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.

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

so I was wrong aand too slow

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

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.

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.

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

http://forums.pelicanparts.com/911-engine-rebuilding-forum/440022-bottom-end-together-again.html

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?

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 . . .

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?

Did anyone answer the question?

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

Thanks
Greg

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)

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

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!

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.

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.

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.

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

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.

OK guys, just ploughed my way thru most of this. I cant help but laugh when I look at the motor I'm working on at moment. It is a friends 2.7 that finally leaked so much oil I was embarassed for him and offered to strip down. About to reassemble this w/end. But the Japanese have got you all beat. This car came via Japan.
There they seem to use just one sealant - some marine grade silcone (white).
You can dispense with the rest, just one large tube does all.
Crankcase halves (was going to take pic, camera flat), nose bearing, crank seals , rocker bushes, all gasket surfaces.
Apparently you just ladle it on with a spoon.
I bought a 930 in via Japan, and same story - same white gunk everywhere.
The 2.7 has about a pound of black RTV underneath to stop spot leaks, my 930 had red instead of black for spot leaks.
So, if you want monochrome, go for white.
If you like variety, red, white and black is available.
Life can be simple. If you are Japanese.
Regards
Alan

lol... :)

Does anyone here NOT use sealant on gasket surfaces. I rebuilt my SC from crank up 3-4 yrs ago. Followed Waynes recipie for sealing the case religiously.
But for all the gasket surfaces I used no sealant.
Just made sure they were true and clean. My Dad was an engineer and taught me that an oil proof gasket should be enough, unless there is an issue.
I know using the gunks is good insurance, and if was doing a shop job for a customer, I would not want it coming back for an oil leak.
But am I the only one not using sealant on gasket surfaces? If you do have to pull anything apart again, it is a quick and easy job. If I had to pull it for a leak, if I could not identify a cause, I'm sure I would use sealant.
My SC is still leak free.
Regards
Alan

I use a very thin film of Curil-T on the gasket surfaces. The gaskets come off very easy and you don't have the problem of cleanup of metal surfaces with paper residue.

I don't use any on valve covers and chain covers... Didn't use any on the chain housing gaskets either. No leaks.... Proper torque helps a lot - especially resisting the urge to give it that one extra twist.....

JB

WEll, that almost covers it (bad pun). That pretty well just leaves little gaskets like breather cover etc.
Alan

LOL! Ya true. I guess the point is, if your surfaces are clean and smooth, AND you assemble everything to spec, adding goop to your gaskets may complicate matters for you on disassembly.

I just this week popped the engine out (last time out was 2005) for some minor cleaning (lots of dirt, and a leaky pully seal and #8 bearing) and adjustments.

http://forums.pelicanparts.com/uploa...1246681656.jpg

It was pretty clean except for one of the tensioner lines, and the seal/#8 area, and all the gaskets released nicely.

JB

A quick note from the resident curmudgeon.

We would all like to believe that if we clean everything and make sure every surface is perfectly flat that the chances for oil leaks disappeared. It's a nice thought but in 1991 (the only time I could get accurate information, all factories hide these kinds of memos) the return from dyno test oil leak rate at the factory was 4%. That's 4% using all new parts. If 4% of the factory engines leak within the first 30 minutes using all new parts what are our chances of leaking using heat cycled parts. Our challenge is greater and requires a more aggressive plan of attack.
Just my humble opinion.

Henry - all factory stats aside, I think the careful backyard Porsche mechanic may take a little more time making sure things are "right" as opposed to the factory engine assember who is under productivity pressures AND has a factory fridge nearby stocked with plenty of fine German bier!

JB

With all due respect.
Sorry but that's just non sense. There is nothing more important than experience when it comes to engine assembly. We have built hundreds of engines and that experience leads to a better product. To think that a back yard mechanic can come close to the consistent quality of a factory engine assembler in naive in the extreme.

Henry - with all due respect, you missed my point entirely! But, we're getting off-track here...
JB

Off track for sure but let's remember that each engine moves though the assembly line with an assemblers number attached. Too many assembly errors lead to very long unpaid vacations.

I saw an interesting special on Discovery Channel recently that focused on the Z06 Corvette. Much of the special was around building the car, and they spent a good bit of time on the engine assembly - which is done by one person who puts his name on the long block. It was fascinating, in part because the assembler had some incredible special tools at his disposal to make the assembly as "perfect" and repeatable as possible. This is all the gentleman does, and he was good at it. There is no way the occasional mechanic (and I put myself in this bucket despite having built about a dozen 911 engines and several 944) can do as clean a job as they do in the factory with all new everything.

This is not what I saw, but you see some of the assembly methods: http://www.youtube.com/watch?v=XdWTz_H0dUA

So, I used sealant on my gaskets! :)

Jim,
I saw a thread recently where a leaky nose bearing was fixed with goop - by machining a tolerance fit piece, inserting goop in the gap and squeezing it somehow thru the cavity.
That is about as much as I understood of it. But if required, could probably find thread.
Regards
Alan

Thanks Alan - I saw that - and bookmarked it!

http://forums.pelicanparts.com/porsche-911-technical-forum/481430-successful-8-bearing-oil-leak-fix.html

Jim

Ok, I'm the novice when it comes to these types of debates, but a simple question remains.

Any reason you won't use either 574 or Curil-T on all your gaskets? With all the time going into cleaning the case, the extra insurance makes sense to me. Nothing is worst then having a newly rebuilt engine run beautifully and drip on the garage floor, or on the exhaust.

IMO, sealants on gaskets is the way to go.

Since I got to decide which to use or not using Loctite at all I read the data sheet and found that:
1. 518 loses half of its strength at a lower temperature than 574, 90 vs 120 degree Celsius, but retained a bit higher strength at 150 degree C or higher
2. 574 cures faster than 518 as ambient temperature increases and may leave less time to torque the bolts
3. heat aging looks similar for both after 400 hours
4. 574 has higher lap shear strength but lower compressive shear and tensile strength

So, your choice. But 518 will be easier to handle if you work in a hot environment.
BTW, John Walker seems to be using the Dirko with good results.

New sealant question (I think):
What sealant do I use between the metal-to-metal joint of the left chain box cover and camshaft collar (through which the cam extends on a '68 with cam driven air injection pump)? I was going to use CurilT...

Ok, I really hate to ask this but is the first page updated with the latest common ideas on what to use? I guess I can read all 10 pages but would prefer not to. I know that there are several schools of thought but I just want to do it right the first time. Thanks and sorry for the lazy stupid question.

Yes, the info on the first post is still good. One change is 1104 is now 1194. Also Yamabond (from Yamaha) and Threebond are the same and Curil-T and Hylomar Blue are just about the same, be careful Curil has several products.