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bay window dude Samba Member
Joined: June 22, 2007 Posts: 144 Location: Portland, OR
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Posted: Sat Aug 09, 2008 11:31 am Post subject: double thrust cam bearing install question |
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this is my first time rebuilding an engine it is a 1800cc from 1974. I noticed there is no little tab on the thrust bearings (i got double thrust bearings). how do you install these so they don't go crazy and spin?
Last edited by bay window dude on Sat Aug 09, 2008 2:35 pm; edited 1 time in total |
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rcnotes Samba Member
Joined: July 09, 2005 Posts: 641 Location: Ann Arbor, MI
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bay window dude Samba Member
Joined: June 22, 2007 Posts: 144 Location: Portland, OR
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Posted: Sat Aug 09, 2008 12:18 pm Post subject: |
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i did search but all of the topics are about type 1 engines which have a tang and my problem is that there are no tangs because it is a type 4 engine! |
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rcnotes Samba Member
Joined: July 09, 2005 Posts: 641 Location: Ann Arbor, MI
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50265
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Posted: Sat Aug 09, 2008 12:43 pm Post subject: |
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That thread doesn't seem to answer his question. |
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rcnotes Samba Member
Joined: July 09, 2005 Posts: 641 Location: Ann Arbor, MI
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bay window dude Samba Member
Joined: June 22, 2007 Posts: 144 Location: Portland, OR
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Posted: Sat Aug 09, 2008 2:03 pm Post subject: |
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THAT IS FOR A TYPE 1 ENGINE I ALREADY SAW THAT! TYPE 4 THRUST BEARINGS DO NOT HAVE ANY TAB!!!! |
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calebmelvin Samba Member
Joined: July 19, 2006 Posts: 3140 Location: Seattle, WA
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GusC2it Samba Member
Joined: June 23, 2005 Posts: 1376 Location: Orlando, Florida, USA
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melville Samba Member
Joined: August 09, 2006 Posts: 1242 Location: Just Outside the Redwood Curtain
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Posted: Sat Aug 09, 2008 6:32 pm Post subject: |
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If your case won't hold the bearing in place, it's not because of the lack of tang. It may indicate a bigger problem. Some people who are obsessed about it will set the bearing shell in the case half and hammer a tang into it, but my T1 and T4 gurus, Berg and Raby respectively, both say it's unnecessary. I believe them, and have built my motors that way (tangless). _________________ 2000 M Roadster
79 R100RS
78 R100/7
75 R75/6
65 Standard Micro
57 Sedan |
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busman78 Samba Member
Joined: August 17, 2004 Posts: 4518 Location: Oklahoma City, OK
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Posted: Sun Aug 10, 2008 7:25 am Post subject: |
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You do not need the tang, the double thrusts will not spin. |
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NASkeet Samba Member
Joined: April 29, 2006 Posts: 2947 Location: South Benfleet, Essex, UK
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Posted: Mon Aug 11, 2008 6:28 am Post subject: VW Type 4 engine, double-thrust camshaft bearings |
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bay window dude wrote: |
i did search but all of the topics are about type 1 engines which have a tang and my problem is that there are no tangs because it is a type 4 engine! |
busman78 wrote: |
You do not need the tang, the double thrusts will not spin. |
One needs to create a tang, on one of the thrust bearings, using a blunt cold-chisel, screwdriver or nail-punch. I favour the nail-punch.
It's possible that double-thrust camshaft bearings, which lack a locking tab, might not spin, owing to the combination of bearing-crush and friction, but I would not wish to risk the possibility of bearing spin, which would necessitate dismantling the engine and perhaps replacing a camshaft with an overheated bearing journal. _________________ Regards.
Nigel A. Skeet
Independent tutor (semi-retired) of mathematics, physics, technology & engineering for secondary, tertiary, further & higher education.
Much modified, RHD 1973 VW "1600" Type 2 Westfalia Continental campervan, with the World's only decent, cross-over-arm, SWF pantograph rear-window wiper
Onetime member, plus former Technical Editor & Editor of Transporter Talk magazine
Volkswagen Type 2 Owners' Club (Great Britain)
http://www.vwt2oc.net |
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busman78 Samba Member
Joined: August 17, 2004 Posts: 4518 Location: Oklahoma City, OK
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Posted: Mon Aug 11, 2008 6:53 am Post subject: |
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Nigel, I have read several post by some that have tried to create the tang, final results were the bearing gets damaged. This weekend I tore down an engine that had double trusts cam bearing installed, although not a lot of miles on it and the thrust bearings were still intact, had not rotated nor was there any indication they had moved. Problem with engine was not the cam.
I also brought this question up on the Aircooled forums and the response was to install the double thrusts as is.
Just out of curiousity, how about putting a thin film of sealant in the saddle, any thoughts on that? |
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GusC2it Samba Member
Joined: June 23, 2005 Posts: 1376 Location: Orlando, Florida, USA
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Posted: Mon Aug 11, 2008 9:19 am Post subject: |
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My posit on this is that the percentage of risk failure with double thrust compared to stock single thrust makes use of double thrust not a viable choice except when the use of double valve springs makes the rotational resistance of the cam sufficiently high that the Helical cut cam gear has to impart additional end loading on the cam to force it to turn. Most engines at this high performance level use straight cut gears any way which don't impart any end loading on the cam. _________________ 75 type 2 http://gusc1.tripod.com/1975vwtype2
Old vices have now been upgraded to bad habits.
http://www.facebook.com/pages/VW-Wild-Weekend-2011-St-Pete-Fl/197064760336111 |
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