High Tech Slant Six

(Pat)>> You're watching Powernation!

(Pat)>> For over a year we've been gathering parts from all around the world for a very special project.

(Frankie)>> A turbocharged slant six! [ Music ]

(Pat)>> Hey everyone, welcome to Engine Power. Today we are gonna embark on an engine building journey, and we're happy for you to come along. We're gonna be putting together one of the most requested engines you guys want, and oddly enough it is no sort of V-8. You might not recognize it from this angle but this is our current project. The venerable, the mighty 225 Chrysler Slat Six. This engine is legendary for its durability, and it's still very popular with gearheads and hot rodders even to this day. We actually did one of these engines on the show a few years ago and it was a very fun build. We assembled it, dropped it into a vintage Duster, chassis dynoed it, and it made great power. But us being us we wanted to see if we could get even more power out of this platform. So on this iteration we decided to step up our game and bring this engine up into modern times with some high tech parts. It all started with finding a late model 225 block that has already been machined. It has been align honed, bored, honed, and decked. We also scoured the internet and found a forged crankshaft. Now that was a bit difficult because they stopped making these things in the mid '70s, but we found one that was already ground, but that doesn't mean that we're not gonna put a little bit of a magic touch on it. The mains are gonna get held down with some ARP fasteners, and for the rest of the rotating assembly we decided to go heavy duty. We contacted our friends at Wiseco and got them to make a custom set of pistons for our bore size. These are forged out of 40-32 alloy, have an antifriction coating on the skirt, and a thermal barrier top coating to keep that combustion in its place. They're gonna be paired with a set of Molnar Technologies H-beam rods. These rods have a seven-inch five-thousandths center to center length, a bushing in the end for full floating wrist pins, and the caps are held on with ARP 2,000 fasteners. Last but certainly not least is a set of Total Seal custom rings to hold in all that combustion gas. These are a gas ported set and they're gonna work great for our application. But you might be asking, why are we putting all these hardcore parts in our little 225? Well we have something special planned for the induction and the top end. Frankie's gonna tell you about it.

(Frankie)>> We are going all out on this build. So the trick parts are not gonna stop with the bottom end. This build is gonna follow the formula of a lot of our six cylinder builds. We're gonna dyno it naturally aspirated, and then we're gonna dyno it turbocharged on 93 octane pump gas. Since we're using pump gas we're not trying to break any world records, but this engine is gonna make some pretty impressive power for its size. In order to do that with durability we needed a bunch of great parts from a bunch of great companies, and we looked all over the US and quite literally all over the world to make that happen. The first one that probably jumps out at you is this cast aluminum intake manifold from Aussiespeed out of Australia. It features an equal length long runner design with a 41-50 style flange. So you can use a larger carburetor or in our case a larger 41-50 style throttle body. That is because this manifold has been converted to port electronic fuel injection by Gil Welding, a fabrication company here in Tennessee, and they offer this service for a bunch of different engines and a bunch of different intake manifold designs. Aussiespeed also has a bunch of other cool parts for the Slant Six like this cast aluminum valve cover, and these Dutra dual cast iron exhaust manifolds. These are a high flowing manifold that are based off of the original Dutra dual by Doctor Dodge himself, and they are fully manufactured by Aussiespeed in Australia. Gil Welding also made us this cool turbo connector that has a T-4 flange to feed our STS 59 millimeter turbo. This build is gonna be using the stock cylinder head that matches our block over there, and there's a ton of stuff you can do to these. For our purposes we're gonna be hand porting it and upgrading a lot of the valvetrain around it. To do that we reached out to another Australian company, YellaTerra, for a set of their shaft rockers. These feature 1.65 to 1 ratio full billet aluminum adjustable roller rockers housed on two billet steel shafts, and they bolt directly to the top of the cylinder head. It's gonna be a huge improvement in terms of durability, strength, and adjustability since the later model rocker arms are non-adjustable. Those are gonna be actuated by a custom ground Comp Cams flat tappet cam shaft, a set of their solid flat tappet lifters with e-d-m oiling holes and controlled by a set of Comp Cams valve springs. In order to make all of the valvetrain move we found a billet double roller adjustable timing set on the internet. Now in order to really bring this engine into the modern era not only are we gonna have sequential port fuel injection, but we're gonna be adding sequential coil-near-plug ignition. To do that we're gonna be using Holley EFI's Smart Coils, and we're gonna be building a custom harness in order to make all of this work. It's all gonna be controlled by a Holley HP e-c-u, which is gonna give us a bunch of functionality and make it really easy to start and tune this engine. Now there is a ton of parts here, and by no means is this a budget build, but this is a dream build for us, and for you slant six fans it's probably a dream build for you as well. We have been gathering parts for quite literally over a year in order to make this happen, but we have not done a slant six to this level before. So there's gonna be a bunch of figuring, a bunch of fabrication, and a bunch of learning, but we're all gonna learn together. Laying out these parts has gotten us pretty excited. So let's get started.

