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Date:         Wed, 4 Jan 2006 23:46:31 -0700
Reply-To:     Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Subject:      Re: Failed Crankshaft seal yet again
Comments: To: John Rodgers <inua@CHARTER.NET>
In-Reply-To:  <43BC88C0.2050507@charter.net>
Content-Type: text/plain; charset="us-ascii"

When I had a plugged breather hose, the pressure came out the dipstick tube, pushing the dipstick out an inch or so. I believe this is the normal route for excess crankcase pressure.

Karl Wolz

> -----Original Message----- > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of > John Rodgers > Sent: Wednesday, January 04, 2006 7:47 PM > To: vanagon@GERRY.VANAGON.COM > Subject: Re: Failed Crankshaft seal yet again > > David, > > I doubt seriously that crankcase pressure is blowing that seal. I had a > pison burn a hole right through it. All the pressure of combustion then > blew right into the crankcase. Talk about crankcase pressure -- but my > engine didn't blow that seal. Instead, the pressure moved through the > crankcase, then to the pushrod tubes the to the rocker covers, there it > blew out the rocker cover seals. And it did that not once but twice > before I realized I had a hole in a piston. The cranskshaft seal is a > much tighter seal that the rocker cover gasket, and so the rocker > gasket blew instead. So I really don't see that crankcase pressure > would ever blow the seal. It will most likely blow something else that > is not seated as tightly as that seal is seated. > > Regards, > > John Rodgers > 88 GL Driver > > David Shepherdson wrote: > > >Thanks to all that gave me feedback on this problem. One suggestion was > >excessive crankcase pressure, I am pretty sure that the breather hose > >(to the intake boot) is OK but will certainly double check (and try > >putting my hand over the oil filler pipe when I get it running to see if > >I can feel it). Another was endplay/endfloat but as I said in my > >original e-mail I did measure that and it seemed to be OK. I don't know > >about the thrust bearing but I am not sure how I can check this (and if > >it means engine disassembly then that pretty much equals a new engine as > >far as I can see). I guess it could be a engine case fault (the engine > >was rebuilt by VW Canada) but I am not sure how to check that (and it > >would necessitate a new engine anyway). The e-mail below by Ratjen is > >certainly food for thought. I have seen a very thin wear line which > >appears to be straight (I do not believe that the wear line is causing > >the problems as the "new" flywheel is the same and it has just been > >machined and inspected) but I will check again. I have heard sounds > >that could be a bearing going but then again I think it might be my > >paranoid imagination because it does not seem to have got worse (and > >sometimes is not there at all). Anyway, I don't think the bearing can > >have been bad through all 6 or 7 oil seals which go back 20k miles or > >so. I am trying to think of ways that I might measure crank or flywheel > >wobble (the engine runs smooth enough - any ideas?). Maybe putting the > >new flywheel on will cure it. By the way Ratjen asks what I mean by > >catastrophic failure? I mean that all the oil drains out in a couple of > >seconds while the engine is running and of course the oil warning buzzer > >comes on. This is caused by actual damage to the seal (the sealing lip > >which contacts the flywheel was torn the first time and the face of the > >seal that faces the flywheel had a small crack in it the second time). > >I can't be sure that this is what happened the times before I bought it, > >it could be just that the seal was dripping oil. Judging by the speed at > >which the oil came out this time I am pretty sure that the seal is > >damaged again for the third time, it will be interesting to see where. > >Could this kind of seal damage occur as a result of crank or flywheel > >wobble or case mis-alignment(I can see how that might cause leaks but it > >is not so obvious why that would damage the seal). I can also rule out > >pilot bearing as I changed this last time it happened. Still looking > >for ideas (and potential solutions)!!! > > > >My list so far looks like this: > >Check crank breather hoses > >Measure endfloat before removing flywheel > >Also try to measure if flywheel is running true > >remove flywheel and note and photograph damage to seal > >Check with straight edge that it is not protruding from the case > >Remove seal and check condition of thrust washers > >Try to measure crank wobble (?) > >Try to determine if case is symetrical > >Check sealing surface of flywheel for wear marks and investigate for > >straightness and continuity > >Try to check end of crankshaft for trueness > >Install new fly wheel and check endfloat and adjust if neccessary > >Remove and install new felt washer, O ring and oil seal > >Install and torque flywheel > >Check flywheel trueness again (??) > >anything else?? > > > >Thanks, > >David > > > > > >------------------------------ > > > >Date: Tue, 3 Jan 2006 12:18:13 -0800 > >From: =?iso-8859-1?Q?Bj=F6rn?