TheSamba.com :: View topic - Use sealant on bearing saddles (web) when sealing case?

Thu May 30, 2013 1:59 pm

Just finished assembling the long block and when looking over the check list again it was then, of course, that I realized I did not apply sealant to the bearing saddles (web) in the center of the engine.

Manuals usually just say apply to "all" mating surfaces so that's why I've put sealant on them in the past, but I've never heard a reason for including them and they aren't mentioned specifically in the many existing "sealant" posts.

My only concern is if the sealant some how helps keep up oil pressure in the bearings - at least the center split bearing.

Is it OK to run the engine without this sealant? Thanks.

Thu May 30, 2013 2:03 pm

wondering that also

Thu May 30, 2013 2:09 pm

JSB wrote: Just finished assembling the long block and when looking over the check list again it was then, of course, that I realized I did not apply sealant to the bearing saddles (web) in the center of the engine.

Manuals usually just say apply to "all" mating surfaces so that's why I've put sealant on them in the past, but I've never heard a reason for including them and they aren't mentioned specifically in the many existing "sealant" posts.

My only concern is if the sealant some how helps keep up oil pressure in the bearings - at least the center split bearing.

Is it OK to run the engine without this sealant? Thanks.

You do not use sealant on the center web, only the O-rings around the studs. The bearing is machined where it comes together and forms a machine fit, no oil will "leak" out. Sealant could potentially be a bad thing in that spot....

Thu May 30, 2013 2:23 pm

as stated above , no sealant just the o rings ..

Thu May 30, 2013 2:25 pm

i put a little anaerobic sealant on the 3 webs.
mainly because Cummins specifies loctite on the main bearing cap mating surfaces to reduce fretting.

i fiqured it couldnt hurt. a poor mans shuffle pin perhaps :?

Thu May 30, 2013 2:27 pm

You do not use sealant on the center web, only the O-rings around the studs. The bearing is machined where it comes together and forms a machine fit, no oil will "leak" out. Sealant could potentially be a bad thing in that spot....[/quote]

SRP1, thanks for the feedback - I had never heard that explaination but it makes sense about them being machined surfaces for the bearing tolerances.

While I would never use silicone to seal an engine case, especially after seeing the effects on someone else's engine, but many still do and if it were used on the bearing web, that could really affect the tolerences while causing other problems in that area.

In the mean time I just checked a rather recent VW magazine article on engine building and they also show a picture with sealant on the center bearing web. Sounds like you need to get the word out to the VW community on this.

Thu May 30, 2013 3:24 pm

VIN wrote: i put a little anaerobic sealant on the 3 webs.
mainly because Cummins specifies loctite on the main bearing cap mating surfaces to reduce fretting.

i fiqured it couldnt hurt. a poor mans shuffle pin perhaps :?

VIN; interesting suggestion, especially for a high HP/reving engine.

Thu May 30, 2013 3:47 pm

I have built many an engine, and never used sealant on the center web.
I can't even imagine why you would? It's not like it's going to leak on it's self inside the case. LOL

Thu May 30, 2013 4:57 pm

Heck no. Don't put sealant on the center web. the gap is supposed to close up when it gets hot, mag expands 2.5 times faster than a steel shelled bearing :shock:

Thu May 30, 2013 6:02 pm

JSB wrote: You do not use sealant on the center web, only the O-rings around the studs. The bearing is machined where it comes together and forms a machine fit, no oil will "leak" out. Sealant could potentially be a bad thing in that spot....

SRP1, thanks for the feedback - I had never heard that explaination but it makes sense about them being machined surfaces for the bearing tolerances.

While I would never use silicone to seal an engine case, especially after seeing the effects on someone else's engine, but many still do and if it were used on the bearing web, that could really affect the tolerences while causing other problems in that area.

In the mean time I just checked a rather recent VW magazine article on engine building and they also show a picture with sealant on the center bearing web. Sounds like you need to get the word out to the VW community on this.[/quote]

as SRP1 and modok has mentioned already..

you could also research on bearing "crush" as to why no sealant is needed there...

Thu May 30, 2013 6:04 pm

JSB wrote: In the mean time I just checked a rather recent VW magazine article on engine building and they also show a picture with sealant on the center bearing web. Sounds like you need to get the word out to the VW community on this.
Never trust the magazines.

Thu May 30, 2013 7:11 pm

SRP1 wrote: I have built many an engine, and never used sealant on the center web.
I can't even imagine why you would? It's not like it's going to leak on it's self inside the case. LOL

silicone or other similar gasket makers, yeah makes no sense.

not as in a sealant for oil; more of a (for lack of a better word)glue. to glue the webs together. or if the individual was concerned about the added clearance that the anaerobic sealant would keep the case halves apart; what about a couple drops of blue loctite, or a sleeve retainer compound??

Thu May 30, 2013 8:19 pm

VIN wrote: SRP1 wrote: I have built many an engine, and never used sealant on the center web.
I can't even imagine why you would? It's not like it's going to leak on it's self inside the case. LOL

silicone or other similar gasket makers, yeah makes no sense.

not as in a sealant for oil; more of a (for lack of a better word)glue. to glue the webs together. or if the individual was concerned about the added clearance that the anaerobic sealant would keep the case halves apart; what about a couple drops of blue loctite, or a sleeve retainer compound?? ..

No amount of glue, sealant, loctite, or whatever type of goop you can dream up will be of any value in this location. The case moves and frets so much at the center web that it would most likely make matters worse. The flat metal machined surface and proper line boring are what keep it together and properly crush the bearing to keep it seated. The only upgrade so to speak is to pin it in place. Hence the name "shuffle pin"

Thu May 30, 2013 8:21 pm

JSB wrote: Sounds like you need to get the word out to the VW community on this.

Oh yea, I'll get right on that..... :lol:

Fri May 31, 2013 5:46 am

SRP1 wrote: JSB wrote: Sounds like you need to get the word out to the VW community on this.

Oh yea, I'll get right on that..... :lol:

SRP1, while I was half kidding, it is the reason I posted my question on TheSamba. In fact, the first responce was from someone wondering the same thing.