4g63 dowels for cyl head studs

Any of 4g63 guys using those dowels for cylinder head? They are going under the head stud washer and they are preventing cylinder head casting from deforming when high torque is applied to the head studs.

Here is the link for them:

https://www.tmzperformance.com/shop/tmz-performance-dsmevo-shouldered-dowels/

Never used them on my applications and never heard of anyone using them...

I have never used them also but I was reading on evolutionm.net forum that people are using them with good results. When you use high torque on the head studs, the alloy in the head will crush and bow but it is also depends what washers are used. I machined washers so they are as big as possible to fit there and I hope aluminum casting will not crush. I actually crush and bow alumium casting on one cyl head but it was on the head that used small diameter washers and it was torqued to 100lbs.

The idea would seem to be to stop the ability of the aluminium under the washer to be displaced into the hole area.

The problem is that these also reduce the potential area under the washer head. I'm not familiar with the OEM washer diameter - if they're significantly larger diameter the trade-off may be worthwhile, though?

You said you've machined larger diameter washers, already, assuming they've reasonable thickness and are steel (preferably hardened), you may have the ability to make some yourself with the larger diameter.

Depending on the hassle, and perceived need, you may be able to use these with larger, hardened, washers machined to allow these to be a close slip fit through their centres.

Oh, I have seen mention of them used elsewhere, especially with 'soft' castings, usually pressed into the castings.

Every one I know is using larger diameter washers. I use regular ones from ARP despite having 136 Nm of torque applied.