Nervous Newbie: Did I screw up sealing the case?

[cowtown]

I used Loctite 574 a couple nights ago to seal up the case of my '77 930 engine, and think I might have made some "mistakes of inexperience" as Bruce Anderson says:

I laid a thin (1/8" or so) bead on both case halves, going all the way around the studs and holes, and spread it out using an acid brush so that the 574 covered the whole sealing surface.

Potential problem 1: when I torqued the perimeter nuts, a significant amount of Loctite squished out...so I'm thinking maybe there is too much between the sealing surfaces and that the case is not fitting together tightly enough.

Potential problem 2: as quickly as I tried to work, and with my neighbor helping, it still took us almost 30 minutes to get all the nuts and through bolts torqued.

I'm nervous that I may have done this job badly, and reading about Leland's rebuild and various threads on 574's quirks have me thinking - Should I pull it apart and try again? I know it's a hard question to answer, but I could use some opinions....
Thanks,
Colin

[Zendalar]

Well, when I put the case halves together, I put the goo only to one side. Even though I put very this layer of this substance (I did not use Loctite) pretty much of it came out, no leaks so far.

If there is an excessive amount of this goo, some of it might inside the case and block some oil passages...or so I have been told, but I let somebody else answer for that.

[Superman]

I'm usually a 'button her up and drive' kind of guy, but in this case I'd split it again. It is just too easy to do this, and the penalty for plugging an oil passage is severe.

Examine the sealer that seeped into the oil passages, if any. I'd particularly look to see how much case sealer it takes to seal the nose bearing well without blocking that oil passage. Clean her up again, really good making sure the passages are all clear. Put sealer on only one side and smooth it flat and thin. Brushes sound very exotic but I'd use my finger. Use silicon grease on the oil pump seals and watch to make sure they mate properly as you lower the case half. Use a drill or something to speed the revolutions of spinning all those perimiter nuts on. I would also quickly spin the throughbolt nuts on and have a litle tension on them during the process. I mean, I'd deal with them all, not just the perimeter ones.

[724doorE]

More than likely your ok, But for your piece of mined and the chance that somthing isn't right, go ahead and split the case and see where the sealand went on the inside. Take a dig pic of it and when you do it again you'll have an idea of where to be carefull if there is a passage nearby. Provided you haven't gone any farther than that it should be a quick check.


Oh yes and post the pic! as that will be good info for others who follow with the same question..


Good luck

[ChrisBennet]

I've done just what you've done a few times - and it leaked.
I'm with Superman, do it over.
An advantage of an anerobic ("absence of air") sealer like 574 is that it won't harden except where it is squished between the flanges - so I don't think you need to worry about it will plugging your oil passages. On the other hand, sealers like RTV have the potential to make "boogers" that will plug oil squirters and the like.
-Chris

[john walker's workshop]

torque the mains first, then the outer case nuts. the chances of the 574 doing the thick buildup thing are probably slim. i used it for years until the one time it remained thick between the case halves. i noticed a leak out of the #8 bearing, between the bearing and the case, and of course the whole damn thing had to be torn down again to fix it. in the process i noticed a thick layer of 574 between the case halves, keeping the case from properly squeezing the #8 o ring. (just happened to be a 77 930 engine). so now i'm kind of gunshy of the stuff.

[cowtown]

Thanks everyone-
I will take your advice and redo it today. I haven't built it up any further, so it should be quick. I think I have already spent more time worrying about it than it would have taken to redo it!

I think I will use my finger to spread the Loctite this time and try to spin the nuts on loosely with my air ratchet instead of by hand, before torquing.

Will post a pic of how I did it the first time....

Thanks!
Colin

[Jim Sims]

If you redo it, get every bit of the old sealant off. The 20 minute (15 minutes to have a margin) interval doesn't start until one puts the halves together and the Loctitie 574 looses contact with the air. One can take a reasonable amount of time applying it carefully. My 17 year old son did it (it was his engine) under the supervision of our mentor. Distribution or speading of bead of 574 with an acid brush is a vertical dabbing motion (end of bristles straight into surface). Even so, we used three people all equipped with their own tools (manual crank type "speed" wrenches to drive nuts, several preset torque wrenches), all parts counted and arranged and assignments practiced with a dry run. It was an exciting and pleasant experience. Jim

[Jim Sims]

Colin, I just sent you a PM. My son is out there at UC Davis and is yearning to do some wrenching to break up his studies. He is willing to show you how we did the Loctite 574 application. Call him if you're interested. Jim

[cowtown]

Jim,
That's an offer I can't refuse...thanks!
Colin