Where to apply sealant
 

Officially in the reassembly mode of my 2.4 rebuild. I did not split the case. Have the reseal kit with all the gaskets etc. Are there areas where I should use sealant? Additionally, are there areas where I should use Locktite? I am using all new hardware (nuts, bolts washers etc.).

Thanks

Chris

73 911 E

Base gaskets: Curil T or aviation gasket maker
Cam towers to heads: Locktite 574
Cam carrier, chain box, chain box cover: Locktite 574
Intake manifolds: Curil T
Bolts for fan shroud: Red Locktite
Flywheel bolts: Red Locktite

Isn't red locktite a bit much for the fan shroud?

I have done this a few times. This is my method (no issues):

-No Silicone RTV anywhere- let's just get it out there - None!

Case perimeter- Threebond 1104/1194
Case main saddles - Loctite 574
#8 Bearing - Threebond 1211
Flywheel seal - Curil T

Base gaskets- Curil T

Cam tower to Heads - Threebond 1104/1194

Chain box to case and chain box to chain box covers - Loctite 518

Anywhere you are using a paper gasket besides valve covers - Loctite 518

Red Loctite on Head Studs - CASE side (and nowhere else) The next guy that takes the flywheel off the motor where you put red loctite is going to want to F-in' kill you (and that may be you, trying to kill yourself in the past). Or if you put it on the exhaust studs that go into the heads. Don't do it!

This is tried and true. It works well to keep the engine from leaking, and it comes apart with minimal fuss. Loctite 574 hardens and requires a razor to remove; it makes gaskets hard and brittle (and stick). Loctite 518 stays supple and fills large gaps when mating with gaskets.

I use 574 on the bottom of the paper gaskets on the chain boxes and bottom of the covers.
Never, repeat never use red locktite....
Bruce

Wow, glad I asked.

So I am clear, Loctite Red is for the threads. The other loctites are a type of form a gasket and supplement the paper gaskets.

Are the base gaskets you are refering to the brass gaskets at the bottom of the cylinders? You are telling me to use the Curil T on the bottom of the brass gaskets(between the gasket and the case). I did not split the case and am leaving all that alone

http://forums.pelicanparts.com/uploa...1286334161.jpg

Why not use 518 on the lower valve covers. I seem to always get some leakage there. Does it leave a mess when doing valve adjustments later?

Chris

73 911 E

I've had few problems with Locktite red on the bolts mentioned above. I think the end use of the motor has a lot to do with your choices though. If you are building a motor that needs frequent dis-assembly, the blue is a better choice as is something other than 574. But if you're building a motor that will stay in the car for the next ten years, I stand by my advice.

There is a thread here called "Ultimate Sealants" that gets to the skinny of it all. Since you said you weren't splitting the case, I stuck with the required procedures for a cylinders up rebuild. There will be infinite opinions here so look around.

Red Loctite is valuable for keeping the flywheel bolts where they belong in the 6 bolt 70.4mm cranks. An impact gun has no problems removing these bolts. They come right out as required.

However, if you are not going to spin the motor up to 8,000 rpm (or above), it is not necessary, and so shouldn't be done.

Walt

Mechanics and future owners everywhere thank you sir. I think labor rates should go up based on every ounce of silicone used by the prior owner.

+1 with what Chris and Scott said!!

I am currently working on a 1978 3.0L and am finding RTV everywhere. What a mess...with little pieces floating around inside the case too. Wonder how the oil was flowing, huh?

Hi to all:
I am in the process of my rebuild and can't find either the TB 1211 or the Curil T. What can be used instead for the cylinder base gaskets and the No. 8 bearing?

Thanks as always,

Francisco Soto

You can get both from Henry Schmidt at Supertec. I used Curil T on my nose bearing O-ring and it leaks. I used aviation gasket maker on the base gaskets and they do not.

Lindy

I use orange Loctite around the outermost part of the nose bearing (outboard of the O ring). No leaks, but then again maybe it wouldn't anyway.

I have never used anything on the base gaskets, and have never had a leak. Or at least not enough so there is a drip. Sometimes a little more dust/grime may gather in that area.

So there are lots of ways which can work (just as there are quite a number of sealants which will work).

And some which don't.

