| cm871 |
| 03-15-2022, (Subject: cm871 ) Post: #1 | |||
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| cm871 Need help!!! im doing inframe on cummins cm871 and was told that i need the cut center bores before i install new sleeves. is this a must? | |||
| 03-15-2022, (Subject: cm871 ) Post: #2 | |||
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RE: cm871 (03-15-2022 )SuperiorT Wrote: Need help!!! im doing inframe on cummins and was told that i need the cut center bores before i install new sleeves. is this a must? What it takes to inframe/rebuild it properly... Things that are NOT in the OEM manuals... If you do not cut the counter-bores (mid-stops) and raise the liners (to 0.015" is recommended on a rebuild) then you will not extend that engines life at all. It will be right back in a shop being rebuilt all over again in a couple or 3 years. here is a related liner height measurements post: http://rawze.com/forums/showthread.php?t...9#pid28349 This is because of heat cycling of the engine block. The clamping force for the liners gets weaker over time, and the liners have to be raised to compensate for this as the engine block ages. Do not give it an excuse to fail.. build it for another million miles.. take no shortcuts.. only ever use a brand new head .. and only ever use OEM parts. Anything less and it is destined to have troubles all over again. My rebuild series covers most all of this in great detail on youtube as well. https://youtu.be/LdTXWXKuhwY I.E.> it needs... ** Only an OEM overhaul kit put in. ** All new rod/main bearings, and verifying ALL of the bearing shell part numbers individually as they come out so, that an alt-size one did not get used on a lobe somewhere when the engine left the factory new (it does happen randomly). This is NOT in any manuals.. but is very necessary, as alt bearing sizes can be put in at factory, sometimes for only one lobe too. ** New oil pump... shim it internally to make 45 psi if ya like. ** ABSOLUTELY has to be counter-bored, raise liner height to 0.015"... or it will not last more than a couple few years at best. This is because heat cycling and stress relief of the block over the years makes for less clamping force, so it has to be compensated for. ** New wrist pin bushings in the connecting rods (or new connecting rods)... or it will suffer a wrist pin failure prematurely sending a piston thru the block at some point before it reaches the next million. ** NEW HEAD .. not a reman and especially NOT A REPAIRED OR RE-WORKED HEAD!... B RAND NEW ONLY!. .. or you will be dong the job all over again in a couple few years. (NOT in the manuals but EXTREMELY IMPORTANT(ISX example given here!!!)... ** Torque new head to 300 ft.lbs same method that the book calls for .. THEN let it sit over night for the gasket to crush.. then torque it a second time the next day again to 300 ft.lbs.. then after this second re-torquing ... do the +90 degrees on the bolts like the manual says to do for the final positions. == Then after the 90+ method that the book recommends, ... And AFTER THIS ... Set a torque wrench on 475 ft.lbs and verify that ALL of the head bolts are at least at or above this torque value. <- Again, none of this is in the manuals. ** New crank shaft damper if it is old ... It is due for replacement at 500k miles, and the extra vibration takes its toll on the wiring and other components + will cause ecm failures. ** on common rail engines.. replace ALL of the guts of the fuel pump, regardless of condition, if it has more than 300k miles or 6,000 hours run time on it. ** On common rail engines, ALWAYS replace the front structure (front gear housing) gasket if it is old, otherwise you will be doing this at some point shortly after the inframe due to it leaking. *** USING A TORQUE WRENCH ON EVERYTHING TO SET IT PROPERLY .. NOT A GODDAM#M SPEED-GUN!.. NOT EVEN FOR COVER BOLTS OR OTHER NON-ESSENTIAL THINGS!... USE A DAMN PROPER TORQUE WRENCH ON EVERYTHING DAMMIT!!!... COVERS, PLATES, INTERNALS, EXTERNAL PARTS AND ALL!!! {and after the engine has been put back together} ... *** Pulling a hard vacuum on the coolant system a few times + topping off the coolant as needed to get all the air out, and ensuring there are no air pockets left for either the engine or its APU unit. - Just letting it idle and run to open the thermostat IS NOT GOOD ENOUGH!. - I have seen many engine failures, distorted liners, etc. on fresh inframes because people do not do this. *** NOT RUNNING THE ENGINE BRAKE ON HIGH for the first 50k miles. Another well known issue that causes engine failures after a fresh head replacement or inframe too. *** A 50K MILES SERVICE!!! ... RE-ADJUSTING THE OVERHEAD VALVES after the first 50k miles. They are going to settle and will be too tall, and can cause compression loss if this is not done. Also doing an injector leak test at the 50k miles mark to ensure the fuel-rail components and injectors has not settled and have gotten leaky. (older engines): http://rawze.com/forums/showthread.php?t...8#pid67948 (common rail engines): http://rawze.com/forums/showthread.php?t...3#pid75483 === Anything less == not a quality rebuild, is simply wasted money, time and efforts. Here is the scenario that a person gets themselves into when things are not a very specific way... ref: http://rawze.com/forums/showthread.php?t...5#pid41315 Here is another reference: http://rawze.com/forums/showthread.php?t...6#pid60226 User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!. | |||
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