= Ratjen <Bjorn@IGLIDE.NET> > >Subject: Re: Failed Crankshaft seal yet again > > > >David, > > > >As I know how frustrating these things can be let=20 > >me wade in with some comments. The seals are made=20 > >to keep oil from wandering along a smooth and=20 > >perfectly round surface. They need to stay in=20 > >place and follow the moving surface in an=20 > >absolutely straight path. If the matching surface=20 > >is either not completely round or wobbles then=20 > >the seal will break. You can look at the surface=20 > >of the moving part. Is there one (or two matching=20 > >the lips of the seal) straight line?=3Dgood. Does=20 > >the line have differing thickness or is it not=20 > >completely straight?=3Dbad. Wobble can occur=20 > >through deformation of the moving part,=20 > >misalignment of mounting surfaces (crankshaft to=20 > >flywheel) or excessive play in bearings. Look=20 > >also for evidence of movement of the seal in the engine block. > > > >When the seal is installed it needs to be tight=20 > >and straight in the engine block. Only press on=20 > >the outer ring for installation. Check for any=20 > >rough parts or burrs in the moving part which=20 > >could damage the seal during installation. The=20 > >seal actually creates a small indentation in the=20 > >moving part over time. Check this indentation=20 > >carefully for any tiny imperfections and measure against seal if > >necessary. > > > >Also check pilot bearing for transmission shaft=20 > >(in flywheel) as too much play can damage transmission seal and oil > >clutch. > > > >I do not know what you mean by "catastrophic"=20 > >failure. A small leak can drain a lot of oil. I=20 > >remember when I spent a day to help a friend to=20 > >replace his aircooled van engine (at a parking=20 > >lot) with another one a friend of his had stored,=20 > >only to find that all the oil drained within=20 > >50kms because the crankshaft seal had simply=20 > >dried up. We bought a tow bar and I towed him=20 > >300kms on the German Autobahn with my VW van=20 > >through the night. As he had a 1600cc engine and=20 > >I had the new! 2000cc engine he found it to be=20 > >almost as fast if he had driven on his own power. :-) > > > >Hope this helps. > > > >Bj=F6rn > > > >At 06:25 AM 03/01/2006, you wrote: > > > > > > > >>Date: Mon, 2 Jan 2006 23:47:14 -0800 > >>From: David Shepherdson <shepherdsond@METRO.DST.OR.US> > >> > >>I just watched my 87 syncro Westfalia being winched onto a flat bed > >> > >> > >tow > > > > > >>truck for the 3rd time in 5 months near Bend Oregon this weekend, all > >>three times were the result of catastrophic failure of the main > >>crankshaft oil seal. I am appealing to the list now to solicit some > >> > >> > >more > > > > > >>ideas about what could be wrong before I drive back to Bend (from > >>Portland, Oregon) next weekend to try and fix it. The first time > >> > >> > >this > > > > > >>happened was on a trip to NWT in Canada. That time it was the part > >> > >> > >of > > > > > >>the seal that contacts the flywheel that ripped. The next time the > >>break was on the face of the seal (hence the hypothesis that the seal > >>had been rubbing on the flywheel (although it did not appear to > >> > >> > >stick > > > > > >>out - the replacement was very well countersunk), of course I don't > >> > >> > >yet > > > > > >>know where it has failed this time. I do however know from looking > >> > >> > >back > > > > > >>through receipts from the previous owner that this 40k engine has now > >>had 6 main seal failures in its life. My current hypothesis from > >>talking to mechanics at VW is that there is something wrong with the > >>flywheel (it looked OK but I did not check the diameter of the > >> > >> > >sealing > > > > > >>surface) so I have a freshly machined replacement from AVP to replace > >> > >> > >it > > > > > >>with. Needless to say the O ring was replaced each of the last 2 > >> > >> > >times > > > > > >>and I also checked the end play last time which appeared to be well > >>within limits (I will measure it again when I dismantle it next > >>weekend). > >> > >>Both the last two times the symptoms have started as soon as the > >> > >> > >engine > > > > > >>was reinstalled. Oil leaked from arround the bell housing from day > >> > >> > >one > > > > > >>after replacing the oil seal. Not a huge amount but enough to spot > >> > >> > >the > > > > > >>rear door after freeway driving and leave a daily oil mark on the > >>driveway. This suggests that the seal is under some sort of stress > >>right from the start. Then after about 2000 miles the seal fails > >>completely and all the oil drains out. I guess if the flywheel > >> > >> > >diameter > > > > > >>was too small it could cause a leak but why the seal then fails > >>completely I dont know. I am wondering if there is anything that > >> > >> > >could > > > > > >>cause the oil pressure to be too high in this area (faulty > >> > >> > >instalation > > > > > >>of bearings??). Or does anyone have any other ideas - I am at a loss > >>now and if it starts to leak again after I replace it this time I > >> > >> > >will > > > > > >>have to replace the engine. Unexpected catastrophic failure of the > >> > >> > >oil > > > > > >>seal is just not something I can live with (it makes me shudder to > >> > >> > >think > > > > > >>of some of the places I have been where this could have happened). > >> > >> > >All > > > > > >>ideas gratefully received! > >>David > >> > >> > >> > > > >------------------------------ > > > > > > > >


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