Replacing main bearings without removing the crank

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318willrun

318willrun

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Some discussion here lately about replacing main bearings without removing the crank. I decided to make a video and post a trick that some of you may know. Obviously, if the crank needs to be polished or turned, then replacing the bearings with the crank removed is best.

 
The thing is, most engines "I've been into" the mains are the LAST thing that needs attention. What this boils down to (in my experience) is that if you are needing to replace mains, USUALLY there are problems that dictate the rest of it should come apart as well
 
Have a 318 that runs great but has a thrust bearing with lots of endplay. I have said **** it and driven
it for almost 50K miles no change? It was a 100 dollar junk yard motor I put in just to get the car running. I plan on a front end rebuild this winter, so I will drop the pan and replace thrust and mains using this method on the cheap?
 
I do the same thing put I use half of a large cotter pin. cut it at the top and bend it over 90 degrees. put it in the oil hole and away you go. But great video if you need to replace mains in the frame it's a great little trick
 
I just push the top half around by tapping the end w a blunt flat srewdriver. Then just grab the exposed end and rotate around.
 
67Dart273 said:
The thing is, most engines "I've been into" the mains are the LAST thing that needs attention. What this boils down to (in my experience) is that if you are needing to replace mains, USUALLY there are problems that dictate the rest of it should come apart as well
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It was a question in a thread here recently, I thought I'd show how. I left the "why's and if's" out... LOL...
 
Somewhere in my archives is a photo of a cotter pin. Stick it in a vise and flatten ring to make a “T”.same idea as a nail.
 
Tooljunkie said:
Somewhere in my archives is a photo of a cotter pin. Stick it in a vise and flatten ring to make a “T”.same idea as a nail.
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cotter pin, nail, bolt with the head ground down, whatever works (and just about anything will... LOL). Hoping when they see it, their brains will work and they can grab whatever is convenient and make it happen. :)
 
You just gotta be careful that you don't scrape some metal off the back of the shell on a sharp edge and have it caught in the bearing ends or between the cap and block; or get some crud behind the shell, which will mess up clearances. Personally, I am with Del and would not bother without pulling the crank unless it was an emergency to just get things going.
 
nm9stheham said:
You just gotta be careful that you don't scrape some metal off the back of the shell on a sharp edge and have it caught in the bearing ends or between the cap and block; or get some crud behind the shell, which will mess up clearances. Personally, I am with Del and would not bother without pulling the crank unless it was an emergency to just get things going.
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Again, not saying this is the best way to do it, nor am I suggesting any certain way. Just showing how to do it without removing the crank, because it's been mentioned in a few threads lately. However, I've replaced mains without crank removal and had no issues
 
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Heavy truck and equipment call it a bearing roll. Common.
 
I had oil starvation cause enough damage I needed to put some new rod bearings in and some mains, but not all. I just loosened all the bolts in the main caps so the crank could drop a few thou. Really helped.
 
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