(Pat)>> Up next, I guess we get started.

(Frankie)>> Plus we take a closer look, and I mean a way closer look at the technology behind piston rings.

(Pat)>> Welcome back to Engine Power where we are in the midst of our turbocharged 225 slant six build. The first thing we're gonna do is balance the crankshaft. Remember, we got this off the internet. So even though it has been ground we have no idea on how well it's balanced. So we have it up on our CWT Industries Multi-Bal 5500 to check it out. Although this is gonna be a very straightforward job it still might take a bit of work to get it where we want it to be.

(Frankie)>> Inline cranks are pretty easy to balance because there's not that much setup. We don't require any bob weights because on an inline engine where all the cylinders are in one straight line the rod journals are evenly spaced around the crankshaft. So they don't require any bob weights. They're also inherently internal balanced. So you don't need a flywheel or a damper. So all we have to do is get it in the machine, get it set up. We have our parameters programmed, and we can give it our first spin.

(Pat)>> Do it! We're immediately revving it up to 750 r-p-m because this inline crank won't be severely out of balance. Okay, not bad, like we expected. About three quarter ounce inch on the front, half ounce inch on the back. Being this engine was not a high r-p-m or high power engine when it was designed that would be perfectly fine and not give you any problems, but because of what we're doing we're gonna turn this thing a little bit higher and make some more power. So we're gonna get those closer, down to our eighth inch. So all we'll do is get to our places where to take off and we'll start tuning on it from there. No drilling will be required since we're removing such a low amount of material. A carbide burr and a sanding disc will be sufficient. Both ends of the crank took very little time to modify. We went a bit overkill on this one but it was purely unintentional but easy to do on an inline crank. Because they are so close to being balanced to begin with, it's easy just to tune on them and get them very, very good. From our balance tolerance of eighth ounce inch we are basically zero/zero, which equates to as this machine measures, one thousandth of a gram on the back, three thousandths of a gram on the front. I don't think we can get it any better. And with the front and back that close this'll be interesting to see where the static is. Yeah, wow, this crankshaft shows a lot of goose eggs, and that's a good thing. Next we'll get our crankshaft in the lathe and give it a super polish with our Goodson crankshaft polishing machine using several steps of belts to give it a better than o-e-m finish.

(Frankie)>> Now that we've got our forged crankshaft balanced and Pat's got it nicely polished in the lathe we can move on to assembly. We could have used a cast crankshaft in this engine. There's rumors about them handling 300 to 400 horsepower pretty reliably, but for what we're doing we wanted something that's a little bit stronger and a little bit more durable. So the forged crankshaft. We also got a forged crankshaft for another reason. The H-beam rods that we decided to use in this build, they're very strong and they're a forged steel, but they are only designed to work on this forged crankshaft. Because of the journal widths they don't fit on the cast crankshaft. We knew going in that the rod journals and the main journals were wider on the forged crankshaft than they were on the case crankshaft, but what we did not realize is that the blocks themselves are also different. You can see on these bearings that a cast crankshaft main thrust bearing is a lot skinnier than the forged crankshaft main thrust bearing, and what this means is if you tried to put the cast crankshaft bearing that came with this block on the forged crankshaft it wouldn't actively control the thrust of the crankshaft. And if we try and put our forged crankshaft bearing in our cast crankshaft block it will go in but it doesn't fit the register of the block properly and has an air gap on either side of the thrust. So we had to figure out a way to make it work.

(Pat)>> Our solution was to machine up some precision thrust bearing spacers here in house on our lathe, and that consists of taking some aluminum round stock and making a couple of rings of different thicknesses. They have to have the proper o-d and i-d, and they also have to be the right thickness. One is 60 thousandths and one is 90 thousandths. I'll get to that in a second. They are split in half, and then made to fit in the already machined part where the thrust bearing goes in the block end cap. So once the bearing is pressed in with the spacers in place they are captured and can't go anywhere. As far as the spacer's thickness is, that allows us to position the crankshaft where we think it needs to be to make everything work. The housing bores on the old style and the new style blocks are the same. So even though we have an old bearing in the new block we have the proper amount of bearing crush. So we'll use the bearings that are supposed to be in this block in one, two, and our four, and our old style one in number three, and that's how you put an old style forged crankshaft in a new style block and make it work.

