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Discussion Starter #41
So, I can't get another look at the bearing photos to confirm this for some reason. But I just compared yours with apx 2500(?) miles on them with mine removed from a 114k 7MGE. Your rod bearings looked like the wear was already through the Clevite's grey top coating, where mine are not. So I think your bearings may be too tight. A couple things you can do. One - use Plastigage to check the clearance. Two, put just the rods on the crank with the caps and bearings torqued with oil during assembly. Will the rods fall down by themselves if pushed away from straight up? If not, that's another indicator the rod bearings are too tight. If this is the case, then the too tight bearings are exerting a piston push against one wall noiselessly from being too tight on the rotating crankshaft, then slapping the full distance to the other side when ignition happens. Not happening with free revving so much would also follow, as when you load the rod bearings by making the engine "do work" the friction also increases because there is not enough oil film and the extra rod pressure causes extra rotating force on the rod/piston. If I were a betting man, Plastigage will reveal those are too tight. And I also think your pistons are indeed not sized right (too small). If you had only one problem or the other, I think you'd never have noted this. For instance, the bearings are increasing the tolerance through wear and that would have gone away if the pistons were the right size. YMMV
Thanks for the input, as i didnt build the bottom end i wasnt sure. My builder did mention that the first set of bearings were kings bearings, he installed them and was too tight thats why he got me the clevite bearings and it was good to go. I will have everything check at the machine shop and go from there.
 

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I have had to relieve bearing shells before and the way to do it is remove material from the BACK of the bearing shell as evenly as you can by hand. Then when you feel you've removed some, do the plastigage again. Tedious but you're essentially hand fitting them lovingly and the engine will appreciate it.
 

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A good machine shop could simply polish the crank a little where needed to open up the bearing clearances. Problem is when they're too loose since you can't add material or a journal is damaged. That's when over sized bearings and a crank regrind is needed.

All I can say is I commend you for all the work you've done chasing this issue. No joke you motivated me to get my car going again and which I did. Had to replace the bottom end. I've had the parts for a built motor but am hesitant after seeing all the nightmares people have with machine shops over the years. Looking like i'm going to take the dive soon though since got all the issues with the standalone sorta on stock blocks.
 

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I would not recommend a shop alter the clearance on the crank to adjust a bearing clearance. It's far easier to polish the bearing shell as I described and its not difficult, either as bearings are a softer material. Just be sure to remove from the back, NEVER the front.
 

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Discussion Starter #47
Ill
I would not recommend a shop alter the clearance on the crank to adjust a bearing clearance. It's far easier to polish the bearing shell as I described and its not difficult, either as bearings are a softer material. Just be sure to remove from the back, NEVER the front.
I’ll look into that when i hear from the machine shop.
 

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Yeah, kind of a bummer to have a stalled build waiting for things to reopen. So far, I'm lucky that I have everything I need and that in our area auto parts stores are not shut down as they're considered critical for the public to have transportation. I am a few days away from bolting my crank back in and plastigaging things. I'm sure I will be doing some bearing clearance adjustments myself since the original toyota various stock sizes are not available - just a kit with all bearings the same size.
 
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