The Complete Engine Sealant Thread...

[im4duke]

The 9340 is a 2 part epoxy used to seal plugs and pins that go from the inside of the
case and chain boxes to the outside.

The grey piece, in actuality it is pink, is Dow mil spec 55 o-ring lubricant.

[dfink]

i will guess the gray putty is epoxy to cover the various case plugs

[dfink]

so I was wrong aand too slow

[sprintamx]

I have a question about sealing the surfaces where the case-halves meet at the bearings (bearing saddles?)--the surfaces that are recommended for the orange Loctite 574. Bear in mind that I am far more of a "credit card mechanic" and I don't pretend to know didly about how to rebuild a motor.

That said, I am not rebuilding a motor, but recently purchased a 3.4 conversion with 7,000 miles on the convesion/rebuild. Making a rather long story short, my local technician (25+ years Porsche specialist, motor rebuilder, race-motor builder, sometime competitive racer, etc.) informed me that the motor was "unbalanced." Again, making a long, and expensive, story short, after disassembling the entire motor, weighing and measuring the rods, pistons and associate parts, spinning both the crank and flywheel to confirm balance/imbalance, he could not find any obvious mechanical/component problem.

His conclusion was that the sealer used on the case halves around the bearings caused enough of a gap to cause the crank to not seat properly and stay positioned in the bearings. He explained that this part of the case should be strictly metal-to-metal.

The evidence, besides the above-mentioned weighing, measuring and balancing tests: uneven/irregular wear on the main bearings--evidence that the crank was unbalanced when spinning; oil between the bearings and the case (not supposed to be any?); pitting and uneven wear on the cams (brand new WebCams) and unenven wear on the rockers (noted as new/refurbished).

I am posting in this thread because a few folks commented that there should not be any sealant in the bearing saddles, and I am curious if that refers to where the bearings are seated or the parts of the case that come together around the bearings?

Thanks,
Aaron

[dfink]

I have to ask was it a motor meister engine.

I hate to inform you that there likely be two answers given for this. Yes and No. The camps are divided. Probably in a perfect world where you are able to get the case halves togeather and torqued using a hardening sealer you would not have the problem you are describing.
Personally I could not get the case togeather fast enough and had thick areas of sealant that leaked and also likely held the halves slightly apart. That is why on the reseal I used hylomar, a non hardening sealer and so far it has worked great.
According to the porsche service manuals the 574 does not even need to be cleaned off before reassembly as they say it will dissolve and reharden. Testing did not show this to be the sitiuation. I believe they also state you have around 20 minutes to put the halves together that is somewhere around one every 20 seconds. Professional engine builders can maybe do it. Me... not quite so fast.

[JFairman]

maybe your guy smeared on the 574 and then the phone rang... oh well.

that said, Kevin Jeanette at Gunnar Porsche Racing uses a thin smear of hylomar to seal the case halves and he doesn't get oil leaks from his motors.
i and many other people consider him one of the best porsche 911 engine builders and THE best porsche racecar restoration person on the planet.

when i worked there in the 80's, he came in really early in the morning before it was light out when he built motors so there would be no phone calls or other people around to distract him.

i don't know what he uses to seal the cam towers to the heads, but you can use hylomar to seal almost everywhere succesfully and it's really easy to clean up with a rag and laquer thinner.
unlike most gasket sealers it completely ignores gasoline so if you need to seal a carb or mechanical fuel pump gasket it is the one to use.

[haycait911]

I had a problem with too fast-setting loctite/slow case assembly, detailed here:

http://forums.pelicanparts.com/showthread.php?t=440022

[sprintamx]

The motor was not modified/rebuilt by motor-meister, but by a well known, well respected builder.

Dfink: If I read your post correctly, are you suggesting that the motors were sealed at the factory with sealant on the case around the bearings, rather than just metal-to-metal?

Also, is it possible that even a bit too much sealant on those particular areas is enough to push the halves far enough apart to prevent proper seating of the crank?

[sprintamx]

Just so I have my terminology right: the parts of the case that seal around the bearings are called bearing "webs"?

