Thumper28

iTrader: (4)

I purchased a set of Mahle pistons with .945" wrist pins for my LS1 that I am planning on using with my stock connecting rods. My stock setup has the wrist pin pressed into the connecting rod but fully floating in the piston with no clips. Are you supposed to use the clips even though my setup will once again have the new wrist pins pressed into the rods?

chrisfrost

iTrader: (8)

No there are 2 different sizes of wrist pin ,,,,,,I believe the factory rods through 2004 used the .927" pins that are for sure pressed in ,,,,,,,if You bought pistons that are for a 2005 and later then they won't work with the pre 2005 rods . So which year are the pistons for that You bought ?

Correction , the pre 2005 pin diameter is .045" and they are press fit without clips,,,,,,,,,,,either 2005 or 2007 they started using a new design connecting rod that is a little stronger and uses full floating pins that are .927" diameter ,,,along with the updated design rods are better bolts that kinda resemble Wave-lock bolts .

Thumper28

iTrader: (4)

My engine is a 2001 and everything measures out at .945. I could be wrong but I don't think the LS1 or LS6 ever had .927" wrist pins.

Even the sticky for LS1/LS6 Dimensions and clearances mention nothing about a .927" wrist pin.:

https://ls1tech.com/forums/generatio...learances.html

KCS

iTrader: (20)

LS7 is the only one I know of that is smaller, with. .925" pin. All others are .945".

The pins should have clearance in the piston whether it's press fit or full floating. When it's full floating, you need the locks or else the pins can come out. If its press fit, the locks are not needed.

ericwilloughby

What kcs said. For some odd reason aftermarket rods use the .927.
There aren't nearly as many forged pistons made for the stock .945 rod as the aftermarket .927.

Also, fwiw, my 2005 gto had floating rods with .943 pins. I had to have them honed out to get the new mahle pistons on. I'm here because I think they were honed too much. There is a slight wobble of the pin in the rod now. What is the max clearance anybody?

A_VAS

iTrader: (16)

gen I small block chevy uses .927 pin
no economics degree is needed to see why the aftermarket focused on .927 pin and 6.125 rod length for LS stuff

ericwilloughby

I see. There was already a rod that would fit.
I found the pin clearance is .0008-.0015. Damn shop honed one of mine to .003 and when I took it back he said it was fine. He also couldn't find bushings to replace it. Do u know where...

Rob_fin

Hi,

One more question related to piston pin diameter...
I have a LQ9 2003 which has conrods with floating piston pin (0.937"). I trusted the filters in Summit and bought very expensive pistons made by Mahle (LS1340030F04), which finally has the pin with 0.945" diameter.
Obviously they do not fit together, so i guess there are two options: Machine the connection rods to have sufficient clearance as floating assembly, but is it safe or will the wall thickness be to thin on this brass bearing? OR can i just keep the brass bearing there and press the piston pin there. I mean can conrods that are designed for floating pin changed to be with pushed pin?

If someone has had the same issue, please advice. The engine have been bored and rotation assembly balanced according to these pistons, so buying a new set of pistons is really not an option...

According to Summit Racing, these pistons fit to all 6.0L engines from 2002 through 2014. Obviously this is not correct, so do i have any change to get them delivering new pistons that really fit to my engine?

ericwilloughby

So if u need 8 thousands honed out they should be able to do that. Ask your shop. Or just send them back. I would not attempt to press into a bushing. I think it'll Crack the brass

Rob_fin

Sorry i had a typo, the piston pin diameter should have been 0.925" not 0.937 as i wrote. So the brass bearing should be honed roughly 0.02" bigger. is that still ok?

ericwilloughby

No. My machine shop expressly told me you can't hone 20 thousands. Send them back. Your piston balance won't change enough to rebalance

KCS

iTrader: (20)

Have you measured everything to verify that there's an issue?

Like I said 4 years ago when I replied to this thread, the titanium rods are the only GM LS rods that have a smaller diameter pin. Every floating pin powdered metal rod I ever measured had a pin bore of about .9435" and a pin diameter of .943". If you're saying that the powdered metal rods from an '03 LQ9 has .925" pins, I would love it if you could provide proof.

ericwilloughby

3 posts up KCS

KCS

iTrader: (20)

I saw that, but I'm curious if that's what he believes it to be or if that's whats has been measured with an OD mic. Again, the stock powdered metal rods are not supposed to be .925" or .937". They're supposed to be .943", so if his really is .925", he has a unicorn engine and it's not Summits fault.

Rob_fin

My conrods indeed were 0.943" and piston pins 0.945". I trusted too much to my memory... Sorry about that.
After some honing they are ready to put in the engine. Still i do not get it, why they can be sold as "press-fit or floating" on all 6.0L/364cid engines from 2002 until 2014, without disclaimer that you may need to machine your conrods?