340 break in question

Small Block Mopar Engine

  1. RustyRatRod

    RustyRatRod I didn't do it. FABO Gold Member

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    Talkin about Engine break in. Yall have seen the beginning of Christine, right? When the engine starts and revs high? THAT is EXACTLY how engines were started on the line and "broken in" back then. Then driven right off the line and parked in the back lot. They MIGHT have run ten minutes if they were lucky. But they were not shy about revving them.
     
    Last edited: Jan 13, 2021
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    • Bewy

      Bewy Well-Known Member

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      Two things I would do before start up.
      [1] If the ign system uses electronic triggering [ ie, anything other than points ], I would set your initial timing at about 20*, not the factory 12*. It can be hard to accurately static time an electronic dist; the engine is more likely to fire having the dist advanced a few degrees, versus the timing being retarded.
      [2] If you are using a mech fuel pump. Prime the carb. Leave till last, have everything ready to start. Pour fuel through the carb vent until fuel dribbles out of the primary boosters.
       
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      • krazykuda

        krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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        I let the engine warm up to full temperature before going to 2000 RPM or revving it.... I keep it at 1000 - 1200 RPM until it reaches temperature and the thermostat opens...

        85% - 90% of engine wear happens when the engine is cold and the friction is higher... The faster you rev it, the more forces are on the moving parts, especially the ones with shear (rubbing) force acting on them... When you let the engine warm up before letting the rpm's get too high, it will last longer.... When the engine warms up, the friction goes down and less wear....

        My #1 rule: NEVER REV A COLD ENGINE!!!!

        If you rev a cold engine you increase the wear on the bearings, cylinders, crank, cam, etc.... Warm it up first, then rev it all you want....

        Do you jump right out of bed and run a mile immediately??? No, you wake up, drink some orange juice, stretch a little, then run...

        Same with an engine, it needs to warm up....
         
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        • moper

          moper FABO Gold Member FABO Gold Member

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          Not for the first start. By the time it reaches temperature the lifters and lobes know each other too well, and there’s been little splash up onto them while they were getting to know each other.
          Pre-oil, verify spark without turning the engine over, and manually fill the carb bowls. Eyeball about 20* of initial, and fire it going right past 2k.
          While you are correct some wear cannot be avoided in any cold start, the first start is to initiate proper wear patterns. As long as you’ve done the above, wear will be minimal during first start.
           
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          • moper

            moper FABO Gold Member FABO Gold Member

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            I bought in bulk last year. You don’t use much in one engine. But I do 5-6 a year so I buy knowing that. Really any paste product is fine. Liquids don’t do anything for those first passes of lifter over lobe as the engine starts and oil pressure comes up. It has to stay in place. That’s why I use an acid brush and apply after cam install, after checking lifter bore size and verifying rotation. Last thing before the lifters go in for good. Then I know it’s where it needs to be.
             
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            • gzig5

              gzig5 FABO Gold Member FABO Gold Member

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              I'm not an expert by any means, but you have to remember that during break-in, the engine is not under load as if it were on a dyno or pushing the car down the road. So the actual load the bearings see is significantly less than if it were under load and the risk of damage occurring is low. The caveat is that there is sufficient oil pressure and supply present when you take it up. Running the motor at 2-3k rpm under no load is not significantly different load-wise than at idle. And if anything the bearings should be seeing higher oil pressure at 2-3k and thus reducing the chance of metal to metal contact.
               
              Last edited: Jan 13, 2021
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              • TT5.9mag

                TT5.9mag Two atmospheres are better than one

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                Nope. I couldn’t disagree more with this post, when using a flat tappet cam. With a roller cam letting it idle is just fine. And even with a roller I bring the idle up a little.
                 
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                • krazykuda

                  krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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                  Then why are you talking????


                  This shows your ignorance...

                  Rotating mass has intertia... Intertia is momentum... Momentum is equal to Mass * Velocity Squared... Or I = MV**2

                  Mass is directly proportional to the force, and velocity increases the force exponentially...

                  At 1000 RPM, your velocity squared is 1000 x 1000 = 1000,000

                  At 3000 RPM, velocity squared is 3000 x 3000 = 9000,000

                  9000,000/1000,000 = 9 times

                  So the momentum and forces go up 9 times at 3000 RPM as they are at 1000 RPM....


                  That said, 1000 RPM is not idle... Most street engines idle around 800 RPM... There will be good oil pressure at 1000 - 1200 RPM...
                   
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                  • yellow rose

                    yellow rose Overnight Sensation FABO Gold Member

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                    The lifters rotate too slow at that low RPM, especially if you are using lobes from the 1990’s or newer. If you are using 1970’s stuff then it probably won’t matter.
                     
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                    • krazykuda

                      krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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                      Roller cams have much less friction on the lobes than a flat tappet cam...

                      Break in is critical with a flat tappet cam as the lifter and cam interface is under shear load... There is no boundary layer lubrication on the cam and lifters like there is with the crank and rod bearings.... The sides of the lifters have pressurized oil, the bottom of the lifter and lobes of the cam are just splash oil...

                      You keep revving your engine cold, I will wait until mine warms up...
                       
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                      • yellow rose

                        yellow rose Overnight Sensation FABO Gold Member

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                        We are talking about break in, not everyday driving. Plus, John Callies, who owns Morel says that roller lifters have a break in period. You can find that on Johncalliesinc.com which is his Morel site.
                         
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                        • krazykuda

                          krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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                          I'm not saying that there is no break in for roller cams and lifters...

                          I'm saying it's a good idea to keep your engine RPM's low as possible until it's warmed up...

                          Here's a graph of engine wear vs operating temperature... This is for cylinder walls, but applies to any pieces that are moving in relation to each other without direct oil pressure on them...

