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vwjoel
Samba Member
Joined: April 14, 2006
Posts: 205
Location: Seattle WA
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 Posted: Tue Jan 22, 2019 1:52 pm Post subject: Main Seal Issues |
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So I'm no professional mechanic but I've replaced quite a few main seals on bugs, busses and Vanagons but I am perplexed with an issue that has come up with my latest build. I'm sure its something simple that one of you will point out! I just built up a 2.1 DJ WBX engine with an Engle 110 cam, solid lifters, Weber IDFs and a Bugpack header. It all seems to be running great but the main seal has now popped out of the block 3 times in less than 200 miles! I've read most of the main seal threads here on The Samba so I figured my first failure was on me for using the seal that came in my ITM brand gasket kit. I was determined to get it right on the second attempt so I ordered the SABO seal with a new O-Ring and new flywheel from Go Westy. The SABO seal is quite a bit thicker and it does fit tighter in the bore of the case. This seal lasted 20 miles before it slid out and melted to the flywheel. When I got it apart I found that I had not set up the end play correctly for the new flywheel and it was too tight. My dumb mistake. The shims were scuffed a bit but the thrust ring on the main bearing looked good. OK, so the third time will do it. I set up the end play to .006" with good shims and installed a new SABO seal and O-Ring. This one lasted a little longer at around 100 miles before it slid out of the block. It seems to me that even the first seal should have lasted longer than it did. Have any of you seen this happen where a seal works its way out of the block?
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Igeo
Samba Member
Joined: September 25, 2018
Posts: 888
Location: Oakland, CA
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| Posted: Tue Jan 22, 2019 2:27 pm Post subject: Re: Main Seal Issues |
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Excess crankcase pressure?
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1987 Westfalia 2.1 WBX Manual |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32632
Location: Reading Pennsylvania
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Howesight
Samba Member
Joined: July 02, 2008
Posts: 3274
Location: Vancouver, B.C.
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| Posted: Tue Jan 22, 2019 2:47 pm Post subject: Re: Main Seal Issues |
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I agree with the above poster. That engine needs better crankcase breathing. It's amazing how crankcase pressure (or vacuum, for that matter) can affect oil seals.
The Weber setup typically has no provision for crankcase gases to pass through the carbs, so inadequate or no ventilation sometimes results if the WBX vent is simply blocked or removed.
The Mann pro-vent is a nice unit. Here is a link to a good thread on crankcase ventilation on the WBX:
https://www.thesamba.com/vw/forum/viewtopic.php?t=295812&highlight=pro-vent
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'86 Syncro Westy SVX |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Tue Jan 22, 2019 3:12 pm Post subject: Re: Main Seal Issues |
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Sorry, my money it is on the oil return from the seal area. It is easy to clog it with sealant when the case halves are assembled. Sealing case halves is not one of those if a little sealant is good, more sealant is better. Hope I am wrong.
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vwjoel
Samba Member
Joined: April 14, 2006
Posts: 205
Location: Seattle WA
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| Posted: Tue Jan 22, 2019 3:21 pm Post subject: Re: Main Seal Issues |
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I've heard of crank pressure pushing seals out. I have my crank vent set up as a 3/4" draft tube to atmosphere under the engine. With the engine idling I can feel pressure pulses coming from the tube. Could it be that the stock 2.1 plastic breather tower can't flow enough air for this setup? Howesight, thanks for the link. I've got more learning to do on crank breathers.
Another thing one of my friends just mentioned to me, who actually is a professional mechanic, is that when I built the engine I could have gotten sealant into the cavity in the case half that drains the oil from behind the seal to the sump. MarkWard, you may be right! He suggested that the oil pressure coming from the main bearing could be enough to push the seal out if it can't drain back to the sump. Does this seem plausible for a 2.1? When I get the flywheel off again I'll definitely check that drain. If this is it hopefully I can ream out the excess sealant in this area.
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Tue Jan 22, 2019 3:50 pm Post subject: Re: Main Seal Issues |
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This came up before. That member split the case. Worth trying to clear it if it is plugged. You would not be the first one to miss this. Good luck.
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DanHoug
Samba Member
Joined: December 05, 2016
Posts: 4800
Location: Bemidji, MN
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| Posted: Tue Jan 22, 2019 4:14 pm Post subject: Re: Main Seal Issues |
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easy to diagnose... see if the drain passes air from a nozzle. with that curve it may be difficult to 'snake' it clear but i'd try a whole bunch before splitting the case. you'll want something with a rounded nose so it follows the channel, chucked in a variable speed drill.
what was the exact sealant used on the case? i'd start trying all your shop chemicals to see if you can find one that softens that sealant on the bench then use it on the channel. spray, drill, air blast, repeat.
