non turbo pistons?

[Sandman817]

well i have been looking aroudn on craigslist for a 6 bolt motor that i could swap into my 99 eclipse gst. i came across one that had a few thousand miles on it, but the guy says he has the N/T pistons in it....Should i stay away from this motor??

This is part of the listing.

The block is out of a 91 GSX and was completely rebuilt by me after being cleaned up and checked at the machine shop. The motor runs strong and does not smoke at all. The block comes with 92 N/T pistons (9.0:1 compression), 1g rods, ARP head studs, ARP main studs. It has the oil pan, 90 oil filter housing (w/ AN fittings), all newer timing components, 2g poly motor mount (bracket trimmed for 6 bolt in a 2g), almost new alternator, power steering pump, AC compressor, and unorthodox racing crank pulley.

 

[9!'clipseDOHC]

I don't know why anyone would put non-turbo pistons in a turbo car. It is common knowledge that non-turbo pistons don't like boost. Cast pistons + high compression + boost = fail.

 

[BLINKY619]

I don't know why anyone would put non-turbo pistons in a turbo car. It is common knowledge that non-turbo pistons don't like boost. Cast pistons + high compression + boost = BOOM.

i think its boom

 

[GsXdSmKingGsX]

why in the world would you put higher compression pistons in a turbo motor? Are you looking to rebuild a 6bolt or just directly swap one in?

 

[JusMX141]

Who does a turbo build using non-turbo pistons? Sounds to me like this guy wanted 9:1 Wisecos on a NPR budget and non-turbo pistons were the compromise. If he wanted cheap pistons that were near the 9:1 ratio he should've bought Evo VIII or IX pistons and had the rods machined.

I'd stay away. The higher compression will detonate easier unless your tuning is spot-on, and the non-turbo pistons are not going to be very forgiving.

 

[9!'clipseDOHC]

i think its boom

True, .

Who does a turbo build using non-turbo pistons? Sounds to me like this guy wanted 9:1 Wisecos on a NPR budget and non-turbo pistons were the compromise. If he wanted cheap pistons that were near the 9:1 ratio he should've bought Evo VIII or IX pistons and had the rods machined.

I'd stay away. The higher compression will detonate easier unless your tuning is spot-on, and the non-turbo pistons are not going to be very forgiving.

I was wondering the same thing. I even read the first post a couple of times to make sure I wasn't reading it wrong. Everything else looks like a quality build (except for the crank pulley). Non-turbo pistons just blow my mind.

 

[peon_slayer]

stay away that motor is most likely on its way out and is knocking hard . like who in their right minds puts n/t pistons into a turbo car???

this guy who is selling the motor= fail
if you stay away from the motor= smart choice

 

[ramsack]

don't knock it until you try it. granted they are not strong pistons but everyone (most to all without first hand experience of it) makes it out to be that they're going to shatter instantly from any slight amount of knock, which isn't true, unless my engine is just a freak of nature.

 

[Sandman817]

not to mention he's askign 1100 for the whole thing without the valve cover.

 

[99gst_racer]

The N/T 4G pistons have a weaker top ring land and cannot handle high cylinder pressures. They'll all break quickly with any decent amount of boost/airflow. They're fine aside from that major issue.

 

[Sandman817]

why in the world would you put higher compression pistons in a turbo motor? Are you looking to rebuild a 6bolt or just directly swap one in?

and i am looking to swap a 6 bolt into my 99 GS-t.

 

[thomcasey]

well i have been looking aroudn on craigslist for a 6 bolt motor that i could swap into my 99 eclipse gst. i came across one that had a few thousand miles on it, but the guy says he has the N/T pistons in it....Should i stay away from this motor??

This is part of the listing.

The block is out of a 91 GSX and was completely rebuilt by me after being cleaned up and checked at the machine shop. The motor runs strong and does not smoke at all. The block comes with 92 N/T pistons (9.0:1 compression), 1g rods, ARP head studs, ARP main studs. It has the oil pan, 90 oil filter housing (w/ AN fittings), all newer timing components, 2g poly motor mount (bracket trimmed for 6 bolt in a 2g), almost new alternator, power steering pump, AC compressor, and unorthodox racing crank pulley.

The motor will work, but you gotta keep the boost below 14lbs and run 93 octane minimum. If you starting having knock, it's gonna fail. The top ring landing is too close to the top of the piston.

I am currently running a NT motor in my TSi AWD, it has worked flawlessly, but I keep the boost @ 12 or below, and never run less than 93 octane fuel. Of course, by compression is probably lower than the 9.0:1 due to the miles on the motor (145k miles).

 

[Sandman817]

okay well i emailed the kid asking a couple questions why he went with those pistons..This is what he replied back to me.

I didn't build the motor, but the turbo pistons aren't forged either. anways the motor held up fine at 22-24psi, had no knock at all, i made 305whp at 22.5psi on it.

 

[JusMX141]

This is what he replied back to me.

I didn't build the motor, but the turbo pistons aren't forged either.

No shit they're not forged....they're cast stockers that are designed for use in the turbo car.

