Earl Brown! Rear Main Seal Install

[Steve Wood]

Earl, I have been waiting for some magical being to come along and do the rear mains on both my Buicks.  Beginning to lose hope and am thinking about sucking it up and doing it myself.

I see several ways suggested it can be done, but the more I read, the more questions I have.

I started with http://www.gnttype.org/techarea/engine/rearmain.html as a basis.

Okay, assuming it get the old cap off and clean it up so it's oil-free, then:

Using a rubber seal (dry according to Fel-Pro) and installing it cocked .

Now my questions begin.

Some say to apply a paper thin layer of anaerobic sealer to the mating surfaces, install the cap, and torque it down to 100 ft lbs, then inject the side cavities of the cap until the sealer seeps out.  YET, others say, lightly snug the cap, then inject the sealer in the side pockets til it's seeping out, and THEN torque the cap down to the 100 ft lb spec.

Okay, that suggests several questions.  First, torque it down it down all the way before filling the side pockets, or fill first, then torque, and inject some more in case there is room for more.

Second, what are your choices for sealer.  I was thinking Right Stuff because it is applied like a caulking gun.  Anaerobic sealer on the face or something else?

In other words, give me the Earl Brown procedure for a leak-proof future in details an old man can understand.  A picture where to apply the sealer between the cap and block would be nice as well if you have such.

Appreciate it!

[TexasT]

Have you a wet coat hanger ready to stick up there to get any air bubbles out of those side passages.

[Steve Wood]

 

[Steve Wood]

One of the reasons I ask is the picture posted by TurboDave at the bottom of this page link  https://turbobuick.com/threads/rear-main-seal-the-right-stuff-grey-or-black.449079/


He shows where he put some silicone in yellow and the red shows where he put some anaerobic sealer.  I don't understand what good it does to put the anaerobic in the main cap register area.  It's in front of the rear seal and it seems that where he put the yellow is where sealer is required as the stuff shot into the side pockets may not reach this area...

[Norm340]

Here's a couple of videos from Steve V that might help a bit?


https://youtu.be/r0an5H4iKps


https://youtu.be/wB2DJqUqDMs


I've got to do mine one of this days (yrs) so let us know how it turns out for you please and thanks. 

[Steve Wood]

Norm, one of those was what added to my confusion as he left the cap untorqued until he shot some silicone into the pockets....I have to reread Paul's write up as he may have suggested the same.


It's always dangerous to consult more than one guru because confusion always follows.  Hence, I asked Earl for a tie breaker



I am hoping I find something like pan gasket leaks as both of my cars are leaking like crazy and I see oil everywhere...t hey have been doing so for a long time, I am just beginning to be irritated


Thanks for the links...

the second one showed what I wanted to see and it agreed with my preconceived ideas so it was even better! 

Now, I am waiting for Earl to mention Yamaguchi #9 as the preferred sealer 

[Tim Hensley]

That Yamaguchi is good stuff for sealant that is a machined surface. It won’t make the cap stand up off its mating surface and give extra bearing clearance like RTV. I’m no guru my vote a dab of RTV on seal ends and Yamahabond on cap torque cap tonight fill the end tomorrow with  a RTV product tomorrow Earl will probably a a beer break in there somewhere.

[wmsonta]

It won’t make the cap stand up off its mating surface and give extra bearing clearance like RTV.

Do people put sealants between the main cap and its register? I have done a number of rope main rear seals, but have not done that.
Hell, I am reasonably sure, I never used silicone sealers. Not sure it existed.

[Steve Wood]

Earl will appear fresh from his latest porn production and proclaim the correct thickness of application to be 0.735 molecule

[earlbrown]

The way I do it is to put the rubber seal in slightly cocked. One TINY dab of Yamabond on the parting faces of the seal.   Then a one molecule thick smear of Yamabond across the back of the block to seal the main cap.

Once the cap is toqued, I shoot The Right Stuff in the side cavities, and jab in some twisted safety wire to act as rebar since I never own any pipe cleaners.    (odds or that step is unnecessary since The Right Stuff is so badass).


Then I put a blob of clay on the aftermarket pickup tube with no trap door and put the pan in place with no gasket.   After I realize the curtain area of the pickup is waaaaaay greater than the tube ID, I bust out the big wrenches and try to straighten out some of the S-curve from the pickup tube without pinching it (while keeping it square with the pan).   

Once I'm happy with the gap, I safety wire the pickup tube bolts, Right Stuff the pan in place with no gasket, and finish drinking beers.


  As as added 'unnecessary step, I started putting a one molecule layer of Yamabond on the OD of the rear main seal.  A few years ago I got my ass handed to me by a 327 that had a loose fit in the register.    That probably won't be an option if you're rolling in a new seal on an assembled engine.

[Steve Wood]

thanks, Earl!  I figured you would use Yamabond somewhere-even if in tiny proportions


Wmsonta, the consensus of opinion today is that most main seal leaks are not around the seal, but more likely, and in greater volume, at the parting lines of the cap with the block.


