Loctite 574 thickness

[GBStu]

My last post showed the #8 bearing leak on my 3.0SC re-build. I was expecting to pull the cases apart today and find the source of the leak (trapped O ring).....well here's the picture!




All I can think of is the thickness of the loctite sealent.....I measured it at about 14 thousands thick.

Do you think this could have caused the leak? I'm at a loss at the moment, I really would like to find the cause so I can guard against it on the next build!!!

Thanks

Stu

[350HP930]

0.014" is way too thick in my opinion.

Unless you let the sealant set up too long you might want to make sure the bore for the nose bearing is not boogered up and keeping the case from properly closing up.

You should also check all the mating services for any dings and mars that may be causing this.

Its a good thing you had to take it apart since thats enough slack to keep the bearing shells from properly crushing/clamping.

[john walker's workshop]

Originally posted by john walker's workshop
when you tear it down, see how thick or thin the 574 is between the case halves. it SHOULD have squeezed out, leaving a super thin filler between the cases. i had an issue with it once, and don't use it anymore. i also use a smear of dirko sealant in the bore where the #8 o-ring would contact, just for an added bit of security against a leak.

yep, never again. it's too unpredictable. dirko rules.

[GBStu]

Thanks for the input John.

I did a quick search on Yahoo and didn’t come up with many places to purchase Dirko sealant.

Where do you get it from?

[Rob 930]

I've also read/heard that some people "de burr" the case sealing surfaces by using a sharp tool to cut a small chamfer on either side of the surface. Apparently, a burr or ding on the edge of a sealing surface can cause the case to stand off from the adjacent surface, potentially causing a leak. Reportedly, this small chamfer eliminates such burrs. Anyone hear of this or have a comment on whether or how to do this?

[cgarr]

What happened to using a #50 silk thread to seal the case? Anyone doing this yet except me?

Craig

[john walker's workshop]

i get it from IMC, but pelican may be able to get it. it's an elring product. elring makes curil T also. use sparingly, so you don't have a lot of squeeze out. i use it between heads and cam towers too. i've warned about the 574 previously, but people have called BS, saying, oh you waited too long, or used too much. waited too long, no, used too much, perhaps, but still, it's not supposed to set up without being deprived of oxygen, and you would think that the quick action of squeezing the case halves together and tightening up the nuts reasonably quickly would not give it sufficient time to set up. wierd stuff. use it at your own risk as they say.

[ken martin]

John, So its Dirko for the case, how about Curil T between the cylinders copper gasket and case?( I think someone uses it?)
Km

[john walker's workshop]

everyone finds something that works for them eventually. the copper gasket actually comes with a thin sealer on it, but i spray them with K+W coppercoat on both sides for a little extra precaution. the base gaskets seal well if the case is true. 2.7s always need the bases cut in a mill. aluminum cases are usually ok.

[Jeff Alton]

Now I am totally confused!! John, is DIRKO going to work to seal the case halves on my 3.6? I have used 574 in the past without trouble, but really do not want any leaks in this engine either.

Jeff

[john walker's workshop]

574 worked for me too on many engines, or at least i thought it did, because there was no obvious reason to tear any down for a #8 bearing leak, or just to see if it caked up or spread out properly. who knows, there may have been a few that had the thickness issue and just didn't leak. it took just one 930 engine and 20 hours lost time for me to throw in the towel on that stuff. britwrench suggested dirko, and i've been using it since with no leakage problems. it will work on a 3.6 just fine.

[350HP930]

What exactly is dirko if its not a anaerobic sealant?

[Porsche_monkey]

From 'a website':

Dirko, a paste-like, cold vulcanizing, elastic sealing and filling compound, gives excellent adhesion to metallic and non-metallic surfaces. Even if fissures, cracks and joint movements are present, Dirko guarantees a secure seal. It has a variety of uses as a gasket, as an addition to a gasket or as a sealant from the outside. Dirko stops oil, water and air leaks. Even parts with hairline cracks are made good again in a few minutes. Ideal for cylinder head joints, gearbox joints, sumps, bearing casings, instrument casings, waterpumps and axle tubes. Temperature Range of Dirko is from approximately -50c to approximately +180c

[ChrisBennet]

Per Henry Schmidt's recommendation I've switched over to using:
Loctite 574 for the webs around the mains
Threebond 1104 (aka Yamanbond) for the case perimeter and for the cam carriers
Threebond 1211 for #8 bearing and 964 cylinder to case junction (no gasket, just O-ring on these)
-Chris

[Eagledriver]

Was the sealant .014 all the way around the case or just near the #8 bearing? Mine looked kind of like yours with about .010-.020 thick around the #8 bearing when the o-ring pinched. It pays to look at the seam carefully after tightening up the case. You can see that kind of gap around the #8 bearing if it's there.

-Andy

[Porsche_monkey]

You should be able to get a feeler gauge in if it's .014". I guess that would be a way to check...

[GBStu]

The .014 inch gap was only around the #8 bearing.

I'm going to assemble it "dry" tonight and make sure both halves come togther tight.

Thanks for your help.

Stu

[GBStu]

Just torqued the two halves together dry with only the #8 bearing assembled......I could fit a 1.5 thou feeler into the case seem.

I guess I must have got the two halves crooked the first time around?

Any comments?

Thanks

stu

[john walker's workshop]

you can actually get a feeler blade all the way thru the halves with the mains and outer nuts all torqued up?

[GBStu]

I only torqued the bolts either side the #8 bearing and a a couple at the other end of the case.

I could only get the feeler about half way through the seam either side of the bearing.