Gti-6 Head On S16 Block - What About Pistons?

[cybernck 400 1 Cars]

As the title suggest (and after having read similar topics), I am interested in finding out if S16 pistons need any

alterations done to them, since GTI-6 head has larger exhaust valves? Or is the valve lift of standard GTI-6 cams

low enough to allow the use of standard S16 pistons?

 

Thanks.

[hcmini1989 16]

Some one else will confirm this but i think it should bolt staight on as the s16 pistons falls 2mm below the top of the block so there should be plenty of room allso i think gti6 head should up the compression abit.

Edited August 13, 2013 by hcmini1989

[Stu 18]

I thought the relief in the S16 piston was more than enough? I'd planned on using S16 rods/pistons, MI16 crank in a '6 block with head to make a high-comp engine when mine eventually dies...

[petert 554]

The XU10J4 piston crown sits 1mm below the deck. The pocket depths are deeper than RS but I'm unsure about radial clearance if using a bigger exhaust valve. The lift @ TDC is very similar between GTi6 and S16 cams, thus there is no problem with depth.

[cybernck 400 1 Cars]

Yes, I was on about radial clearance. Aren't GTI-6 exhaust valves bigger than S16 ones?

[cybernck 400 1 Cars]

So, has anyone ACTUALLY DONE this combination successfully?

[welshpug 1,626]

1.1mm larger exhaust, 0.5mm smaller inlet,

 

couldn't comment whether there is a large enough radius to the valve cutout but there seems to be plenty of meat to the piston to allow more clearance to be added, would only need 0.55mm adding to the radius.

[petert 554]

So, has anyone ACTUALLY DONE this combination successfully?

 

A great opportunity for you to measure it all up accurately and post the results.

[cybernck 400 1 Cars]

Not really, as I don't have an S16 block to try it on. On the other hand, a guy who wants to buy my GTI-6 head does,

but I wouldn't sell it to him (and he wouldn't buy it either) if it doesn't fit for sure. I've read numerous posts

on here and the 306 GTI-6 forum that it supposedly fits, but it all seems to be pure guesswork.

[welshpug 1,626]

The block is the same, pistons have plenty of meat if machining is required, why not?

[cybernck 400 1 Cars]

Because the question here is if they fit without ANY alterations, as if it was a GTI-6 bottom end instead.

[welshpug 1,626]

couldn't tell without measuring the valve relief radius!