05-07-2019, 10:36 PM | #1 |
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Join Date: May 2010
Posts: 36
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Tight Bearings
I haven't posted a question for several years but this is now my third post in as many weeks.Have received some good help from the members. My 1930 roadster was getting a wee bit noisy so I pulled the engine and tightened up the main and conn rod bearings to what I thought was between .001 and 0.002 using plasti-guage. At the end (I now realize that I should have checked as I went along) I now find that it takes a real effort to get it to break loose to even start to turn over, but then it rotates smoothly with about 35 ft.lbs effort.
Start from the beginning again checking clearances? Would appreciate all advice. Thank you, George |
05-07-2019, 10:43 PM | #2 |
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Location: Oregon
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Re: Tight Bearings
.001 is a bit close did you check the crank journals to see if there was any out of round involved? .001 should be ok with a round journal.
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05-08-2019, 05:44 AM | #3 |
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Location: Largo Florida
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Re: Tight Bearings
As long as the engine is out it makes things a bit easier. Loosen one at a time to see if you can find the offender. Like J mentioned, .001" is a bit tight.
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05-08-2019, 06:53 AM | #4 |
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Location: Asheville,NC
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Re: Tight Bearings
After adjusting the bearings to the correct clearance, this is often the case. Put it in and run it. After a couple of minutes it will work as before but with better clearances.
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05-08-2019, 07:22 AM | #5 |
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Re: Tight Bearings
PM sent ...
Last edited by Benson; 05-09-2019 at 09:50 AM. |
05-08-2019, 08:48 AM | #6 |
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Re: Tight Bearings
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05-08-2019, 12:13 PM | #7 |
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Location: Alabama
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Re: Tight Bearings
One thousand clearance isn't enough for my use . I polish the journals with fine journal sand paper to remove any babbit residue before adjusting . I set my rod and main bearings at twio thousants clearance . There needs to be enough clearance for an oil film to cushion the babbit and prevent as much metal to metal contact as possible and two thousand isn't really that much . Some believe that a real tight engine will be like new and last longer . Heat causes expansion and Friction causes quicker wear . I've never seen a too tight engine last very long or go very fast . I'm not a professional engine rebuilder but I overhaul my own engines with good success over the years .
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05-08-2019, 12:16 PM | #8 |
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Location: Oregon
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Re: Tight Bearings
The center main usually has more wear than the front and ream mains. Adjusting all three to the same clearance on a used motor can result in tightness in the center main if that journal has runout. I prefer to run a dial guage on the center crank journal to see if it is running true, then adjust the center main last.
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05-08-2019, 12:27 PM | #9 |
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Location: Sacramento
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Re: Tight Bearings
Ford didnt run engines to break them in,they spun them,and if they achieved a proper resistance value they were used.
If you dont want to go back into it,you can run it and the bearings will burnish.If you not comfortable with your work,if it's possible it's not just a tight adjustment,go back in.. |
05-09-2019, 11:00 AM | #10 |
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Location: Temecula, CA
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Re: Tight Bearings
Use oil or assembly lube on all bearings before final assembly.
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