Which Pistons to use??

[BernZ97GSX]

i am boring out my block 20 over and wants to if i have to use a specific piston for my 1g swap or will any piston do? im going with a a oem replacement because im on a budget and need to know the size or application.

 

[91_laser]

nope, you can just do 2g overbores

 

[BernZ97GSX]

i dont think 2g's will fit my 1g rods unless i machine the rods to have them fit. i could be wrong tho.

 

[NDgsx]

Most cost effective would be mitsu oem 6 bolt pistons. However keep in mind now you will have 7.8 instead of 8.5 compression.

 

[BernZ97GSX]

isnt stock compression on 6bolt pistons 9:1???? and the 2g's are 8:8:1??

 

[super95awd]

2g is 8.5:1, 1g is 7.8:1.

 

[BernZ97GSX]

ok so none of these posts still havent answered my question???? :thumbdown

 

[boostedinaz]

i dont think 2g's will fit my 1g rods unless i machine the rods to have them fit. i could be wrong tho.

The big rods will need to be machined for the 2G pistons and that would be your best bet if you have the time and money. If you dont then just put the .20 over 1G pistons in and call it a day.

Michael

 

[91_laser]

Any piston will do and it is your choice on which one you want to do! If you are looking for a cheap stock rebuild kit on the shortblock, slowboy racing has a shortblock rebuild kit for like $500. has everything you need but the rods. but since you are doing a 1g swap to your 2g i presume you can just use the stock 6 bolt rods. any other questions?

 

[BernZ97GSX]

the swaps already been done but just had problems with it so i got a new head and had the block bored out 20 over with new pistons and every thing. i had a problem cuz i had a puddle of oil ontop of my #4 piston and couldnt solve where the leak was comming from after replacing valve seals and guides. so im just doing everything over brand new. thanx anyway looks like im going with the oem pistons for a 20 overbore.

 

[1995badgsx]

use je pistons, cant go wrong

just make sure and check your clearances (piston to wall, and ring gap) if you dont, your screwed

 

[kooka]

use je pistons, cant go wrong

piston slap anyone? [/kidding]

honestly, with stock pistons going 130+ mph time and time again in the qtr mile, there's really no need for building a motor unless you plan on going bigger than 500whp.

Don't put aftermarket pistons in a motor because you're just in there and it's added security. It's just a waste of money.

 

[NDgsx]

use je pistons, cant go wrong

just make sure and check your clearances (piston to wall, and ring gap) if you dont, your screwed

You've got to be kidding me. JE has their skirt profiles so wrong for the 4G63, DSMs stopped using JEs widely about three years ago. You have to run JEs really loose (relative t Ross or Wiseco) to keep the skirts from seizing in the bores. Piston slap on cold startup actually is a problem with the proper clearance. If you follow JEs recomended clearance and actually make power have fun rebuilding your motor after it seizes.

 

[heavyD]

You've got to be kidding me. JE has their skirt profiles so wrong for the 4G63, DSMs stopped using JEs widely about three years ago. You have to run JEs really loose (relative t Ross or Wiseco) to keep the skirts from seizing in the bores. Piston slap on cold startup actually is a problem with the proper clearance. If you follow JEs recomended clearance and actually make power have fun rebuilding your motor after it seizes.

Apparently JE pistons don't work so hot on SR20DET's either. Sounds like they have QC or poor engineering problems.

 

[sweet97]

WOW! I am about to start getting a 6-bolt rebuilt for my '93 AWD. Ross are too heavy according to Dave Buschur and here the JE's are "wrong for the DSM's". Can the $350./set w/rngs from buschur be the way to go? If i wanted to get the pistons ordered before measureing the bore of this 86k mile block should I go with the .040" over? Wait until the measure and get .020's if I can?
The price is so good that why go with a 95 piston and then have machining of the rods done? I can get a 9:1. guys? Thanks in advance, Mark

 

[Devicex]

Can the $350./set w/rngs from buschur be the way to go?

If you're talking about the Wiseco's on buschurs site for $350 it seems to be a good deal although I've run into nothing but trouble with the kit I recieved from them (not the fault of buschur) If you care to read about here is a link Click.

 

[anomalyinva]

It depends on your power goals. Under 500whp, stick with OEM stuff (not Topline get true OEM pistons). Over 500whp Ross or Wiseco are your best bet. Ross tend to be slightly cheaper, though the Buschur deal seems quite good. The Ross are about 8 grams a piece heavier, which is quite significant to rotating mass, but they are no where near 'too heavy' unless you plan to go in the 10krpm range. I know of tons of people who have taken Ross Eagle combo to 9500rpm at the track and never had problems. If I had to do it again, I would have gone with Wiseco, however. I got the Ross for cheap, $320 with rings shipped, and at the time the cheapest I could find the Wiseco was $100 more. Either way, you can't really go wrong. If you are planning on going over 500whp, I doubt you would have asked this question anyways. You would have put in enough research to see what is needed.

 

[sweet97]

No I don't think 500whp is going to happen! I run a 50 trim and just want to build a 6-bolt I have around here. For pistons I will go forged for the insurance, probbly the Wiseco's as the price is very good. My 1G 6-bolt is from a '91 and I am thinking of going with them. I need to check out a rod post I saw. I really should getthe head pulled so te bore can be checked so I can order the pistons. Or is an .040" overbore a standard way to go? Mark

 

[MNGSX]

Just get a Wiseco/Eagle combo from a Ebay seller with a decent rating...

You will be around $800.. But you will have good rods and forged slugs with offset pins that don't make a bunch of piston slap... Make up your mind before the final bore honing because getting the .003" piston to cyl clearance dead nuts is really important.

