Topic: Stainless flange nuts

[Register]

Any issue using stainless steel flange nuts to torque down cylinder head?

[pjlogue]

Shouldn't be any problem if you are talking about the nuts that go on the cylinder studs.  If you are talking about using stainless bolts going into aluminum then you need to be sure you use plenty of antiseize on the threads.  Not sure why you want to use SS nuts in a place that is bathed in oil unless you have a ton of SS nuts you want to use.

-P.

[Register]

Yes nuts for cylinder studs.

I just happen to have some and the originals are chewed up

Thanks

[slikwilli420]

Make sure they are high grade like ARP and not hardware store grade.

[Register]

A4 DIN 6923

What ever that means

[Register]

means this apparently

A4 Stainless is often referred to as ‘Type 314’, and contains the same 18% chromium and 8% zinc, but with the addition of 2-3% molybdenum which provides the extra resistance and gives the ‘A4’ or ‘Type 314’ grade. A4 is often also referred to as ‘Marine Grade’ and has the very highest level of corrosion resistance. Such is the grade of A4, that it is used for surgical implants and used for underwater installations.

[slikwilli420]

Good corrosion resistance but I wouldn't bolt a head on with them. Get quality nuts from ARP.

[madmtnmotors]

Good corrosion resistance but I wouldn't bolt a head on with them. Get quality nuts from ARP.

+1

[DaveBarbier]

Is it really an issue? These heads don’t see more than 20lb/ft.

[calj737]

Is it really an issue? These heads don’t see more than 20lb/ft.

If you are re-using the stock studs, maybe not. But I surely wouldn’t. 18-8 stainless isn’t terribly strong in tensile strength so the threads are more likely to release than a Grade 8 would with 18-8 being more comparable to Grade 5.

[Tracksnblades1]

314 stainless has TSI strentgh of 95-100 (95,000-100,000). Yields @ 50,000.  Rockwell hardness of b85.
I would be more concerned with its thread engagement percentage, when using it on a dissimilar alloy stud. Some aftermarket studs have rolled threads. Since 314ss has good higher heat performance, I would check that the thread engagement hasn't been modified for such as well.

Grade 5 TSI 105 (105,000), yields @ 81,000, Rockwell  c24-c25.

Rockwell b and c use different standards. Some comparison charts indicate
C23-C25 on the C chart is similar to B100 on the Rockwell B chart.

[Register]

Reusing stock studs, threads are perfect.

Tracksnblades1 - thanks, but way beyond my level of understanding

[bryanj]

Here in UK if you buy flanged nuts of any material the underside of the flange tends to be serated to stop vibration lossening them I would not use this type for head nuts.