So with 96k miles its time for new pistons. The oil consumption has gotten so bad, at idle I'm pouring smoke through the exhaust and engine,- while I tracked that down to, too much pressure from the rear pcv block. it just reminds I need engine work. (long story but switched the OCC, to the rear port and it remedy some of this)

But before I do this I have a few questions- the forums don't answer all of them, and I'm having information overload. Hoping you guys can answer some of them.

1: I'm Planning on using Mahle 4032 forged pistons, which should be adequate for my daily, I just can't find information on whether these will bolt to the OEM rods. I know stock pistons are forged, and its said you can't match forged and cast, so I'm assuming the rods are forged.

2: My first priority isn't to gain power from these, but will they add BHP's?

3: Do I really need to tune this after, especially if its running the the stock C/R ratio?; Tuning has gotten expensive after 4 times.

 

Question..
If the pistons are fine, why not clean them and use new rings?
Pistons are usually changed if you bore out the motor...you Might Be OK with your miles...a good builder can tell you once the motor has been opened up....

 

The stock pistons are NOT forged neither are the rods.

 

Gotta agree with ZippyNH --- wait 'til it's torn down before you decide what's needed. After 93K, you might need to bore it out to .050 oversize, then worry about new pistons matching rods. If no boring req'd, go for cleaning and new rings. Do the valves while it's apart --- grind, reseat, etc. Should run like new after all this, and postpone the next walnut blast.

I changed pistons / rods after about 70K. Cylinder bores were slightly worn, just needed glaze broken. You might be OK at 93K, depends on how much TLC you gave it.

Also, oil smoke can be caused by a shot PCV system, not necessarily rings. You should do at least compression or leak-down test before any teardown.

New pistons / rings will only add power if going oversized or higher C/R. And no, you shouldn't need another tune, if retaining OEM rated parts. Save the next tune for the next mod, not a repair.

 

I was going to replace the stock piston eventually to deal with the oil consumption. I just hadn't really had a reason until now to do it. I definitely don't want to pay all that labor just to throw in the stock pistons, and continue with the oil consumption, and well not do something performance oriented to it.

I mean I guess it could be a shot pcv valve cover, its relatively new though and doesn't show any signs of leakage. I actually blew something a while back, and all the ignition coils blew with a bunch of weird codes, they're gone now, so I'm thinking just rebuild and find any problems with it.

 

Time for a new platform to work on. Pistons at 96K miles, boy the N14 is a winner