Why put sealant on the right case half?

[304065]

Wayne's book says put sealant on the RIGHT case half, the one bristling with studs, the one that the crankshaft and oil pump and intermediate shaft rest in.

The factory workshop manual for the 3,2 (left over from when I owned my '88 Carrera, dug it out of storage to compare to the early manual) says use sealant on the LEFT case half, the one without the studs, and use a medium-nap roller to spread 574 onto the mating surface, then raise it over the rod and chain props and then seal it up.

I assume there's a reason for the right half, can anyone comment as to why this is so?

Not that the factory had it perfect, either-- they say you don't have to remove all the old 574 if you split the case-- just clean off all the grease and reapply new 574 and it will dissolve the old solvent and seal. Perhaps if you had no choice. . . then again they also talk about not mixing up used bearing shells-- perhaps they wrote the procedures for someone experiencing a teardown early in the engine's life. Who knows.

[cgarr]

I would assume it’s a lot easier to apply the sealant to the side without all those studs. I think you have to be rather quick with this stuff too? Left

[efhughes3]

I was just looking at this today for my project: The start of my re-BUILD; let the games begin!!

I'm going to put sealant on the left 1/2. Funny note about leaving the old sealant on and putting new over. I saw that myself today in the factory book, which made me shake my head.

[Jeff Alton]

I put in on the left side, but I am not a pro....

Cheers

[Walt Fricke]

Well, if you apply the sealant from the tube as a thin bead directly to the case half, you can easily apply it to the right side, which is sitting there facing you anyway at that point. You don't have to use a roller.

I think the factory had it right in asserting that you don't need to remove all the old dried orange Loctite. I don't, and it has never been a problem. Ditto with the heads. I knock down any of the ridges where the previous application had squeezed out and hardened, and leave it at that.

But there is certainly no harm in removing the old stuff - just takes more time.

Walt Fricke

[efhughes3]

Originally Posted by Walt Fricke

Well, if you apply the sealant from the tube as a thin bead directly to the case half, you can easily apply it to the right side, which is sitting there facing you anyway at that point. You don't have to use a roller.

I think the factory had it right in asserting that you don't need to remove all the old dried orange Loctite. I don't, and it has never been a problem. Ditto with the heads. I knock down any of the ridges where the previous application had squeezed out and hardened, and leave it at that.

But there is certainly no harm in removing the old stuff - just takes more time.

Walt Fricke

Walt, I'm sure you've got the right touch with your experience, but that scenario above is pretty subjective, and is probably where some first time engine builders get in trouble. I think the roller method may be a little easier to get the proper/even amount of sealant on the flange.

[Eagledriver]

There is clearly no right answer here. You need to decide which method will give you the best chance of success. For some who are good at laying down an even bead the right side will be best. For others who are more comfortable using a roller on the left half, they should do that. I use the white RTV (Dow 730 i believe) forming a small bead around the perimeter of the left half. It's what I'm most comfortable with now.

-Andy

[gtihop]

I used threebond on the half with the studs- so far after 5,000 kms no leaks yet!

[efhughes3]

Originally Posted by gtihop

I used threebond on the half with the studs- so far after 5,000 kms no leaks yet!

How did you apply it?

[Jeff Alton]

I used three bond too, first time I have used it. I squeezed it out of the tube and then spread it with a plastic spatula/putty knife. It also comes with a small metal spreader.

The stuff gets "stringy" quickly so be careful and work quickly.

Cheers

[patkeefe]

I shmutz up the side in the stand, the right side. I use Wurth Orange Flange Sealer, in the little accordian type squeeze bottle. Less messy that way; it seems hard to manipulate the left half onto the right half when it's covered with sealant.
Pat

[Walt Fricke]

I have noticed the same assembly advantages Pat has by applying to the right side. The roller method pretty much requires that you apply to the left half.

I purchased a large tube of 574. It will probably last my lifetime, as I only do my own motors. But I don't have to worry about it running out mid-job. And I found it easier to squeeze out a consistent bead than I did pushing in the accordion, which required more finger strength depending on how empty it was getting.

I think the real message for those approaching their first assembly is that there are several roads to Rome. If you use one of at least three proven sealants, cope with their characteristics (cure time, in particular), and apply enough so that there is some sealant forming a complete barrier along the seam at all points (and don't inadvertently wipe it off somewhere), the results should be good.

Unlike silicone, whose excess can cause trouble, with these other sealants (at least with the orange Loctites, and I assume with the others) a small bead squeezed into the case is not going to be a problem any more than a small bead squeezed to the outside might be.

I still have the little paint trim roller I used my first time, shut up in a zip lock, with some 15 year old Loctite still tacky on it. I just don't use it any more. I can't claim to be leakless, but the leaks have come from gaskets of one sort or another, or from rocker shafts reused many times in equally seasoned cam carriers, or from my habit of reusing crush washers, etc. Not from the seams.

Walt Fricke

[cstreit]

I put it on the right side only because that's the one I have sitting on the stand for oil-pump and layshaft installation. If you want to use the roller method, gotta do the left.

[efhughes3]

How is everyone putting the 1104 on? Small bead spread out with a spatula or finger so that there is an even film?

[sand_man]

Originally Posted by efhughes3

How is everyone putting the 1104 on? Small bead spread out with a spatula or finger so that there is an even film?

I applied a thin coat of 1104 with clean fingers to the case half WITHOUT studs. Nearing 10,000 miles on a daily driven engine and no leaks...YMMV.

[gtihop]

I used the 1104 and squeezed out an even bead around the case. Then used an acid brush to evenly spread it out all around. It's not the easiest stuff to work with. I found that the loctite was alot easier to wok with , seemed to be a little thicker.

[patkeefe]

In theory, the amount of sealant actually necessary to effectively seal the case is about 1/20th the amount we put on, as most of it squishes out. The effective sealant layer is likely way less than 0.001" thick. We are just filling the scratches and imperfections.

[cgarr]

First time I ever voted Left in my life