4K Pistons

[Sephiroth]

Hey guys just wondering if anyone has any recommendations on some 4k pistons doing some work to one and wondering what good pistons are around

 

Cheers

[altezzaclub]

5K "O"-dish ones.... You know they will fit the rods, the gudgeon pins and the deck height.

 

But really, who would make forged pistons for 4K motors??

 

The guy with the 4AGE head on the 4K block used 4AGE aftermarket pistons, but it was a lot of maching to do it.

 

Someone else I read about used VW ones at 80mm, but they might have needed machining too.

 

What are you planning for the motor??

[kickn5k]

 

But really, who would make forged pistons for 4K motors??

 

 

I do!

[Jono.C]

Aren't 1ggte pistons supposed to fit?

[Sephiroth]

What are you planning for the motor??

 

4k bottom end 3kBP head mild cams and a side draft and I want run som good comp pistons

 

Just want my 30 to be a bit zippy So I thort I'd ask before I start ringing our parts blokes and get recommended pistons buy some one who has no idea

 

I do!

 

I'm interested

[altezzaclub]

I do!

 

Yeah- seriously, if you do, then you should have that better known on here kickn!

 

Do you machine down something larger?

[Taz_Rx]

Yeah- seriously, if you do, then you should have that better known on here kickn!

 

Do you machine down something larger?

 

He works at a place that makes pistons....... no everybody needs to advertise where they work.

 

BTW altezza you might be a bit supprised to find that you can also get Arias & JL (+ more) 4k forgies!!!

[kickn5k]

He works at a place that makes pistons....... no everybody needs to advertise where they work.

 

BTW altezza you might be a bit supprised to find that you can also get Arias & JL (+ more) 4k forgies!!!

 

Thanks Taz. That's about it, learnt a big lesson on broadcasting where I work years ago on another forum.

 

I work making custom forged pistons, here in Vic. The pistons are machined down out of a forged "blank" and are completely custom made(we usually don't have much on the shelf). We also offer a modification service as well(valve pockets, cutting for circlips, resizing and cutting bowls etc. ).

 

Also any custom piston can be purchased from the US suppliers as Taz said. Main benefit of ours is your not waiting 6 to 8 weeks and if they aren't right we are a far quicker turn around and postage isn't cheap to and from the states.

I'll shoot a few links in pm's when I get home. I'm not really keen to be inundated with pm's after cheap stuff.

 

Stu.

[Sephiroth]

Ok so if I understand right 5k engine from what I've been told is basically a 4k with a longer stroke so I can understand being able use 5k pistons but what difference is there are the pistons altezza club mentioned standard 5k pistons or after market ones?

 

Or I can go custom forgies as kickn5k has mentioned and can understand not posting where you work even mates knowing where you work can be a bad thing I learnt that the hard way

[snot35]

Stroke is the same, bore is larger. That's why people put 4AG pistons in. 4K is 75mm, 5K 80.5mm and 81 for 4AG. Boring as far as 80.5mm might be difficult in a 4K block.

 

I don't know if you need forged pistons for what you want to do. People seem to have success with ACL pistons.

Edited February 6, 2012 by snot35

[altezzaclub]

It really depends on how hard a time you intend to give it.

 

I've collected a few stories of guys who have had success in boring their 4K block out to take 5K pistons, but obviously the walls are thinner and if you turbo it or go crazy with compression it will flex. Then again, i think the guy with the 4AGE head on the 4K that hauls 9000rpm used 4AGE pistons in the stock block... They must be tougher than we think!

 

I haven't come across any stories of guys who have bored it to 80mm & had it blow up or anything. The answer seems to be to have the block sonically tested to check wall thickness & position the rebore to get even thickness walls.

 

You get an instant 1500cc instead of 1300, and all the other gear stays the same. if you want something that will go hard like this, get a forged set. I didn't realise so many were available.

 

http://www.youtube.com/watch?v=vu8ahJEsnpw

[snot35]

Oh I don't doubt it's possible, it just seems a lot of mucking around for something that isn't going to be too over the top?

[ke70dave]

all i see is a mild cam, side draft carbies and slighty higher compression.

 

no need for expensive forged pistons there!

 

oem replacements through a reputable company will be fine!

Edited February 6, 2012 by ke70dave

[Sephiroth]

Thanks for the opinions guys and yeah forgies prob will be over the top like I said I just want something that has a bit of get up and go when I need it just want to focus on reliability more than power if I wanted power I wouldn't bother with a 4k

 

I don't give my rolla hard time and being an apprentice mechanic last thing I want to be doing is spending money and time after work fixing stuff I've broken so mite look into those ACL or just get standard ones

 

Thanks for the time and help guys 

[rolla80]

so what i understand of this 5k pistons will fit in the 4k block with a little boreing? but before this get it sonic tested ? any other things i have to do to the block so i wont have any troubles in the future ??

 

cheers