Oil Galley plugs at Camshaft

Small Block Mopar Engine

  1. toolmanmike

    toolmanmike Moderator Staff Member FABO Gold Member

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  2. yellow rose

    yellow rose Overnight Sensation

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    Yep. I can't think of one engine I took apart that I knew was a virgin when I got in there had those plugs in them.
     
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    • Wyrmrider

      Wyrmrider Well-Known Member

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      I think I posted way back that I use cups or plugs and drill them about .040 to bleed air and foam from the oil galleys- and to oil the chain drill the plate a little larger
      someone could put a link to this thread in the oiling stickie
       
    • yellow rose

      yellow rose Overnight Sensation

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      A 50% loss of oil pressure from that plate seems damn near impossible to me. You can leave a plug or and have that kind of pressure.

      That's unreal.
       
    • yellow rose

      yellow rose Overnight Sensation

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      Yep. Piss poor engineering.
       
    • krazykuda

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

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      Doubt it if you want, I will always use the freeze plugs in mine...
       
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      • nm9stheham

        nm9stheham Well-Known Member

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        IMHO, there is nothing guaranteeing that plate will always seal true to the block. It is machined flat on the back but who knows for sure. I can easily see one getting a kink, or a burr on the edge that raises it in one corner, from being dropped, poorly machined at the factory. etc. And the bolts are spread too far to make sure you get a good seal.

        OP, IMHO, you are asking for potential trouble by not putting some short plugs in there. It's the same reason as above... the plate for the tensioner is not at all designed to guarantee an oil seal. One bit of warpage, a burr in the wrong place, etc., and you are losing pressure. I don't think those tensioner plates are machined flat on the back like the original plates tend to be.

        Are the threaded plugs all the way in? If so, I'd find some shallower one, or grind those down 'til the fit under the tensioner plate. Then drill an oiling hole on one plug (in the driver's side IMHO, since any loss there is less critical to the engine) and another hole in the cover plate in front of it, or use a drilled jet like suggested.

        BTW a 1/64" hole is only about .015" diameter.....maybe you meant 3/64" ?
         
      • Wyrmrider

        Wyrmrider Well-Known Member

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        1 /16 is too big 3/64 would work anything around .040
         
      • yellow rose

        yellow rose Overnight Sensation

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        I've got to pull the timing cover off a 340 on the stand in the shop. It's got a used 100k plus mile cam plate on it. Before I take the cam plate off I'm going to see if I can get a feeler gauge in there anywhere around the plate.

        I'm beating it's .000 all the way around, but even if it's .010 how could that small leak, even if it's all the way around the plate drop idle pressure by 50%?

        I'll also check the most likely chicom made chain tensioner plate the same way when it goes on and see how much gap there is.

        I might as well get a straight edge out and verify the block is flat, as it ain't that hard.

        Then hopefully later this spring FABO member Zigs and I will be be assembling his 340 and I'll do the same and post his results if it's ok with him.

        And when I put my R block strokes together with the Milodon gear drive I'll do all the same measurements. Then we can see across several blocks with several different can retaining systems look as far as plate seal.

        My best guess is there will be little to no gap on any of them.
         
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        • Needswork

          Needswork Well-Known Member

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          Hi YR, You might try spinning the oil pump when you have the timing cover off. If there are no plugs behind the cam plate I bet you will see oil squirting out. I did this and that's what happened to me (flat block and plate). Is it a lot of oil? No. But it will probably make a mess with the cover off. Does it cause a big oil pressure loss? Not in my experience. I ran without plugs behind the cam plate and did not experience low oil pressure. But, during a cam change I spun up the oil pump with the cover off and noticed oil squirting out (40+ psi on the gauge). I put the plugs in before wrapping up my cam change. Just my experience.
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          Too big "for what"? I wouldn't hesitate to go 1/8". No way in hell will it effect oil pressure "that much". Especially with a high performance build running a high volume and or pressure oil pump.
           
