So a friend of mine picked up a broke (what we first thought was an LS2) LS6 for ultra cheap just to see what might be salvageable. So I tore it apart for him on Wednesday and we discovered something that had me a bit confused... he's not much of an LS guru, and I'm still learning as I go, but I figured someone here might be able to shed some light on this.

Now we don't know the history at all of the motor... not sure about miles or if it's been opened and rebuilt... don't know ****.

So I get it completely apart assuming I could use one of the rods out of it for my 1998 LS1 stockish rebuild. Well apparently the rods are very different. Based on the pictures I've found here at ls1tech, it appears the ones out of this broken motor are LS2 or LQ9 rods. They have the dimple, a gold bushing and a floating pin with the locks. So now we think "maybe it is an LS2." So we go ahead and place a micrometer on the pistons and low and behold the reading is right at 3.898. The pistons look bone stock... I looked over them and found the Mahle stamp on them with a few different numbers, and the skirts looked as if they had a bit of coating... is that normal? The tops were completely flat and had a tiny hole looking thing (obviously not a hole, but I think anyone that has seen a stock ls1 piston knows what I'm talking about). I found a small article that spoke about the LS6's coming with Mahle cast pistons, so I can only assume this is the case.

I think the part that has me confused is whether or not these are stock cast pistons. I wasn't aware there was ever a stock 3.898 piston combined with the beefier LS2/LQ9 rods straight from the factory. Will any stock ls1 piston work with a floating type rod or is it the piston that has to be capable of floating?? Yes that is a dumb question... but I have to learn somehow right? After tearing this motor down, it makes me want to go this same route with my motor... but unfortunately there is one rod and piston missing from carnage, and I still don't know if it's even possible to do with stock parts. Is there a stock 3.898 piston that will work in a floating setup like the LS2/LQ9 rods???

The motor had the LS6 valley cover, that much I do know... but I'm curious what everyone's thoughts are on what may have been done here. LS2/LQ9 rods in an LS6?? This thing had to have been gone through and switched up... agreed? Thoughts? Comments? Any insight would certainly be appreciated. Thanks for reading.

Brad

 

LS pistons are made by Mahle. Sounds like you have a stock LS2. Whats the block casting say on the back right corner? 6.0L? Whats the block casting number?

 

"So we go ahead and place a micrometer on the pistons and low and behold the reading is right at 3.898."

How can it be an LS2 with "3.898" pistons? My book show that LS2 pistons are "4.000."

 

Bumping for the late night crowd. Anybody else have any thoughts? Thanks to both of you for responding.

 

Bump! I'm going to see if I can take a picture of this "mystery" combination. At least it seems I've stumped the ls1 world, lol. I'm so proud, ha! This sucks... it's driving me crazy. Any more ideas?

 

I believe the LS2 bores are 4.0" while the piston are slightly undersize for clearance in the bore. I still suggest like Arc00TA said, check the block for a casting that says 6.0L.

 

get the casting # off the block.... it will tell you a lot of info with a simple google search
you may be able to find a vin stamped on the block somewhere as well...then you can find out what vehicle it was in

sounds like a GTO LS6 or a corvette ls6 engine from 2003/2004

 

Okay, I called the shop to have them take a look at the block and see if they can find any numbers on it. I found out the oil pan has part number 12577901 on it... which doesn't help a whole lot being as apparently it was used on both an ls2 and an ls6... the valley cover is definitely an ls6 valley cover, but the rods are definitely NOT ls6 rods, and the pistons are still a big *** mystery, lol. Now an ls6 valley cover won't fit an ls2 block, correct? AND, ls2 pistons will not fit an ls6 block, yes? It would take a good bit of boring to do that, correct? I've found a few numbers on the pistons, but google searching and searching here for those numbers bring up nothing. Thanks again to the guys who've responded. I appreciate it. I'll post again when I get word on a number on the block.

 

Alright, casting number is 12561168. So it must be an LS6 block with handicapped pistons and ls2/lq9 rods. Guess we've stumbled upon the world's rarest ls6. Something just doesn't add up. Guess it's time to start looking through Mahle's catalog for old cast FLOATING pistons with a .945 pin and 3.898 bore size. This really pisses me off, lol. K, I'm done venting. If anybody else has some sort of idea on where these magical pistons came from, please let me know. Thanks again to all those who've input a little.

Brad

 

honestly... sounds like a 2003/2004 vette ls6

stock with Mahle pistons.. GM has been using them for years

 

With a floating piston that uses locks??? Plus I don't think the LS6 ever had rods like these:



Anymore thoughts?

 

yes.... 2004 LS6 Vette

FLOATING PIN PISTONS

The 5.7L LS1 and LS6 V-8s are equipped with new floating-pin pistons. First introduced on GM Powertrain’s Vortec 6000 H.0. V-8, these pistons feature wrist pins that “float” inside the rod bushing and the pin bores in the piston barrel. Previously, the LS1 and LS6 used a fixed-pin assembly, in which the connecting rod is fixed to the piston’s wrist pin, and the pin rotates in the pin bore. Snap rings now retain the wrist pin in the piston, while the rod moves laterally on a bushing around the pin. The floating pins were introduced as an interim change late in the 2004 model year.



The pistons, piston rings and connecting rods are identical to those used previously. The new floating-pin assembly allows tighter pin to pin-bore tolerances and reduces noise. The LS6 pistons were already validated for 200,000 miles of operation. The floating pin pistons should extend durability even further and reduce operational noise, even in brief, limited circumstances the customer may not have noticed to begin with.

 

last year ls6 vettes got the floating rods/pistons. Maybe the 2005 goat too?

If it has a 3.898 bore/piston its an ls1/ls6. no other way around it. they don't run .100" clearance. these things barely run a couple thou.

 

2005 GTO got the 6.0

 

Alright, I guess I'm going to have to hunt for one 2004 LS6 piston (who wants to find a picture of one so I can see if this is for real?) I've been so stumped. Now the rods used in the ls6 were always the same as the ls1 correct? Or they were for the most part, yes? Only the LS2, LQ9, late LQ4 and LSA rods were the same as what I've shown above... that sound right? This is going to become one of those threads filled with a lot of good information if I can keep your guys' brains working, lol. Thanks again, guys. I greatly appreciate all the help!

Brad

 

The floating rods are different than the previous set of rods. They are the lq9 style and all newer engines got them. My l33 rods where the same as the ones you have, yet thats a 5.3.

If it got floating pistons, it got the floating rods with it.

You have the proof in front of you that they made a floating pin ls6.

read:
http://www.fastfieros.com/enginesava..._ls1ls2ls6.htm