 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / Driving, Maintenance, Tuning / 4x4 Cars / September 2004connecting rod nuts
I am rebuilding a 350 Chevy small block engine. Having seen what happens when a connecting rod is "thrown" I am wondering if it might be beneficial to use Loctight thread locker. Anyone ever use thread locker with disastrous results? Recommendations for or against using thread locker on the connecting rod bolts would be appreciated? Blue, Red or High temp? Dave >I am rebuilding a 350 Chevy small block engine. Having seen what happens > when a connecting rod is "thrown" I am wondering if it might be beneficial [quoted text clipped - 5 lines] > > Dave Do not use anything on the bolts use new conrod bolts and torque properly. If your conrods bolt holes are sloppy get new ones.  SignatureHarryS Should I lightly oil the bolts before I install them or just install dry? 45 lbs. of torque as per the guidelines or a different torque when dry? > >I am rebuilding a 350 Chevy small block engine. Having seen what happens > > when a connecting rod is "thrown" I am wondering if it might be beneficial [quoted text clipped - 11 lines] > -- > HarryS > Should I lightly oil the bolts before I install them or just install dry? > > 45 lbs. of torque as per the guidelines or a different torque when dry? Most torques specs are based on dry threads if it is not stated otherwise. If you use oil, you will over torque and amy strip them. If you felt them *give* as was stated in your previous post, throw them out and start over. yes, I will start over. thank you. > > Should I lightly oil the bolts before I install them or just install dry? > > [quoted text clipped - 4 lines] > you felt them *give* as was stated in your previous post, throw them out > and start over. the proper way to torque rod bolts is to measure the rod bolt stretch while torqing to specified value. rod bolts/nuts should not be re-used especially in a H/P application. SignatureMad-Dog '79 Chevy K-10 Slightly modified http://mad-dog16.tripod.com/ -- > I am rebuilding a 350 Chevy small block engine. Having seen what happens > when a connecting rod is "thrown" I am wondering if it might be beneficial [quoted text clipped - 5 lines] > > Dave I have never heard of measuring bolt stretch before, not that I would have any reason to know such things. How would that be done? I have a few Micrometers and a set of calipers so I could measure each bolt before installation to get a base line, but measuring each bolt for stretch while in the process of, would present a few obvious difficulties. Is the suggested torque based on the stretch that will theoretically occur to the given bolt? Is this a percentage of the length or the diameter of the bolt? I did feel what seemed to be a slight give while tortuing down the connecting rod bolts but assumed that I was in the early stages of stripping the threads. To be honest I thought I had over torqued the bolts and did order new ones. I then posted to the news group with my question. Being ignorant of the proper technique I thought it best to ask for help. Perhaps my first attempt was correct and I just didn't know it. Either way I have new bolts now and would very much like to feel confident in my assembly of same. Dave. > the proper way to torque rod bolts is > to measure the rod bolt stretch while torqing to specified value. [quoted text clipped - 16 lines] > > > > Dave Bolt stretch is the BEST way to measure the actual clamping force of a fastener, BUT for some applications it isn't possible. So folks came up with a torque table and the angle gauge systems as a tool to help in those applications. However con-rod bolts are easy if you have a gauge. Since you don't you could use mics but it may take a while. I have a bolt gauge that slides over the rod and reads stretch directly off the bolt (looks like a C-clamp with a dial indicator on the top. The stretch amount varies though depending on grade of the bolt and manufacturers specs. SignatureSteve Williams Near Cooperstown NY > I have never heard of measuring bolt stretch before, not that I would have > any reason to know such things. How would that be done? I have a few [quoted text clipped - 41 lines] > > > > > > Dave > Bolt stretch is the BEST way to measure the actual clamping force of a > fastener, BUT for some applications it isn't possible. So folks came up [quoted text clipped - 5 lines] > amount varies though depending on grade of the bolt and manufacturers > specs. > > I have never heard