Alternative exhaust manifold studs and nuts

Post by **FireFox31** » 09 Jul 2025, 01:27

I'm hoping to replace my rusty exhaust manifold studs and nuts, but it would be "nuts" to pay $120 for the Volvo branded parts ($6 each x 10 studs + nuts). I'm hoping to find high quality alternatives at McMaster Carr or elsewhere.

Does anyone have a 2000 V70 exhaust manifold stud, part 982667, which they could measure the length for me. I believe these are shorter than the other studs used around this time. FCP said the nut is "M8 x 1.25 distorted thread lock nut".

What kind of finish, grade, and material should I get for high quality hardware. Black, anodized, stainless, galvanized? Thanks.

Post by **abscate** » 09 Jul 2025, 04:10

I used these on my multiple cylinder head jobs over the past five years…..naturally with the MVS Amazon link…

https://www.amazon.com/dp/B078WS5MJZ?re ... tle_1&th=1

Oly850 · Post by **Oly850** » 09 Jul 2025, 13:46

May I present to you the ARP head stud kit. The hip kids making Subarus into 1000hp rally dragsters use them and they will absolutely never fail you. Expensive you say? Well good lord yes, but who cares, really?

https://arp-bolts.com/kits/arpkit-detai ... ordID=4967

Oly

Post by **FireFox31** » 09 Jul 2025, 13:57

Interesting, thanks. Amazon says those are 35 mm long. I found one post on MVS listing the studs as M8 x 1.25 x 50 mm long. The FCP picture shows them with ~38 threads, thus 50 mm. McMaster-Carr has 18-8 stainless for $3.22 each, or zinc-plated low strength steel for $8.50 for five.

They also have studs with an unthreaded center, but the threaded lengths vary. What thread length is needed to fit into the block and hold the manifold nut?

Oly850 wrote: 09 Jul 2025, 13:46 Expensive you say? Well good lord yes, but who cares, really?

Thanks, but the car they're going on cost that much.

Oly850 · Post by **Oly850** » 09 Jul 2025, 16:53

Touché.

Oly850 · Post by **Oly850** » 09 Jul 2025, 17:39

In all seriousness, +1 for stainless with these electroplated copper nuts. They torque down just fine, and stay put but taking them apart is much easier:

https://a.co/d/fYZURFS

Post by **FireFox31** » 09 Jul 2025, 23:22

Thanks. I'm always looking for more corrosion resistant fasteners. But the exhaust manifold is an extreme environment. Can I use stainless there due to heat and physical stress? Can anti-seize be used there (is it copper for high heat)?

Post by **abscate** » 10 Jul 2025, 03:23

By far the worst work will be getting the old ones off. Geromino has a 10 year life expectancy so anything you use will last that lifetime.