the stock pistons in the 3.1L VIN T

[cutlass_driver91]

hey guys, what size are the pistons in the the 3.1L Vin T .020 .030 .040 .060

 

 

 

http://www.engine-parts.com/GMV6/gm2831stkr.html check this site out they make a stroker kit for the 2.8 3.1 i bought the stroker kit with .030's and built a custom turbo kit with a HKS GT turbo and ARI Performance Cylinder Heads (Cast Iron, Large Valve)-Stainless Steel Valve Set

just need to make sure i got the right pistons for the comprsson ratio

and a(gunna try) 2 1/2 inc custom exhaust

 

 

oh and is the flywheels in the 4t60e hydramatic tranny blanced or not?

[Guest TurboSedan]

hey guys, what size are the pistons in the the 3.1L Vin T .020 .030 .040 .060

 

um none of the above? it has an 89mm bore.

 

http://www.engine-parts.com/GMV6/gm2831stkr.html check this site out they make a stroker kit for the 2.8 3.1 i bought the stroker kit with .030's and built a custom turbo kit with a HKS GT turbo and ARI Performance Cylinder Heads (Cast Iron, Large Valve)-Stainless Steel Valve Set

just need to make sure i got the right pistons for the comprsson ratio

and a(gunna try) 2 1/2 inc custom exhaust

 

if you bought .030 pistons then you'll need to bore the block .030 over. i would have tried using standard size or .020 but that's just me. regardless, an overbore should not change CR IIRC. what kind of heads did you get?? cast iron? hard to say what you'll end up with in terms of CR. sounds like you are spending money before doing your research.

[GutlessSupreme]

hey guys, what size are the pistons in the the 3.1L Vin T .020 .030 .040 .060

 

 

 

http://www.engine-parts.com/GMV6/gm2831stkr.html check this site out they make a stroker kit for the 2.8 3.1 i bought the stroker kit with .030's and built a custom turbo kit with a HKS GT turbo and ARI Performance Cylinder Heads (Cast Iron, Large Valve)-Stainless Steel Valve Set

just need to make sure i got the right pistons for the comprsson ratio

and a(gunna try) 2 1/2 inc custom exhaust

 

 

oh and is the flywheels in the 4t60e hydramatic tranny blanced or not?

 

Assuming, right now, that your sig reflects your car, then

1) You already have a 3.1, and getting a stroker kit for a 2.8 is just like buying new stock parts for your 3.1

2) You have a 4T60, not a 4T60E.

 

And as Josh said, your pistons are 89mm, and ordering .030 pistons mean they are .030 overbored and are not going to fit your block unless you bore .030 over. I would think that increasing your bore would decrease your CR though, Josh?

[Guest TurboSedan]

And as Josh said, your pistons are 89mm, and ordering .030 pistons mean they are .030 overbored and are not going to fit your block unless you bore .030 over. I would think that increasing your bore would decrease your CR though, Josh?

 

the difference between the area in the combustion chamber at BDC and TDC should remain the same wether it is bored over or not, so i don't see how the ratio could change.

 

i'm not too good with this stuff so maybe i'm wrong.

[GutlessSupreme]

And as Josh said, your pistons are 89mm, and ordering .030 pistons mean they are .030 overbored and are not going to fit your block unless you bore .030 over. I would think that increasing your bore would decrease your CR though, Josh?

 

the difference between the area in the combustion chamber at BDC and TDC should remain the same wether it is bored over or not, so i don't see how the ratio could change.

 

i'm not too good with this stuff so maybe i'm wrong.

 

actually, that sounds right. (equally) more volume, same ratio.

[mfewtrail]

" Cylinder Swept Volume

 

The swept volume of the cylinder indicates how much air the piston displaces as it moves from BDC to TDC. Increasing the cylinder volume without making any other changes will increase the compression ratio because it enlarges the cylinder volume without increasing the combustion chamber volume. In other words, the piston will have to cram more air into the same amount of space. Cylinder volume is calculated using the bore and stroke of the engine with this formula: Cylinder volume = 0.7853982 x bore2 x stroke"

[GutlessSupreme]

good call :oops:

[95oldsVan]

Overboring adds some small cubic inches.For example,a 350 chevy engine bored out .030 over increases its cubic inches to 355.Not much but every little helps.Overboring is usually used when the cylinder walls need a fresh cut if theyre out of specs a bit,or when some guys just want to squeeze a few extra ponies out of the engine.

[cutlass_driver91]

i havnt orderd any parts yet im not really good with 60 degree eninges but 90% of the W-body nuts on here are i just need some advice on how to go about building this eninge so i dont screw it up .....and with turboing it i know i need to lower the compresion ratio....should i just put the STD. .020(89mm) pistons in it or bore it out to .030.....only eninge parts i have bought/had built is my 2 1/2 Harrell exhust and Harrell performance header (yes i have my own line of parts for my car) this is what i do with my time when im borde...but anyways with the addtion of the turbo should i keep the .020 pistons with the 8:9.1 ratio or what??????????