(Frankie)>> With the rear main seal installed and lube on the bearings, we can drop in our forged crankshaft. We'll install the main caps one by one... set our crankshaft thrust and torque the ARP bolts to 85 pound feet.

(Pat)>> Up next, when it comes to piston rings you can never be too thin or too tough.

(Frankie)>> Plus, the slant six receives the rest of its rotating assembly.

(Frankie)>> Here in Engine Power we always stress the importance of accuracy and measuring in engine building, and a company that shares that sentiment is Total Seal Piston Rings.

(Pat)>> Now hones have really had to step up their game lately because the materials and the proc1esses for rings has drastically changed. So we have Lake Speed Junior here. Tell us a little bit about the history of piston rings.

(Lake)>> The piston ring is actually older than the internal combustion engine. So back in 1852, a good 20 something years before Nicklaus Otto invented the internal combustion engine, this engineer named John Ramsbottom invented the piston ring for steam loco motives. Back in the old days they were cast iron, and that's what everyone used for 50, 60 more years. It had to be really big to have any kind of life to it because it was soft and it wore really quickly. Then we came up with the idea of let's put chrome on it. So you put a chrome face on that cast iron ring, and that made it live longer. The only downside to chrome was it was lumpy, and bumpy, and hard. So it took forever to break in. You had to do all these weird things to make sure your motor broke in with a chrome ring in it. Then along comes moly where you could actually take that cast iron ring, upgrade the material ductile iron, make it a little bit harder, and then you could cut a channel in it and spray in molybdenum, which is softer but it was also porous. So now it would break in really easy, it held its own oil, and life was really good. Over time racers figured out that the thinner you go in the ring the less wear you have, and they're really strong because they're made out of steel now as opposed to the cast iron or ductile iron. The only way you can make those thin rings is through that better material technology. When you get real thin like that it's very hard to spray that moly on there. For example, this little ring right here, this hot rod little piece, has titanium nitride coating on it. This is actually three times harder than that old school ductile iron ring right here. So this moly ring right here is a sixteenth ring, this is a point seven millimeter ring. This is 800 Vickers hardness; this is 2,400 Vickers hardness. In a modern race engine this will live three times longer than this, but the trick is this ring right here does not hold any oil. There's no porosity. Now what you do is rely on the hone to actually create a surface finish that's flat on top with these valleys underneath. They call it a plateau type finish. That valley holds the oil because oil is the gasket between the piston ring and the cylinder wall. If you don't have oil you're not gonna have much compression. Put a little bit of oil in there what happens?

(Frankie)>> Seals it right up. The important part of that is knowing what the surface finish is gonna be cause if you're not measuring it. Like we always say, if you're not measuring it you're guessing. In order to get that right you really have to have the technology to measure that, and you guys have really excelled in that department.

(Lake)>> So the profilometer has that little diamond tipped stylus that's dragging across the surface, measuring those peaks and valleys, and just measuring down to one millionth of an inch. The thing is that whole surface that it's creating with that honing process is really only about a tenth of a thousandth. Not a thousandths, tenth of a thousandths. The trick was with the old profilometers, that little bity screen, you really couldn't trust and see the trace. So you had to use the numbers, which were derived from the trace. With the software now you can actually see that trace, you can see it on scale, and you can begin to see what's going on. So that way you can dial in your process.

(Frankie)>> Let's say we give it a run. I want to see this thing work.

(Lake)>> So this thing just drops right in there. You can locate it in the bore. Hit the space button and it's gonna begin to measure it.

(Pat)>> That's a long trace on there. It's 480 thousandths.

(Lake)>> It's gonna take a little while for it to do it, but the reality is you want to see that bigger picture. The whole idea is you want to get as much information as you can from that trace to be able to understand what that surface really looks like.

(Pat)>> And the best part about this is now we have this data but now we can see it optically.

(Lake)>> This microscope lets you see in the block. So we can come right in here and open up the hatch view software.

(Pat)>> And it's showing included angle.

(Lake)>> It gives you the included angle on the screen. What's neat about this is you can go anywhere you want to. So we can roll all the way down here to the bottom of that cylinder and you can see that cross hatch flattens out.

