate info, not ish... ****