If you note in the last video provided by Norms40, he (steve v) shows how the sealant seeps out of the seams and the effort he goes to in order to leave no void unfilled.  Kinda like Earl's movies, one might say.


In the video he uses the same silicone he is forcing into the cavities on the bottom of the cap.  This is where Earl uses a thin coat of Yamabond #5, I believe.  Operative word is thin.


The guy in the video leaves the cap untorqued to help the the silicone fill the cracks, voids, what ever.  Some do this.  Earl torques it down and then forces it in.  Seems to be about 50-50 from what I can determine.


I think one would like to get it right the first time because it will be a lot more difficult to break loose the second time.


The sealer of choice seems to be either Right Stuff black or gray Or black ultra silicone both of which are more oil impervious.  Right Stuff seems to flow a bit better and you can get it in a pump that makes it easier to push in the pockets and surrounding seams.  (Further reading suggests that the Ultra is a bit thinner than Right Stuff so it should flow easier)


It's important to run a wet wire or such into the pocket and eliminate air pockets plus force the sealer into any spots it had not gone when filling it.  Then refill it with some more of the sealer.


The FelPro rubber seals come with a couple of inserts to force into the pockets after filling them.  I think this is to try to force the sealer further into the voids.  I don't think many use them and do it as shown in the video/described by Earl


Now Earl positions the pick up closer to the bottom of the pan than it probably came from the factory.  It's just good engine practice and I am sure you have done that many a time.  Don't bet on me doing it 


He also glues the pan on instead of using a gasket.  It won't leak that way but I gave my plasma cutter to someone and I am not going to make my descendants use a sledge hammer to break the pan loose.


The rubber gaskets from the factory are a son of gun.  They are made to be torqued to 96 inch lbs  (actually the book says 88 inch lbs) and if you torque them to 100 inch lbs, they will probably cut and leak like a fiend.  Also they tend to come loose with so little tension so hold them so blue locktite is a good idea.


I would probably use a cork style gasket -If I misspoke some where above, the guys will correct me

[earlbrown]

After splitting 3 rubber pan gaskets in one day and using The Right Stuff on try #4, I'll never use a gasket again.    You can also peen down the titties on the pan to gain a little pickup to pan distance.

I have pan gaskets on my eBay story and I always feel kinda off when I mail them out.


Pulling the pan after using that stuff really isn't as bad as it's made out to be. The 20 bolt pan has a very strong rail, so a wedge in the corner will pip the pan off in one big jump.  The Right Stuff isn't stretchy like conventional RTV,so one you overcome it's adhesive limit, it comes off swiftly.


The cool thing about Yamabond4 is how thin it is (5 is thicker and more gooey).   It actually has a learning curve to use it. It almost pours out of the tube with VERY LITTLE squeezing.  After you're done, the tube has to be snatched away from the workpiece quickly.  Otherwise you'll have a 10' flying spiderweb that will find your face or armhair.   I don't worry about it screwing with my bearing clearances or taper when I put it under the main cap either.  It also doesn't give a crap about oil, gas, or water. 

As another awesome use, is smearing it around water ports on the head and deck when using MLS gaskets without copper coat.  It's also what I use to seal head studs.   And pipe threads if I'm not using teflon tape.

Back when I was a teen my TVR used to be bad about coolant eroding way my composite head gaskets at the water ports. When the material was removed at the fire ring, they'd collapse and hydrolock the engine when I cut it off.  I speared some Yamabond4 on the ID of the holes and stopped that problem dead in it's tracks. It's still like that today.


It also works to 'rig' up a leaky O-ring seal against a pitted bore. 4 is thin enough to get out of the way and not make things worse, but still fill in scratches and pits in the bore to make a seal.   I don't recommend that, but it has worked for me in the past.


It's truly amazing stuff for what it is. It's a shame most people have never heard of it.

[Steve Wood]

Okay, I thought 5 was the thinner one...so 4 is the one to use if I understand correctly.

[Steve Wood]

I watched a guy split two in a row.  When he started to do the third one, I told him that he was using too much torque.  After an argument, I bet him $25 that he was wrong.  I won the money and the third time was the charm.  You might have convinced me to give it a shot.  There is so much oil everywhere that I am not sure where it is coming from.

[wmsonta]

Wmsonta, the consensus of opinion today is that most main seal leaks are not around the seal, but more likely, and in greater volume, at the parting lines of the cap with the block.

If I agree or not, it's not going to change what works/has worked for me. Last fall when I decided to sell everything, I owned 6 rope seal engines. A Vega, a Monza, a GN and 3 Caddy 500's. I did 3 rope main seal repairs before I was old enough to drive. All 3 had unacceptable results. Have not had a failure since.

I am not going to put anything on the main cap mating surface. I can't get that surface clean enough to suit me.

Use what works for you or what ever you want. Things are better now. The first repairs I attempted were rope for both the crankshaft and the 'H' (side) seals. By the early '70's mechanics used 6 cyl (single lip) crank seals/Felpro neoprene side seals, on all those Vega's parked everywhere.

I do not see a problem.