(Frankie)>> That's what we love about working with you guys is you guys obviously have been progressing piston rings for years but you've also been progressing the technology around that surface finish, the ability to measure it. You guys have your own dyno. You guys are doing the testing to make sure your customers not only get a good product but they get the support for it as well.

(Lake)>> We want to be not just a piston ring provider but also be a technology partner. We're very fortunate to get to work with the NHRA Pro Stock teams, the Nascar teams, Formula One. We have access to a lot of technology, and what we want to do is take that technology, make it accessible for everybody else so that everyone can build engines that are more powerful and have better longevity. That's the goal in the end.

(Pat)>> We want to thank you for coming in.

(Lake)>> Thanks for having us be a part of it cause this is what we want to do.

(Pat)>> Up next, our slant six achieves short block status.

(Frankie)>> In today's Summit Tech Tip we're gonna talk about something that's very important when planning your build, and to help us we have NHRA Top Fuel driver Clay Millican. Now Clay, there's a bunch of different styles of injector but why is fuel injector sizing really important?

(Clay)>> According to what you're building and what kind of power level you're trying to achieve there's a lot of different injectors out there, and what you've got to do is call the experts at Summit. Tell them what kind of power you're planning on making and they'll tell you the injector that you need to fit your application.

(Frankie)>> There's a pretty simple formula that you can use to help calculate that. It's your estimated horsepower multiplied by the brake specific fuel consumption of the fuel you're using. For gasoline we generally use point five. Then that figure is divided by the number of injectors multiplied by the required duty cycle of the injector, for which we generally use 80 percent.

(Clay)>> Frankie, that's a whole lot of math that I don't totally understand. So I'm gonna call the folks at Summit. They're gonna pick out the injector I need and all the other components I need to go right along with it.

(Frankie)>> Just a point of note. It's always a good idea to have a little bit more injector than not enough.

(Clay)>> That's because lean is mean, and it can burn your stuff up. [ Music ]

(Frankie)>> We're well on our way with the rotating assembly in our turbocharged 225 slant six. We're using a total seal gas ported steel ring set. We're setting our end gaps to 27 thousandths on the second ring and 25 thousandths on the top ring as per the instructions for boosted applications. Our Summit Racing Pro Ring Filer makes it easy to accurately set each ring gap. If you don't have a ring squaring tool you can use a piston with the oil control rings installed to square up the piston ring before measuring the gap. [ Music ]

(Pat)>> Next we'll assemble our Molnar seven inch five thousandths long H-beam rods and our Wiseco three-four-60 bore pistons. The pistons have a 6cc valve relief and use a one millimeter, one point two millimeter, 2.8 millimeter ring pack. [ Music ] The rod and piston assemblies receive a generous coating of Total Seal assembly lube. [ Music ] The bores have already been cleaned with lacquer thinner and also got Total Seal assembly lube on them. Since it's an inline six cylinder installing the rod and piston assemblies is very quick, especially with two people working on it. [ Music ] [ drill humming ]

(Pat)>> The ARP 2,000 rod bolts are torqued to 60 pound feet the proper stretch of 56 to 60 ten thousandths. [ Music ]

(Frankie)>> Like we said earlier, this is a custom ground flat tappet cam shaft from Comp Cams. The lobes we picked out have durations at 50 thousandths lift of 218 degrees on the intake and 230 degrees on the exhaust. They are set on a 114 degree lobe separation angle, and lift at the valve for both is 487 thousandths. [ Music ] Because we're actively controlling the location of our crankshaft with our thrust washers we knew we were gonna have a bit of misalignment between our crank timing gear and our cam timing gear of our timing set. We don't want to modify the cam timing gear because that actively controls location of the camshaft and we don't want to move it. So what we did was machine some material from the back of the crank gear in order to have them properly aligned. [ hammer tapping ]

(Frankie)>> Before we install our timing set we'll make sure to install the threaded pipe plug that goes into the main oil gallery. We'll install our double roller timing set in the negative four degree keyway position to start with. [ Music ]

(Pat)>> Where did you end up?

(Frankie)>> I put the intake centerline at 114.5, half degree retarded. I think for where we want this thing to make peak power n/a that's gonna work really good and it will help with cylinder pressure once we start putting it under boost.

(Pat)>> Now we have gotten a lot done on this. We have a solid short block assembly, but there's still plenty to do. The next time you see this we're gonna run it on the dyno and see what it makes naturally aspirated and with a little bit of artificial atmosphere.

(Frankie)>> And if you want to see more of our unique builds like this one you can always go find them at Powernation.