GM 3.6L Piston facts - BONUS PICS!!

[gectek]

Ok, so as we have all been aware since somewhere in early 05-06, GM decided to revive the 60* DOHC. It really comes in 2 forms (duh). The 3.6 PFI (port fuel injected) and the 3.6 DI (direct injected). Obviously being such largely different designs, they have quite a few differences.

Intake manifolds are one. Pistons, rods, rings. Actually quite a bit is diff.

I have some interesting info ill share through the course of today and tomorrow. As well as pictures.

First off, the DI piston is completely diff from the PFI piston. The PFI is a flat top with 4 valve reliefs. It appears to be non directional, but it still has a dot on it for reference. They all have the notch for the timing wheel on the crank, the PFI version has it on both sides. The DI piston has a "ricardo" cup in it to take the fuel charge on a quench pad. This cup is machined onto the cast domed and valve relieved face of the piston. It is a different design indeed.

I am running out of time, so i will wrap this up. I have some pictures I will post tomorrow along with technical specs. If there is anything you want to know, please post up.

one pic for teaser

[SappySE107]

That looks a lot different than the piston I had here. Id love to know the compression ratio when used in a 3500:P

[gectek]

[gectek]

Only (so far) the 3.6 DI piston has this coating. I have heard it could be a hard anodized due to using a steel top ring.

[IsaacHayes]

You'd think all those sharp edges in that piston would create hot spots... Got a pic of the DI head combustion chamber?

[Superdave]

I'll take 6 of the regular 3.6 pistons please.

[IsaacHayes]

How will the longer stroke of that piston affect it in an LX9? Is the piston any different in that regards? Flat top and 10.2:1 in the 3.6 with valve reliefs, does look nice for your motor Dave...

[91LQ1Lumina]

Dumb question, but since this is from the newer 60's. wouldn't the bore be a lot larger then the LX9?

[robertisaar]

wikipedia:

bore of 3.70 in (94.0 mm) and a stroke of 3.37 in (85.6 mm).

3500 has the same bore.

[91LQ1Lumina]

That's good to know, I thought this engine would share the same bore and crank center line as the 3500/3900VVT. Guess that is what I get for assuming. (However I just made an ass out of I, anyone want to be the U?)

[bob442]

shouldnt this be in the pushrod section as your measuring it up for a pushrod application? haha

[SappySE107]

He isn't measuring this for pushrod use, but it works for pushrod use with different rods.

[bob442]

i thought he was... my bad

[Jimmyfloyd]

what are these out of?

[gectek]

they are out of the newer GM 3.6L engines.

They could be used in the 3500 based on correct CH for the rod length and stroke. Would be very neat. But the valve reliefs are all wrong. Way too small. If you need them of course. Heh. Ill put up alot more specs tomorrow.