                          Wear vs Temp.jpg
                           
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                          • yellow rose

                            yellow rose Overnight Sensation FABO Gold Member

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                            I’ve seen that before. Not sure what year it’s from. I do know that cooler coolant temps do not increase cylinder wear. Cold, thick oil does.

                            If you can get the coolant down to 160 (or lower) and use a good oil and get it 180 or hotter it will make more power and not wear out the cylinders.

                            EDIT: bore geometry has as much impact on cylinder wear as anything else. If the bores aren’t finished correctly it won’t matter what the coolant temp is or what oil you use. It will wear out and not seal.

                            The harder the ring, the deeper the valleys need to be to retain oil. The oil is what seals the ring to the cylinder. The softer the ring, or the more porous the ring face, the more shallow the valleys can be.

                            The included angle of the crosshatch makes a big difference in oil control, cylinder wear, ring rotation speed and oil consumption.

                            It’s not just a one finish fits all deal and it hasn’t been that way since the early 1990’s.
                             
                            Last edited: Jan 13, 2021
                          • TT5.9mag

                            TT5.9mag Two atmospheres are better than one

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                            I understand how oiling works. Just to be clear, your argument goes against not only my opinion and many others, but also just about everything you could ever find to read on the subject of engine break in. Once my engines have oil pressure they get RPM, for break in.
                             
                          • flyfish

                            flyfish C8H18+N2O = :-D

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                            The bolded portion of your text above is EXACTLY why you need to get the RPM's up to 2000-2500 ASAP during cam break in...you NEED the splash oiling. For everyday stuff AFTER break in I would agree, warm it up before you beat on it.
                             
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                            • RustyRatRod

                              RustyRatRod I didn't do it. FABO Gold Member

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                              A cold, freshly built engine unfired engine is already oiled. It's called assembly lube.
                               
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                              • flyfish

                                flyfish C8H18+N2O = :-D

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                                Also.......If this was a roller motor non of this would matter at all....my last roller motor I fired up, set timing, drove to the gas station 1 mile down the road to seat the rings (pulling up on second gear to 3500RPM and letting the car slow on its own, over and over for 1 mile), checked for leaks (it was warmed up by then), turned around and floored it home, shifting at 6500. That motor ran mid 10's for many years, no issues.
                                 
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                                • flyfish

                                  flyfish C8H18+N2O = :-D

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                                  Dear lord....If you are going to use comma's in your numbers, please do it right........(1,000,000 not 1000,000)
                                   
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                                  • RustyRatRod

                                    RustyRatRod I didn't do it. FABO Gold Member

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                                    Yeah what is that number? A thousand thousand? LOL
                                     
                                  • dukeboy_318

                                    dukeboy_318 Our Lives, Our Fortunes and Our Sacred Honor. FABO Gold Member

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                                    :rofl:Ok, I say we build two identical engines, break one in one way and the other the other way, tear down and examine the results, those arguing get to foot the bill. Problem solved. Next
                                    :lol::drama:
                                     
                                  • RustyRatRod

                                    RustyRatRod I didn't do it. FABO Gold Member

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                                    Yeah you're right. This has just turned stupid. I'm done.
                                     
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                                    • dukeboy_318

                                      dukeboy_318 Our Lives, Our Fortunes and Our Sacred Honor. FABO Gold Member

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                                      ]It’s a funny thing when it comes to assembling an engine. There’s so many different accepted approaches. In both internet form and book form. For example, last week there was the discussion about which order to put the pistons in my 440. One book says start at number 1, then go 7,2,8,3,6,5,4; the other book says start at 3, go to 6, 4, 5, 1,8,2,7 and then the 1980s Haynes manual says 3,4,5,6,1,2,7,8 .


                                      Then the same books, have 3 different orders for torquing the mains and setting the thrust bearing, then on top of that, the Haynes book shows the anchor slots being on opposite sides on the rod from each other, but if you do that, the oil holes in the bearings don’t line up.

                                      crazy crazy


                                      I posted this in another thread but it applies here too
                                       
                                    • gzig5

                                      gzig5 FABO Gold Member FABO Gold Member

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                                      I'm talking because I'm an engineer and have been designing, building, and working on production and manufacturing machines for 30+ years, most of which use plain bearings and all have splash and pressure lubricated sliding surfaces. I'm smart enough to know that there is more pressure applied to surfaces at higher rpm but when the motor is not loaded those forces are not significant. If you have to wait for the motor to get to 180 degrees before coming off idle unloaded, your clearances are wrong, or you are using the wrong oil. We are discussing cam break in, not full operation loads. As others have pointed out, there will be a lubrication shortage to the areas that are supplied by splash and not a direct pressure feed. You do it the way you want, its a free country for a few more days.
                                       
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                                      • I8NEMO

                                        I8NEMO FABO Gold Member FABO Gold Member

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                                        Agreed. My experience in the last 2 years asking questions and acquiring parts has been similar. The internet is great yet, there's a rabbit hole waiting at every junction, even simple stuff like fuel filters, micron particles before and after pump, 2 different clutch rod lengths, tubing nut sizes, radiators with and without attach points for shrouds. Ive got a long way to go and have learned to roll with the punches. Im thankful this is my hobby, and if I get frustrated I've learned to walk away for a day or 12 which was really hard to do when I was younger. Here's to an awesome week to all of you!
                                        Tim
                                         
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                                        • dukeboy_318

                                          dukeboy_318 Our Lives, Our Fortunes and Our Sacred Honor. FABO Gold Member

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                                          Yep, you can stop right there, tells us all we need to know. As a mechanical designer, I work with actual engineers daily. So I know how you all think. Which is normally not correct :rofl::rofl::rofl::rofl::rofl:

                                          F309F923-5CB5-4932-AAE3-6605586F803E.png
                                           
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