JE vs stock pistons

[IJ.]

Why do you say forged pistons won't last as long as cast? I disagree, and the reason automakers use cast pistons is cost, and nothing more.

To get a Forged Piston close in weight to a cast one they usually make them with short skirts and this can effect longevity as it increases thrust loads on the bore but only by a few % nothing to worry about.

Built correctly no reason why a motor with Forged pistons won't last.

 

[chevyeater]

I think the stock shortblock would go ~1,000,000 miles if bore wear was the limiting factor. The bores in my original ~200,000 mile block looked genuinely untouched, cross hatch all the way around. IDK how drastic the accelerated bore wear would be with a set of JEs but, I'd gamble it shouldn't be an issue for at least ~100,000 miles if machined, installed and maintained properly.

 

[IJ.]

Brian: Agreed 100% Toyota use some of the hardest Cast Iron I've come across!

 

[csnow]

I disagree, and the reason automakers use cast pistons is cost, and nothing more.

To say that automakers don't use forged to keep cost down is not accurate. What about the LS7 motor? The LS7 is probably one of the best engineered motors off all time. It comes with cast pistons. I don't think the additional cost of forged pistons had any thing to do with the design considering that the rods are forged titanium. Did Toyota release cast pistons in the 2J to keep cost down on a $45k car a decade ago? I have never heard, other than this forum, of forged pistons outlasting cast pistons. Do some searching on google. Not to say that IJ and Chevyeater don't know their stuff. On the contrary, I search for IJ's threads to gather information and Chevyeater always has a wealth of information as well. I just have to disagree on this one.

 

[lowbudgettarga]

just a guess...

But I'd say another reason automakers don't use forged pistons is ...well... Find someone with forged pistons, ask them to go start their car when it's cold, like after being parked overnight, then go drive it without warming it up like so many people that don't care about their cars do. Hear that? until forged pistons expand they slap around in the cylinder bore really bad and it's not only annoying, but it can't be good for your cylinder walls.

if i still have factory bore, will i need to have the cylinders honed to compensate for thermal growth of the forged units?

JE recommends 4 thousandths of an inch piston to wall clearance which will probably mean that yes, you will need to hone the cylinders out to that size. you should also measure each piston individually and bore each cylinder to match a specific piston, as they are not all exactly the same size, I measured all mine with some fancy lazer made fore measuring pistons at my work and they were all different.

 

[IJ.]

Don't think Brian or I said anything about Forged outlasting Cast that I can remember my point was built correctly Forged will give good service life.

If I get 75>100.000 KM's from a performance motor I'm ecstatic and don't mind chucking a fresh set of pistons at it!

 

[chevyeater]

To say that automakers don't use forged to keep cost down is not accurate. What about the LS7 motor? The LS7 is probably one of the best engineered motors off all time. It comes with cast pistons. I don't think the additional cost of forged pistons had any thing to do with the design considering that the rods are forged titanium. Did Toyota release cast pistons in the 2J to keep cost down on a $45k car a decade ago? I have never heard, other than this forum, of forged pistons outlasting cast pistons. Do some searching on google. Not to say that IJ and Chevyeater don't know their stuff. On the contrary, I search for IJ's threads to gather information and Chevyeater always has a wealth of information as well. I just have to disagree on this one.

I agreed with you for the most part. It just isn't a big deal. You'll blow something else up way before the piston and bore wear become an issue, this is an FI engine we are talking about.

OEM piston choice is a whole different ball of wax but, as an example that comes to mind, there are plenty of older 5.0 Mustangs and newer FI mod motors running around with forged pistons from the factory, with more than 100,000 miles on them.

 

[nickel and dimed]

Well I think that I am leaning towards the factory set up for now. I know they can hold what I need and still have the life I want out of them. Since I am not going to be boosting high just yet, I think it will be better for me to just run with the stockers. Just so you all know the JE pistons were going to run me about $137 dollars canadian, a piston plus $150 for the rings and %7 gst (in Alberta Cananda). Unfortunately toyota charges about the same for the stockers but at least i will get what i want in the end.

To everyone that is shaking there heads at me right now, just know that I am a student and that I cant be "throwing a set of pistons" at the 7M, every100, 000 km. Maybe once i get out of school. :icon_bigg

Thank you all again for the advice, it was very appreciated.

Just outta curiousity, is $137 per JE piston a good price?

 

[chevyeater]

Well I think that I am leaning towards the factory set up for now. I know they can hold what I need and still have the life I want out of them. Since I am not going to be boosting high just yet, I think it will be better for me to just run with the stockers. Just so you all know the JE pistons were going to run me about $137 dollars canadian, a piston plus $150 for the rings and %7 gst (in Alberta Cananda). Unfortunately toyota charges about the same for the stockers but at least i will get what i want in the end.

To everyone that is shaking there heads at me right now, just know that I am a student and that I cant be "throwing a set of pistons" at the 7M, every100, 000 km. Maybe once i get out of school. :icon_bigg

Thank you all again for the advice, it was very appreciated.

Just outta curiousity, is $137 per JE piston a good price?

That price is ok, I've seen better.

How many miles (or kilometers if you prefer) are you hoping to get out of this 400 rwhp 3 liter engine?

edit- dammit, forgot about the currency exchange. Eh, actually, I've still seen better than that, lol.

 

[nickel and dimed]

Well I am not going to be getting the power that I want right away. It will be about 1-2 years until I get all the supporting mods and goodies that I require to run an efficient 400-425hp supra. I expect with porper maintaince and respectable daily driving (with a little fun during the odd weekend) I will be able to get a good 4-5 years outta it at least or at least 150000km (I change my oil every 3000km and filter as well)

 

[csnow]

I agreed with you for the most part. It just isn't a big deal. You'll blow something else up way before the piston and bore wear become an issue, this is an FI engine we are talking about.

OEM piston choice is a whole different ball of wax but, as an example that comes to mind, there are plenty of older 5.0 Mustangs and newer FI mod motors running around with forged pistons from the factory, with more than 100,000 miles on them.

Yeah, the 87 to 92 stangs came with forged. These weren't a true forged piston like a JE though were they? I thought they were kind of a hybrid. Not sure, I was always a SB Chevy guy and wouldn't drive a Ford back in the 80's. Don't get me wrong, I am going with forged on my rebuild, unless I get the 2000 vette that I test drove today

 

[jdub]

This is a pretty decent price for Ross pistons...been using them for 6 months now. No issues...nice quiet & smooth.

http://cgi.ebay.com/ebaymotors/Mits...043102913QQcategoryZ33623QQrdZ1QQcmdZViewItem

 

[aljordan]

FWIW.. there are a handfull of production motors that have forged pistons. A generation of the viper.. and a recent generation of the mustang had them. In fact.. my 100 series land cruiser has them. You tell me that thing won't go 250k miles without a hickup.

As long as the machine work is done properly to specification you will not have a problem at all.

My buddy has a set of Ross pistons in his 7m, and we hear NO slap upon startup in that motor. It just sounds nothing but solid.