of measuring bolt stretch before, not that I would > have [quoted text clipped - 50 lines] > > > > > > > > Dave A little overkill don't you think? For stock rods with stock bolts just torque to spec's and all should be well. Rod failure tends to happen once the bearing spins. >From: Edward Strauss > Rod failure tends to >happen once the bearing spins. its all connected(no pun intended).... the bearing usually spins due to too much clearance, which can alot of times be a direct result of the rod bolts stretching, causing excessive clearance. this usually does not happen in stock engines that are run the way they were intended, but does happen when stock rods are used in performance applications.... ARP rod bolts are a great upgrade for this reason.... ------------------- Chris Perdue "Sometimes you're the windshield, sometimes you're the bug!" Remove "PANTS" to e-mail If people would get in the habit of: Checking the rod large ends for roundness, there would be less rebuild rod bearing failures. When you torque the caps, you notice there is a certain degree of bearing squash at the parting lines, so even an undertorqued rod would suffice in a normal everyday driver. Refinish King > >From: Edward Strauss > [quoted text clipped - 13 lines] > > Remove "PANTS" to e-mail >From: "Refinish King" >If people would get in the habit of: > >Checking the rod large ends for roundness, there would be less rebuild rod >bearing failures. i agree... >When you torque the caps, you notice there is a certain degree of bearing >squash at the parting lines, so even an undertorqued rod would suffice in a >normal everyday driver. i somewhat agree...however over time....... ------------------- Chris Perdue "Sometimes you're the windshield, sometimes you're the bug!" Remove "PANTS" to e-mail > If people would get in the habit of: > [quoted text clipped - 6 lines] > > Refinish King I agree, if the caps and rods are out of shape the bearings won't last. BTW, don't know if you remember REfinish King, but I have the 350 with the rod knock, and I've just ordered a new Goodwrench crate engine for it. If that doesn't fix it nothing will. ;-) On the plus side I'm selling the knocking engine to a friend who races on the local dirt tracks, he plans to build it up and stick it in his car. He's already blown two this year, and is happy to get a good block. > > >From: Edward Strauss > > [quoted text clipped - 18 lines] > > > > Remove "PANTS" to e-mail Good luck! I wish you the best and hope you follow a careful break in and maintenance schedule. The crate motor will last you forever, especially if you use synthetic oil! Refinish King > > If people would get in the habit of: > > [quoted text clipped - 39 lines] > > > > > > Remove "PANTS" to e-mail Do you really think the synthetic oil is worth the extra money? Same on a Diesel engine? Any recommendations (as if this won't create a few responses) on the break in schedule for a rebuilt small block GM gasoline engine? Given a well built engine, installed on a pickup truck that will occasionally pull, well carry, 1 1/2 tons I would appreciate a nice conservative, yet not excessively extended, break-in schedule. Dave > Good luck! > [quoted text clipped - 54 lines] > > > > > > > > Remove "PANTS" to e-mail > Good luck! > [quoted text clipped - 3 lines] > > Refinish King Thank you, the engine just arrived, fast delivery. I'm long past the lead foot age, I intend to treat it right. I've been wondering about synthtic oil, I think I will use it. Should I use the same weight synthetic as I do regular oil? With a little luck and a lot of work I'll get it installed this weekend. I don't work as fast as I used to. ;-) > > > If people would get in the habit of: > > > [quoted text clipped - 46 lines] > > > > > > > > Remove "PANTS" to e-mail > >From: Edward Strauss > > Rod failure tends to > >happen once the bearing spins. > its all connected(no pun intended).... the bearing usually spins due to too > much clearance, which can alot of times be a direct result of the rod bolts > stretching, causing excessive clearance. this usually does not happen in stock > engines that are run the way they were intended, but does happen when stock > rods are used in performance applications.... ARP rod bolts are a great upgrade > for this reason.... Hmm... Or maybe due to lack of proper lubrication the bearing overheats, welding itself to the crank, then spinning. Anyway, make sure your crank is round and torque to spec's. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.