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Cometic MLS Head Gaskets
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COMP Cams Roller Lifters
Summit Racing
Moroso Timing Pointer
Summit Racing
Summit Racing Billet Timing Set
Summit Racing
Total Seal Assembly Lube
Summit Racing
Total Seal Piston Rings
Summit Racing
Trick Flow Cast Aluminum Valve Covers
Summit Racing
Trick Flow Roller Rocker Arms
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Trick Flow Specialties Intake Manifold
Summit Racing
Trick Flow Super 23 195 Cylinder Heads
Summit Racing
Trick Flow Track Max Hydraulic Roller Camshafts
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Tools, Hardware, Shop Supplies

Episode Transcript

(Pat)>> You're watching Powernation!

(Frankie)>> Somebody call a psychiatrist because we've developed an unhealthy compression obsession.

(Pat)>> There's a limit on how much compression you can safely build using pump gas, and today we just might find it. [ Music ]

(Pat)>> Today on Engine Power we are getting back on the revamping of our backyard small block Chevy build into a dyno mule so we can do a little bit of r&d. We're gonna show you today how you can run your static compression higher than you normally think you ever could and still run it on pump gas. We've had to ditch most of the stock parts in favor of some shiny new high performance ones to get the job done. If you want to see what we've done to this engine to get it to this point watch this. Frankie hunted down a worn out small block that also came with some parts intended for the seller's engine project. After a complete rebuild including new springs, a bigger cam, and a bunch of top end components, we fired it up just for fun in the parking lot. [ engine starting and idling ]

(Pat)>> Then we rolled it into the dyno cell.

(Frankie)>> Look at that! Woo!

(Pat)>> The Chevy was good for 276 horsepower and 345-pound feet of torque, but we want more power and for this build part of that equation is increasing dynamic compression.

(Frankie)>> After teardown and inspection we prepped the engine for forged rods and pistons, gas ported rings, a couple of cam shaft choices, adjustable timing set, 195cc heads, dual plane intake, and a user friendly e-f-i system. To achieve the proper cylinder wall finish and to let us install bigger, better pistons the cylinders were honed to 4.062 and two-tenths.

(Pat)>> You know what you're gonna say?

(Frankie)>> I think so.

(Pat)>> Alright, go ahead. [ can clanging on floor ]

(Frankie)>> We also went ahead and tapped our oil galleries in the front for some threaded plugs, deburred most of the block, and cleaned up some of our oil galleries to improve oil flow. Now static compression ratio you're probably wondering how we're gonna run something that's so high and still be on pump gas, and that's because static compression ratio is only part of the equation. Another huge part of it is dynamic compression ratio. We talked about what that was before and today we're gonna talk about how you can actually affect it with the components you choose for your engine. Now since this is an r&d engine not only are we gonna cover the tech, but we're also gonna show you how it improves performance, or not, on the dyno. This thing looks ready. So, let's move on to assembly.

(Pat)>> Time to get working. [ Music ]

(Frankie)>> As always, the first part of the assembly process is measuring oil clearance on our main bearings. Since the undersized bearings are basically brand new, we are going to reuse them. The ARP main bolt kit is torqued to 70-pound feet just like final assembly. For each journal we'll set our micrometer to the journal's size and use the micrometer to zero out the dial bore gauge. Our clearances come in between 19 and 20 ten-thousandths. That sounds a little tight but it's well within the o-e spec. We'll repeat the process for all the rods, which are within stock Chevy specification as well. Next the cam shaft bearings are finally pressed in.

(Pat)>> The pistons will receive Total Seal's gas ported top ring set. This gives you all of the benefits of a horizontal gas ported piston without having to machine the piston itself. Since our dyno mule engine will probably see some abuse, we'll gap the ring a little larger to 22 thousandths on the top ring and 24 thousandths on the second ring. We'll go slowly and check our work often. [ Music ] Not to be overlooked is deburring the ring with a fine India stone after it's been filed. This ensures the ring doesn't damage the piston or the cylinder wall. [ Music ]

(Frankie)>> With everything cleaned we'll lube up the bearings and reinstall our re-balanced and polished stock crank shaft. This was done by our favorite machine shop, Shacklett Automotive Machine. [ Music ] Just like before, the final torque value on the four bolt mains is 70-pound feet. [ ratchet clicking ]

