bearing clearance
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Postmaster
Joined: Nov 2001
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From: Escondido, CA
bearing clearance
What is the clearnace required on the main and rod bearings? I haven't been able to find it on google or using the forum search. I would like to start building my engine in the morning if at all possible. Thanks guys.
Hotshot
Joined: Dec 2003
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From: iowa
According to my book that I have handy mains are .0008-.0026, rods are .0008-.0025, I prefer to use more along the lines of .0020-.0025 on a street engine that you want to live (.0008 seems a lot too tight to me, min I would accept would be around .0018 if it was my motor but just quoting from the manual) On a race engine I run .0035 +/- .0003 and rods I run .0030-.0035
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Postmaster
Joined: Nov 2001
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From: Escondido, CA
Using the plasti-guage kit that came with my bearings, I have a .0015 on the mains and .0015 on the rods as well. I checked it several times on different bearings to make sure too. Do you think having assembly lube on the bottom side of the crank is going to throw the reading off that much? I called a few machine shops in my area and they all agree that it isn't too tight with assembly lube in there as well. I am pretty amazed to find it this tight though. I put a TQ wrench on it to see what it takes to spin the crank alone and it is spinning at 4 Ft-Lbs. With all the rods and pistons I am pulling 24 Ft-Lbs. I also measured end play to be .005 which is almost in the middle if those shops are right. So far so good for the build up. I am waiting for some 8802 sealant to harden in the timing cover before I put it on.
Hopefully by the 15th of Nov I will have the engine installed in the truck to mock up the fuel lines. I've been in the garage a lot of the past month or so keeping my truck company rather then my wife. She informed me of this earlier today after I forgot to go to lunch with her.
Hopefully by the 15th of Nov I will have the engine installed in the truck to mock up the fuel lines. I've been in the garage a lot of the past month or so keeping my truck company rather then my wife. She informed me of this earlier today after I forgot to go to lunch with her.
Hotshot
Joined: Dec 2003
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From: iowa
You can't check the bearing clearence with assembly lube on the crank and expect it to be right .0015 is pretty tight until you take the assembly lube into context. But I don't think your rolling torque figures are too bad so I think you are all right.
Junior User
Joined: Oct 2005
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Originally Posted by airharley
I have a .0015 on the mains and .0015 on the rods as well. I checked it several times on different bearings to make sure too. I am pretty amazed to find it this tight though. I also measured end play to be .005 which is almost in the middle if those shops are right.
If you have a very high performance engine, though, then you should dismiss this recommendation and post more specifics about your build.
Paul
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