The Complete Engine Sealant Thread...

[Alan L]

Hesitate to jump in here, but +1 on Dennis' post. I guess there are points both ways here, but the value of this forum is shared experience - so we don't repeat, or manage to avoid mistakes.
Henry with 400 engine builds beats me by about 396. So I greatly value the contribution by guys like Henry who freely share their experience. Experience being the key word here.
Henry has something that works for him - time and time again. So it will probably work for others also. There may be other options/alternatives, and if others choose to go another path, so be it. But I don't think castigating someone for not ditching a tried system that works, for some other plausible option gets us very far.
I've seen very valued experts having their shared thoughts torn up on these boards before, and choose not to post. Easier to ignore the forum and get on with what pays the bills. Hopefully guys like Henry will continue to share with us, and if others have another view, post it. But if it works for 400 engine builds, surely we can accept it is a viable useful technique at least in this specific instance (and thanks for sharing it).
Alan

[Lapkritis]

Alan - I hear you and many other members of the forum on that point. Henry wins the popularity contest hands down with his claims of business. I offer only facts for analytical minds and submit no resume for review as it only distracts from the topic of the moment. Those with the herd mentality may continue to drink their punch none the wiser but don't sandbag new, revealing information that those with brains and decision making power may find useful.

The main difference in this case, and the reason why I am so passionate about getting the information out, is the danger of a half opinion that Henry has shared. His suggestion of DC55 is contingent upon the case being beveled. That prerequisite is omitted (dangerously in my opinion) from the sealant list. If you're not beveling your case halves then DC55 is an absolutely terrible suggestion for the lube to use. I would further the recommendation against the DC55 due to the thread on the bolt.

[Iciclehead]

Originally Posted by Lapkritis

Alan - I hear you and many other members of the forum on that point. Henry wins the popularity contest hands down with his claims of business. I offer only facts for analytical minds and submit no resume for review as it only distracts from the topic of the moment. Those with the herd mentality may continue to drink their punch none the wiser but don't sandbag new, revealing information that those with brains and decision making power may find useful.

The main difference in this case, and the reason why I am so passionate about getting the information out, is the danger of a half opinion that Henry has shared. His suggestion of DC55 is contingent upon the case being beveled. That prerequisite is omitted (dangerously in my opinion) from the sealant list. If you're not beveling your case halves then DC55 is an absolutely terrible suggestion for the lube to use. I would further the recommendation against the DC55 due to the thread on the bolt.

We hear you, understand your point of view. Is there a way you can draw a line under this area of discussion as neither Henry nor you are likely to change your mind on this particular topic.

We, the great unwashed, want to ensure that neither of you get so ticked off with this particular brushfire that they cease to post, whereby we collectively lose the valued experience that us home mechanics need.

We have seen too many skilled people leave these groups because of the kind of argumentation you are engaged in....please stop on this particular detail, it is not helping.

Dennis

[WERK I]

Amen!

[Lapkritis]

Sure, we can draw a line under it. I'm not ticked off just insisting that the horse stands before the water to consider a drink before jumping over it and proceeding down the trail. Be rest assured that every time someone chimes in that DC55 "it's simply the best" for this application, that I'll be waiting with the asterisk to say "not so fast" and show people why they need to be careful with partial advice.



DuPont Krytox GPL 207 Grease, Pure PFPE / PTFE No Additives, 0.5 oz Tube: Amazon.com: Industrial & Scientific

http://www.krytox.com
http://www2.dupont.com/Lubricants/en_US/assets/downloads/elastomer_compatibility_profile_K20565_1.pdf

[boosted79]

Google Dupont Krytox. $140 for 8 oz!!!! I think I'll take my chances with Dow 55

Edit - I was typing while Lapkritis put up the last post. I can live with $20.

[gtc]

What is the rationale behind using the silicone-based 1211 on the #8 saddle, rather than just using 1104 (rubber based) like the rest of the case perimeter?

Am I asking for trouble if I use 1104 here?

[KTL]

Whatever you use on the #8 saddle, apply it SUPER thin. The #8 is a precise fit in the case halves (it has to be, since it acts as a locating/alignment sleeve at the end of the case) and therefore it will squish out whatever excess it doesn't want in there.

The rationale for any sealant here is that it is a backup plan for o-ring leakage. I like to use the inert Dow 112 o-ring lube since it not only lubes the o-ring but it also protects it from oil contact that degrades the rubber.

