Case perimeter washers

[RockhillMTR]

On a mag case, I know the correct setup for case perimeter fasteners is aluminum washer with nyloc nut. However reading through threads there seems to be some issues with the alloy washers distorting under torque. My Elring gasket set did not come with new washers, thought it would. Is there a known good quality alloy washer that holds up? The Porsche part number 900-031-014-30 reveals either the aluminum style or in some cases a zinc washer. Pelican seems to sell two, the OEM Porsche one and another by Fischer and Plath. One better than the other?
All that aside, my inclination is to use a 8mm steel wavy washer although I did note that for instance Henry only uses those on aluminum case motors. Is there a real risk of distortion of the mag case using a steel washer?
I have no problem using the original style aluminum however I also don’t want to be bolting the case halves together only to find out the alloy washers are crushing and squeezing out and have no alternative at the ready.

[john walker's workshop]

I've always used steel flat washers.

[Flat6pac]

Waves washers are used inside the motor with regular nuts, not nyloc.
Flat steel washers on the perimeter with nyloc and on the valve covers.
Bruce

[Dpmulvan]

Elring use to supply 24 steel slightly dished washers with their kits. I made the mistake of ordering quantity aluminum washers from bel metric and they’re junk. Steel isn’t going to give you any problems.

[RockhillMTR]

Thanks very much for the info guys

[Henry Schmidt]

We build all mag case motors with quality aluminum washers and Nylock nuts.
This combination allows the case to move (mag cases grow when heated) and it maintains the concours appearance.
Most mag cased 911 cars are becoming collectable and maintaining originality is important to many owners. Don't care about originality, we still build them with quality allow washers.
Early aluminum 2.0 cases are assembled with steel wave washers and standard 8mm hex nuts.
Late aluminum case are assembled with hardened steel washers and prevailing torque nuts.
Be careful not to use the prevailing torque nuts on mag cases because they grab the case studs so securely that when you try to remove them the stud comes out of the case (quite often with threads attached).

[stownsen914]

Thank you, Henry - that's excellent information