Thread sealer

[johnbeck]

Today is the first I've heard of using thread sealer. Apparently older small block Fords use thread sealer on bolts that go into water journals and the crankcase. Anyone familiar with when this product is recommended? I'm attaching my flex plate to the rear of the crankshaft and the bolts extend into the engine's crankcase. Anyone use this material? Thanks

 

[T-7ToNewOldB]

You definately need to seal the mounting bolts on the flexplate. Thread sealant not thread lock should be used. Here is what I used.

 

[T-7ToNewOldB]

Thread Sealant



Other types you can use for sure.

 

[T-7ToNewOldB]

Loctite makes a ton of stuff. People refer to loctite as the thread lock only. Don’t confuse the two. You need thread sealant. It can work with thread lock but don’t do it that way. Wrong tool for the job.

 

[T-7ToNewOldB]

This is a quote from Blueprint when I asked a similar question for the 347 I installed.

“Make sure to put RTV sealant, like Threebond 1217H or Permatex Right-Stuff Black, on the flexplate/flywheel points to prevent oil from leaking out. The threads are tapped thru and if not sealed, oil will work it’s way out and you’ll think the rear main seal is leaking. “

 

[DirtDonk]

I wonder what the whole reason for through-tapping the crank bolt flange is? Just convenience for that size of material? Maybe to keep rust to a minimum where just anti-seizing or mild thread-locking the bolts won't do?
Or perhaps it's ultimately a strength thing?

I wonder if it's ever been documented outside of Ford?

Paul

 

[T-7ToNewOldB]

I have no idea. Only guess is they didn’t have enough metal to allow for a safety margin and made it more flexible for bolt length and got them a few more threads on the bolt. But honestly, no idea. Kind of dumb really.

 

[Timmy390]

Permatex Thread Sealant with PTFE is what I use.....It's not let me down yet but then again I've not had to use it on any flywheel or flexplate bolts.....

Tim

 

[blubuckaroo]

Lots of engines have threads that go into water jackets and some even go into oil galleys. I've always used good old Permatex #2 on those. It doesn't harden and make disassembly difficult. Also it doesn't affect head bolt torque.

 

[73azbronco]

Permatex Thread Sealant with PTFE is what I use.....It's not let me down yet but then again I've not had to use it on any flywheel or flexplate bolts.....

Tim

This stuff^^^^ the bomb. Also used on head bolts into water jacket.

 

[ugly74]

I’ve always used this stuff from permatex
https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/

 

[Steve83]

Threadlocker is also thread sealer and anti-seize - it works for all 3 purposes. For bolts whose torque is critical, I wouldn't use anything that lubricates, like PTFE paste - it could allow the bolts to back out, OR cause them to become over-torqued (because the specified torque values are based on the expected friction). For various bolts & applications, I've used red or blue threadlocker, silicone, RightStuff, IndianHead, CopperCoat, Hylomar...

 

[T-7ToNewOldB]

Threadlocker is also thread sealer and anti-seize - it works for all 3 purposes. For bolts whose torque is critical, I wouldn't use anything that lubricates, like PTFE paste - it could allow the bolts to back out, OR cause them to become over-torqued (because the specified torque values are based on the expected friction). For various bolts & applications, I've used red or blue threadlocker, silicone, RightStuff, IndianHead, CopperCoat, Hylomar...

Blueprint was rather specific not to use just threadlocker. Just because it worked in the past doesn’t mean it is the correct choice. As you pointed out on the PTFE paste. I work in an industry that has a much harder time with thread sealing than automotive. Threadlock is never used because it’s failure rate is so high.

Not saying it can’t work, just saying if you are choosing correctly that is not what should be chosen here. Even the manufacturers would say so.


The permatex thread sealant with PTFE is rated for this application though, probably not a bad choice. Haven’t heard of it causing stuff to back out over time, besides conjecture. Though I’m a self-admitted non-expert. Just use the stuff all the time.

 

[T-7ToNewOldB]

Another issue with threadlock is temp rating. Standard blue is only rated to 300F. Just need to be careful on where you are putting it.

For thread sealant that we really care about we use one of the two in the link below. They have methacrylate in them so once you bolt down it continues reacting expanding into any available gaps. Functions as a low strength threadlock as well. Good stuff. But as noted by different posters there are more than a few things that will work.

https://www.gracoroberts.com/home/wp-content/uploads/2016/09/LOCTITE-567-and-577.pdf

 

[Steve83]

Blueprint was rather specific not to use just threadlocker.

What blueprint are you talking about?

I work in an industry that has a much harder time with thread sealing than automotive.

Great, but this discussion is specifically about the automotive application. And threadlocker is effective for all 3 purposes here.

...that is not what should be chosen here. Even the manufacturers would say so.

What manufacturer have you consulted about that? Threadlocker manufacturer?
https://www.permatex.com/products/t...permatex-medium-strength-threadlocker-blue-2/
That says it locks, seals, and prevents corrosion allowing hand-tool disassembly (which is a pretty good definition of anti-seize).

Or did you mean bolt manufacturers? Or the engine manufacturer - Ford?

Coat the threads of the flywheel attaching bolts with oil-resistant sealer and install the bolts.

Nothing saying threadlocker is wrong.

 

[T-7ToNewOldB]

Steve,

Part time job with the FBI??

Blueprint Engines, they work with engines a bit more than I do.

 

[T-7ToNewOldB]

As of 2017 they have built over 200,000 engines. Might be a little more than you or I.

I have nothing more of value to add to this thread. Probably won’t stop me anyway. . . .

 

[T-7ToNewOldB]

And in case not clear, that was a friendly jab. I don’t really care that much what people use. Just passing on what I have been told from people I trust as well as my experience.

 

[Steve83]

As of 2017 they have built over 200,000 engines. Might be a little more than you or I.

Do you think they've built more than Ford? Or have more experience with thread sealants than Permatex?

I'm just passing on facts that anyone can find on the web, or in a Ford service manual, or on the packaging of thread sealants.

 

[bax]

Have you tried the compressive line of flex seal and flex paste products???