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Hey guys, I have some questions about my bearings. I have the engine all torn down with everything off of the block but the cam bearings. For a block with no machine work done, should I get undersized, oversized, or original sized bearings? Also the same with the rod bearings, I値l get the crank polished to make sure it痴 100% good to go, but does that require oversized bearings? The ones on it look like typical wear.. They haven't spun or been abused, they池e the same ones from the factory though, 95k miles. I値l post pics below. I plan to get the cam bearings replaced while I知 this far as well.
Also, thank y'all for all of the help in my prior posts too, you guys rock!
The crank is what determines which bearings you need, not the block. Mike the crank journals. If they are worn, the crank needs to be turned, and how much will determine which bearings you need.
You'll need to have the crank and rods measured then you can calculate the bearing size by how much clearance you want. Or if you feel like you got a lot of ***** you could just assemble it with standard bearings and check clearance with plastigage.
The crank is what determines which bearings you need, not the block. Mike the crank journals. If they are worn, the crank needs to be turned, and how much will determine which bearings you need.
I値l post a pic up tomorrow of the crank, and you tell me what you think. I think they look fine for standard bearings, but a second opinion is always reassuring. Thanks!
You'll need to have the crank and rods measured then you can calculate the bearing size by how much clearance you want. Or if you feel like you got a lot of ***** you could just assemble it with standard bearings and check clearance with plastigage.
What is stock clearance? I壇 like to test the ones I have just to see how worn they actually are. Won稚 use them obviously, but wouldn't that be a good DIY way to check? Just a thought here lol.
Pat,
From looking at the pictures it looks like standard bearings will be fine. But like Joe said a picture really does not mean a lot. Polishing does not take any measurable amount off the crankshaft.
However . . . . there were instances of GM using non standard bearings to make up for machining differences on crankshafts. The bearings were called "select fit" bearings. They will usually be stamped with an undersize such as .0005 etc.
If you are going to have the crankshaft polished just have your machine shop measure it for you and tell you what size it is.
If it makes you feel any better, when I did the 307 in my Wifes Riviera about a year ago the bearings looked perfect just like yours and the crankshaft measured perfect. All I did was polish it and used standard bearings. It had well over 200K miles on it
The operative term is "measured". Sorry, but I don't understand the need to do this half-fast. Mike the crank and be certain.
Got it. Just not trying to have a ton of money in the build. Parts prices are high enough, and machining isn't cheap. Not at all trying to do it halfway, I知 just more of a body/upholstery guy who isn't quite up to par with his engine knowledge. Thanks again for the info though!
Pat,
From looking at the pictures it looks like standard bearings will be fine. But like Joe said a picture really does not mean a lot. Polishing does not take any measurable amount off the crankshaft.
However . . . . there were instances of GM using non standard bearings to make up for machining differences on crankshafts. The bearings were called "select fit" bearings. They will usually be stamped with an undersize such as .0005 etc.
If you are going to have the crankshaft polished just have your machine shop measure it for you and tell you what size it is.
If it makes you feel any better, when I did the 307 in my Wifes Riviera about a year ago the bearings looked perfect just like yours and the crankshaft measured perfect. All I did was polish it and used standard bearings. It had well over 200K miles on it
Can do! Thanks, I値l measure it and check it all out.
November 7th, 2019, 12:48 PM