By the time you get 1G "Big" rods setup for 2g pistons or sleeved for floating pins you still dont have ARP rod bolts. By the time you buy them and have them resized they are way too close to the cost of Eagles to not be exactly the same weight as each other and not forged. You will only save $300 max working with OEM parts.

 

[boostedinaz]

No I don't think 500whp is going to happen! I run a 50 trim and just want to build a 6-bolt I have around here. For pistons I will go forged for the insurance, probbly the Wiseco's as the price is very good. My 1G 6-bolt is from a '91 and I am thinking of going with them. I need to check out a rod post I saw. I really should getthe head pulled so te bore can be checked so I can order the pistons. Or is an .040" overbore a standard way to go? Mark

Insurnace for what??? So that if you have a crappy tune you car will last 5 minutes longer than the OEM piston. If a motor is going to die it is going to die. A proper tune is the key to real insurance. So many people want to have a "built" motor just for the fact that it is cool to have/say. If you arent going to make a ton of power then why not save a few bucks and a bit of a hassle and go with the OEM stuff.

Plus if you go forged I hope you have a really good machinst that has done alot of 4G63's with forged internals. If not have fun doing all this again.

 

[MNGSX]

No they just have to know how to measure a Wiseco to set bore clearance from the right point. Someone who has worked only with other pistons on a SBC could lock up wisecos just as bad by measuring them too high.

 

[sweet97]

Why not go Wiseo's on the 1g rod? Some pricesI have seen. Wiseco's-$350. w/rings
'95 OEM pistons/$225. no rings or pins?
$700. tomachine 1g rods to fit the 2g pistons
All prices at Buschur.
Remember I am just starting to research and gather info.
As far as a forged piston and a bad tune lasting mintes longer that is a worse case scenario. Given the equal cost to use the '95 pistons and the wiseco's why choose the OEM's? The machinist is competent and has done DSM's before. Having the corect specs for the motor is paramount, after that he will meet those specs.
I have heardNOT to turn a DSM crank but only polish it. If it is out of spec replace it. True? Correct info again is paramount. Mark

 

[boostedinaz]

Why not go Wiseo's on the 1g rod? Some pricesI have seen. Wiseco's-$350. w/rings
'95 OEM pistons/$225. no rings or pins?
$700. tomachine 1g rods to fit the 2g pistons
All prices at Buschur.
Remember I am just starting to research and gather info.
As far as a forged piston and a bad tune lasting mintes longer that is a worse case scenario. Given the equal cost to use the '95 pistons and the wiseco's why choose the OEM's? The machinist is competent and has done DSM's before. Having the corect specs for the motor is paramount, after that he will meet those specs.
I have heardNOT to turn a DSM crank but only polish it. If it is out of spec replace it. True? Correct info again is paramount. Mark

Wow 700.00 to fit rods to pistons. No wonder I dont buy anything from them.

You say it is a worse case I say perhaps not. I have heard and seen alot of people tune there car and becasue they have forged psitons they think a little detonation isnt a big deal. "They are forged they can handle it". Like I said a good tune is alot better insurance.

Very true a good machinist will make all the difference but I have yet to see him say that he has a good machinst. Not to mention that fact that you really dont know if he is good till you have a good amount of miles on you motor, unless he has done a few 4G63's for others and has a good reputaiton.

The reason for not turning a DSM crank is because they are hardened. The hardedning only goes so deep. If you turn it and go to deep all that is gone.

 

[MNGSX]

Why not go Wiseo's on the 1g rod? Some pricesI have seen. Wiseco's-$350. w/rings
'95 OEM pistons/$225. no rings or pins?
$700. tomachine 1g rods to fit the 2g pistons

I think that is $70 to machine the rods. But that does'nt include other things like I'd add ARP rod bolts that requires resize of the big end... Plus guess what.. wisecos and any other forged pistons run floating pins so.. I said that aready

By the time you get 1G "Big" rods setup for 2g pistons or sleeved for floating pins you still dont have ARP rod bolts. By the time you buy them and have them resized they are way too close to the cost of Eagles to not be exactly the same weight as each other and not forged. You will only save $300 max working with OEM parts.

I'll stick with saying... 1g rods + 1g pistons or a Eagle rod /Wiseco piston combo only things that make sense. Oh and on 2.4's and high 9k+ 2.0's Id upgrade and get eagles with the L-19 ARP (higher grade ARP) bolts.

 

[sweet97]

The $700. Buschur charges is the price if I send in my 1grods and he machines them for the '95 pistons which he supplies along with the pins and rings.
The tuning issue is one I agree with totally. my point is the same as yours, a guy running his car hard simply because he has forged is nuts. that is what i consider a worse case scenario, running hard on a poor tune.
I want more ompression than the 1G 7.8 thus the Wiseco's. I will see what is the cost of refurbishing the 1G rods but i thought they were strong. I do not plan more than the 7000 rpm stock redline. I have a running 6-built that I can have rebuilt for backup for the time the motor in the '93 dies. Tough to get 3 guys to agree on a decent piston/rod combo. Again what is wrong with the '91 rod and the Wiseco's? What is the going rate to refurbish 4 rods? Are wiseco's floaters?
The way I see it the rod is an upgrade and the 9:1 Wiseco is an upgrade. Any opinions on bore size? When I rebuilt my 2.6 Conquest motor a .040 was standard fare. Is it bes to tr to keep the 2.0 to a .020" overbore if possible? Thanks again and please keep wth me as I have a ways to go. Piston/rod combofirst. Thanks for the Eagle/Wiseco advice. Mark