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Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 2,604
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Marks in Case and Bearings
A while ago I asked about the marks on the bearings and the general consensus was, it was due to some sort of high current electrical charge running through the engine.. maybe someone did some welding and grounded through the case etc..
The crankshaft also has delamination on the mains... not sure if that was caused by the electricity purported to have run through it? But what about the marks on the backs of the bearings and on the main bore of the case? Check this out..
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01-13-2025, 01:12 AM
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I Did some research on this and I doubt it’s from welding, If you research the manufacturing techniques of bearings you’ll see that those irregularities probably happened in the manufacturing process.
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01-13-2025, 07:10 AM
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when welding current grounds through the engine block, it can arc across bearing surfaces, causing pitting or cratering in the Water Pump bearings themselves and sometimes leaving burn or arc marks on the backs of the bearings and in the main bores of the case. That delamination you see on the crankshaft mains could also be related, since electrical discharge can locally heat and weaken the bearing overlay and the crank journal surface, eventually causing the layers to separate under load. If you have evidence of this on both the bearing at https://en.tradebearings.com/NJ205E.TVP2-512.html faces and the bearing backs, along with the crank damage, it’s a pretty strong indication that electricity did indeed travel through the assembled engine rather than just isolated parts, which can ruin bearings very quickly.
Last edited by tonychap; 07-03-2025 at 05:28 PM.. |
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07-02-2025, 11:27 PM
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It sure does appear like electrical arc damage. Was the ground cable from the body to the trans ok? When you engage the starter motor without a good ground, it WILL find a ground. It won't be the one you like, but it WILL find a ground path.
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07-03-2025, 06:02 AM
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Join Date: Feb 2009
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There was a thread about SC cranks flaking off what looks like the hardening layer, what you describe as delaminating. We starting seeing this in the 80’s. Your bearing looks like what we saw then. We threw the cranks away, probably repairable today.
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07-03-2025, 02:20 PM
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