Exhaust stud thread sealant?

[okieflats]

I think those "all-thread" studs are just a bad idea for several reasons. For one thing, when you remove the nut, the stud is supposed to stay in the head. If you're using all-thread it's likely the whole thing will come out. With the other type they have the effect of being jammed in there and will tend to stay.

[OLD MAN]

I think those "all-thread" studs are just a bad idea for several reasons. For one thing, when you remove the nut, the stud is supposed to stay in the head. If you're using all-thread it's likely the whole thing will come out. With the other type they have the effect of being jammed in there and will tend to stay.

Agreed - vise grips till they are "TIGHT". Just saying.

[320iAman]

I use stainless steel nuts on exhaust and intake studs and have had no problems installing or removing them, Stainless steel nuts do have one catch they have torque threshold that's not as good as hardened nuts, yet the torque on the exhaust and intake nuts is not high 22 to 24 ft lbs which is within there torque threshold, so all is good. I had a leak like Amarino, used stainless steel nuts and lock washers and LM 508 antisieze , no leaks any more, they do loosen up over time so they should be checked from time to time. As too length of the studs so long as they are not too long and that they lock into the cylinder head threaded holes and have enough room left after the gaskets and manifolds are installed to put a nut and washer-if you like on securely up to torque-it makes no difference at all functionally or looks wise.

Randy

[okieflats]

I like the idea of these steel lock nuts for this, but i have never actually used them here. I have used them other places. I call them "pinch nuts" because they pinch the thread of the bolt they get threaded onto.

[autox320]

Stainless(rolled threads) with steel (cut threads) on exhaust is always a bad idea. It will gall and eventually bind. When it does happen ends in cutting or drilling. If ever had to drill stainless would understand; that is always engraved in my mind. Stainless is weak and yes like BMW's crappy copper factory nuts will loosen over time.

Best setup I've found is pic'd above. I use it on all my cars and never again lost a stud. We don't use washers cause it allows the nut to have more "bite" not to vibrate turn out. Washers spread the clamp load lessening it, and also allow spin. Same concept is true with the rocker arms we use higher grade steel nuts for the pinch clamping and no washers. The eccentric doesn't have to be tightened as hard for the same clamp load keeping from breaking the rocker under stress. The higher grade nuts also don't wear like the factory over time.

Been through this enough times that I just stick to what works. Nothing worse than redoing a job multiple times over it's lifespan. When pushing it hard it's whole life, replacing exhaust studs and nuts becomes annoying taking too much time better spent beer drinking.

[320iAman]

It depends on the quality of the stainless steel, quality stainless steel is used in jet engines, turbos from the factory and so forth, there are several grades of stainless, mine were not cheap, I hand tightened the nuts with open end wrench and there is no leaks what so ever, in fact after 6 mos it was only the 1st and 4th nuts on the exhaust side that needed to be cinched up , on the intake side they have been tight for many years since installed..

Randy

[autox320]

It depends on the quality of the stainless steel, quality stainless steel is used in jet engines, turbos from the factory and so forth, there are several grades of stainless, mine were not cheap, I hand tightened the nuts with open end wrench and there is no leaks what so ever, in fact after 6 mos it was only the 1st and 4th nuts on the exhaust side that needed to be cinched up , on the intake side they have been tight for many years since installed..

Randy

Understood Randy. Believe me I get to hear more than I care about stainless grades cause my bro constantly reminds me being a avid sailor living on his boat. I do laugh at low grades especially when some people are confused still attracted by a magnet.

Point on the metal top locks and proper sealed seated studs is never lose a stud. Never ever had to re tighten mine again which was something we always checked after each event. Haven't had to do it in so long it has been forgotten. Until I see one of these threads I'm reminded how much bs it was laying on my back under a car swapping studs or double nutting to put back in. Especially on a more problematic S14 with large euro 50/50 headers. The room for a wrench or socket is ridiculous. Broken ones were a nightmare. Broke a few very high grade stainless ones in my S14 head after tracking it. Thought the "kit" would last forever but the truth is like many aftermarket garbage. Story short on that I sent the head to the one guy I trust in the US, that ported it for me to DTM spec and prayed he could remove them. He got them out and I will never use stainless again. Another incident was the header flange was studded with stainless hardware once. Very choice words once cut off wheeled the nut end thinking in the clear, only to have to still drill each stud out where it was broken inside the opposing flange on the header. Laying on back with drills took more than a 6pk and days of choice words to remedy that situation. POS as Dad says handing me beers and grinning (Plain ol' steel) and never look back. Anti seize if want to avoid rust but steel always comes off for us.

[320iAman]

lol, marine grade , I use marine grade when I can find it, I use marine grade heat shrink as it has an adhesive that seals to the cable insulation and to terminals ends, better than non adhesive types of heat shrink for wiring its resistant to salt water, water, coolant ,oil , air , ect. Cheaper grades of anything basically will cause problems down the line, that's not to say someone didn't pay for it-sometimes items are just not "good quality". I could find a more permanent solution yet these BMW's are labor intensive , service 2's every 3 months and service 1 every year as set up by BMW, I like to keep after it, these cars are for people who like to wrench or pay someone else to check them every 3 months--the stock ones that is.

Randy

[amarino]

Thanks for the insight everyone. Finally got everything buttoned up today and went for an extended test drive. No more leaking and smoking it seems. Wil re-check the torque tomorrow once it cools down and again in a month. I ended up only using the Permatex 59235 High Temperature Thread Sealant.

IMG_20200208_185443.jpg2020-02-08_203704.jpg
The stain under the #1 plug wire is me being too lazy to get the manifold spotless before re-installing. Will keep an eye on it.

Also im leaving off the bolt-in heat shield for a bit to more easily see if the studs leak now. Also its just caked in thick oil / grease and needs a good scrub to get it clean.

[320iAman]

I checked my sealants I have and I have the same sealant Permatex 59235 with Curil T, Hylomar Blue, Liquidmoly LM 508, Threadlocker Blue, High Temp Thread locker Red, Permatex HT Copper and Blue cant have enough thread lockers, gasket makers, and thread sealants. I had leaks in oil pan gasket & bolts and timing chain covers gaskets when using Ultra black after about a year, switched to Curil T and its been many years now , no leaks, finding the right sealants, gasket makers, and thread lockers is an adventure, lol.

Randy