Case Sealing Opinions Wanted

[Kevin G.]

I will be buttoning down the bottom end this evening or tomorrow morning, and for me it's time to fish or cut bait. I have been following the case sealing debates for several months while I was getting ready to re-assemble, but I still cannot seem to make a decision on the 2 following questions...

Ein. Dow Corning 731 or Locktite 574. I have both, so if you were rebuilding and had both available, what would you use?

Swei. Do I apply the sealant to the case mating surfaces totally within the case, or leave them bare? I don't think this debate ever came to a conclusion.

On the type of sealant, figure into the equation that I only have 2 hands that are not as fast as some of you more experienced motorhackers.

Thanks!

[Wayne 962]

Both work well, and both have been debated to death on this board. There is no right or wrong answer on this one. I suggest you search the archives in this forum, and then make your own decision based upon what you read. I recommend the 574 - been working for many, many years. If you do use the Dow Corning stuff, don't spread it like the 574, but instead use a very, very small (1/16th of an inch maybe) bead.

-Wayne

[Henry Schmidt]

For many years we used 574 Loctite but now ( for the last 4 years) we use ThreeBond 1104 and 1211 for perimeter sealing on the case ( 1211 on # 8 main bearing) Where the case joins at the through bolts we use 574. For the the cam towers we use 1104 and where there are gaskets we use a very thin coat (very thin mind you) of 574. On the cylinder base gaskets we use Curil T. Four glues equal no leaks. Over kill ? MAYBE No leaks GUARANTEED.

[ChrisBennet]

Henry,
For 964 motors do you use any sealant or "tricks" for the cylinder to case junction?
-Chris

[Henry Schmidt]

Originally posted by ChrisBennet
Henry,
For 964 motors do you use any sealant or "tricks" for the cylinder to case junction?
-Chris

O-ringing the case spigot seems to be the best repair. We have been using ThreeBond 1211 on 3.6 cylinders bases when it is not possible the o-ring the case spigot.
It has worked well and would recommend this process if o-ringing is not an option.
I know some of you will flame me for recommending an option that is not the best but sometimes a repair not a rebuild is in the best interest of the consumer.
Good luck.

[ChrisBennet]

Thanks Henry. Another engine builder told me something similar. I think he used some Mopar Gearbox Sealant RTV. He told me it's some other (better known) sealant but with Mopar's name on it.
-Chris

[john_colasante]

Originally posted by Henry Schmidt
No leaks GUARANTEED.

Hi Henry, thanks for sharing your knowledge. I am always impressed with your posts.

Does your guarantee apply to DIY case sealing?

[Henry Schmidt]

The best thing I can say to guarantee your success is get your cases as clean as possible. CLEAN CLEAN CLEAN CLEAN CLEAN
We use MEK and a stainless tooth brush to clean all sealing surfaces, but be careful, MEK is poison and it will make you sick if you get it on your hands or breath it. Please!! Use gloves and a mask.

[YTNUKLR]

Sorry, what's MEK and where do you get it? Stainless tooth brush?

[Henry Schmidt]

Methyl Ethyl Ketone ( paint stores, Home Depot).
Small brush that looks like a tooth brush with stainless steel bristles.

[Fishcop]

Is MEK the hardener for Fibreglass resin?

[KevinG]

Thanks for all the information. Case is now sealed with Locktite. Since I had previously used the Dow Corning 731, I can add my impressions of the two.

The Dow 731 was of thicker consistency than the Locktite, yet was much easier to smooth in a flat, consistent thickness over the case halves. The Locktite seemed to want to clump up and took more time to smooth out in an acceptable manner (to me).

Conversely, the 731 'skinned' over fairly quickly, while the 574 seemed workable all the way until I got the halves together. Squeeze out was good on both, with more apparent from the Locktite - this may be because I could not get it to truly lay flat prior to joining the case halves, and may have used too much to make sure of adequate coverage.

On to deck height.

[john walker's workshop]

a thick layer of 574 often ends up being a thick layer between the case halves. get all the tools ready and all the orings on the studs and don't waste any time. tighten the perimeter nuts first and then the mains. with other sealers, i would normally tighten the mains first, but the anaerobic quality of the 574 is tricky and may set up faster than you think when case halves are assembled. yes, the 730/731 product does skin over quickly, and has a tendency to not stick as well to the half it wasn't applied to. if you ever split a case in the future you will see what i mean.

[ChrisBennet]

Originally posted by KevinG
Thanks for all the information. Case is now sealed with Locktite. Since I had previously used the Dow Corning 731, I can add my impressions of the two.

Do you mean Dow Corning 730? Just curious.
-Chris

[TimT]

HA.. years ago I used "gasgacinch" (sp) as a sealer....it worked well.... then the EPA started clamping down on VOC's

[Henry Schmidt]

Dow 730 is an RTV silicone and not a good choice for case sealing. It beads up on both sides of the case and the bead on the in side breaks off and can get stuck in bearings causing poor oil flow to bearing surfaces.
Gasgacinch [memories of VWs gone past] is a rubber cement and perhaps the poorest choice for sealing engine cases. Because it is a none hardening rubber it is not nearly durable enough for the task being asked of it.
574 is a decent choice but as I stated earlier, ThreeBond 1104 in concert with TB 1211, Ciril T and Loctite 574 has proven to out perform all previously mentioned products. No one product does everything properly.
You choose and I'll wait to hear what happens.

[Henry Schmidt]

Originally posted by Fishcop
Is MEK the hardener for Fibreglass resin?

I'm not certain what it is used for, but I think it's just a toxic cleaning solvent like acetone.

Because I live in the Peoples Republic of California, I'm sure it will be outlawed soon, you know "for my own protection".

Add on: MEK is a fast evaporating solvent for thinning epoxies, lacquers and adhesives as well as polyester resins used in fiberglass.
As stated on the can.

[Fishcop]

Henry, life for you will be much better if you just succumb. They know much better than you or I what is good for us, we shouldn't argue. I believe next on the agenda is beer, followed by food. Frankly the world will be better when cars are legislated and speed limited to 40mph. It is for our protection...

[briankeithsmith]

OK, on my current cam housings, the previous builder used Loctite 574 between the heads and cam housings. Let me tell ya, it is a pain to get it off.

I'm interested in trying the Threebond 1104 for the case/head sealing, but the problem I have is where the heck do you buy the stuff?

And how hard will it be to get it off if I need to pull the motor later on?

And let's review:
Between case halves - general consensus - Loctite 574 or ThreeBond 1104 and 1211
Cylinder base gaskets - Curil-T
Cam towers - Threebond 1104

Now, where can I get the Threebond?

Brian

[ChrisBennet]

Originally posted by briankeithsmith
OK, on my current cam housings, the previous builder used Loctite 574 between the heads and cam housings. Let me tell ya, it is a pain to get it off.

I'm interested in trying the Threebond 1104 for the case/head sealing, but the problem I have is where the heck do you buy the stuff?

And how hard will it be to get it off if I need to pull the motor later on?

And let's review:
Between case halves - general consensus - Loctite 574 or ThreeBond 1104 and 1211
Cylinder base gaskets - Curil-T
Cam towers - Threebond 1104

Now, where can I get the Threebond?

Brian

I use Permatex gasket remover on 574. Works great but be careful not to get it on anything painted (like an engine stand ).
I see Henry/Supertec has three bond. 1104 is available lots of places (do a web search) but 1211 is hard to find.
-Chris