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          • Wyrmrider

            Wyrmrider Well-Known Member

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            never used 1/8 did try 1/16
            remember I'm just trying to bleed air out of the galleys and btw some chain lube
            but sbm needs all the oil to the crank (and rods you can get- well they all do)
             
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            • yellow rose

              yellow rose Overnight Sensation

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              I may try it. I'm not exactly ready to prime it yet, but I guess I can.

              If I can't get over a .010 feeler gauge in there, how much oil can it pass.

              And I just pulled the .010 number out of my hat. I'll be surprised if there is more than .002 gap anywhere on that plate.

              I guess I need to break one of my rules and get a YouTube channel. It's probably easier to make a video of all that and post the video than to take pictures and post the pictures and type all the words.

              I hate making videos.
               
            • nm9stheham

              nm9stheham Well-Known Member

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              Just my best thought of why it may make a difference to have the plugs or not. The flow area of a .040" hole is .00125 sq in. The flow area of a .005" gap across a 1" long bowed up plate area is .005 sq in... so any plate bowing or lack of flatness can add up fast in that area. And I can see guys getting burrs and grit in there, or leaving out a bolt like a top bolt to oil the chain like came on some SBM's and the plate has a pretty god gap and let's out oil. I'd bet YR is pretty meticulous on his assembly and so is likely to not have such issues.

              It is just not a guaranteed oil pressure seal area. So it may be fine on one engine and a crap seal on another that has plate issues or is done in a way that can leak without realizing it. And a weaker oil pump will show pressure losses a lot more readily with any leaks whatsoever. So a lot of variables as to why it may become an issue.... or not.

              YouTube channel? That would be interesting....!
               
            • yellow rose

              yellow rose Overnight Sensation

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              LOL. My wife is having a pretty good sized tantrum when I told her about the YouTube channel. She is NOT on board with it. She's afraid I'll take video of her doing stuff and posting it.




              The thought has crossed my mind...but I have to sleep sometime and she is scary. And I'm a coward.
               
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              • nm9stheham

                nm9stheham Well-Known Member

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                LOL.. marriage teaches you that there are some places you just don't go!
                 
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                • Wyrmrider

                  Wyrmrider Well-Known Member

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                  yep no chance for revenge rodding
                   
                • yellow rose

                  yellow rose Overnight Sensation

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                  Right after I made that post, I found a YouTube video where a guy is using his phone to record his wife snoring.

                  She sounds just like an airplane, so every time she snored, he would fly this little red plane in front of the camera.

                  Absolutely made me ROTFLMAO. The wife wanted to see it, so I let her.

                  The verbal lashing I got for even thinking I might try something like that was exceptional. I should have recorder that and put it on YouTube.

                  And now you see the issues!!
                   
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                  • Needswork

                    Needswork Well-Known Member

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                    I took my own advice on my suggestion to YR. I'm working on my own stroker 340 and was doing some test fitting of parts and such. I went ahead and bolted on my oil pump, pan, added some oil and spun the oil pump with a drill. This is with NO galley plugs, just the cam plate (4 bolts). With 5-30 oil and 50 psi on the mechanical gauge I hooked up, there was only a small amount of oil escaping behind the cam plate. It didn't make a big mess like I expected (or remembered from the past). Instead, it just dribbles down the front of the block. My guess is maybe 1 cup of oil a minute. Other setups might be different. A plate with only 3 bolts might "leak" more. Just my experience. I'm still going to install the plugs.
                     
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                    • yellow rose

                      yellow rose Overnight Sensation

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                      Take a quick look at your cam plate (not trying to convince you to not use the plugs...it doesn't matter to me either way but I'm glad you did your own test) and see if your plate has a relief cut away at one of the galleries.

                      I forget for sure which gallery has the relief but IIRC it's the drivers side. That relief was put in there so oil would leak past the plate and down onto that cheese ball little metal tab that bolted to the bottom right hole in the plate (looking from the front of the engine).

