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Registered
Join Date: Dec 2013
Location: Minneapolis, MN
Posts: 202
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Main bearing specs - '71 2.2 T engine
Hi all, picked up a set of main bearings for my 2.2T std/std build, I did get the Glyco bearings (made in Poland)
I've seen the threads on here about potential quality issues and I'd like to ensure they're within spec, and if not return them. I have the measurement tools already but in Waynes book I can't find the requirement for bearing thickness anywhere. I will be installing and using a dial bore gauge as a next step but I was hoping to be able to do an initial check of the thicknesses. edit: maybe that was a stupid question... I can infer the bearing thickness tolerances by using math can't I? Last edited by Optimusglen; 08-18-2017 at 07:04 AM.. |
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Administrator
Join Date: Aug 2016
Location: Los Angeles, CA
Posts: 6,087
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Hello - please feel free to give us a call at 888-280-7799 and one of our Porsche part specialists will be happy to help you out with the specs.
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Member 911 Anonymous
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Couple of things:
Did you measure and verify the shaft and case journals to insure they also are all within spec and straight? Let's assume you did. The trick is to measure with a mic three points on each bearing like Porsche would before offering the bearings for sale, If I may suggest, make certain they are pretty close or better yet match the pairs and place in order of how the shaft measured some of the journals maybe worn more than others so you want to place the little thicker ones there. I hope I am making sense. When I got the Yellow STD Goetz bearings I matched each bearing and I had several that were a bit thicker but within spec so I placed them at #8, #7 & #6 as those measured a bit worn more so then the rest of the shaft. Probably not needed but I wanted the engine to have every little chance it can to wear evenly. I know some builders when shaft is severely worn and not wanting to re-grind will mix and match bearings from STD to thicker bearings.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC Last edited by DRACO A5OG; 08-18-2017 at 05:25 PM.. |
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Registered
Join Date: Dec 2013
Location: Minneapolis, MN
Posts: 202
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Yes, crank journals are all in spec, high end of the tolerance window so I'm good there. Runout is also in spec.
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Member 911 Anonymous
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Good, then measure each bearing thickness and try to pair them to balance the journal out and mark them with a sharpie where they will go then you should be good to go. I know a bit OCD but I personally felt better when I did that.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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Under the radar
Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
Posts: 7,129
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You can measure the thickness of every bearing shell in three places. Center and near each end. If every measurement is identical you should be good. You can verify your clearances using plasti-gauge during a trial assembly.
BTW, I have not heard of any of the 2,2 main bearings being suspect. But it is a good idea to double check every thing anyway. Personally, I would be more concerned with the case bores being straight. The old school check for that is to look at all the old bearings. If they all look evenly worn, and none looking way more worn than the others, you are probably OK. Again the 2,2 T motors do not have the most stressed cases.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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Registered
Join Date: Dec 2013
Location: Minneapolis, MN
Posts: 202
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Quote:
http://c1.staticflickr.com/5/4322/35777912632_b735575e68_o.jpg I put the case together without any bearings, mating surfaces all clean and dry. Through bolts torqued to spec. And I measured the bores with a dial bore gauge. Most of the bores were actually under spec by 0.11mm on average (.0043 inches) My assumption is that this is mag case squish and I probably need to send the case to Ollies but that's a tough pill to swallow. My cheap childcare (sister in-law) is moving several states away, so my car budget just dropped significantly. |
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Under the radar
Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
Posts: 7,129
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After my last post, I remembered that I saw your bearings in your other post.
I agree, they looked fine. The odd wear on two of those bearings was probably due to some small debris when they were installed. Now if one of your main bearings looked like that IS bearing, I would be concerned. My #1 bearing, in the motor I just finished, had a worn area, somewhat like yours. Believe it or not there was a small piece of metal under the bearing. They were the original FACTORY bearings. If I was you I would do a trial assembly of the crank and main bearings in the case. If the crank turns freely, WTH, I would call the case good. Then using Plasti-guage you could double check all your bearing clearances. If all your clearances are good, no problem, IMO. You have case savers already, so, that is something you won't have to worry about.
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage Last edited by Trackrash; 08-19-2017 at 02:45 PM.. |
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Member 911 Anonymous
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+1, the bearing are not horrible, #1 Thrust Side is worn as expected, #2 & #4 are wearing where they should as that is where the shaft sits prior to start.
Depending on your intended use, if Street only I would slap it together and call it a day but would not hurt to take that extra step of plastigauge and keep an eye on 1, 2 & 4. If obviously varied, send it out if not then move forward.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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Registered
Join Date: Dec 2013
Location: Minneapolis, MN
Posts: 202
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Thanks guys, yeah currently just planning a stock rebuild of the 2.2, street driven, no track use.
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