Teflon in a tube, I use permatex.

 

Use Teflon in the bottle permatex brand.
https://www.amazon.com/Permatex-80632-Thread-Sealant-PTFE/dp/B000HBNTGY

 

I was worried about the temperature rating on this Jeb. 300 degrees only.

 

The only sealant that I have had zero issues with is The Permetex silicone
Ultra series....I have had issues with the various teflons and other random
Thread sealers and I will tell you why I think this is.

In a Engine application that is using an electric water pump the water pressure
that the Head bolt/Stud threads see's is going to be far less than what a engine
that is using a belt driven pump will see.....I have measured block Intake
manifold crossover pressures of 65+ PSI which means block pressure will be
higher when using a belt driven pump.....I have read of others that have been
even higher than what I saw.

Most of my experience has been with belt driven pumps and It is no fun
removing all of the studs with the engine in the car to remove the teflon
sealer and repalce it with the silicone as I helped a friend do one time.

Like I said zero issues using the permatex ultra, I usually use the Hi temp
copper ultra since I always seem to have it on hand.....clean the threads
with brake clean- carb cleaner seems to have some oil in it
and use a small screwdriver to wipe some into the block threads and then
put some on the stud threads and roll your finger around them spreading
it evenly....then screw the studs in to the block and I prefer to let it sit
overnight as it makes cleaning the excess bead that builds up around the
stud easier.

Lots of opinions on this But I feel the amount of water pressure your
threads will see plays into this. Best wishes.

https://www.permatex.com/our-brands/ultra-series/

 

If they go into water, use silicone, everything else will leak.
If they're dry, just some light oil.
If into aluminum, anti sieze.

 

Interesting to learn that silicon works better than actual thread sealer. This is good news to me. I used to only use ARP 9904, that costs over $9/1.69 oz. Cheaper to buy a tube of ultra copper and one less thing to keep on the shelf. Nice!

 

Interesting to learn that silicon works better than actual thread sealer.

Typical thread sealers are made for use with tapered threads. The taper forces the sealant into the voids of the fittings, forming the seal.

 

if you go to the dart block you may not need it. I thought dart uses holes that don't go into coolant?

 

Great point. I have purchased the Dart block, but its at the machine shop. I only got a quick look at it. That will be great if they don't go into the water jackets.

 

Any major brand of thread sealer/anti-seize product will work fine. Make sure the threads (stud and block) are clean and dry. Use a thread chasing/cleaning tool to clean the threads, not a tap and die set. Apply the thread sealer very sparingly on the stud threads and install them in the block. Hand tighten only! Thread sealant/antiseize should be used on all studs, even those that are installed into a blind hole. Apply the product very sparingly to the bottom 1/3 of the stud threads, if too much goop is in the hole it will cause a hydraulic condition when the studs are installed.

 

when i was putting my small block together i had the same question and the most common and best answer i had found was permatex #2 non hardening thread sealant. used it and havent had any issues!

 

A lot of thread sealants have ptfe-teflon to help tighten a tapered fitting, I've always herd it was the taper that sealed npt stuff but some materials do need something to fill in small voids. Not long ago I found this out as I used the thicker type teflon tape and still had leaks on some brass plumbing, also how I found out I need to use a non-teflon sealer on some materials. I know you don't wanna use threadlocker cause it expands and could start a crack.

 

Forgot to ask, How many use permatex high temp thread sealer?

 

Never tried it but they do say it is for head bolts and studs that go into fluids.

 

Years ago I used this all the time.

 

Silicone like right stuff is fine for a stud, not for bolts. Since the nut is torqued on a stud the silicone does not affect the torque, a bolt on the other hand will. Since silicone is slipperier than thread lubes and thread sealers it will affect the torque. Over the years many a thread was pulled out on a deck from the use of silicone.

 

Silicon goop should never be used for thread sealer nor thread lubricant.

 

I use Permatex #2 non-hardening. Seems to work and never had any issues.
Thanks Rick

 

I've used this with no problems https://www.summitracing.com/parts/lct-1158514