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 Blocks / Cranks/ Rods and Pistons
 main & rod bearing clearances
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beertracker
Cochise

442 Posts

Posted - 25 Jan 2019 :  01:53:14 AM  Show Profile  Reply with Quote
I am getting ready to check main & rod bearing clearance on my 455 using plasti-gage. Can some one tell me the clearance ranges for main & rod bearings.

My setup is 455, 60lb oil pump, factory crank cut .010" on main and rod journals.

Thanks,bt

Edited by - beertracker on 26 Jan 2019 12:42:15 AM

Corncob2061
Crazy Horse

USA
570 Posts

Posted - 25 Jan 2019 :  1:55:50 PM  Show Profile  Reply with Quote
.002-.0025 on the rods, I prefer closer to .0025.

.003-.0035 on the mains.

Jay
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beertracker
Cochise

442 Posts

Posted - 25 Jan 2019 :  5:29:14 PM  Show Profile  Reply with Quote
Forgot to ask how many sheets of plasti gage would it take to do a engine? I am planning on checking each main and rod.

bt

Edited by - beertracker on 26 Jan 2019 03:29:09 AM
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tjs44
Crazy Horse

USA
630 Posts

Posted - 25 Jan 2019 :  6:48:15 PM  Show Profile  Reply with Quote
Do it right,get a mic!JMO,Tom
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 25 Jan 2019 :  8:39:55 PM  Show Profile  Reply with Quote
I use a mic to check and double check with plasti gage. Might just be out of habit, but I have caught some line honing issues with the plasti gage that the mic missed. Not every machine shop is equal, one we use sometimes gets in a hurrry. Sometimes when something seems off, I triple check in two dimensions on the mains for line bore.

Usually 2 sheets catches a engine. Jay

Edited by - Corncob2061 on 25 Jan 2019 8:46:57 PM
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beertracker
Cochise

442 Posts

Posted - 21 Mar 2019 :  4:39:19 PM  Show Profile  Reply with Quote
deleted

Edited by - beertracker on 25 Mar 2019 3:25:00 PM
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beertracker
Cochise

442 Posts

Posted - 04 Nov 2019 :  6:33:59 PM  Show Profile  Reply with Quote
I know you are supposed to use a dial bore gauge and micrometer to measure main bearing clearance. I wondered if any one here has had luck using a telescoping gauge and micrometer to measure main bearing clearance. Use the micrometer to get the crank main journal OD and the telescoping gauge to get the main bearing ID then use the micrometer to measure the ID. Seems like it should work?? A telescoping gauge set is cheaper than a dial bore gauge. bt
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beertracker
Cochise

442 Posts

Posted - 06 Nov 2019 :  2:17:00 PM  Show Profile  Reply with Quote
Would this dial bore gauge work for measuring main bores and rod bores? https://www.summitracing.com/parts/sum-900041?seid=srese2&utm_source=bing&utm_medium=cpc&utm_campaign=Brands+|+S&utm_term=4581390076893073&utm_content=GSAPI+5ba29eacb7da9

This one reads in steps of .0005" but I thought for main and rod bores we need one that reads increments of .0001"?



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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 10 Nov 2019 :  11:06:34 AM  Show Profile  Reply with Quote
What does the telescopic gauge set look like? Are the ends sharp enough to get good measurements on the bores? Do they have any kind of feel to them when your extending them for full extension in the bore? Jay

Edited by - Corncob2061 on 10 Nov 2019 11:13:43 AM
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 10 Nov 2019 :  2:41:22 PM  Show Profile  Reply with Quote
The only differences I have noticed going between my dial bore gauge and telescopic gauge is once the dial bore gauge is set the measuring goes faster because you can go off the dial versus checking the telescopic guage with a mic for every measurement. One telescopic gauge I have used had a mic built into it to. A little more tedious to read though. I have never used a cheaper telescopic gauge, maybe they not as accurate? They are price wise pretty economical, I wonder if the accuracy goes south on those? Jay
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 10 Nov 2019 :  3:32:43 PM  Show Profile  Reply with Quote
These telescopic gauges all came with in .0002. For what they cost ($66). That is pretty good accuaracy.
A comparison:

https://m.youtube.com/watch?v=ugL_h6PoKJI
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beertracker
Cochise

