STI vs RS

[Guest]

Ok so my engine bent a rod

I now have a set of sti rods and pistons

I was cleaning up the sti pistons and noticed they look different to my RS pistons

The RS pistons have 4 holes behind the oil ring and have cross hatching inside the piston above the gudgeon pin with a flat top, It has 4 recess for the valves

Now the STI pistons have a long slot along each side behind the oil ring and a small circle inside the piston with a small raised area between the 4 recess for the valves

Would this matter?

The STI rods look exactly the same as my RS rods and they are the same length as well

Please let me know as I dont want to put them in then have them die

[BC5RA]

You will have to look into head gasket thickness and/or WRX heads.

Otherwise no issues running them. The cross hatching indicates that they are a cast piston.

[Guest]

 BC5RA said:

You will have to look into head gasket thickness and/or WRX heads.

Otherwise no issues running them. The cross hatching indicates that they are a cast piston.

I am using wrx heads that Im picking up off koom tonight

so what does no marks mean?

the STI pistons feel a little bit lighter ???

[BC5RA]

 liquid_ice said:

te]

I am using wrx heads that Im picking up off koom tonight

so what does no marks mean?

the STI pistons feel a little bit lighter ???

No marks on the crown of the piston or the underside?

[Guest]

 BC5RA']

[quote name='liquid_ice said:

te]

I am using wrx heads that Im picking up off koom tonight

so what does no marks mean?

the STI pistons feel a little bit lighter ???

No marks on the crown of the piston or the underside?

On the crown there is a "A" and a "R" and a small circle

[BC5RA]

If your going to see Koom then take your pistons as well and ask him.

What year STI were they out of?

[funkytown]

 liquid_ice']

[quote name='liquid_ice said:

te]

I am using wrx heads that Im picking up off koom tonight

so what does no marks mean?

the STI pistons feel a little bit lighter ???

No marks on the crown of the piston or the underside?

On the crown there is a "A" and a "R" and a small circle

they should be A or B.. thats the different sizes iirc.. and they probably are lighter as STI pistons were forged - which came with the A and B's stamped on them.

[Guest]

 BC5RA said:

If your going to see Koom then take your pistons as well and ask him.

What year STI were they out of?

Just taking pictures with my web cam lol ;D

[Guest]

Pictures

STI Pistons

RS Pistons

Any Ideas?

[funkytown]

as i said above.. i told you what A's and B's should be. Il see if i cant find my old V3 piston photos.

[Koom]

The marks are so you can see which side of the engine to put them on. I'm not sure if all the factory pistons have offset pins but if you get a piston round the wrong way you'll have a rattly motor and make more power.

You're only going to have major problems if they are V5+ STI pistons as they will push your compression right up.

Could have minor problems if your cylinders aren't matched nicely to them i.e. A sized piston in a B sized hole or vice versa. Can get C sized aswell but I haven't seen one.

The STI rods most likely are very much the same as your original rods as they were similar up til ~V7.

[Guest]

 funkytown said:

as i said above.. i told you what A's and B's should be. Il see if i cant find my old V3 piston photos.

So take them to koom???

[Koom]

Also, if you're going to accurately measure your bores, at least check the top of the block and see which cylinders are "A" sized and which are "B" sized and try to match them to the pistons.

And yeah, bring them over and I'll see if I can deduce anything.

[funkytown]

 liquid_ice']

[quote name='funkytown said:

as i said above.. i told you what A's and B's should be. Il see if i cant find my old V3 piston photos.

/quote]

So take them to koom???

i would yer.. or to someone that knows how to put an engine together.. seems like your doing a lot of guessing..

[Guest]

 Koom said:

Also, if you're going to accurately measure your bores, at least check the top of the block and see which cylinders are "A" sized and which are "B" sized and try to match them to the pistons.

And yeah, bring them over and I'll see if I can deduce anything.

Welcome lol

Should I head over now ;D

[Koom]

Yeah thats all good. Just watching the news.

[Guest]

 Koom said:

Yeah thats all good. Just watching the news.

COMING!!! "straps mighty civic rocket pack to back" ;D

[Guest]

Wooop thanks for the info and the heads ;D