The Complete Engine Sealant Thread...

[Neil Harvey]

A little history here. Porsche did dowel the case halves together on may engines. They used the through bolt with a stepped center to do the same. A little plug here, PD is in the process of remaking our head studs we used to sell years ago before most, along with these doweled through bolts. I remember Henry coming to my shop and looking at our studs before he made his.

Whatever means you hold the two case halves together and stop from moving is a good thing. These cranks are heavy and the strokes are quite big. The crank moves around a lot and all this movement is transmitted into the bearings and into the case holding the bearings. The nose of the crank moves the most and acts like one of those pool noodles you buy. If you watch a crank at 7000 RPM it will scare the life out of you, how much it moves.

As for gluing the bearing caps, I would never do it as it stops what from leaking? Glue is applied for one reason only and that to stop leaks. If someone could tell me what can leak if no glue is applied here, I'm listening.

Could it change the bearing clamp? From some of the photos posted on this forum showing how much glue is applied on parts of these engines, I would say yes, absolutely. Heavens forbid, is it applied under the guise of, some is ok but more is better????

Why stop at one bottle, hey the store you bought it from has more, so get more and keep gupping it on. It may help out balancing out the corner weights????

[KTL]

Thanks for the clarifications. I figured the case bolting sequence is just typical of most other applications- bolt from the center, outward.

[rs-vic]

FYI the 1200 series Threebond like the 1211 are RTV silicone sealers. The 1100 series like the 1184 are solvent based, (some type of rubber?) semi drying sealers. RTV sealers are not gasoline resistant whereas solvent based sealers are gasoline resistant.

The instructions for the 1184 say to let it dry for 1 minute before assembly. Of course sealing a 911 case takes longer than one minute. My understanding is that solvent based sealers need to have the solvent evaporate before assembly in order to adhere and seal properly. Curil T and K2 are like this where you need to let the solvent evaporate except they never harden.

Permatex has a fairly new sealer called MotoSeal. It is like the 1184, a solvent based sealer. I wonder if it is a knock-off. I have yet to try it.

Vic

[Will 1967]

Threebond products seems to be very challenging to get hold at least to people living outside US or central Europe.
I managed to buy Hondabond 4 (Threebond 1184) from dealer who will actually ship it, but still searching for 1215. Loctite products are available everywhere here so buying e.g. 574 is very easy, and I will most likely use that on case sealing flanges. (also Wurth products are available)
Is there tried and tested Loctite product that is alternative to Threebond 1215? And to Curil T?

I'm not trying to save any penny, I'm just sure there are good alternative (OEM) products here for engines made in Germany.

Edit. I faund 1215 now also, but I still think question is valid

[tristartiste]

Hi all!
I'm from Belgium and it's my first post here.
I have read plenty of threads here which were very helpful for my current project, thank you for that!
I'm in the process of re-assembling my 3.2 engine (Targa MY1984...imported from LA last winter! )

I have one question regarding the nose bearing sealing.

I understand it's recommended to apply a thin layer of Threebond 1211 on both sides of the case.

I guess using Loctite 598 will have the same effect? (beside the fact that it's black!) The only difference I see is that Threebond is non acid. But boths are RTV, right?


No side effect if the sealant goes in the "venting" oil channel (the small lateral groove on the top?)


Since it's recommended to use silicon grease on the o'ring for fitting...How to avoid that both are working against each others? (grease will disturb the drying process, won't it??)

thanks for your help!

[mikedsilva]

Originally Posted by CBRacerX

NEW LIST (I've lost the ability to Edit Post #1 since it is from 2008...)

Outer Case Halves: Threebond 1104 (now 1184)

Bearing Saddle Surfaces: Loctite 574

#8 Bearing (balancer end) O-Ring: Threebond 1211 (now 1215)

Case Thru Bolts: Dow Corning 111 on Green Viton O-Rings

Flywheel Seal: DRY

Balancer Seal: DRY

Intermediate Shaft Cover to Case: ThreeBond 1211 (now 1215)

Oil Breather Cover to Case: ThreeBond 1211 (now 1215)

Cylinders to Case: Curil K-2 or ThreeBond 1211 (now 1215)

Cam Towers to Cylinder Heads: Threebond 1104 (now 1184)

Cam Chain Housings to Case: Threebond 1104 (now 1184)

Cam Chain Housings to Cam Towers: Threebond 1104 (now 1184)

Cam Chain Housing Cover to Cam Chain Housing: Threebond 1104 (now 1184)

Gaskets: Thin coat of Loctite 574

Thanks a lot folks, I really appreciate the feedback!

EDIT: Most Popular solutions for sealing added to each item above to include superseded items.

What are people using (if anything) on the large o rings that seal the camshaft flange plate to the cam tower?
999-701-468-40-M213
molycote?
curil t?

[VFR750]

I used Molycote 55 on all o-rings

[KTL]

Agreed with VFR750. Use of a silicone paste like Molykote 55, Dow Corning 111 or 112, even SIL-Glyde, helps the o-ring slip into place and protects it from oil contamination over the long term

I would not recommend Curil-T. That sticky goo will just create more mess and other products are better suited for use here. Curil-T will work there but I don’t think it’s wise when other stuff is readily available. Heck, I’d use basic petroleum jelly there before using something sticky

[Alan L]

I use WD40 - not sure if called same in US. Not as a sealant - as a lube so slips in to place easily. They seem to seal OK on their own - as long as properly seated.
Alan

[mikedsilva]

Originally Posted by Alan L

I use WD40 - not sure if called same in US. Not as a sealant - as a lube so slips in to place easily. They seem to seal OK on their own - as long as properly seated.
Alan

I'm just not sure if WD40 has anything in it, that may be detrimental to rubber?

