ThreeBond 1194 between the heads and cam towers...yay or nay?
 

Built a 3.2 Carrera engine 1800 miles ago and *very carefully* set the cam towers (carriers) to the heads with Loctite 574. Proper torque sequences observed, etc. I've developed a weeping oil leak near the exhaust port on #1 between the head and cam tower.

I'd go Dow 730 here to fix it when I have it all apart again...its $100 a tube though. I happen to have a fresh tube of ThreeBond 1194 on hand.

Would the 1194 do it? The box says its a semi-curing sealant. I'm done using 574 in this area.

Thanks...

I use 1194 to join Ferrari 308/328/Dino blocks to transaxles, and join flat 12 Boxer case halves and it works great. I think you will be fine.

Curious as to your thinking on why 574 is responsible as opposed to say slightly un-true mating surfaces or uneven clamping pressure developing over time, even if not introduced by you during assembly? Not implying anything here, asking a question.

Isn't it the 1104 that's used in these areas? Or don't they make this anymore and I just happen to have an old tube?

Not sure and don't know, that's why I asked about my tube of 1194. They make all different grades. Only thing concerning to me is the upper temp range of 1194, from what I can find it looks to retain its properties to about 300 F.

The trouble with 3 bond is you hsve to apply to both surfaces which gives you lots of excess to deal with.
Bruce

You're actually probably spot on. With the age of the parts and any minor variances in machining, simply temperature cycling the parts in the extremes a few times could cause the 574 to crack away from one of the mating surfaces when shifted. It is not flexible stuff when heat cycled.

I use Permatex Aerosol copper gasket spray - a few coats in the pattern on the bottom of the cam tower and then around the studs/dowels on the heads.

http://forums.pelicanparts.com/7449834-post215.html

http://i458.photobucket.com/albums/q...ps97c2ce79.jpg

http://i458.photobucket.com/albums/q...ps6330ec20.jpg

Gasket Sealants : Permatex® Copper Spray-A-Gasket® Hi-Temp Sealant

I've used Yamabond on engines in the past but it's not as easy to work with... last time I used it was 2003.

How much working time with the copper spray? How did it work for you?

The Three Bond products are perfect for this application.
We switched from 574 15 years ago.
1104 was the original product but was pulled form the self by EPA regulation. (lead)
1194 replaced it and now 1184 has replaced 1194.
We use ThreeBond products in our sealing system that has hundreds of success stories. We have used these products in over a hundred engines and sold hundreds of sealing kits containing these products with zero complaints.
Is it possible that people have used our sealing recommendations, failed and not told us of the failure? sure, but that really isn't common in the Porsche community.



BTW: proper installation of 1184 is clean both surfaces and install a thin layer to one part of the joint.

Thank you Henry. -BG

Maybe 5mins between coats. Works great. I also use it on my turbo car to dress the head gasket that sees 35lbs of boost from time to time. On that same turbo car I had used yamabond previously and that also worked well... but was a son of a gun to get clear of the surfaces when I had to go back in and doesn't have the same thermal transfer properties. IE, it traps heat by insulating the surfaces from each other. Not ideal.

What Henry said....

Like Henry, we only apply it one side, never both.....

Copper gasket spray
 

One of the benefits of 574 is that you don't need to clean it all off after taking things apart. Doesn't hurt to do that, we all knock off any big chunks of squeeze-out that hardened, but new 574 dissolves (softens?) old. The data sheet may not say so, but Porsche says it does in a variety of their publications over the years, and that you don't need to clean it all off. This has worked for me.

While, like many, I am set in my ways and see no reason to change what has worked for me (nor to try to persuade anyone else to change what works for them), and like just applying a bead of 574 around each opening, and each stud hole, and keeping the central part where no oil will ever be clear, it is nice to know what else works. Overspray is my first thought with a spray application, though doubtless that is manageable.

But, along with hardening time, what clean-up is called out for the copper spray? Do you need to take it all off next go around? Will something dissolve it, or is it kind of labor intensive to remove when it has been thoroughly heat cycled anaerobically?

The copper spray wipes off with brake cleaner and paper towels. Mask with blue painters tape to control over-spray and save wiping up if you like. I did.

I have had a good success rate on problem sealing areas using the Permatex copper spray on gaskets. It stays tacky forever so re-positioning is not a problem. No squeeze out is another benefit, it is a part of my sealing "toolbox". Threebond products are my favorite, used them for many a motorcycle case sealing with never an issue.

I used 1184 and the results were perfect.

Question: Is Permatex Copper Spray-A-Gasket® Hi-Temp Adhesive Sealant (80697) a good product for joining two aluminum engine components together without a gasket? The sealant needs to retain an oil splash with little or no oil pressure.
If not what would you recommend? Thank you

Our experience is that the cam tower to head joint is rarely flat and as such require a high viscosity sealant rated to fill gaps in excess of .015" Loctite 574 is rated at around .015" but has been reported to fail to seal in this application in a number of projects over the years. 574 also offers an incredible clean up challenge on race engines where disassembly occurs frequently.

You left out an important detail in your inquiry. There is no gasket space and the surfaces are flat. Nice try though... I absolutely would not recommend black silicone here, would you???

I've found myself moving away from the 574 for the various reasons mentioned here. The squeeze out is pretty significant, which means you've got to be diligent about not over-applying your coat. I don't like when those chunks of squeeze out find their way into the sump or wherever else they like to migrate. I hear what Walt is saying about the dissolving, as i've seen that in print as well. But the chunks don't dissolve. I've seen them on the sump screen of the oil pump. Sump screen is constantly soaked in oil so you'd think chunks would eventually break down. They don't appear to though.

The nice feature about the 574 is it's shear strength. That's a nice attribute for the main bearing webs where the case halves mate. Those mating surfaces clearly have some micro wiggling going on and anything that can help with that is a plus. Otherwise everywhere else in the engine the 574 shear strength isn't really important.

Speaking of the cam tower itself, it's nutted and doweled so many locations that shuffling/movement seems like it'd be a non-issue. But even with all that bolting the housings are still prone to twisting and I suspect that's BG's issue here. Not uncommon to have to resurface a cam housing on the head mating surface

I am sort of anal when it comes to cleaning so that gripes me about the 574 as well. Cleanup is nowadays much more fussy due to gasket removers being less effective than in the past. The Permatex low VOC gasket remover spray sucks butt compared to the previous formulation. Previous Permatex remover kicked the crap out of 574 in one application. It worked fantastic. Heck, even Loctite's own "Chisel Remover" product requires several applications to remove dried crusty 574. I know many guys like to use MEK but that evaporates so quick its also a hassle IMO. Nasty stuff too....

Another option for this sealant location is Permatex Aviation Gasket Maker. I'm surprised the Permatex rep didn't suggest that. I agree Ultra Black is a terrible recommendation and that points to the rep's knowledge? Aviation works good here and cleans up very nicely. Brake or carb cleaner hoses it right off. Only downside i've seen to Aviation is that it runs when hot. So any squeeze out runs down the engine in various places. Nonetheless it seals very well.

One of the nice features of 1194 or 1184 is its cleanup. When prepping for reassembly, I think the stuff cleans up very nicely compared to typical RTV products.