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checking rod and crank bearings


Lozer

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I'm of the opinion that if it aint broke, don't "fix" it so I have to ask, why do you think you need to check or replace your bearings?

 

If you have never done this before, please pay close attention when you are taking it apart. If you check the bearings and they aren't excessively worn, just re-use them, but be sure to put them back in the same holes that they came out of. Nissan color codes their bearings to indicate thickness so putting them back where they came from is important.

 

If you think you need to replace the bearings, make extra sure. If you replace a perfectly usable OEM bearing with an auto parts store brand, you may be worse off than when you started. OEM bearings are a tri-metal construction with a steel shell lined with copper and then sprayed with a lead final layer. Aftermarket bearings are often a steel backing with an aluminum liner that doesn't compare favorably to OEM bearings.

 

Yes you can re-use the rod bolts and nuts. Lube them to re-torque them.

 

This may be a long winded response, but you don't sound particularly sure about what you are doing. Post pics of the bearings if you want a difinitive answer of whether or not they should be replaced.

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I would not just blindly replace old bearings with new. Your'e going to need to take some measurements that require a good micrometer and a bore gauge. Or at the least, a set of telescoping gauges and know how to use them. A pin mic helps too, to measure any deviations in brg thickness. I just use a 0-1 mic with a test pin.

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Good info guys. I'm refreshing the motor and have no history on it so before I throw it in the dime I'm going through it. Valve seats were shot when I did a leakdown. The rings seem fine. As all the leakage was from the exhaust valves. I was just going to inspect the bearings to make sure none were toast. If they are then its off to the machine shop if not then back in they go. I had read somewhere that you need to replace the rod studs after removal.

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From what I wad tought you should never reuse the bearings ones you pull the cap. But if your going through all that trouble to pull I'll of that off why not just change the rings out to? So you don't have to do it again when your rings go and your bearings are new

As i said earlier in this thread:

 

"If you have never done this before, please pay close attention when you are taking it apart. If you check the bearings and they aren't excessively worn, just re-use them, but be sure to put them back in the same holes that they came out of. Nissan color codes their bearings to indicate thickness so putting them back where they came from is important.

 

If you think you need to replace the bearings, make extra sure. If you replace a perfectly usable OEM bearing with an auto parts store brand, you may be worse off than when you started. OEM bearings are a tri-metal construction with a steel shell lined with copper and then sprayed with a lead final layer. Aftermarket bearings are often a steel backing with an aluminum liner that doesn't compare favorably to OEM bearings."

 

You can absolutely re-use old bearings and sometimes re-using a factory OEM style bearing is a far better option than replacing them.

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Have to say bearing clearance is bearing clearance weather lead lined or aluminum. A used factory bearing can only be good as new or slightly worn. A new after market bearing surely is as good as a factory new bearing, or why make them? How long would Clevite or anyone else stay in business if their bearings were not as good as new stock ones??

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Where would most people shop for rod and main bearings? The auto parts store.

 

What bearings do most auto parts stores push? They tend to push the cheap, readily available bearing.

 

Name brands like King are not always good bearings. They are aluminum sprayed onto steel. They don't hold up to detonation or heat as well as a tri metal bearing. So yes, aftermarket bearings are as good as OEM, but only if they are the tri metal type.

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Probably my dad's '51 chev had them. It was splash oiling no oil pumps back then. I remember our mechanic neighbor came over while I was at school and did something to the main bearings. Shimmed the bearings? I can't remember.
 

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An old foreman told me of his younger days traveling around northern Ontario looking for work. Had an old flat head Ford six. They were nowhere near home, broke and fried a piston. They took the rod and piston out. Carved a poplar branch and hammered it into the bore to seal it up. Threw the flat head on and kept going. Said it took them hundreds of miles before the heat dried the wood and it shrunk and fell out.

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That's a gret story too. Nothing like a little outside the box thinking.

 

We were snow wheeling a few years ago up on the Rubicon. It was into the -20's at night. We woke up one morning and got going when we heard a loud bang. My buddy snapped off his right rear brake caliper while trying to get moving. Apparently the pads froze to the rotor overnight. He wanted to take the caliper off and cut and pinch the brake line. Instead, I took the caliper off and wired it up to the frame while he went and cut a slice of a poplar tree and stuffed it into the caliper so the pads wouldn't fall out.

 

When you're hosed, you're not really hosed. You just have to think about your options at the time. Usually a solution presents itself.

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