442 Posts

Posted - 10 Nov 2019 :  5:56:55 PM  Show Profile  Reply with Quote
quote:
Originally posted by Corncob2061

What does the telescopic gauge set look like? Are the ends sharp enough to get good measurements on the bores? Do they have any kind of feel to them when your extending them for full extension in the bore? Jay



I am using a new Pittsburgh 6 pc telescoping gauge set 5649 from Harbor Freight.

The telescopic gauge is spring loaded and the arms have rounded edges. The arms fit well inside the main bore housing. I offset the arms 10 deg. from vertical then lock in place and force the measurement onto
the gauge. I can feel the arms move inward as I push down on the gauge handle and the measurement is forced onto the gauge. The gauge arms do not move as I take the mic measurement.

When placing the gauge arms inside the bore I am working against opposing spring pressure. bt

Edited by - beertracker on 10 Nov 2019 6:06:33 PM
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beertracker
Cochise

442 Posts

Posted - 10 Nov 2019 :  6:28:16 PM  Show Profile  Reply with Quote
quote:
Originally posted by Corncob2061

These telescopic gauges all came with in .0002. For what they cost ($66). That is pretty good accuaracy.
A comparison:

https://m.youtube.com/watch?v=ugL_h6PoKJI



After reading the link above. It's time to throw my Harbor Freight telescopic gauges away. Wish I had known this before I bought them.
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 10 Nov 2019 :  10:54:48 PM  Show Profile  Reply with Quote
quote:
Originally posted by beertracker

quote:
Originally posted by Corncob2061

What does the telescopic gauge set look like? Are the ends sharp enough to get good measurements on the bores? Do they have any kind of feel to them when your extending them for full extension in the bore? Jay



I am using a new Pittsburgh 6 pc telescoping gauge set 5649 from Harbor Freight.

The telescopic gauge is spring loaded and the arms have rounded edges. The arms fit well inside the main bore housing. I offset the arms 10 deg. from vertical then lock in place and force the measurement onto
the gauge. I can feel the arms move inward as I push down on the gauge handle and the measurement is forced onto the gauge. The gauge arms do not move as I take the mic measurement.

When placing the gauge arms inside the bore I am working against opposing spring pressure. bt



I looked up the Pittsburgh set up, they had pretty good reviews, considering that is a $16 set. As near as I can tell accuracy for that set is closer to .001 or slightly better, according to some of the online reviews. Jay

Edited by - Corncob2061 on 10 Nov 2019 10:59:36 PM
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67drake
Sitting Duck

Azerbaijan
1550 Posts

Posted - 12 Nov 2019 :  11:30:46 PM  Show Profile  Reply with Quote
Beer tracker, I have the exact same dial bore gauge you posted. It works fine. I bought it maybe 5 years ago but I don?t think I paid more than $65-70 or so for it. You might want to shop around. I think I got mine from Shars. If that?s spelled right?


71' GTO Original 400 M20 3.23 posi
13.95@102.1 MPH on street tires
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67drake
Sitting Duck

Azerbaijan
1550 Posts

Posted - 13 Nov 2019 :  02:43:02 AM  Show Profile  Reply with Quote
Here ya go
https://www.shars.com/2-6-dial-bore-gauge-0-0005

LOL. I must be getting old. I just pulled the 221 V8 out of my ?62 Mercury for an overhaul. I was going to use my snap gauges and micrometers to take measurements because I forgot I even bought the dial bore gauge. Then I found it in my toolbox while looking for my pulley puller! BUT I remember exactly what I paid for it!


71' GTO Original 400 M20 3.23 posi
13.95@102.1 MPH on street tires

Edited by - 67drake on 13 Nov 2019 02:57:19 AM
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