                      Not every engine got those plates but I've found almost all of the aftermarket plates have the relief. It's possible that's where that oil is coming from.

                      Just an FYI.


                      Edit: I just looked at a picture of a plate with that relief. It's on the drivers side, and the cheese ball metal tab bolts to the lower left hole and has a finger that goes into the lower right mounting hole. Like I said, not all the plates have that relief, but most every aftermarket plate I've seen had that.
                       
                    • nm9stheham

                      nm9stheham Well-Known Member

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                      Thanks for doing this; it is some extra work and I appreciate the effort.. very much! But there is a matter that is making the resulting leakage quite misleading.... the oil is not hot and so the viscosity is waaay off. Kinematic viscosity for that 5W30 oil will be around 80 at room temp, and around 60 at 100F, but the viscosity will drop like a rock to around 10 at 200 degrees F. So such leak tests are not valid with the viscosity that far off from actual operating conditions. Folks don't fully appreciate the extent of the viscosity changes as temps go down.

                      As an example of what you have to do to simulate this properly: I am preparing for some oil pump pressure and flow tests on another engine, and to simulate a hot 10W40 or 20W50 engine oil with the test oil at 100F, I have to use a 2.5W shock oil to get the same kinematic viscosity number. (There is no motor oil type or grade out there that will have the proper viscosity at 100F for my tests.)

                      So if you want to see what the leak really is with the oil hot, then get a few quarts of Motul 2.5W Expert fork oil and see what you get. Even then, that oil's viscosity is not quite as low as that 5W30 will be at 200F, but you will be a lot closer.
                       
                      Last edited: Jan 24, 2020
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                      • Cudafever

                        Cudafever Well-Known Member

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                        I have never seen a virgin block with the freeze plugs in.
                        I have never built a eng without them installed.
                        My first eng had the bolt hole that fed oil from the valley to the cam with the pointer.

                        All the rest have not had that hollow bolt installed. I have drilled a small hole in passenger side lifter galley and installed 4 bolts.

                        The oil slinger serves 2 purposes. 1) to sling oil back up on the timing chain. 2) to keep from overloading the front crank oil seal during heavy braking.

                        A stock small block, that has weak spring, small(stock) cam don't need much oil to go 200,000 miles.

                        The more cam, and spring pressure not only need more lube........to lube. But also need more lube to Cool the chain.
                        Just like the valve spring need oil....not for lube but to keep them cool enough so they don't lose their tension.

                        Chry wasn't dumb.
                        In stock form, they lived! and that's what mattered (Warranty) You bet There asssss all the imperfections of are sbm would have been addressed if it cost then warranty money
                        In STOCK form there is nothing wrong with this block.

                        I know this is going long but one more thing.

                        To the person that had threaded plugs in the oil galley up front. Get a file and make the flat surface, flat again. them thread will be pushed up to the surface.
                        Freeze plugs will do you no good on this block so i would make sure both surfaces are flat and bolt it on just like chry did in the beginning.
                        drilling a small hole to have pressurized oil to the cam.....Well that's your call.
                         
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                        • SSG_Karg

                          SSG_Karg I am the Nightrider!

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                          upload_2020-1-24_10-31-41.jpeg
                           
                        • Cudafever

                          Cudafever Well-Known Member

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                          If that's the definition of this thread....well, then Yes!:D
                           
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                          • nm9stheham

                            nm9stheham Well-Known Member

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                            I assume you meant 'front gallery' plugs? Now that is interesting... made me go look at my unmolested '68 273 block.... no plugs in the front. So just the plate in stock form.

                            One thing I did not realize is how close behind the front of the block that the oil passages to/from the #1 main bearing sit in the galleries; it is less than 1/2". So you had better not drive any such front gallery plugs in too deep. I wonder how often THAT has happened.....
                             
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