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Old 05-07-2019, 10:36 PM   #1
Geo.T
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Default 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
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Old 05-07-2019, 10:43 PM   #2
J Franklin
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Default 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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Old 05-08-2019, 05:44 AM   #3
Patrick L.
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Default 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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Old 05-08-2019, 06:53 AM   #4
James Rogers
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Default 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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Old 05-08-2019, 07:22 AM   #5
Benson
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Default Re: Tight Bearings

PM sent ...

Last edited by Benson; 05-09-2019 at 09:50 AM.
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Old 05-08-2019, 08:48 AM   #6
Nosetime
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Default Re: Tight Bearings

Andrews book suggests around 25ft.lbs to rotate the assembly. I had the same problem you ran into...a fair bit more as nothing was "round". I disassembled entire engine to rehabilitate. One thing I found was, since I installed a hotter regrind cam I had to do a "blind" valve adjustment. My adjustable lifter nuts were not visible at the standard adjustment location...so after rotating it around and "sneaking up" on the adjustments many, many times..Ha ha! Low and behold everything loosened up to an acceptable drag. Now, keep in mind I hand scraped and fitted a different rear main bearing, and everything had assembly lube on it. My point being, would a few minutes spent turning it over by hand loosen things up a bit? Greg
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Old 05-08-2019, 12:13 PM   #7
Purdy Swoft
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Default 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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Old 05-08-2019, 12:16 PM   #8
ursus
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Default 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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Old 05-08-2019, 12:27 PM   #9
Railcarmover
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Default 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..
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Old 05-09-2019, 11:00 AM   #10
Jim Brierley
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Default Re: Tight Bearings

Use oil or assembly lube on all bearings before final assembly.
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