[Guest TurboSedan]

standard pistons are 89mm. .020 are larger than standard by two hundredths of an inch. you'd still need to bore the block .020 over if you choose .020 pistons.

 

you really don't need to get lower compression pistons just to turbocharge your 3.1MPFI engine as long as you don't get crazy with the boost level. my never-been-rebuilt ~240,000 mile 3.1 is taking 10psi no sweat....not that i recommend that

[JoroCorona]

If the pistons are like the DOHC pistons they are practical flat tops with valve reliefs. To lower compression abit you could get dished pistons.

 

However, Josh is right. That motor will take 7 psi safely... 10 psi if your a nut job like josh.

[Guest TurboSedan]

If the pistons are like the DOHC pistons they are practical flat tops with valve reliefs. To lower compression abit you could get dished pistons.

 

However, Josh is right. That motor will take 7 psi safely... 10 psi if your a nut job like josh.

 

 

3.1 Turbo pistons and 3.1 NA pistons actually look just alike. the minor difference in compression ratio between the turbo 3.1 and NA 3.1 are in the heads. 3.1 Turbo pistons are stronger though from what i have heard. they are dished unlike the DOHC pistons.

[JoroCorona]

Okay, so they are already dished, nix that idea.

 

Another quick was to decrease compression is run a wide head gasket or even two stock headgaskets.

[Guest TurboSedan]

i wouldn't run two head gaskets together :shock:

 

really no reason you can't run 10psi on a stock 3.1 MPFI 'LH0' engine if everything is done right. might sound crazy but i certainly have no problems. i've been using the Fel-Pro head gaskets and they have been fine. i'm sure there have been times i have pushed more than 10psi. i do abuse this high mileage engine! i deliver pizza 5 days a week and it sees WOT VERY often. maybe i have been just lucky, but i think the LH0 can take alot.

 

i'm likely going to take the Cutlass off the road soon though, only because the front suspension and brakes are starting to make the car unsafe. however the drivetrain seems like it would last to 300,000 at this point.

 

i don't recommend pushing 10psi through an LH0, but i only say that as a disclaimer.

[cutlass_driver91]

okay sweet so stroker kit, port/polish perfomace heads,stainless valve train.2 1/2 exhaust, custom trubo kit,cutom header's and block bored out to .020 and remap the ecu and install a performance chip??????????????

[mfewtrail]

If the pistons are like the DOHC pistons they are practical flat tops with valve reliefs. To lower compression abit you could get dished pistons.

 

However, Josh is right. That motor will take 7 psi safely... 10 psi if your a nut job like josh.

 

 

3.1 Turbo pistons and 3.1 NA pistons actually look just alike. the minor difference in compression ratio between the turbo 3.1 and NA 3.1 are in the heads. 3.1 Turbo pistons are stronger though from what i have heard. they are dished unlike the DOHC pistons.

 

The NA and turbo 3.1 pistons are exactly the same.(sleeperred90tgp aka Jud has actually compared them).

 

"TGP and n/a pistons are the same with a -.257 dish @ 26cc’s"

 

 

To Anthony: How many miles are on your 3.1? What kind of shape is it in? If it runs fine now and doesn't burn oil, I would simply go ahead and turbocharge it and not worry about trying to bore or stroke it...you're not gaining many cubic inches with these motors at all so it's not worth it in my opinion(unless you simply need to freshen up the motor/bore out the cylinders if needed).

[Guest TurboSedan]

The NA and turbo 3.1 pistons are exactly the same.(sleeperred90tgp aka Jud has actually compared them).

 

"TGP and n/a pistons are the same with a -.257 dish @ 26cc’s"

 

 

i know they have the same dish, i meant the 3.1 piston (NA & Turbo) are dished unlike the DOHC pistons. i think the 3.1 turbo piston & 3.1 NA pistons are the same (in terms of strength) but i only mentioned it because some people have argued the 3.1 Turbo pistons have a steel reinforcing band in them. i'd have to see it to believe it.

[mfewtrail]

The NA and turbo 3.1 pistons are exactly the same.(sleeperred90tgp aka Jud has actually compared them).

 

"TGP and n/a pistons are the same with a -.257 dish @ 26cc’s"

 

 

i know they have the same dish, i meant the 3.1 piston (NA & Turbo) are dished unlike the DOHC pistons. i think the 3.1 turbo piston & 3.1 NA pistons are the same (in terms of strength) but i only mentioned it because some people have argued the 3.1 Turbo pistons have a steel reinforcing band in them. i'd have to see it to believe it.

 

Oops...I kinda skipped over where Jon was mentioning the "DOHC" pistons there...