(Pat)>> It's time to put a cam in our engine, which brings us to why we are doing this entire operation, adjusting dynamic compression ratio. A lot of the time people get hung up on just static compression ratio to determine the octane and fuel they will use when dynamic compression ratio is just as important as static. It is calculated the same way but you have to know a couple different things about your engine. One is the connecting rod length, and two where the intake valve closes in the cycle, and that is directly affected by the cam shaft. To calculate dynamic we have to use something called effective stroke, and that is the amount of stroke left after the intake valve closes. Now that is a large equation, and if you're good at trigonometry you can get it figured out, but if you know all of your numbers you can plug it into a few online resources and the math will be done for you.

(Frankie)>> When we built our engine in the parking lot it had a measured static compression ratio of 8.82 to 1, and had a dynamic of 7.27 to 1. Now with our new parts like our 13cc effective dome, our head gasket size, and our head chamber size, we have a measured static compression ratio of 13.15 to 1. Now that seems high but we're gonna use cam shaft selection to make our dynamic compression ratio pretty manageable. We have two Trick Flow Track Max hydraulic roller cam shafts on the table. One is a little bit small, one that's a little bit bigger. The smaller one has durations at 50 thousandths lift of 230 degrees on the intake and 234 degrees on the exhaust on a 110-degree lobe separation angle. The larger cam shaft has durations at 50 thousandths lift of 246 degrees on the intake and 254 degrees on the exhaust on a 112-degree lobe separation angle. Because of our part selection and where we want this engine to make power, we're going to use the smaller of the two cam shafts. We also have a Summit Racing billet double row timing set that is adjustable so we can dial in our intake valve centerline to where we need it to be to be manageable and also run pump gas on the dyno.

(Pat)>> Coming up, we get this small block together and get it on the dyno.

(Pat)>> Before the cam shaft can go in our threaded oil gallery plugs must be installed. [ ratchet clicking ]

(Frankie)>> You're probably wondering why we choose the smaller of the two cam shafts, and because of our parts choice and the purpose of this exercise we want our engine to make power a little bit lower in the r-p-m range. It's also gonna affect our dynamic compression ratio. Generally, as a rule choosing a shorter duration cam shaft will increase dynamic compression and choosing a longer duration cam shaft will decrease it. We're also gonna be a able to adjust it like we said with the intake valve centerline. Advancing the cam shaft will make the intake valve close sooner, increasing effective stroke, and retarding the cam shaft will make it close later, decreasing effective stroke. [ drill humming ]

(Pat)>> With the timing set snugged down we'll temporarily install the number one piston without rings so we can degree the cam shaft. We're putting the cam's intake centerline in very late at 112.75 degrees, which is 2.75 degrees retarded.

(Frankie)>> Because we are using a stock crankshaft, we know our physical stroke is 3.480, but because of where our intake centerline is placed our effective stroke is reduced down to 2.341, and that makes our dynamic compression ratio 9.17 to 1, but what does that number actually mean? To us it's very important because we know the dynamic compression of all the engines we've built, and we've ran things on pump gas all the way down at 6.2 to 1, all the way up to 9.24 to 1. So this, although it's on the top end of the range, will run just fine with that cylinder pressure on pump gas.

(Pat)>> In order to accurately check piston to valve clearance we're installing a set of Cometic m-l-s head gaskets with a 4.060 bore and a 40 thousandths compressed thickness. [ drill humming ]

(Pat)>> With cylinder one's valvetrain mocked up we'll start by checking the exhaust valve clearance at 10 degrees before t-d-c on split overlap. It comes in at 225 thousandths. Doing the same for the intake at 10 degrees after t-d-c on split overlap it comes in at 249 thousandths. That's plenty of clearance.

(Frankie)>> With all of the Icon pistons hung on the full floating Scat rods the Total Seal ring pack can go on. The pistons get a light coat of Total Seal assembly lube, which is worked into the ring lands to ensure proper break-in. The cylinder walls are lubed as well. [ Music ] An ARP tapered ring compressor at 4.060 bore makes installing the piston assemblies much easier. [ drill humming ] [ Music ]

(Frankie)>> After breaking the rod bolts loose they get torqued to 43-pound feet to make sure they do not exceed the manufacturer's maximum stretch of 47 ten-thousandths.

