Forged piston with stock bore (85mm)

[shidie6990]

I need some advice from expert here. Mod are in my list.

I'm planning to get 450-500++whp (on dynodynamics) soon. I got few questions for you guys:

1.Is it advisable to plunk in 85mm forged piston? Provide my cylinder wall is in great conditioned. I know wiseco, manley and wossner made 85mm bore for 4g63 engine. I just rebuild my stock 6bolt bottom end for about 2000km and its still in good running conditioned.

2. From the 3 manufacture, which one is your choice? and what CR? I only have 93octane here.

3. Between Scat, Eagle and Manley connecting rod, which one is your choice?

 

[1995gsx20g]

I would not just throw in pistons before knowing exact specs of what my cylinder walls are even if they "look ok" but that's just me i don't take chances or guess when i don't have to.

Personally i like the wiseco standard forged pistons and the manley h-beam rods. i haven't started my build yet but that is the route i will be taking and will be going to run a hx35 or hx40 so around 500-550awhp.

also some good head studs like the L19's and a metal oem headgasket and your more than set.

on 93oct i would most likely stay at 9:1 CR.

 

[shidie6990]

I would not just throw in pistons before knowing exact specs of what my cylinder walls are even if they "look ok" but that's just me i don't take chances or guess when i don't have to.

Personally i like the wiseco standard forged pistons and the manley h-beam rods. i haven't started my build yet but that is the route i will be taking and will be going to run a hx35 or hx40 so around 500-550awhp.

also some good head studs like the L19's and a metal oem headgasket and your more than set.

on 93oct i would most likely stay at 9:1 CR.

how to make sure ok or not? right now my engine is in good running conditioned and kick ass.

Assume my cylinder wall in good conditioned, and measurement is within spec, am I good to go?

 

[whe3ls]

you need to measure the bore with a dial bore indicator.

 

[1995gsx20g]

you have to find out the size but only after you deglaze the cylinder walls. also you need to check for taper and out of round. all of this can be done with a dial bore gauge or micrometer with bore adaptors if your good enough and take your time to learn how each tool works and then do it properly. i would have a buddy a little more experienced in machining/motors walk me threw the steps if you don't feel up to it. and plus a second set of eyes is always a good thing.

 

[JamiesTSI]

I would choose the piston then have a competent machine shop check your piston to wall clearances, based on the pistons you choose. Different pistons have different PTW clearances. Also like mentioned the machinist will make sure the bore is perfectly round. The horse power you are aiming for also plays a part in PTW clearances. The higher the horsepower the more PTW clearance.

 

[shidie6990]

Thank you guy for your feedback. Lets assume I have check PTW and its in spec, so I good to go?

 

[Sumopower87]

How did this build go? What rods & pistons did you go with? Hows the engine running with the 93 octane?