Exhaust manifold studs

[CaptainAhab]

I am replacing my head gasket shortly. I am planning to replace the exhaust manifold nuts with brass or copper items. Can anyone tell me what thread I should be asking for?

[93240se]

Try this link, or alternatively give Simon a call at Brookhouse


http://www.volvoclub.org.uk/faq/Exha...ds_Replacement



Parts. Buy ONLY Volvo OEM parts for these applications. They are specially treated to resist heat and corrosion. For all B230 engines, the exhaust manifold nuts are Volvo p/n 948645; washers are p/n 949362. For non-turbos, studs are p/n 953049. For the turbo engines, the studs are p/n 953048. If you need the nuts for the turbo-to-manifold stud, the p/n is 977209.

Removing the Existing Nuts and Studs:

Applying Penetrants. [Response 1: Onkel Udo] Spray the studs using penetrating oil repeatedly (PBlaster highly recommended) for the preceding days. When removing the nuts, use a quality six-point socket. One trick for breaking them free is to first tighten them a very slight amount just to get them to "crack", then apply more penetrant and rotate counterclockwise to remove. When you reassemble, use nickel-based high-temperature antiseize compound on the new studs. [Jay Simkin] To ease nut removal, after several drenchings with PB Blaster I wire-brushed the end of each stud that protrudes past the nut. I used a Dremel and a stainless steel brush. Once the nuts "cracked free", wire-brushing the stud ends eased nut removal: the nuts did not have to push aside 20 years of corrosion on the exposed stud ends. Easing nut removal cut the risk of shearing a stud. [Phil Connell] I've started using beeswax to loosen rusty nuts/threads. Heat up the stud with a torch, then press a chunk of beeswax on the end of the stud. Capillary action draws the melted wax into the thread ands makes removal a breeze. I get the chunks of beeswax off ebay for very low prices.



regards, Richard.

[Dirty Rooster]

Originally Posted by CaptainAhab

I am replacing my head gasket shortly. I am planning to replace the exhaust manifold nuts with brass or copper items. Can anyone tell me what thread I should be asking for?

I had no idea there were any different threads!

Did I make a mistake in using copper nuts from the garage's tray of stock manifold studs and nuts?
The OEM Volvo ones coming off were hideously rusty and jammed on : surely that can't be ideal, even if recommended by Volvo themselves ...

[Clan]

the volvo studs are the best quality , very hard and strong . If you want better nuts use the titanium ones used to hold the turbo to the manifold .. expensive but super quality .

[CaptainAhab]

That's great info guys, very much appreciated. Love the beeswax idea, I'll give that a run out if the plus gas fails.

Rooster; there are a great many different threads. Although most you will come across these days are UNF/ UNC (Unified thread) there are still many variances in threads per cm etc. Massive subject.

Thanks again guys.

Cap

[Stephen Edwin]

Mine came off quite easily. I have replaced them with brass nuts from my local tool shop, and thick washers. If OEM nuts are designed to resist corrosion, the design is a failure? The titanium nuts sound interesting.

I re assembled with copper based grease. Nickel based sounds interesting.

If they have not been re-assembled with a serious grease, then I reckon keeping an occasional small application of say Plus Gas on those stud threads is a useful part of preventative maintenance.

[CaptainAhab]

While I agree with all the removal tips above, and will have a nut splitter (love that name) on hand for any that are too far gone, I am still mulling the replacement issue.

My car is a non turbo, so I dont see the nuts having to take too much in the way of shearing forces. Skandix are selling copper coated steel items which I am leaning towards on the basis of easy removal later on etc...

Also, they are only 75p each, so if they fail I'll go for the OEM HC ones.

Thanks again guys, I'll keep you posted.