(Pat)>> We are reusing the stock timing cover but the smaller six and five-eighths inch s-f-i approved balancer doesn't line up with our stock seven inch timing pointer. So, we got a Moroso adjustable one to replace it. All we've got to do is switch them out.

(Frankie)>> Whoa! [ Music ]

(Pat)>> An ARP oil pump stud will retain the Melling oil pump. It's torqued to 55-pound feet. [ Music ] A little fresh silicone in the corners, and the one piece oil pan gasket and stock oil pan are re-installed. They're held on with ARP 12-point stainless fasteners. [ Music ]

(Frankie)>> Up next, the Chevy receives free flowing cylinder heads and a no nonsense e-f-i system.

(Frankie)>> We've only got the top end to complete before this small block heads to the dyno cell. After a coating of break-in oil, the Comp hydraulic roller lifters we got from Summit Racing slide in. The heads are Trick Flow Super 23 Degree Fast as Cast 195cc. As with all small block Chevys, the head bolts receive Ultra Torque under the heads and sealant on the threads.

(Pat)>> Hey that rhymes!

(Frankie)>> The heads are torqued in three equal steps to 70-pound feet. [ Music ] The 7.400 long Comp push rods are lubed and dropped in. Trick Flow's 1.5 ratio full roller rockers are dropped on, and pre-load is set to one half turn past zero lash. [ Music ]

(Pat)>> We'll lay some silicone around the water ports before installing the intake manifold gaskets. After getting an immaculate bead of silicone on the China walls the Trick Flow dual plane Street Burner intake manifold with added coolant crossovers is gently laid into position. ARP's 12-point stainless intake manifold bolt kit holds it down. [ Music ] The heads are sealed up with some Trick Flow tall cast aluminum valve covers.

(Frankie)>> Picking the right flywheel for your street or strip vehicle is much more important than you think, and today's tech tip is all about the different kinds of flywheels, and we have a few different options on the table from Summit Racing to help us out. The first kind is gray cast iron. This is generally used by o-e manufacturers because it's cost effective and easy to produce and will generally hold up to the power levels and r-p-m range of a stock vehicle. If they are gonna build a vehicle that's gonna see more abuse, like a truck or a high performance car, they can use a nodular cast iron flywheel. The big difference between the two is in nodular cast iron the graphite and carbon molecules are in the form of spheres instead of flakes, and this doesn't exactly increase the tensile strength of the material but it does improve its load impact resistance for higher abuse situations. If you're going full on high performance the next step is a billet steel flywheel. Like the name suggests, it's machined from one giant chunk of steel, and it's gonna be much stronger than the cast versions. If you're building any kind of high performance vehicle this is a go to. If you're gonna be doing some form of racing that requires the engine to accelerate and decelerate quickly a great way to help that is to reduce rotating weight, and you can do that with an aluminum flywheel. This is machined from a big chunk of aluminum. So, it's still s-f-i approved but it has an insert here that's either bolted or riveted in for the clutch material to contact. These are great in racing but if you're building a high performance street car the extra inertia and heat cycle durability of a billet steel flywheel is probably going to be the better choice. If you need help figuring out what type of flywheel is best for your application you can talk to the experts at Summit Racing Equipment. We're using a billet steel externally balanced flywheel on our engine. It's torque to 80-pound feet. [ Music ]

(Pat)>> We are getting dangerously close to firing up our small block on the dyno, but to do that we need to top off the induction system, and for that we will be using FiTech e-f-i. This is their Go-EFI classic black. This is a direct replacement for any 41-50 style or square bore carburetor. It contains four 62 pound per hour injectors, and it will support up to 550 horsepower. To keep that classic carburetor look the e-c-u is separate from the throttle body itself. Everything is controlled, monitored, and programmed through their handheld. Now this is a great system that comes with everything that you need to hook it up in the car. Gaskets, it's own wide band O-2, all the wiring harness, and it also comes with a clamp on style O-2 bung. Now if you don't have a way of welding an O-2 bung into your exhaust this is a great way to get an O-2 into your system. [ Music ] If you've ever bolted on a carburetor before the FiTech goes on just as easy. It even uses the same throttle bracket. [ Music ] An o-e-m quality O-2 sensor feeds information to the e-c-u so the system can self learn after initial startup. [ Music ] The e-c-u is very compact, and it easily mounts in or outside of the engine bay. [ Music ] Up next, the small block struts its stuff in the dyno cell.

