Pistons

[Sideways s12]

Whats A good set of pistons to use for the stock rods? I want to do stock rods but upgraded pistons any suggestions?

[nickhebert]

I would go with cp pistons, that allows you to use the oil squirts. If you go with wiesco pistons you can not use the oil squirts,

[boost_boy]

CP is fine.

[cbh148]

I'm currently running SuperTech pistons with stock rods. Still using the oil squirters too. No complaints; would buy again.

[beans33]

Cp pistons with stock rods for me...doing just fine

[Sideways s12]

Cp it is then. Where is a good place to order them from also what the cost look like so i can know what to expect...

[Sideways s12]

Also if I'm going with a fairly stock rebuild what size should I go with? And when I say stock I mean bottomend stock

[beans33]

I got mine from importautoperformance.net they were right at 600 bucks but that was 4 years ago. I went with a .20 over piston, had some scoring in the cylinder walls so I just got it bored a little to start fresh.

[nickhebert]

if your cylinder wall's are in good shape I would go with the stock 83mm but if you have scoring then get it bored .20 over.

[cbh148]

or you could be like me and get a random gash in one of your cylinder walls then have to go a full 1mm over bore, and technically have a 1.9 liter (if you round the numbers right ) as a result.

[dom666]

i have cp piston 84mm with rod pauter 4340 very good job

[mdb4879]

I've always wondered, is it a good idea to get stock sized forged pistons? I know the piston to wall clearance is usually different for forged v. cast, so wouldn't it be a better idea to start with the first oversize and a fresh bore anyways? I figure $150 bore on top of a $600 set of pistons isn't a big deal.

[float_6969]

CP here, have been for years. I even re-used them after the oil filter failure.

As for piston wall clearance, CP pistons require more clearance than the stock piston, so you'll likely still need to bore out slightly, even in a stock sized piston.

[Sideways s12]

Ok so I'll go with a .20 over then.... Thanks guys!

[blownhemi]

Being an experienced guy you probably know it already, but I'm repeating just to be sure... don't send your block to the machine shop for boring out before you have your pistons and their spec sheet in hand. Aftermarket forged ones may need quite a different bore size, than you'd need with the stock pistons. Get pistons -> measure crowns -> wall clearance from spec sheet -> machine shop.

(PS. CP is good, but I never got used to the cold piston slap. It's very disturbing. Of course, it's just a psychological thing, you may or may not be susceptible to it... )

(PPS. As I'm writing this, an FJ20 S12 just passed by. There's, like, 3 or 4 of those in my country, I never see them in person... what are the chances?)

[float_6969]

He's right about having the pistons BEFORE you have it' bored out. He's also right about CP's being noisy when cold. The type of aluminum they use is very resistant to damage, but also has a high rate of expansion. This means they have too much clearance when cold and make some noise.

[cbh148]

I'm guessing SuperTech's aluminum must not have those expansion/contraction characteristics. I've never heard mine make a sound.

[Sideways s12]

Being an experienced guy you probably know it already, but I'm repeating just to be sure... don't send your block to the machine shop for boring out before you have your pistons and their spec sheet in hand. Aftermarket forged ones may need quite a different bore size, than you'd need with the stock pistons. Get pistons -> measure crowns -> wall clearance from spec sheet -> machine shop.

(PS. CP is good, but I never got used to the cold piston slap. It's very disturbing. Of course, it's just a psychological thing, you may or may not be susceptible to it... )

(PPS. As I'm writing this, an FJ20 S12 just passed by. There's, like, 3 or 4 of those in my country, I never see them in person... what are the chances?)

Yeah Thats why i posed the question on what pistons were good im going to order them first then have the motor bored thanks for the heads up tho i def appreciate it. Anx i wish we got the fj in the states if we did i wouldnt be playing with the ca lol

[float_6969]

Yea, the weisco's and supertechs don't use the same material. My understanding is that the material CP (and others) use is more durable, but obviously has the noise issue when cold.

[nickhebert]

the piston slap doesnt pose a risk of harming anything?

[blownhemi]

the piston slap doesnt pose a risk of harming anything?

I was skeptic about them, because my common sense dictated too, that two metals slamming together for long enough would take its toll on something, but I kept hearing and reading from experienced people, that it doesn't harm anything.
(But obviously, no flooring it or high loads until the engine has warmed up properly. I don't even move the car, unless the water is completely warmed up.)

CP is used a lot, and not just in CAs. And it's not like engines with CPs are regularly falling apart, or need to be torn down and rebuilt every 10k miles. So I guess forged AlSi alloy is not quite as soft as we think it is.

float has recently (year?) disassembled his engine after some 10k miles (?), and he has found no measurable wear, or out of round on the bores, IIRC, but he'll be able to give details.

[float_6969]

The piston slap when cold is mainly an annoyance. Honestly, I didn't even notice it until I figured out my oil pressure problems and got the lifters to quiet down. On my engine, it's only really noticeable when it's REALLY cold out. As long as you let the engine warm up for a 30 seconds or so, and you don't go beating on it until it's fully warmed up, then there isn't any harm that can be done.

As blownhemi said, when I tore the engine down (about 40K miles on it) to rebuild it after the oil filter failure, the pistons were in pretty good shape. Slight wear on the skirts, but only enough that the machining marks had worn smooth. The cylinders were still round and in good shape. The only work that was needed for the cylinders and pistons were to re-hone the cylinders (I don't even thing a ridge reamer was used) and re-ring the pistons. And this wasn't 40K miles of highway driving. I beat the CRAP out of that motor every time I drove it. There wasn't one day it was driven that it didn't see 8K rpms at least once. Often it was multiple times a day.

CP makes a great piston, and regardless of the what happens in the future, if I'm building a motor, it WILL have CP pistons in it.

[boost_boy]

CP is my piston choice as well. Even though I have WISECO pistons in my fully built engine, I do have CPs in my sentra's CA and have had those same pistons for over 10 years with no ill effects whatsoever. I also built "OverBoosted180's" engine using standard 83mm CP pistons. They just work, period. You guys can use what you want as they all will work if your engine is prepared properly, but I'll take the CPs anyday.

[Sideways s12]

yeah I'm going to go with the cps for sure thanks guys...