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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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| | | | Joined: Jan 2012 Posts: 32 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2012 Posts: 32 | going to use plastiguage to check clearance on the main bearings and possibly the rod bearings, anyone know what the maximum or minimum clearance is or where I might find that information? | | | | | Joined: Feb 2004 Posts: 29,844 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,844 | No specifications, but virtually all the engines I've worked on over the past 50-something years live pretty well with oil clearances of .002" or slightly less. If you get much over .003" it's hard to maintain a film of oil between the parts unless you run very heavyweight oil. Some air-cooled engines with wide piston to cylinder clearances are the only exception, and that's more about heat expansion of the pistons than lubrication.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Mar 2004 Posts: 6,227 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,227 | The 1935 Shop Manual explains how to adjust the Mains and Rods without plastigauge (it wasn't around back then). Mike B  | | | | | Joined: Feb 2004 Posts: 29,844 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,844 | I learned to use a thin strip of .002" shim stock between the bearing and the crankshaft and shim the cap for a "firm drag" when the crankshaft was turned carefully, then move on to the next bearing and do the same thing.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jan 2012 Posts: 32 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2012 Posts: 32 | thanks, what is the torque for the bolts? | | | | | Joined: Feb 2004 Posts: 29,844 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,844 | Not sure- - -if the bolt diameter is 1/2", 80-90 ft./lbs. is about right. If they're 7/16", try 65-70.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Mar 2004 Posts: 6,227 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,227 | Mains 100-110 Rods 55-60 Head 75-80 Mike B | | | | | Joined: Oct 2006 Posts: 1,847 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 1,847 | to avoid having to ask these questions and wait for a reply and then wonder if they are actually correct. Go to the old car manual project and they have virtually all the shop manuals online, or you can go to most of the common vendors and they can get you a paper copy, maybe even a digital. The manual is nearly essential to working on these old vehicles. Not only that they are kind of cool to see how they thought back then. | | | | | Joined: Jan 2012 Posts: 32 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2012 Posts: 32 | i've got the shop manual for 1934, but they don't have torque specs. in it | | | | | Joined: Mar 2002 Posts: 9,115 'Bolter | | 'Bolter Joined: Mar 2002 Posts: 9,115 | The torque for the rods on my 1951 216 are speced at 35 to 45 ft lbs. I would be careful going above that. | | | | | Joined: Feb 2004 Posts: 29,844 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,844 | Rod bolt torque in the 50-60 ft/lb range would require a bigger diameter bolt than 3/8". That's approaching the 7/16" bolt torque range, even with Grade 8 bolts.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | The engineering default clearance is .00075" to .001" per inch of journal diameter. | | | | | Joined: Mar 2004 Posts: 6,227 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,227 | Mains 100-110 Rods 55-60 Head 75-80 Mike B I should have noted these torque specs were found in my Motor's Manual 14th Edition (1935-51). For some unknown reason Chevrolet didn't publish their torque requirements in their shop manual. Mike B | | | | | Joined: Apr 2005 Posts: 507 Shop Shark | | Shop Shark Joined: Apr 2005 Posts: 507 | Here is a link to the tech articles page on the Filling Stations website. With a reasonable explanation of their data. www.fillingstation.com/
Last edited by 41Chevy; 02/14/2015 6:04 PM.
"If it ain't Steel it ain't Real" "Earth the insane aslyum for the rest of the Universe" 41 1/2-ton, a work in progress 68 Shortbed stepside 327/325hp/700R4
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