I recently put an engine that I got off Ebay into my s10. (it's a sbc 400) We fired it up, and have at least two problems: first, as reflected in an earlier question, the flywheel wobbles quite a bit. I got a new one, thinking that perhaps the old one was warped, but it stayed the same. Second, there was a periodic metal-on-metal noise. Anyway, I thought maybe the crank was bent or something- as I don't know what else would be the problem with the flywheel- so we ended up pulling the engine and taking off the oil pan. We found that no oil was getting to the front two rod bearings and front main bearing- thus causing them to wear against the crank (the metal-on-metal noise). Thus, my problem is multi-pronged: What could be causing the lack of oil, and is the flywheel wobble somehow related to this, or is that something else?
Anonymous2009-03-13T19:24:08Z
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Plugged oil gallery, tear down the engine and have it flushed and rod it out
A small block 400 is externally ballanced at the flex plate. The flex plate is indexed to the crankshaft by a pin in the end of the crankshaft. The wobble you see is because either #1, the incorrect flywheel was supplied with the engine,or #2 the flywheel is installed so that the indexing pin is not lined up to the hole in the flex plate. Seen both senerios with 400's many times. You need the 400's original flywheel/flex plate. As for oil not reaching the front bearings? It must have been, If it wasn't, the engine would have run only about 2-3 minutes before it siezed solid. So I'm thinking what ever damage your seeing is from the crank being hammered for an aft by the incorrectly installed flex plate. If the oil pressure is poor,and the crank bearings are good, then the cam bearings are shot, or the incorrect ones were installed. Oil to the crank comes down from the cam oil gallery on a sb gm. All your problems point directly to the incorrect/or incorrectly installed flex plate. Hope I was of some help. good luck.
the may be blockage in the oil passages in the crank or in the block,its for sure though you got problems with it,and you could have a slightly warped crank in it,but id start checking things with a micrometer to see how much wear and damage it has done to it,since the front bearings wasn't getting no oil it probably has damaged the crank in it,beware of engines you buy off e-bey,good luck.
If your car or truck is a automatic the flex plate needs to be FOR a 400 small block because they are externaly balanced,so if it was not the correct one the engine will be off balance.