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I couldn’t find any new old stock under the 916 prefix number. I’m machining a fixture to hold the new bearings and turn them down to the size my old bearings measure.
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Depending on my outcome, and I feel 99.9999%, I’ll offer to the community to machine anyones bearings to the older dimensions.
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,728
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Granted a little neanderthal, but since the shoulder height of the bearing is relatively non-critical, would it be acceptable to remove .8 mm or whatever the correct amount is, using a belt sander (very carefully of course)?
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PCA Member since 1988
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You could grind the edge on a rock until it fits. THAT would be Neanderthal. The edge of the thrust face isn't critical.
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1973.5 911T with RoW 1980 SC CIS stroked to 3.2, 10:1 Mahle Sport p/c's, TBC exhaust ports, M1 cams, SSI's. RSR bushings & adj spring plates, Koni Sports, 21/26mm T-bars, stock swaybars, 16x7 Fuchs w Michelin Pilot Sport A/S 3+, 205/55-16 at all 4 corners. Cars are for driving. If you want art, get something you can hang on the wall! |
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,728
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Just measured the layshaft bearings I acquired recently, and they are 5 mm. I think the video mentions this is the "old" measurement and would be OK.
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Location: denver
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I am getting ready to assemble a 3.0L SC engine and read this post. I had just purchased the latest Glyco IMS bearings.
![]() I did not have the same issue with them sitting high mine were flush. ![]() I decided to check some of the other cases I have to see if there would be a issue. I found Porsche factory bearings in the two I checked. One had 916 series (86 930 case probably factory installed) and a previously rebuilt 2.7 with 993 prefix bearings. I tried the new Glyco in each case and found it fit the same as pictured. ![]() ![]() When I compared the 3 bearings the 916 and 993 appeared identical. And the bearing surface is .9 inches wide. ![]() The 996 version has a couple differences I can see so far. There is no hole drilled in the bearing, the thrust face is a little wider and the bearing surface is wider at 1.05 inches. ![]() All three bearings appear to be the same height at .68 inches from table to highest point on bearing. Left to right 916.993. 996. ![]() ![]() Based on what I have measured so far I would prefer the 996 version for the wider bearing surface. ![]() I purchased some NOS 916 bearing and will measure to see if there is any difference in clearance when they show up. John Last edited by targa72e; 02-04-2024 at 06:04 PM.. |
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
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Well after spending some undisclosed hours, ok I’m retired… doesn’t really matter…
I machined a lathe fixture to hold an IS thrust bearing to machine it to fit early engines. ![]() ![]() ![]() ![]() |
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I wish the interchange would get straightened out across the board. Not much chance of that since the central authority (Porsche’s parts manuals), has it wrong in all there manuals, (1965-1969), (1970-1973), (1974-1977), (1978-1983). They all show the 993-101-137-01 as compatible and the superseded part number. Vendors look at that as the gospel. What are the chances Porsche will correct this?
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Mods:
Maybe a sticky note is in order |
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Hi
Looking at the very first photo: How can you be sure that the bearing shell is seated correctly in the case ? (You cannot see because of the shell thrust faces.) Suggest you fit both bearing shells and carefully assemble case halves and watch what happens as the adjacent case bolts are torqued up. Do the two bearing shells seat correctly ? Is the inside bore diameter of the installed bearing shells within limits ? Best regards |
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Magyar Kiwi, read the whole thread. There is a problem with the later bearings, with respect to flange diameter, in the engine cases prior to the 996 engine. If the bearing half is sitting proud.015” and the same for the second half, that’s .030”, the case will not close and that .030” is way off any intended bearing crush. After I machined the bearing outer flange diameter to the diameter of my removed bearing, they nested where they should be. I researched the part numbers in all the current porsche parts manuals that are available on the Porsche website all the way back to 1965 year model and the 996 part number shows up. It seems to me that the manuals are living manuals, meaning Porsche updates them from time to time. The problem started throughout the parts network because Porsche made an error with supersedure. One gentleman had unfortunately assembled his engine and had a leak because of this bearing causing a gap in the case.
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Hi
Thank you for the clarification. The key information is in the youtube link at Post 14. I have now watched it. Best regards |
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Porschedude996, I disagree with you conclusion that all the 996 int shaft bearings are an issue.
"There is a problem with the later bearings, with respect to flange diameter, in the engine cases prior to the 996 engine." I have the same part number 02 8005 Glyco bearings (996 part number on box). They appear to be made 12 of 21 (not the best picture). ![]() I did not find the same issue you did. I installed the 996 bearing in a 3.0, 3.3 and 2.7 case and none had the issue you experienced. The bearing was flush in all the cases I tested. Maybe it was a limited production issue or there is a difference in how your case was machined. I purchased a set of NOS 916 bearings. ![]() I measured the bore diameter with a bore gauge after bolting down the case halves comparing the 916 and 996 bearing. I found they were almost the same (the 916 bearing was .0005" smaller), which given the clearance range is nothing. Based on my case fitting and my measuring as saw no issue with using the 996 bearing. With the wider bearing surface of the 996 bearing (measured in earlier post) I would prefer the 996 bearing to earlier 916 or 993 bearing. john |
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Huh, I took a look at my original bearings and they are stamped with a porsche number of 916.137.00. They fit my case perfectly, the superseded to the 996 number didn’t fit. I find no reason to measure the inside bore, I know it’s going to be good when the bearing doesn’t sit proudly above the case mating surface. My .015” height surely was not going to allow the case to close.
![]() Last edited by porschedude996; 02-13-2024 at 07:28 PM.. |
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This post and the Breitworks video really freaked me out!
I'm getting closer to closing up my 2.7 case, so I ordered a set of bearings from our host. They were not marked where they were made. I put them in to see how they looked, and they seem fine to me. I can barely catch a fingernail across the tops. ![]() ![]()
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Always learning. www.aircooledporsches.com.au See me bumble my way through my first EFI and TURBO conversion! https://youtu.be/bpPWLH1hhgo?si=GufVhpk_80N4K4RP Last edited by mikedsilva; 02-20-2024 at 01:47 AM.. |
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