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Glenb Samba Member
Joined: September 29, 2005 Posts: 8
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Posted: Sun Aug 01, 2021 6:50 pm Post subject: Cam bent or case warped? |
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Trouble now with reassembly of a T1 1600 case using original stock crank and Mahle (stock size/grind) cam that worked well together before the disassembly.
Align bored case and shop provided corresponding Silverline bearings for ground and polished crank. I was told cam was polished and in good shape so instructed to purchase Standard size bearings for cam. I purchased Silverline standard size double trust bearings for the cam. Cam end play is seems good at .003”. Everything good until some tightening of the main studs. Noticeable resistance at 15 ft lbs and then quite difficult before 20. Same situation with or without 14 ft lbs of the perimeter nuts.
Crank only (without cam) the mains take 25 ft lbs and still turns easily. Then cam alone is where issue occurs. I reached out to the machine shop and learned the cam center saddle is sometimes out so was referred to an older VW mechanic known to have a bore tool for this cam saddle. I took the case there and went through that process, with expected shavings, but to no avail. Same issue with that mechanic’s spare set of single thrust bearing attempted.
Back home I remounted a case half then removed the middle cam bearing to check for warp on the corresponding area of camshaft and found no movement from the dial indicator during rotation. Adding the crank back to the mix on the case half I did find turns well as long as timing marks are aligned but if I set the gear teeth to random positions the cam will want to walk out at specific spots of the rotation. Of course the engine would never run with incorrect timing position between the crank and cam gears.. but is this a sign that one or both is bent? Or possible indication the case is warped, etc.? |
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Pruneman99 Samba Member
Joined: February 22, 2012 Posts: 5013 Location: Oceanside
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Posted: Sun Aug 01, 2021 7:03 pm Post subject: Re: Cam bent or case warped? |
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Take the silverline double thrust bearings out, and throw them in the trash.
Then go find something Malhe double thrust, install, and smile.
I messed around with 3 different sets of the silverline double thrust bearings before gave up. It was like each half bearing was 50.1% of a circle. When you tightened the case, the bearings went all taco shaped and locked the cam. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21520 Location: Oklahoma City
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Posted: Sun Aug 01, 2021 7:11 pm Post subject: Re: Cam bent or case warped? |
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I have no experience with the silverline bearings....
....but dig through this and pay attention to the section about crush points, warpage and especially the chamfer o the inside side of the thrust bearing bores.
https://www.thesamba.com/vw/forum/viewtopic.php?t=694420
My finding has been that...at least on type 4's...since teh factory never used a double thrust bearing...they didn't bother to chamfer as much on the side that is unused....and also different bearing brands and makes have a different radius where teh flange is pressed that may not fit the chamfer of the case
Ray |
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Chickensoup Samba Member
Joined: January 06, 2018 Posts: 5368 Location: Good Hope, GA
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Posted: Sun Aug 01, 2021 7:46 pm Post subject: Re: Cam bent or case warped? |
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sorry, i didnt read all of it, but the silverline double thrust cam bearings have tabs on both thrust shells. one needs to be filed flat. _________________ -'85 c10 5.3 LS, 222 cam, long tubes, x pipe, 3 inch spin tech's
-'05 B5.5 TDI Wagon 17in sport rims ;EGR + BSM + ASV Delete, Stage-2 Tune, straight pipe
'65 Tourist Delivery Build
'66 RIP
'69 RIP
Hosea 4:6 "My people are destroyed for lack of knowledge" |
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Glenb Samba Member
Joined: September 29, 2005 Posts: 8
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Posted: Mon Aug 02, 2021 6:09 pm Post subject: Re: Cam bent or case warped? |
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Pruneman99 wrote: |
Take the silverline double thrust bearings out, and throw them in the trash.
Then go find something Malhe double thrust, install, and smile.
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I recall now during forum investigation that Modok also pointed out that Mahle gives a little more clearance. With your recommendation, I ordered a set of Mahle double thrust to try out. Thx!
Last edited by Glenb on Mon Aug 02, 2021 6:25 pm; edited 1 time in total |
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Glenb Samba Member
Joined: September 29, 2005 Posts: 8
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Posted: Mon Aug 02, 2021 6:17 pm Post subject: Re: Cam bent or case warped? |
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raygreenwood wrote: |
....but dig through this and pay attention to the section about crush points, warpage and especially the chamfer o the inside side of the thrust bearing bores.
https://www.thesamba.com/vw/forum/viewtopic.php?t=694420
My finding has been that...at least on type 4's...since teh factory never used a double thrust bearing...they didn't bother to chamfer as much on the side that is unused....and also different bearing brands and makes have a different radius where teh flange is pressed that may not fit the chamfer of the case
Ray |
Thanks Ray. I did read that link and tried to follow the advice as I was working through this even before taking to another shop for middle cam saddle bore. I did make case adjustments and some filing of tab on the double thrust bearing a bit like the article points out also. For now will try another set from different manufacture (Mahle).
Q: What I describe on original post that cam will walk out if not aligned with crank gear marks - is that normal? I would think they just rotate smoothly against each other. |
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Glenb Samba Member
Joined: September 29, 2005 Posts: 8
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Posted: Mon Aug 02, 2021 6:22 pm Post subject: Re: Cam bent or case warped? |
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Chickensoup wrote: |
sorry, i didnt read all of it, but the silverline double thrust cam bearings have tabs on both thrust shells. one needs to be filed flat. |
I did see that early on and addressed similar to the link Ray provided. Good callout but I tackled that fit also before posting my observations and questions. I probably should have mentioned that in original post but felt it was getting too long already. |
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Glenb Samba Member
Joined: September 29, 2005 Posts: 8
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Posted: Wed Mar 09, 2022 7:05 pm Post subject: Re: Cam bent or case warped? |
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Thanks again everyone for your input! The suggestion from Pruneman99 worked for this situation.
Was still able to install double thrust cam bearings as planned. The solution was to remove the Silverline cam bearings and insert Mahle double thrust cam bearings instead. Ends up the cam is also Mahle so not a surprise they play well together.
Now spins well at proper case studs/nuts torque. |
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Pruneman99 Samba Member
Joined: February 22, 2012 Posts: 5013 Location: Oceanside
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Posted: Wed Mar 09, 2022 8:26 pm Post subject: Re: Cam bent or case warped? |
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Glenb wrote: |
Thanks again everyone for your input! The suggestion from Pruneman99 worked for this situation.
Was still able to install double thrust cam bearings as planned. The solution was to remove the Silverline cam bearings and insert Mahle double thrust cam bearings instead. Ends up the cam is also Mahle so not a surprise they play well together.
Now spins well at proper case studs/nuts torque. |
Glad I could help. It took me multiple sets of cam bearings before my dumb brain could find the answer. I have more $$$ in cam bearings than I have in the cam. |
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nsracing Samba Member
Joined: November 16, 2003 Posts: 9481 Location: NOVA
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Posted: Thu Mar 10, 2022 5:47 am Post subject: Re: Cam bent or case warped? |
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Learning from your experiences - nothing like it.
YOu gotta catch up w/ some posts. YOu have been here awhile. |
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