[KTL]

WD40 is a water dispersant and primarily a rust preventer. It’s primary ingredient is fish oil

I like WD40 and have used it for decades. But it’s got to be one of the most misused “lubricants” ever. Not saying AlanL’s use of it is wrong. I completely agree you want to put something on the o-rings to allow movement during assembly to avoid o-ring damage. WD40 seems like a good choice for that

[DMadigan]

WD-40 is good for cleaning off parts but has to be completely removed from the surface if they are left out. It will gather dust like a magnet.
If you want to lube the o-rings, why not use an o-ring lube such as Super Lube, a synthetic grease with PTFE? The problem with using a lube is if any gets into the sealing area between the cases it will keep the sealant from adhering.
For static o-rings I use Loctite Gasket Eliminator 515. It lets the o-rings move on assembly then seals any imperfections in the surfaces. It is an anerobic so there is no assembly time constraint. 518 works better on contaminated surfaces and has a faster setting time.
If it can keep an old British motorcycle from leaking it can work on anything. A Lycoming service bulletin calls out using 515.

[Alan L]

Yes, WD40 leaves a sticky residue over time. Not suitable as a lube on stuff you want to stay clean and free moving.
I think Waynes assembly book suggests a wipe of engine oil on the O rings.
Alan

[mikedsilva]

Originally Posted by KTL

Agreed with VFR750. Use of a silicone paste like Molykote 55, Dow Corning 111 or 112, even SIL-Glyde, helps the o-ring slip into place and protects it from oil contamination over the long term

I would not recommend Curil-T. That sticky goo will just create more mess and other products are better suited for use here. Curil-T will work there but I don’t think it’s wise when other stuff is readily available. Heck, I’d use basic petroleum jelly there before using something sticky

Incidentally, the Wayne Dempsey book ("that book") uses Curil T on the Camshaft Flange O ring and also the gasket that interfaces between the flange and the camshaft tower. I'm not defending it, just mentioning it.

[KTL]

Yep I recall “the book” mentions the green goo on the 3-bolt paper gasket for the cam thrust plate. Not a big fan of that tip either. The orange 574 goo is a better choice since it allows for a bit of slipperiness when seating the thrust plate with the three bolts.

He also mentions the use of the Curil on the crankshaft seals at both the flywheel end and the pulley end. Doing that is just plain wrong. There’s also the mention of using black RTV silicone sealant under the engine case through bolt washers and that too is a bad idea. I think it’s ill advised due to future cleanup and possible chunks of RTV coming loose, clogging oil passages years later

That said, those thrust plate gaskets are notorious for moving out of place a bit during assembly. So you have to watch behind the chain housing very closely during assembly. You don’t want a leak there because it’s a lot of work to re-do that pesky little gasket

[gsxrken]

Is there a list or a thread (maybe this is it) where “overrides” to the book’s suggested techniques or where new products have come out are compiled? I’m amassing knowledge here for my reseal and intend to follow the book unless convinced otherwise, but suggestions like the last two above are sprinkled like needles in the forum haystack. I’d like to scribble in my book ahead of time where to disregard or try another product.

[CBRacerX]

Originally Posted by gsxrken

Is there a list or a thread (maybe this is it) where “overrides” to the book’s suggested techniques or where new products have come out are compiled? I’m amassing knowledge here for my reseal and intend to follow the book unless convinced otherwise, but suggestions like the last two above are sprinkled like needles in the forum haystack. I’d like to scribble in my book ahead of time where to disregard or try another product.

This thread is it See the consolidated list a few posts above.

[gsxrken]

Originally Posted by Tom '74 911

I've decided to use Threebond 1211 on my #8 nose bearing during assembly and wanted to verify where to put it exactly - on both halves @ the case bearing web all around? Is it better to try NOT to get it on the o-ring or OK to get it on the o-ring? Is it OK if it get's in/near the oil supply hole in the case & in the bearing itself? Super thin coat so as not to mess w/tolerances as much as possible...?
Also, I'm assuming that doing this slightly amends the assembly procedure and timing as the crank has to be OUT of the case in order to apply the 1211 in the nose bearing area, THEN the crank goes in the case, THEN you apply the perimeter & main bearing web sealant, THEN you mate the case halves... All of which adds an extra step or 2 during the scramble to mate the case halves before the sealant goes off - is that correct? Tom

My heart sank as I read this- I buttoned up my case 3 hours ago and applied the white 1211 over the entire nose bearing O-ring in a mis- interpretation of the diagram/instructions in Henry’s kit.

Henry- am I screwed? Do I need to undo the case and redo the #8 situation, or will the 1211 be ok on the o-§ring?

[Henry Schmidt]

Originally Posted by gsxrken

My heart sank as I read this- I buttoned up my case 3 hours ago and applied the white 1211 over the entire nose bearing and O-ring in a mis- interpretation of the diagram/instructions in Henry’s kit.

Henry- am I screwed? Do I need to undo the case and redo the #8 situation, or will the 1211 be ok on the o-§ring?

You're fine. We've been this method for years.
I resisted sealing/gluing the number 8 main bearing but after measuring too many cases that were out of round, we decided the best alternative to aline boring the #8 was to glue it.

[gsxrken]

Thanks Henry. I hope we’re saying the same thing or I’m explaining it properly. A picture may be worth a thousand words here - I applied it to the o-ring, not the bearing.