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Discussion Starter · #1 ·
So I am in the process of having machine work done. I call the shop to check on some thing, mainly to figure out if I need to order oversized bearings or not. They tell me std size is what I need. They asked where I was getting them and I told them Toyota Dealership. I took him the TSRM for my car so he could use that as reference. He starts talking about the different sizes for the bearings. Long story short, he made the mains and con-rod all the same size. To me it sounds like instead of using different bearings in different journals, I am just gonna have 1 size. Is this a problem? Is my only real option to call them and tell them to overbore it? This kinda pisses me off that they went against what the TSRM said. If this is the kind of work they do, I am suprised this place has been in business as long as it has, and was recommended to me by multiple people.
 

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The Great Kruso
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djmtpocket said:
So I am in the process of having machine work done. I call the shop to check on some thing, mainly to figure out if I need to order oversized bearings or not. They tell me std size is what I need. They asked where I was getting them and I told them Toyota Dealership. I took him the TSRM for my car so he could use that as reference. He starts talking about the different sizes for the bearings. Long story short, he made the mains and con-rod all the same size. To me it sounds like instead of using different bearings in different journals, I am just gonna have 1 size. Is this a problem? Is my only real option to call them and tell them to overbore it? This kinda pisses me off that they went against what the TSRM said. If this is the kind of work they do, I am suprised this place has been in business as long as it has, and was recommended to me by multiple people.
Uh....im guessing this was the first time you had this done.....if a crank is worn, or requires ANY type of resizing no machine shop is going to sit there and resize the crank back to the factory specs. To the answer to your question, what he did is normal and fine and pretty much the only way all the machine shops do this. Instead of what toyota did, having different size of bearing for each rod, machine shops shave (sometimes weld and THEN shave) a little off of the crank, all the journals the same size. After doing so, you wouldnt have to go through the hastle of getting different size of bearings for your motor. Instead all the bearings are the same size.

Kruso
 

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I disagree, your shop is taking the easy way out. Even if they have to grind the crank (which I wouldn't recommend as the surface hardness will decrease), they are not going to be able to hold all the diameters within +/- a tenth, which is what would be required to use all the same size OEM bearings.
 

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Discussion Starter · #4 ·
The crank was fine, just polished. Since he noticed they were different sizes he made them (mains and con-rod big ends respective) the same size. Sounded like he made them all the size as the biggest one. I believe he said they are within 2/1000ths of each other.

So should I just figure out what size that biggest one was, and then order 7 of the same bearings for the mains, and do the same for the con rod ends?
 

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If he said they were within 2 thou (0.002"), you are in a world of hurt if he wants to use the same size bearings. If he said 2 tenths (0.0002"), then you are in the ballpark, though I would still mic everything and use the chart in the TSRM to determine which bearings to purchase.
 

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Discussion Starter · #6 ·
Thanks turbo...I am going to double check with him when I pick it up next week. I might call him tomorrow and have him do all the micing and use the chart in the TRSM to figure out ,and then have him show me when I get there. Its retarded .....I took them the book for this exact reason...so he wouldnt have to guess.
 

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25psi = 14" brakes :)
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Ah the joys of our engines in the hands of domestic machinists. There really is no good reason for multiple sized bearings if the journals are all perfect. However as noted, not much is perfect in this world.
(This is why I'm coating my crank and bearings with molydisulfied.) Poor or slightly off clearances will be no problem as the coatings will burnish themselves into the soft bearing material, and any pores in the crank journals. TO keep clearances correct, they suggest buffing the bearings and journals with scotch brite before they are installed. (You don't want them too tight, just right.)
I'm shooting for a zero metal to metal contact motor. Everything will be coated that could cause friction.
Check out the coatings at techlinecoatings.com
Later
 
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turbotoy said:
If he said they were within 2 thou (0.002"), you are in a world of hurt if he wants to use the same size bearings. If he said 2 tenths (0.0002"), then you are in the ballpark, though I would still mic everything and use the chart in the TSRM to determine which bearings to purchase.
2 tenths would be .2 or 2/10
2 ten thousandths would be .0002 or 2/10000

Just to clear things up
 

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adjuster said:
Ah the joys of our engines in the hands of domestic machinists. There really is no good reason for multiple sized bearings if the journals are all perfect. However as noted, not much is perfect in this world.
(This is why I'm coating my crank and bearings with molydisulfied.) Poor or slightly off clearances will be no problem as the coatings will burnish themselves into the soft bearing material, and any pores in the crank journals. TO keep clearances correct, they suggest buffing the bearings and journals with scotch brite before they are installed. (You don't want them too tight, just right.)
I'm shooting for a zero metal to metal contact motor. Everything will be coated that could cause friction.
Check out the coatings at techlinecoatings.com
Later
ACK! The Coating King strikes again!
 
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