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-dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32632
Location: Reading Pennsylvania
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vwjoel
Samba Member
Joined: April 14, 2006
Posts: 205
Location: Seattle WA
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| Posted: Tue Jan 22, 2019 4:22 pm Post subject: Re: Main Seal Issues |
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| I've been dreaming up a tool to clean out the passage behind the seal without splitting the case. I'm thinking of a bicycle brake cable in a drill with the wires at the end of the cable splayed out. A dab of solder just back of the splayed part to hold the rest of the cable together. The sealant I used was Permatex Right Stuff. If I can get something into the cavity under the stub of the crank shaft I'll get the sealant out of there. It'll end up in the sump though. I'm wary of softening the sealant with chemicals since it might effect the bits of sealant between the case halves where it is supposed to be. I'll see how it goes through purely mechanical means first. |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32632
Location: Reading Pennsylvania
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DanHoug
Samba Member
Joined: December 05, 2016
Posts: 4800
Location: Bemidji, MN
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| Posted: Tue Jan 22, 2019 5:07 pm Post subject: Re: Main Seal Issues |
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The Right Stuff is pretty tough... it is more of a structural bond than generic sealants. it'll be hard to grub out so keep us posted as to what you come up with!
personally, i think a bit of TRS into the sump wouldn't be a big deal. if it gets sucked up by the oil pump, it won't hurt the gears and just pass into the filter. and if it doesn't, it may not be destructive to anything.
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-dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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jberger
Samba Member
Joined: November 17, 2003
Posts: 2476
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| Posted: Tue Jan 22, 2019 8:05 pm Post subject: Re: Main Seal Issues |
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My first attempt would be a shot of air from the blow gun on my compressor. Pretty easy to tell if it's flowing by keeping the oil fill tube open and listening. If that didn't work I'd push a small length of Tig wire of appropriate diameter that would bend as it was inserted. I'm betting the air pressure works a treat.
J |
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dabaron
Samba Member
Joined: June 21, 2018
Posts: 2561
Location: Philly, mang
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| Posted: Tue Jan 22, 2019 8:09 pm Post subject: Re: Main Seal Issues |
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when i go to put my case together i know to now watch for excessive sealant at the oil passages. thanks the samba!
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1991 Vanagon GL Camper
i had no idea i wanted to be a mechanic
"burnin oil and cookin coils" -- Destructo
BiWerks Design, LLC |
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uberaudi
Samba Member
Joined: June 24, 2013
Posts: 503
Location: Hi-top Country
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| Posted: Tue Jan 22, 2019 9:07 pm Post subject: Re: Main Seal Issues |
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I just watched a Bostig/Boston Bob video about the rear main/flywheel seal. I'm sure someone will repost it...
Are you recessing the seal on the seal bore or is it flush with the case? Also, there are two thicknesses if seals out there that carry the same part number...a 12mm thick for use with the automatics, and a 10 mm used in the manuals...
If it's not recessed (causing the dish of the flywheel to rub on it), or if you're using the 12mm thick one, the seal won't stand a chance and will fail quickly. |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Tue Jan 22, 2019 9:12 pm Post subject: Re: Main Seal Issues |
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| Maybe a short piece of 10 or 12 gauge solid copper wire and a 6-8 ounce hammer to drive it into the slot. |
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uberaudi
Samba Member
Joined: June 24, 2013
Posts: 503
Location: Hi-top Country
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32632
Location: Reading Pennsylvania
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vwjoel
Samba Member
Joined: April 14, 2006
Posts: 205
Location: Seattle WA
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| Posted: Wed Jan 23, 2019 11:35 am Post subject: Re: Main Seal Issues |
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Love the Boston Bob video. Thanks for the link uberaudi. That answers a lot of questions. Bob does mention in the video to not use the thicker seal for a manual trans with a standard flywheel. This is the only seal that GoWesty recommends though. Has anyone else had experience using the thicker SABO seal from GoWesty with a standard flywheel?
Dave, I've got some reading to do on case sealant. Hopefully I don't have to split the case again but next time I'll be better informed. |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Wed Jan 23, 2019 12:25 pm Post subject: Re: Main Seal Issues |
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| I have had a Sabo seal in both my VW Type 4 engine and my WBXer engine for quite a few years at this point in time, both engines have flywheels and are dry. |
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