Can You Deck A Numbers Matching Engine Block?

this video is sponsored by Squarespace the all-in-one platform that makes it easy to build and manage your online presence we'll have more on them later but for now welcome back to the gmz online YouTube channel let's get into it alright so we're back here working on the 396 Big Block first thing we're going to do here is rough bore our sleeves for our Pistons but we're also going to be going through the process of decking the block now a lot of you commented on the first video about how we did all this work for a numbers matching block but how are we going to deck it and not remove the numbers so we're going to be showing you that process here but we want to take as little Material off the decks as it takes to clean up and square them up so the first thing I'm going to do here is measure our two different deck Heights to figure out which side is taller because we want to start on the side that is already shorter clean up just as much as it takes to clean up and then cut the other deck to match this is our deck height gauge basically what we do is set it up taking into account the compression height of the Piston the Center to Center length of the connecting rod half the stroke length of the crankshaft and then we subtract half the diameter of the main Journal down in the bottom the main bore so that basically this references the bottom of the main board and then our dial indicator references the top here so getting about 8.324 here coming in eight 26 326 or 27 here so we're actually a little bit taller here than we are over here which tells me that relative to the crankshaft basically the deck is not perfectly parallel [Music] so on this side we're getting about 8 3 22 couple files shorter on this deck height 8 3 23 there what we just figured out is relative to the crankshaft Center Line this deck height is already shorter than the other side okay so now that we know we want to start on this Bank of cylinders I'm going to put the square in down here to get the block all squared up and level and then I'm going to switch over to our boring head set up a cutter and we'll bore our first cylinder as you can see the block fixture here references off of the main bore of the block and uses a Precision Square relative to the pan rail in order to make sure that the two Banks of cylinders end up bored and decked exactly perpendicular to each other it doesn't matter whether you bore the block first or deck the block first so I opted to bore and then deck being a 396 standard bore size is 4.094 inches and unfortunately the Pistons were using seem to be obsolete in standard size so we're forced to make the block Thirty thousands oversized we'll be boring the Block in two cuts one bringing us to about 14 thousands below finish size and the second cut bringing us to within four thousandths of finish size leaving a small amount of material to remove in a cylinder home got our finger in here so we can Center up I'm close but I'm not perfect I'm gonna call that good and lock the table down last thing I really need to do here is set my stop so I'm going to put a cutter in and again I've got that cutter set for our rough bore because we want to leave a few thousands to hone sealer gauge with a three thou feeler gauge I slowly run the spindle down until I just feel resistance on the feeler gauge indicating that the cutter is about three thousands from the deck so I want to I want to bore six and five sixteenths based on that the machine has an automatic stop which we're setting based on the length of the cylinder to avoid crashing into the main webbing in the bottom of the block start around 480. sounds good looks good [Music] with the board gauge set with zero as our nominal finish board side so we can see that after our first cut we're coming in right around 14 000 under finished size exactly where we want to be [Music] our next cut should remove just around 10 thousandths of additional material bringing us to within four thousandths of our finished bore size leaving just the right amount of material to remove in the cylinder home last step of the boring process is to chamfer the top edge of the cylinder to break the sharp edge and Aid in piston and ring installation later on at this point we'll simply repeat the process on the remaining three cylinders on this Bank [Applause] [Music] with all four cylinders on this Bank board we're going to go ahead and switch back over to our surfacing head and resurface this side of the block switching between tools is fairly quick and easy on this machine since it's equipped with the spindle caddy we simply unbolt the spindle set it on the caddy rotate over to the next tool and bolt it back up to the machine Okay so we've got our CBN in here our CBN cutter we're gonna deck the block now but we have to stop before we go all the way across this edge here because we don't want to take off the numbers that's what makes the block valuable for the customer I'm just going to run over here and run down close with our cutter before I turn it on make sure this is pulled out so it doesn't start feeding [Music] I'm just going to go down until it just touches okay I just heard a touch hopefully you guys can hear that too we've just skimmed right there you can just barely see where it's cut that line same thing on the back side here we've just barely skimmed so that's our zero point at minus 5.1875 on the Z did the same thing on the opposite end here just to double check z-axis we're minus 5.1870 So within a half thousandth of the other side so that's that's good news so I did a little bit of feeding it by hand on the x-axis here basically I was just skimming it and we got over two just before those numbers because we want to surface as far this way as we can so we're going to stop there and what I did is I put in a zero mark on the x-axis there on the dro so we know where to run the cutter over to [Music] that cutter probably needs turned [Music] [Laughter] kind of two ways I can stop it I can either pull the stop on the on the wheel down here that disengages the table or I can slow it down by basically slowing the speed of the motor to zero I think I'm probably gonna do it just by disengaging the table here foreign right now I'm traversing the z-axis to get as far that direction as we can and we'll see how that looks I don't know if that's what I'll do for the final cut or not yet before we see how we did let's take a quick break to talk about our sponsor for this video Squarespace I first designed a website for our machine shop using Squarespace clearback in 2015 because I knew we needed to start building our businesses online presence Squarespace makes it easy to build your brand with the custom domain purchased through the platform and once you have a domain the user interface is simple and easy to use even for someone with no web design or coding experience once your site is live there's a full Suite of analytics allowing you to get stats on your traffic to help you grow you can tell here that our traffic has grown a lot especially over the past two years with our growth on social media head to squarespace.com for a free trial and when you're ready to launch go to squarespace.com Jim's automotive to save 10 off your first purchase of a website or domain on the first cut here basically what we did we had the block moved that direction as far not as far as we could but pretty far that way so that the center of the cutter came