Lindy:

Thanks for your quick reply. But I live in Puerto Rico and I think these sealants can't be send by air (because of flammability, I think). I was thinking about using Permatex 518 Anaerobic gasket maker (which I already have) for the nose bearing (between the o'ring and exterior part) and maybe TB 1194 in the cylinder base gaskets.
What do you think?

Thanks,
Francisco

John was kind enough to post this picture a few years ago and it's how we've been sealing engines for years.

http://forums.pelicanparts.com/uploa...1286984104.jpg
Outer case halves perimeter : Threebond 1104 or 1194

Bearing web surfaces: Loctite 574

#8 Bearing O-Ring: Threebond 1211

Case Thru Bolts: Dow Corning 55 on Green Viton O-Rings

Flywheel Seal: dry

Front pulley Seal: dry

Intermediate Shaft Cover to Case: o-ring Dow 55, gasket style 574

Oil Breather Cover to Case: Loctite 574

Cylinders to Case: Curil T

Cam Towers to Cylinder Heads: Threebond 1104

Cam Chain Housings to Case: gaskets Loctite 574

Cam Chain Housings to Cam Towers: gasket Loctite 574

Cam Chain Housing Cover to Cam Chain Housing: Gasket Loctite574

Gaskets: Thin coat of Loctite 574

Thanks Henry, I saw that picture before, but would like to know what other brand can substitute the TB1211 on the no. 8 bearing? Maybe Permatex 518 Anaerobic gasket maker?

Thanks,
Francisco

Over the years we resisted putting any glue on the #8 main bearing but after measuring the case bore we consistently found that it was not round. Sometimes as much as .015 out of round. Boring the case is an option but most of the shops that do align bore only bore this bearing location if they are shaving the case and bringing the case back to standard.
We tried using a slightly larger o-ring but finally succumbed to the need for a consistent technique.
To answer your question: there are probably many sealants that will work for this application but to date ThreeBond 1211 is the best we've found.
Good luck if you choose to experiment. Let us know how that goes. We are always looking for improved methods for assembling these old engine.
Cheers

Why would it be necessary to put any sealant on the bearing saddles?

These is no leakage path and the sealant should not stabilize the saddles.

I have been told it should not be done.

I have articulated and documented the theory of shear resistance offered by LocTite 574 flange sealant. I have illustrated in previous posts the movement called shuffle that occurs where the case halves come together at the main webs. There is absolutely no down side to properly applying Loctite to the main webs.
The choice is yours.

One additional thought: Shuffle is a real issue in a high performance Porsche engine that can be best addressed by methods like shuffle pins or hollow dowels. That said, anything that can add to the stability of the engine platform is a good thing and we have first hand experience that gluing the webs reduces shuffle.

Henry

Thanks for you input...learn something new every day here.

I can't find Loctite 574 anywhere. Looked at the local stores and online. Anything else work as well.

Chris

dirko,dirko,dirko.superior silocone.loctite and all permatex's are similar to t.rex,as are most people who use them.i.m.c.sells dirko.

Elring Dirko is an RTV Silicone. As such there are very limited uses on a 911 engine.
This was used extensively back in the 70s by type 1 VW engine builders then abandoned as more efficient products became available. It works pretty well for sealing the water pump on a Chevy V8.

Most Porsche engine builders find RTV Silicones inappropriate for assembling air cooled 911 engines.

Chris,

574 and all the other sealants are available here at Pelican and from Supertec.

Lindy

Thanks, Just placed on order with Pelican for the Loctite 574 and the Curil T.

Chris
73 911 E

What is the best way to apply 574, between the cam tower and cylinder heads, with a small paint roller?

Tommy

The books all say a small paint roller, and show you what to cover - the whole of the milled flat carrier surface. And that works.

But I just squeeze out a thin line on the carrier around the port openings, with loops around all the stud holes. Works fine, as it squeezes out to cover a larger area. And in the area between intake and exhaust you don't need any, because nothing is going on there, so it is a waste of Loctite.

Walt

I just saw a post by Trevor Dawe (Peter Dawe's son) on Facebook about this. He says main webs should be clean and dry. William Knight says the same thing. When a case in line bored, is any sealant on the main webs? I don't think so. So why would you put sealant there when assembling an engine? All it can do is mess up clearances.

