Claying pistons for clearance

[digger]

I laser cut a gasket from 2mm aluminium sheet. It's just a fancy spacer, itvwont Marr the head not that i noticed the stock gasket did. I use it as reference to work out how thick of a mls ( not cheap) I need

[nando]

I don't think there's enough clamping force on the head bolts to "dent" the head around the compression ring.

[e30davie]

Yah ive never seen a "dents" from the rings on any head i've removed, bmw or otherwise.

[zaq123]

my m20 head had clearly visible and tangible marks in it from HG. Maybe I'm too ocd. I can see spacer not marring the head but OEM head gasket isn't all metal

[digger]

was it indention of just discoloration / deposits?

[TobyB]

The only time I've seen a head deformed by the gasket is the
2002 'cutting ring' gasket- it has a ridge in the head side that's
designed to o- ring itself into the head material.
And even that made a gouge not much over.005" deep.

Other than that, a flat gasket just won't hurt the head surface...

...and I just use an old gasket, too. Snugged, but not torqued.

t

[zaq123]

was it indention of just discoloration / deposits?

It possibly was a discoloration......the head was skimmed and for some reason I remember indentations around HG rings....Maybe it was the deck....the deck definitely had some electrolysis pitting/corrosion around the rings before it was resurfaced.

I don't have old HG. So you guys recommend to torque new cheap HG all the way with old bolts to clay it properly?

[digger]

no need to torque the hell out of it IMO but if you have an old set of bolts and cheap HG then go right ahead, i would use a VR gasket or similar of the same thickness. i usually order a VR topend gasket kit and an OE HG gasket (better quality) so there is a spare HG left over anyway

[zaq123]

quick update:

Pistons are 10:1 advertized. I got VR test gasket (+0.3 oversized) and used 2mm solder wire. My P dome to H clearances are in mm...

cyl1 - 1.33 cyl2-1.30 cyl3-1.26 cyl4-1.25 cyl5-1.19 cyl6-1.21

Mahle recommended clearance for steel rods 0.04" or 1.02mm. I'm using H beam forged 4340 rods

I already have STD size OEM gasket but it will reduce recommended clearance to 0.035" on cyl5 with my setup. I haven't checked P to V yet (waiting on the TB parts) but IE/Mahle pockets look deep (I will obviously verify the exact P to V clearance).
Putting P to V clearance aside at this moment.....would you guys recommend to run +0.3 heads gasket with or go with STD one? This build should be capable to run on pump premium gas.

no need to torque the hell out of it IMO but if you have an old set of bolts and cheap HG then go right ahead, i would use a VR gasket or similar of the same thickness. i usually order a VR topend gasket kit and an OE HG gasket (better quality) so there is a spare HG left over anyway

[digger]

Standard, the better squish more than offsets the slight increase in CR