compression and a few other questions

[97gtconv.]

a friend of mine might be giving me his stock rods and pistons out of his 03 cobra. which is great but i have some questions. what cc is the 03-04 pistons? what compression would i be with P.I. 2valve heads? is my cam choices changed since there might be less clearence between the valve and the piston? would it be wise to go with the cometic head gaskets to reduce compression? if so what cams would you recommend? thanks alot, jason

 

[Superhereaux]

is my cam choices changed since there might be less clearence between the valve and the piston?

you can get any cams you want actually, you'll have all the room in the world with those pistons










hint: they're dished, they lower compression

 

[97gtconv.]

dumb me. had brain fart. so around 9:1-1 compression or so?

 

[Superhereaux]

couldn't tell you although i'm sure it'd be much lower than that

 

[bdcardinal]

dont use those pistons. they are the weak point of the terminator.

 

[97gtconv.]

that kinda sucks. really would've like to use the pistons but i guess i'll have to rethink my options cause i wanna stay n/a with dope. future would be built motor and turbo but i'm a college kid so i'm naturally poor

 

[Superhereaux]

dont use those pistons. they are the weak point of the terminator.

really?


you'd think with a couple of 700hp 'o3-o4 cobras running around they'd be plenty tough

 

[bdcardinal]

they are the first part to crack usually. the ringlands tend to crack from what ive seen. ford was supposed to use Manley pistons, but ended up using a less expensive company.

 

[01Steeda]

they are the first part to crack usually. the ringlands tend to crack from what ive seen. ford was supposed to use Manley pistons, but ended up using a less expensive company.

he is right. I wouldnt waste my time on that swap. just get manley from the get go.

 

[Dragstr05]

really?


you'd think with a couple of 700hp 'o3-o4 cobras running around they'd be plenty tough

Thats what I was thinking. Is the "cracking" relative to power output, or are they just cracking by defect?

 

[Kilgore Trout]

Cobra pistons do suck in the 4V they are aluminum and only have .001 PTW clearance and they seize to the cylinder walls under high speed pulls when they expand from heat.

Do not put used parts on you car especially suspension and drivetrain components.

 

[97gtconv.]

thanks, not even the rods cause the rods measured good.

 

[Kilgore Trout]

The rods would be a major step up from GT rods. The 2V rods are very weak.

 

[97gtconv.]

ok so would my stock pistons and SHM ring kit do you think it would safely take a 125 tuned wet kit consistenly?

 

[jstreet0204]

There is nothing wrong with using those pistons and rods, as long as you have them magna fluxed and checked over. They are going to be stronger than your gt pistons and rods. They do have pretty tight clearances on a stock cobra which causes some problems in extreme conditions, but as anybody that has any actual engine building experience knows, that can be taken care of in the final hone. Now they are dished so your compression ratio is going to go down, where as in a nitrous motor you want more compression, so that is going to be a negative factor. Bottom line, is if you are getting them for a good price and they check out ok, and you can live with the lower comp ratio, they should be fine.