(Pat)>> We have our engine fired up and it was easy to do. The FiTech only needs to know a few things, and we need to tell it what we want. Like we told it we wanted a 12.8 to 1 wide open air/fuel ratio, and that's about it. The tune-up is conservative but that's for a reason.

(Frankie)>> It's all about cylinder pressure. Whether you're increasing cylinder pressure with boost, or nitrous, or dynamic compression ratio your tune-up has to change accordingly to that. Because we're trying to run this engine on pump gas the tune-up needs to become a lot more conservative. So that's why we only have 22 degrees of timing and a target air/fuel ratio of 12.8. This engine's actually really similar to a stroked Mopar that we did that had a 9.05 to 1 dynamic compression ratio, and it has similar air flow through the heads. So, it'll actually be interesting to see how much this thing makes compared to that one in terms of power per cube.

(Pat)>> Alright, well we're gonna find out right this second.

(Frankie)>> Do it! Let's see what it does. [ engine revving ]

(Pat)>> Nice torque, good oil pressure! Wow, that was uneventful like it should have been.

(Frankie)>> That was pretty good.

(Pat)>> 426.9-pound feet, yeah baby, and 411.8 horsepower.

(Frankie)>> Peak torque right at 4,000, peak power right at 5,500.

(Pat)>> I think we're not gonna stretch this thing out past 6,000. Let's raise the r-p-m and go to 6,000.

(Frankie)>> Get a clear peak there, and just back up that run. That was a nice solid run.

(Pat)>> 93 octane, 13 to 1.

(Frankie)>> And it made very similar torque per cube to that Mopar that I was just talking about. That's very interesting.

(Pat)>> I'm not saying everyone should run out and put their engine at 13 to 1, but we're doing this. This is an r&d engine. We can do whatever we want. We have controlled the conditions to do it. I'm gonna raise that up a little bit, 2,500 to 6,000. Let's see if she crests over. Got a little heat in the oil here. [ engine revving ]

(Pat)>> Spicy! Right there, 413 horse. Nice curve at 6,000. You could leg it out more but it's just gonna drop.

(Frankie)>> Peak horsepower happened right at 5,400. So just a teeny bit lower, but that's pretty close.

(Pat)>> Excellent, 424.8-pound feet.

(Frankie)>> It's a long line isn't it.

(Pat)>> The graph is nice and flat. Oil pressure goes up. It has a little bit of vacuum in the manifold, not much, and it has vacuum in the pan. So, it's not detonating. I'm gonna shut this down.

(Frankie)>> That's cool! That was the point of the exercise. This is very extreme. You're not gonna go out and make all your street engines 13 to 1, but we did this for a reason. To show that it's not all about static compression ratio. It's about dynamic, and more importantly, cylinder pressure.

(Pat)>> What did we learn? We learned that the engine doesn't care how it gets cylinder pressure. You can do it a bunch of different ways, and there are many factors that have to come together. It's not just one over the other. Static compression ratio is important, but it's just a number. Dynamic compression ratio is as important because it takes into account when things start to compress. Now there are other factors involved like volumetric efficiency, and how much restriction is in the intake tract, how much are cylinder heads flowing, how high are you turning the engine. This is a very versatile engine because we could actually change up a few things on this and then it is a race engine.

(Frankie)>> Exactly, but what it shows you is that your parts selection is really important, and then what we've shown here is that your tune-up is also really important. If you plan on running pump gas. We put race gas in it we can crank the tune to it and this thing will probably make a lot more power, but because we're on pump gas that's another factor that needs to be thought of as to what the tune-up is going to be.

(Pat)>> The tune-up is very narrow. Because of the compression and because of the dynamic compression, and because of what we're doing the tuning window has narrowed. Because this is a controlled dyno condition we can do this relatively safely.

(Frankie)>> If you were gonna put this in a car and get it up to 180, 200 degrees and then go and try to make a full hit on it things would probably not work out.

(Pat)>> The foundation is really good, and I think it'd be fun to see what else we could do with this.

(Frankie)>> I think there's a lot more tech that we could do on this. Even what's on it right now I think there's some more we could do.

(Pat)>> I'm a tech guy!

(Frankie)>> So am I! If you want to see more cool tech like this go check out our website.
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