Forged non-turbo pistons would be....well, turbo pistons.

anways the motor held up fine at 22-24psi, had no knock at all, i made 305whp at 22.5psi on it.

Sooo he's telling you the ring lands are already broken?

 

[rarest_90_DsM]

i run a n/a motor turbocharged its a hell of a street setup imo always run 93 octane watermeth and a hell of fuel system, car has seen 18 psi no problems (SUPER TOURQIE)But its not a dd just a toy . Id go with turbo pistons do a frank motor easy effective good dd setup.

 

[ramsack]

forged non-turbo pistons would be turbo pistons? stock turbo pistons are cast. the closest mitsu ever came to a forged piston in this engine was the evo9, and they are evidently 2-piece, with the top being forged, and the rest being cast.

i really don't see an issue with running non-turbo pistons if you aren't trying to make crazy power. i have always run just the stock 11 psi. i still have knock every time i accelerate in boost or not (agressive 1g timing.) it is my daily driver. i run 93 octane. i tried 100 octane gas from sunoco and the bastard ran like a champ! anyway i've been driving this thing for 6 months this way. the knock sensing system is there to prevent the car from blowing up, and evidently it works, because my engine is still going strong. IMO 7.8:1 is a pathetic pick for a compression ratio for a street car not running insane boost. if you're that worried about the n/t piston stigma and still want a higher compression piston cheap there are the 2g pistons or the evo8 cast, or evo9 1/2 forged. any way timing can be taken out with something like a dsmlink. if you plan to run something like an safc you're best off using the 7.8:1 engine.

 

[LKWTSI]

I can't post some pic's right now as I'm on a work computer and the pic's are on my laptop. I found myself in the same situation..bought a "so called turbo 6 bolt" from a guy, to replace my blown motor. Paid $600, for the block and head. Here's the deal, it had been to the machine shop and looked the part. All I had to do was transfer my oil pan and mounts and put the cams in and timing cover.

I pulled the head to install ARP studs and found the WRONG pistons in it. Non turbo versus turbo..what's worse since all of this I now found out that the prick, obviously had a TB spring on him and bent some valves and put the motor back together with new valves to replace the bent ones and got the shop to machine the nick out where it tore the cylinder wall. I have a couple threads on all this going, end result is I was told as you are DON'T run N/T pistons and get the proper ones. I did and now have to send my block in to get worked and for all this I have a POS Non turbo block that's crap and have to re-do the valves.

Had I not pulled the head and just stuck this in and ran it, I'd probably have blown this up in a few miles. SO save yourself the heartache and just swap them now while you can.

I can post pic's of the piston differences if you want. You'll see what the guys are talking about with regards to the ring positions.

 

[ramsack]

there is a difference if you buy a motor or a car and it was this way, and you weren't expecting it, than knowing what you have and keeping a safe tune. you never even ran it. if you're expecting to run high boost, then stay away. my car came with this engine in it. the reason the ringlands crack isn't really cause they're weak, it's because the rings themselves are end-gapped smaller, and they cannot take the heat of forced induction. when they got hot like that they expand, and with a small end gap they will deform. the only way to deform is up or down, in turn cracking a ring land. maybe whoever put this engine in my car gapped the rings accordingly for a turbo application, i really don't know. all i know is i haven't had any problems, and as i said i can feel that i am constantly knocking.

 

[LKWTSI]

Just for reference and a picture is worth a thousand words sometimes. Anyway, here's a pic of N/T v's Turbo pistons. Piston with the rings still in, are the N/T.

 

[Sandman817]

yea the kid emailed me back saying he was runnin20-24psi of boost and making a bit over 300 whp with no knock.... thanks for the help, defiantly passing on this one

 

[thomcasey]

I haven't had any knock on my turbo'd N/T motor. Though, maybe it's age/miles have lowered the compression enough to compensate?

 

[Sandman817]

the motor only has a few thousand on it so im sure the compression is still up there

 

[artismal]

I sort of have a similar situation. My engine threw a rod a month ago in my 93 gsx (7 bolt) and I just got a replacement engine for it but its a 6 bolt non turbo. So do I still need to swap out the pistons for turbo pistons even though I think I heard someone say the 6 bolts have lower compression or would they handle the extra pressure from the turbo? And then if I did need to swap the pistons, what engine should I pull them from? And anything else I would need? I'm not looking to spend a lot of money and I won't be passing 300hp anytime soon. I only have a few hundred to throw at it right now and I'm doing it all myself. I'm sure I'll rip it all apart and rebuild it anyway in a year or so but I want it to last until then and maybe have some balls at the same time.

 

[ramsack]

It would just be easier to find another block than to try to work with used pistons.

 

[9!'clipseDOHC]

So do I still need to swap out the pistons for turbo pistons even though I think I heard someone say the 6 bolts have lower compression or would they handle the extra pressure from the turbo?

4G63T 6 bolt - 7.8:1 compression
4G63N/T 6 bolt - 9:1 compression

The non turbo pistons, even if they are 6 bolts, have higher compression, cast pistons.