[gtc]

So you just use the lube and no sealant?

[KTL]

Yep no sealant there since my engine gets taken apart way too often. For a long term leak free engine, I think the sealant around the #8 is a a really good idea. Just use it very sparingly. You don't want any squish getting into the oiling holes.

[Henry Schmidt]

The reason for gluing the #8 main bearing is that the cases (more often than not) are no longer completely round. Over years of use, they tend to become oblong.
This part of the case is generally not align bored (although there are over-sized bearings) so correcting this ovality is somewhat problematic.
By gluing this bearing you overcoming this inconsistency. Will it seal without glue? usually. Is there any drawback to gluing this area? not that we have seen.
We use 1211 because it tends to be slightly more elastic to deal with the expansion difference in the early mag cases.

[Jeff Alton]

Have built over 25 engines using techniques and products like Henry suggests. Our engines don't leak. But, remember, no choice of sealants will overcome poor cleaning, inspection and preparation...

We use an "o-ring lube" we get from a local motorcycle shop on o-rings and have not had any issues. I am out and need to source some more... I don't know the properties of it, but I know it has worked well for us.

Cheers

[Jcslocum]

I hate to prolong the argument and as a technical guy, that chart is showing tensile strength measurement. And it does show a loss. These o-rings under the case bolt washers are used in compression to make the seal as I understand it. If I'm wrong, please correct me.

[Lapkritis]

We've beaten it to death. You're not compressing the ring against the bolt thread just as you are not compressing a tomato with the blade of a knife.

And there are other such edges in the joint especially if it is not chamfered/machined.

[gtc]

Since it doesn't seem to be covered in Wayne's book, how and when do you apply sealant to the cylinder base gaskets? I don't see how it would be possible to apply the sealant, get the heads and cam towers on, then torque the head studs all in 30 minutes (curing time for 1211)

FWIW, this is on my 3.2 with .5mm bare copper .5mm gaskets.

[Henry Schmidt]

Originally Posted by gtc

Since it doesn't seem to be covered in Wayne's book, how and when do you apply sealant to the cylinder base gaskets? I don't see how it would be possible to apply the sealant, get the heads and cam towers on, then torque the head studs all in 30 minutes (curing time for 1211)

FWIW, this is on my 3.2 with .5mm bare copper .5mm gaskets.

I only recommend 1211 in certain applications.
The best product we've found for cylinder bases with copper gaskets is Curil T. It never hardens so assembly time becomes a moot point.


As for the comment by our resident antagonist: We use Dow 55 on all case o-rings (chamfer or not) with exceptional, long term results.

Edit: we actually use Dow 55 on every o-ring during the air-cooled 911 engine assembly not just case through bolts. It works exceptionally well on oil return tubes, cam joint rings, RSR rocker shaft seals, cooler seals as well as all rotating surfaces within seal.

[efhughes3]

Hmm, take advice from a guy who builds engines for a living, whose name is on here plainly and on what he sells, or someone anonymous in name AND location? What to do.....??

I knew what I did on the two builds I have done, and I took Henry's advice.

[gtc]

Originally Posted by Henry Schmidt

The best product we've found for cylinder bases with copper gaskets is Curil T. It never hardens so assembly time becomes a moot point.

Thanks, Henry.
Do you think one is likely to see a leak here if sealant is not used?

[Henry Schmidt]

Originally Posted by gtc

Thanks, Henry.
Do you think one is likely to see a leak here if sealant is not used?

It's a toss up. The cylinders are constantly moving so there is a opportunity for leakage but there is no steadfast rule. Sometimes they leak and sometimes not. With sealant you improve your chances.
Most of this thread is about just that: not what is "right" or "wrong" but what can I do to improve my chances. What I offer is for just that purpose....best possible chance based on my experience.
Cheers

[JFairman]

I'm just glad to see Henry posting his great advice again.
When I put my new top end on last April I would have used Curil T on them if I had some but I used blue hylomar I bought off ebay because I had a tube of it.

I think they're kinda similar because they both never dry and stay gooey and resist gas and oil. Lacquer thinner will desolve hylomar and I use a rag wet with it to wipe off any hylomar squeeze out after tightening things down.
Anyway, they havn't leaked or sweated any oil.

I used Hondabond 4 on the cam tower to head surface and it's not leaking either. Lacquer thinner on a rag cleans it up too.