Jump to content
HybridZ

Where to get better intake and exhaust studs?


Guest 73Turbo240z

Recommended Posts

Guest 73Turbo240z

Alright were out here in the shop assembling my L28, next phase is the intake and exhaust studs on the cylinder head, is there a better than OEM offering, perhaps stainless? ARP? or some other variant that is better about resisting rust, siezing, etc?

 

or do i just need to go order all new hardware from victoria british?

Link to comment
Share on other sites

Guest Phil1934

I'm not sure what's out there for metric, but even for headers I buy brass exh. manifold nuts. They save the bolts and won't seize.

Link to comment
Share on other sites

Guest 73Turbo240z
http://www.mcmaster.com

 

Page 2979 Threaded Studs - both ends threaded (thread lengths different) - Metric black oxide coated - 125' date='000psi strength.[/quote']

 

nice, anyone have the dimensions for the stock studs? or do i need to go buy some calipers..

Link to comment
Share on other sites

Guest 73Turbo240z
ARP has them in their sport compact section. M8 X 1.25 X 45 should work. They are stainless steel with nuts and washers. You should own a caliper anyway if you are working on your car.

 

got a part number handy? cause a search of ARP's website yielded that the only M8 bolts they have are 1.75 and 2.000 in overall length...

Link to comment
Share on other sites

manifold nuts/bolts tightening tourque is at 10-13 foot pounds for size 8m and 25 -36 foot pounds for size 10 m fasteners... not much torque for the average manifold fastner but the exhaust fastners get hot and could lose strength over time. Stainless steel or black oxide should help with corrosion problems and grade 8 would almost be unbreakable for manifold applications, Brass exhaust nuts and black oxide studs rated at 125,000 # as previously suggested maybe an excellant combination from a reputable or reliable source

Link to comment
Share on other sites

Stainless Steel is not such a great solution for holding the exhaust manifold on - it expands and contracts too much with temperature changes and will work its way loose. Also, I'm not convinced that the grade 10.9+ ratings will help that much, as the heat treat tends to get 'cooked' out.

 

Honestly, I've not found anything that I like better than the OEM studs with prevailing torque nuts for this - the OEM studs have a longer 'head side' than the aftermarket ones did (at least the ones that I was able to come up with), and get much better penetration into the head. Also, if you can locate "Jet" or "Kay" style nuts (racer wholesale, pegasus, truechoice, etc) , the hex head is smaller, which allows far better access for tightening.

Link to comment
Share on other sites

Also, if you can locate "Jet" or "Kay" style nuts (racer wholesale, pegasus, truechoice, etc) , the hex head is smaller, which allows far better access for tightening.

 

I tried Jet nuts with a complete stud setup and every time I pulled the manifolds the studs came out while backing out the nut. I tried "loosening up" the Jet nuts by running them up and down 2' lengths of all-thread but that didn't work either.

 

I eventually went back to nuts and lock washers. I always had to have extras because I would lose a couple every time I removed the manifolds. If I ever move out of my shop I'll probably find 30lbs of nuts and lock washers under cabinets and behind equipment.

Link to comment
Share on other sites

Been there; lots of poor quality studs out there. Stay away from the CAD plated, copper colored ones; they will strip easily. Use locktite on head end and alway use antiseize on nut end. I like SS locking flange nuts and never had a stud back out. No need for Grade 8 or 10 on high heat application; too brittle and may snap.

Link to comment
Share on other sites

  • 3 months later...
Guest bastaad525

at some point someone replaced all of the studs on my L28ET head with bolts, and I am happy that they did.

 

That being said, I do want to get new bolts for whenever I get around to replacing my manifold gasket... what should the bolts be made out of and what rating or whatever number should I look for for the exhaust in particular?

Link to comment
Share on other sites

I just used some Saturn exhaust studs and nuts (92 SL2 twincam engine) to install a MS header on a customer car. Perfect length with cool little inverted Torx heads for ease of install. Black oxide coated. Nuts are 13 mm class 4 (metal self locking) and will probably pull the studs out when removed many years from now but will not loosen up. Would have rather had 12mm heads but I was able to get to all except the inner nuts on #1 and 6 with a socket and the two I couldn't reach with socket were accessable to a wrench. Worked great. Got into locking portion of nut about 2.5 turns before tightening to the manifold. Full retail at Saturn: studs .99 nuts .79. I ordered 11 of each and did all locations on manifold.

Was going to buy studs from Pallnet but he got into a Hurricane right about the time I needed them. I am sure his stuff is higher quality than the Saturn parts but the Saturn stuff fit far better than I expected. Was cheap and easy to get also.

Link to comment
Share on other sites

Let's see if this helps out a little. I just got off the phone with ARP, regarding the issue of SS vs CrMo exhaust stud/bolts. ARP uses a propietary 300 series SS for their studs and bolt as well as their head and rod studs/bolts. It has a 170,000 psi tensile strength and is impervious to extreme heat and corrosion. They also offer a 8740 CrMo version of the exhaust studs/bolts which has a +180,000 psi tensile strength. These have a black oxide finish and provide much less corrosion resistance. I ask their tech guy if they recommend any special thread prep, when installing exhaust studs or bolts......their recommendation is to first insure the threads you intend to install the studs or bolts into is cleaned well. They use a molly lube or 30wt. oils for installation and do not use a thread locking agent. So, I ask the guy which material is better for the exhaust studs od bolts? I'm told either material is good, but if you want corrosion resistance go with the SS. I also asked him about the thermal expansion characteristics between the two materials and he came back with....Well, we use the SS for head bolt/stud as well as rod bolts, which are much more tolerance critical (as far as thermal expansion) than exhaust studs or bolt. So, here it is staight from the horses mouth (ARP). Draw your own conclusions on which material you think is best for your application. Me, I've been using their SS exhaust studs for years without any issues...but that just me. Hope this helps a bit?

Link to comment
Share on other sites

I will not disclose the maker of the studs I buy for my kits but I can tell you this.

 

If there is a problem with the grade then a fist full of major car makers will have some serious problems.

 

I don't sell anything without serious testing being done by myself and/or the manufacturer.

 

Thanks fellas.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...