The Complete Engine Sealant Thread...

[Henry Schmidt]

First, there are any number of techniques that have worked for different builders over the years. What I offer here is the techniques we've developed over 35+ years and well over 400 911 engine builds.
Now to the meat and potatoes.
Main bearings* are installed dry on the back with a coat of your favorite assembly lube on the face. We dry film (Moly) coat all of our bearings but that is an option for the builder to decide.
* Over the years we've found that a thin coat of 1211 on the #8 main saddle is good insurance but not necessary if the case/saddle is perfectly round....I've measure that saddle .015" out of round.
Applying 574 to the main webs is for the experienced builder only. You must apply a very thin coat and the case halves must be assembled quickly and with confidence.
Too much glue, too slowly assembled could result in oil pressure diversion.
We still use Curil T on all surfaces prone to movement. Cylinders move with expansion so Curil T on the base gasket is advised but not necessary.

[dannobee]

Dennis, the #8 nose bearing is at the other end, near the crank pulley/fan/alternator.

No sealant on any kind of the backs of the main bearings, except as Henry said, #8 nose bearing. A very light coat of 12 series ThreeBond on the nose bearing. Use assembly lube on the face of the bearings, where they meet the crankshaft.

11 series around the perimeter of the case, but everything must be spotlessly clean and ready to go before you apply it, then carefully but quickly apply the sealant and bolt the two case halves together.

No sealant of any kind on the main webbing, just like it says in the factory manual.

Dow Corning 111 is a clear thick paste, Dow Corning 55 is a white, thin, runny lube. DC111 is the go-to in automotive circles. Use it on the o-ring on the #8 nose bearing. Clean off any excess before installing into the case, and make sure the bearing lines up correctly with the pin.

Use the 12 series in place of the gasket on the chimney stack/crankcase vent. Again, spotlessly clean, OMIT THE GASKET.

[YurkTurk]

I will be sealing the case halves on my 3.6 in the next couple weeks as well, so this thread has perfect

[85RedCarrera]

I’ll be assembling my case halves pretty soon. It’s been 1.5 years since the last post in this sealant thread.

Have there been any further developments/ changes regarding which sealants to use on what, or should I move forward with the list provided in this thread? Thanks for any new info…

[Henry Schmidt]

Over the last 18 months, we have been doing some in-house testing of hi temp Dirko Grey.
So far the results are good.
Elasticity, elongated breakaway and chemical resistance is impressive.
The shear strength is better than ThreeBond 1184 and the tensile strength is comparable.
Pressure @ .080" gap is better than ThreeBond or Loctite 574.

[4kidsno911]

Just curious if the experts can chime in on the amount of time you have to torque the bolts with 574 and the other sealants Henry recommends here. I have heard 15 minutes once the halves initially go together.

thanks! Brian

[efhughes3]

Originally Posted by 4kidsno911

Just curious if the experts can chime in on the amount of time you have to torque the bolts with 574 and the other sealants Henry recommends here. I have heard 15 minutes once the halves initially go together.

thanks! Brian

Why use 574 for joining the case halves, as noted in the list, there are better, much better choices! At least that is how I interpreted the question.

[4kidsno911]

Sorry maybe I was not clear, not using 574 on the perimeter of the case. Using the sealants in the areas Henry recommends. I have purchased his sealant kit and studs from him. The mention of 574 was for the optional section in the middle of the case that has been discussed. I have done a practice run and think I can get it done in 15 - 18 minutes with an assistant.

[mikedsilva]

Originally Posted by 4kidsno911

Sorry maybe I was not clear, not using 574 on the perimeter of the case. Using the sealants in the areas Henry recommends. I have purchased his sealant kit and studs from him. The mention of 574 was for the optional section in the middle of the case that has been discussed. I have done a practice run and think I can get it done in 15 - 18 minutes with an assistant.

If you have all your o rings mounted on the bolts, and all nuts and washers ready to go, along with all tools, then yes, 15 mins is definately doable.

Are you planning to use 1104 on the perimeter of the case? If so, are you planning to apply it to both sides, or just one?

That stuff skins over and gets touch dry VERY quickly.

[4kidsno911]

Yes planning on using the 1104 on the perimeter. Did not know it sets up quickly so thanks for that info. Also just planned on using on one half not both. Not sure I have seen anyone put sealant on both case half’s unless I missed a conversation on that.

Thanks, Brian

[Flat6pac]

Read the instructions on the tube, three bond, Yamaha bond, etc needs to be applied both sides on flanges because the products skin over so quickly it won’t seal to the opposite flange
Bruce

[4kidsno911]

Okay got it. Not read the package yet. Just got my kit from Henry so thanks for the heads up.

Brian

[Henry Schmidt]

Originally Posted by Flat6pac

Read the instructions on the tube, three bond, Yamaha bond, etc needs to be applied both sides on flanges because the products skin over so quickly it won’t seal to the opposite flange
Bruce

We never coat both case halves. There is no way to apply the products to both halves without creating excess squeeze out. Although the TB products and now the Dirko we use both have exceptional break-away retention, too much squeeze out will leave the risk of the excess breaking off ans traveling through the engine.
This break-away residue can easily clog bearings, piston squirters and cam oilers.

The key is to simply set up your assemble parts so when you're ready to put the case halves together there is no delay.
Make sure your case through bolts are ready (o-rings installed and lubed) the #8 saddle have a thin smear of 1211 and your oil pump seals, main seal, chains and rods are positioned for quick assembly.

[4kidsno911]

Thanks Henry

[4kidsno911]

One last question and just out of curiosity. If there is a small amount of squeeze out of the Dirko Grey in the case I would assume this is okay and the motor can consume and flush it out if some breaks off?

Thanks again, Brian

[Henry Schmidt]

Originally Posted by 4kidsno911

One last question and just out of curiosity. If there is a small amount of squeeze out of the Dirko Grey in the case I would assume this is okay and the motor can consume and flush it out if some breaks off?

Thanks again, Brian

Some squeeze out is inevitable. The key is to use a product that resists break-away.
Both Tree-Bond (1184) and Dirko Grey have excellent resistance to break-away as long as the squeeze ridge is minimal.
How do we know? we tested both torque resistance and break-away in a controlled environment.

If applied evenly you should be able to gauge the "squeeze ridge" by inspecting the outside of the case as torquing.

[JoeMag]

I think you're always going to get some squeeze out. You're probably squeezing out 80% of what was put on the surface. Clearly not the experience of Henry... I've rebuild my motor few times, put threebond 1184 on one case half (basically completely cover the one surface). Some may run down inside of case (maybe I applied too much). These few streaks (not large rivers) have stuck to inside of case (if case is very clean, it should, right? the surface is quite rough so lots to bond to). It takes work to get them off when you split case again.

[4kidsno911]

Got it, I did an experiment with the dirko grey on some old valve covers that were not really that clean. Amazing bond

[JoeMag]

Had to apply some 1184 to a location that I wanted to apply fairly accurately and surface not that wide. Decided to put some in a syringe with a ~1mm hole and give it a whirl. ...worked really well. You could get a fairly fine line (better than I show in pic) and not have strings all over the place. Little bumps are bubbles as I was at the end of emptying syringe.