Case Sealant - #8 Main Bearing

[Walt Fricke]

Henry

I've never worried about the orange Loctite excess squeezed out of the case sealing areas getting into the oil in the case. It will be strained by the scavange pickup screen, then macerated by the pump, then filtered by the filter, and then macerated again by the pump before it finds its way any small oil passages.

But excess sealant on the #8 bearing saddle by the oil inlet area looks like it will be carried into the crank passages.

Since you have done this on so many engines, it can't be a practical problem. Does this mean that the viscosity of undried sealant is such that it just passes through the bearings with the oil?

And that one doesn't need to worry about blocking the oil return slot, because the sealant prevents any oil from reaching the O ring in the first place?

Walt

[304065]

Walt,

If you are concerned about blocking the spraybars, how about one of these inline for the breakin period! Used by NASCAR to filter valve train spraybar oil!



I plan to glue the #8 bearing in place on the outer side. But I'm also leaving the slot clear: that wasn't just an Up-fixen author who proposed using a fine-tooth saw blade to cut a groove in the bearing, that advice appears in the supplements to the engine section of the Factory Workshop Manual.

[Walt Fricke]

John

As it happens, Peterson (aka Mortons Motorsports) is only about 20 miles from where I live, so I get stuff there from time to time.

But it isn't the spray bars I was wondering about - Loctite orange oversquish hasn't caused any problems there for me because it has such an obstacle course to pass through before getting there from the case sump.

Rather it is the crank oiling passages. A friend once had a piece of a case bolt O ring get into his (easy to see how this could happen if you weren't pretty careful with disassembly/cleaning, and pulling the plugs in the crank is a pain for the home brewer). This proved to him that a Carillo rod was strong enough to sieze on the crank (once it stopped the engine at idle) without breaking. A nice even blue color all around the big end.

I don't suppose a little uncured anaerobic sealant would do something like that, but I don't know it for sure.

Walt

[304065]

Walt,

I have started a new thread on this subject called, "Break-in oil debris."

[johncmng]

This is what I use to prevent any oil leaks from there. I got it from Tom Amon. I'll let you know how long it last.

Tom Amon showed up at my house with new gadget!!

[quattrorunner]

So?

[John McM]

Reviving the thread. What if anything is used on the #8 bearing o-ring if the entire saddle is sealed with 1211. My leak is the #8 area so getting this wrong will impact on a lot of time and money to get to the point of resealing it.

[spydr32000]

John I would be replacing the O ring and coating it and that immediate area lightly with the Three Bond 1211. Keep the groove free of it and just use the sealant on the area of the O ring. Has that had a sealing flange added to the outside of the bearing? If so that should not be required after correct sealing is completed!

[John McM]

Originally Posted by spydr32000

John I would be replacing the O ring and coating it and that immediate area lightly with the Three Bond 1211. Keep the groove free of it and just use the sealant on the area of the O ring. Has that had a sealing flange added to the outside of the bearing? If so that should not be required after correct sealing is completed!

Thanks.

The nasty looking item on the outside of the bearing is a half destroyed Tom Amon collar. It broke away from the case but was so well stuck to the bearing that I need total removal of the bearing from the engine to safely cut it off.

[Walt Fricke]

John - I don't like the idea of coating the entire #8 bearing saddle. The sealing should be done by the O ring. I don't want sealant any where near where the oil enters the bearing, headed for the crank. I've had good results using my overall sealant (I have had good results from 574, but obviously there are lots of other sealants which do the job)only outward of the groove in which the O ring sits. And I don't want sealant in that axial groove - my supposition is that its function is to relieve any pressure there might be on oil which makes it to the O ring and then gets in the circumferential ring groove. Maybe it is just there to help you position the bearing so it mates with the locating pin, but you shouldn't need more.

The factory, and our host in his book, doesn't show any sealant on the bearing (which is where it makes some sense to apply it, at least after the bearing and crank are in place, rather than on the other case half. Since the crank usually sits in the case half for quite a while relative to curing time before the other half is lowered down, I find that I can just lift up the nose bearing enough to coat that area just before I am ready to lower the other half, and then I can coat the part of the upper side I want to coat.

[stevepaa]

in 2005 I did my 964 engine as described in post 3. no leaks YMMV with type of engine

[Henry Schmidt]

14 years over 130 engines, zero reporting a # 8 main leak and less than 2% reported leaks of any sort using our sealing technique.
In 1990 (the only year I have data) the factory experienced a 4% leakage rate from new engines on the dyno.

[bpu699]

Originally Posted by Henry Schmidt

14 years over 130 engines, zero reporting a # 8 main leak and less than 2% reported leaks of any sort using our sealing technique.
In 1990 (the only year I have data) the factory experienced a 4% leakage rate from new engines on the dyno.

Henry, with the number 8 bearing, why is sealant applied along the INSIDE of the bearing saddle towards the center, rather than just by the oring?

I ask as the oil supply hole in the case feeds into the bearing about midway. So any goop applied medial to this, towards the inside of the case, would never keep oil from "seeping out."

If anything, if there were seepage between the case and the bearing, the goop towards the inside may force the oil to find a different path, and then it leaks outward?

Again, seems like a nonissue as you have been doing this for a long time. I just don't understand the mechanism of applying good medially helps keep oil from leaking out? If it leaks "into" the case, its a nonissue...

Bo

[Henry Schmidt]

Originally Posted by bpu699

Henry, with the number 8 bearing, why is sealant applied along the INSIDE of the bearing saddle towards the center, rather than just by the oring?

I ask as the oil supply hole in the case feeds into the bearing about midway. So any goop applied medial to this, towards the inside of the case, would never keep oil from "seeping out."

If anything, if there were seepage between the case and the bearing, the goop towards the inside may force the oil to find a different path, and then it leaks outward?

Again, seems like a nonissue as you have been doing this for a long time. I just don't understand the mechanism of applying good medially helps keep oil from leaking out? If it leaks "into" the case, its a nonissue...

Bo

The idea is to help seal the oil transfer hole.
If oil doesn't leak at that union, then oil will not leak at all.
If the oil leaks from the transfer hole you can have an oil pressure issue.
Although I resisted sealing this area for years at this point, we see no downside to a thin coat of sealant sealing the entire bearing.
Old parts change shape with heat and we prefer to error on the side of "no leaks".

[bpu699]

Originally Posted by Henry Schmidt

The idea is to help seal the oil transfer hole.
If oil doesn't leak at that union, then oil will not leak at all.
If the oil leaks from the transfer hole you can have an oil pressure issue.
Although I resisted sealing this area for years at this point, we see no downside to a thin coat of sealant sealing the entire bearing.
Old parts change shape with heat and we prefer to error on the side of "no leaks".

Anything that helps oil pressure is a good thing .

Along the same lines, any reason that the ims aluminum plug isn't also sealed with something into the IMS shaft? Its a pretty loose fit, that has to seep some oil pressure. Or, is that loose fit intentional?

Bo