to right here because it's you know a circular cutter so it's not going to cut straight across so we brought it out to right here and then I moved the block that direction to get as far out this direction as we could and this black line here is the outside of the gasket I'd like it to look better than it does here and there's a little bit of an edge here I genuinely don't think it would bother the gasket I think the gasket would seal fine but we're going to try to get it a little bit better I rotated the cutter a little bit because it was dull that's why the surface finish looks the way it does but we're going to take another half thousands here and see what we can do but I'm going to do it the opposite direction I'm going to move the block that direction as far as I can and bring it across and when we get over here we'll Traverse the other way thank you [Music] [Music] [Applause] [Music] I think that was such a light cut that we still left a little remnants of the first cut here and if this funny business happens out here I'm not as worried about it but I think it's looking good but that being said we need to do another cut because we're not cleaning up over here we've got some low spots [Music] [Music] I'm happy with what we've got here I definitely cut it a little bit close on the numbers but they are still there you can read them we're good there gasket looks good filed this part down so it's even and everything should be good gonna roll over to the other side now so on this side our sleeves actually protrude a little bit the sleeves were kind of different lengths so these ones actually are hanging out a little bit more so I zeroed off or basically ran the cutter down until we just touched the top of this sleeve because this is the highest one so now we're gonna basically trim off the top of the sleeves until we get level and then our number on the z-axis of the dro we need to go to is minus 5.1905 to make the deck height identical on this bank and this Bank [Music] so hopefully you guys remember earlier in the video we showed that this side of the deck had not had previously not been cut even from front to back and that's showing up here as we have cleaned up over here on this side but we have really only touched to about here and you can see some waviness in the surface as well by where it's shined up already and where it's not so we're gonna keep going so we're six thousands from our final height right now I'm gonna do it in a 5 000 cut or five and a half thousands cut and then we'll do a half thou finish cut thank you so I'll take this to 190 Five Point minus 5 190. finishes 51905 to match the other side so it's gonna be a heavier cut [Applause] after our rep cut we made a half thou finish cut to make the deck height equal on both Banks of cylinders [Music] once the second side of the block was decked the final step in the process before moving over to the cylinder hone is to rub for all of the Second Bank of cylinders for our 30 thousandths oversized Pistons the Pistons we've opted to move forward with on this build are a forged stock replacement piston for the 396 big block from Speed Pro as mentioned earlier the standard size seem to be obsolete so we've moved to the first oversize of 30 thousandths of an inch larger the manufacturer lists a recommended minimum piston to wall clearance of one thousandth of an inch although we're going to be adding an extra half a thousandth to that number bringing our final finished bore size to 4.1245 inches with the main caps torqued on the Block we're getting set up in the cylinder hone in order to hone the cylinders to the finished bore size we're going to be honing with a torque plate but first we need to do a bit of setup on the machine using the machine setting fixture we first shim the Guides of the hone head as well as the stones to the proper size next we adjust the stroke length of the machine for the proper length of the cylinders we also adjust the different Drive belts on the machine to adjust the stroke rate of the machine as well as the RPM of the home head finally we adjust the height of the engine block in order to achieve the desired overstroke on the top and bottom of the cylinder we've got our roughing stones in here because I'm still around three thousands to go to finish size these stones are a rougher grit they're going to take material out more quickly but they're going to leave a rougher surface finish so [Music] right at the top we're a little bit tight so I'm gonna dwell a little bit at the Top If I can but it's not too much so I've used Our rough stones to get us out closer to our finished size and here's just kind of an idea of what kind of surface finish that leaves so here you can see now we're going to switch to a little bit finer grit Stone a little bit finer grit than the stone we were just using and we're going to sneak up on our closer to our final size here and for reference it might be a little difficult to tell a difference on video but compare the surface finish of this cylinder with that of one of the other cylinders here you can see it's a little rougher here compared to the stone we're using right here so now just for fun I want to show that's the cylinder I just finished honing so we've got 72 degrees everywhere else and we're 74 or 75 on that one the rest of the block is sitting around 70 or 71. so I'm going to let this cool for a little bit before I do our final honing step to make sure that we're getting an accurate size reading okay so at this point we're almost to our finished size we've got one more Stone here that we're going to use that is the finest grit size that I use and we're going to take it to our finished size foreign so here hopefully again hopefully you can tell the difference I know it's it's pretty subtle but this cylinder is at our finished size with our fine Stone and this cylinder is not quite to finish size so we still have to do our final Stone on this cylinder you can see the surface finishes just a little bit coarser compared to this got our cylinders to size the last step we do a little Plateau brush that we run through the cylinders just a few strokes and the idea is that's going to kind of take off any of those last little broken edges that are remaining at that point our first bank of cylinders is wrapped up so we can move the torque plate to the opposite Bank of cylinders and bring them to our finished size zero on the gauge is our minimum one thousandths clearance and you can see that we're within a couple of tenths either way of our half thousandth larger than that which I'm happy with with the honing process wrapped up the Machining of this engine block is finished so it'll move on to get final cleaned before we assemble the short block for our customer stay tuned for more to come and we'll see you in the next one

Channel: Jim's Automotive Machine Shop, Inc.

Views: 350,827

Keywords: Engines, Engine Machine Shop, Machine Shop, Engine Shop, Machining, Automotive Machine Shop, Automotive, Cars, Trucks, Tractors, Gas, Diesel, Performance, rebuild, high performance, internal combustion engine, pistons, cylinder heads, jim’s, jim's automotive, jamsi, jamsi online, Blueprinting, rebuilding, engine building, connecting rods, engine block, boring, valve job, engine rebuilding, jim's automotive machine shop, Big Block Chevy, Chevy, BBC, 396, 396 BBC, 396 Big Block, Chevrolet, Restore

Id: hKUGR5FOC2Y

Length: 19min 39sec (1179 seconds)

Published: Sun Jan 08 2023