And, too much sealant there is bad thing . . .

[alniki]

I presume hylomar or Curil-T can be used in the case web so that we amateurs can torque the through-case bolts without worrying about the sealant hardens too soon. And with the periphery sealed by Threebond 1104 we would not need Loctite 574 any more and there would be "NO" oil leaking outside of the case. Feasible?

[mrgt350]

Did anyone answer the question?

Do you put sealer on the bearing web mating surface of the case halfs????

Thanks
Greg

[Henry Schmidt]

Originally Posted by alniki

I presume hylomar or Curil-T can be used in the case web so that we amateurs can torque the through-case bolts without worrying about the sealant hardens too soon. And with the periphery sealed by Threebond 1104 we would not need Loctite 574 any more and there would be oil leaking outside of the case. Feasible?

The 574 used on the main webs is not used as a sealant. The case webs are glued together the insure/ increase case stability. The case is in shear at this point and 574 applied properly reduces case movement caused by the shear forces.
Curil T and Hylomar offer no stability hence would be inappropriate applied in this place. We have been building these engine for decades and if we thought we could do the same job with less products we would pursue that option. IMPO, the system I have posted has proven to be the best method .
Although the materials in the spec below are different you can easily infer the improved adhesion.

TYPICAL PERFORMANCE OF CURED MATERIAL
Adhesive Properties
After 24 hours @ 22 °C.
Compressive Shear Strength, ISO 10123:
Steel pins and collars N/mm² ≥6.0LMS
(psi) (≥870)
Lap Shear Strength, ISO 4587:
Steel (grit blasted) N/mm² 8.5
(psi) (1,230)
Tensile Strength, ISO 6922:
Steel (grit blasted) N/mm² 5
(psi) (725)

[alniki]

Henry, that makes huge sense to me -- glue the case for shear forces.
Thanks a lot!
Now it's pretty clear what to do.

[jacksd3]

Just sealed my case and this thread was absolutely golden for me. To add my .02c I used the following:

Threebond 1194 on the case perimeter applied to the left non-stud half
Threebond 1121 on the #8
Loctite 574 in the bearing saddles
Permatex Black with green viton o-rings for the case thru bolts
Threebond 1121 on the intermediate shaft cover o-ring
Loctite 574 on the paper gasket under the oil breather
30 Weight oil on the o-rings for the oil pump, thermostat, and distributor
Dry install of the flywheel seal and the crank pulley seal
JB Weld 50/50 mix on the dowel pin/plug locations

Thanks to everyone who contributed to this thread and especially Henry!

[CBRacerX]

Originally Posted by jacksd3

...
Permatex Black with green viton o-rings for the case thru bolts
...

I used ThreeBond 1121 in this application and on my o-ring less cylinder bases with similar excellent results (NO leaks). Did not want to use any sealant on the case thru bolts, but my first attempt without it was less than successful.

[Gregsgroup]

Loctite 574 - how long should it take to cure? I joined my case three days ago I still had wet material at the case halves which seemed somewhat odd. Thoughts as to why. I was under the impression 574 cured rather quickly.

After reading this thread, my case has just be pulled apart again and three different glues ordered. Don't want a leak after all this work, time and effort.

[jimbauman]

Any squeezed out 574 will not set because it's anaroebic - it will only harden where there is no air, so the sealing surfaces will be OK.

[CBRacerX]

I am still leak free if you don't count the lower valve cover gaskets

[Gregsgroup]

one more question. Is Yamaha-bond and Three bond 1194 comparable? I plan on using the Yamaha bond for the case thru o-rings and was wondering if you can use it for the outer case. If so, I have an entire day to build my motor. Its about time

[WERK I]

Originally Posted by Gregsgroup

one more question. Is Yamaha-bond and Three bond 1194 comparable? I plan on using the Yamaha bond for the case thru o-rings and was wondering if you can use it for the outer case. If so, I have an entire day to build my motor. Its about time

No, don't use either. The o-rings need to be compliant to handle thermal expansion/contraction. Use Dow Corning 111 to lube the o-rings.