I bought head studs, rocker arms and a sealant kit from Henry, and believe he is a top notch builder, and he is qualified to put sealant on the case webs at the main bearing locations.
I also consoled with Peter Dawe, and had my case, and rotating assembly checked by the machinist he uses. All bearing clearances were checked with the case assembled dry, and I was told all NOT to put anything on the case halves at the main webs. He said if your an expert like Henry, fast, and do it perfectly you might only add a few tenths (.0001"). I am not that expert, and I will assemble the webs dry, just like the factory did. Just like any precision bolted assembly that gets measured dry. I hope to put this engine together one time.
Sealant on the webs can and does go wrong, leading to oil pressure problems.
David

.0002-.0003 of an inch is the expected crush on 574 when properly used.
Properly applied and assembled is the key phrase. Timing is everything. If you are not confident in your assembly technique avoid using 574 on the webs.

Shear strength of 574 is well documented. Reducing main web shuffle, especially in mag case motors is valuable. I have seen zero documentation [claims of detrimental effects] of stabilizing main web contact. The theory that it "may" cause significant tolerance issues is just that, an undocumented theory.

Here's a homework assignment for those of you who prefer research over experience.
Look up the tolerance for main bearings bores. Then look up the crank main journal tolerances. Then take into account bearing fluctuations.
Given the factory prescribed tolerances, do any of you believe that Peter Dawe, William Knight or Hans Mezger himself would be concerned with a tolerance variance of two to three ten thousands?
Many race engine builders, Porsche and otherwise are recommending and building engines with over .001" additional main bearing clearance over the Porsche prescribed numbers. .0003" really?

Reviving an eleven year old thread....

http://forums.pelicanparts.com/uploa...1635522262.png

Henry, as I said I think it's possible to do it correctly so that the bore only gets bigger by a few tenths. But yes, Peter and machinist Nick told me not to do it, and they had torn down fresh rebuilds where there customer's had followed your advice and way too much cured sealant on the webs, then had oil pressure issues. Maybe it was outdated Loctite curing too fast, but for me it's not worth the risk or stress of wondering if I did the assembly fast enough.....
Of course nothing about my rebuild is happening fast.
David
Plodding along
But enjoying every minute of it.

No worries. As the engine builder, you are responsible for assessing your best route to success.
As a successful engine builder, it my pleasure to share our methods for success.

Is Threebond 1194 now 1184?

The wonderful thing about building engines I have found over the years is, nothing is an absolute nor is it the only way. What works for some may not work for others. And that's what makes it great. We learn something from others.

I personally would not add anything to the main webs. Solving the fretting should be done in other ways. But if it works by adding sealant there, who's to say "don't do it".

If you sleep better at night by doing it and your engine runs just fine, then what's the problem.

We all have our own quirks, do's and don'ts and engine builders are full of them. I'm over flowing with them. I hate when air cooled cylinders are call "jugs". You put milk in jugs. Never use an engine as a tool bench. That's what benches and tool boxes are for. I could write a book.

Yes

Yes I noticed that... someone apparently is trying so hard to be "right" and win the internet..

Not sure what cred being a checkbook mechanic gives..

Yeah, sure....

Actually, I read this thread a while ago when I was doing research on sealant used on engine cases, heads, cam towers, etc. Why? I had to pull the heads off of my race engine to get them R&R'd as I bent some valves on a missed shift. I took the heads off and I was going to be putting them back on. In the end, William Knight flew out and we reassembled the engine together. I could have done it myself but I am glad he was there to show me how he did it.

Anyway, I was puzzled as to why you would want to use sealant on the main webs as they don't need to be sealed and the roundness of case bore would be affected by the sealant. I had seen several Factory engines taken apart and with no sealant used on the main webs. I was pretty sure I saw an Andial engine being put together with no 574 on the main webs either.

Fast forward to yesterday and I saw a post on Facebook showing a case with 574 that was .0035" thick. The post admonished people to leave the the main webs "clean and dry".

That reminded me of what I read in this thread. So there you go. Maybe someone that knows what they are doing can get the 574 applied thinly enough and the case torqued tight before the 574 cures too much. But clearly this did not happen in the Facebook example.