This is the 340 in Jon Grasher's '69 Barracuda.
How Much Is Too Much?
Jon Grasher, via CarCraft.com: I am working on a '69 Barracuda with a mildly reworked 340. I have had the engine reworked with a roller cam, Edelbrock RPM heads, and an Air-Gap intake topped with a Retrotech Stage II EFI. I've relocated the oil filter from the stock, impossible-to-change-without-spillage-onto-the-headers location to the fender. The engine has a Melling high-volume pump. When the engine is first started, the gauge reads one increment above the 80-psi limit. As the engine warms, the pressure drops to 70 psi at idle but pegs the gauge when the rpm comes up. Is this pressure too high? If so, what damage can occur? Changing the oil pump pressure relief spring would require pulling the engine to access the pump, which is not one of my wishes. But if it has to be . . . .
Jeff Smith: The short answer, Jon, is that high oil pressure is not necessarily bad for your engine, but it does place a greater load on the oil pump driveshaft and camshaft drive. It takes additional power to make greater pressure. We talked with veteran engine builder and NHRA drag racer Bob Lambeck who has a long history of competition engine building, which includes Mopar small-blocks. Lambeck says he would try a different, mechanical oil pressure gauge to ensure the readings are accurate. He has seen many oil pressure gauges go bad, although they generally read lower rather than higher, but anything's possible. Assuming the pressure is as high as it appears, Lambeck also says it's only a matter of time before that small oil pump driveshaft either rounds off or breaks in half from the greater load. Small-block Mopar engines need good oil pressure because, like 351 Cleveland and 429/460 Fords, they feed the mains only after pushing oil through the lifters. Lambeck says at normal engine temperature, idle oil pressure should be more like 30 to 35 psi, and peak rpm pressure will work fine between 60 and 70 psi.
You didn't mention the oil viscosity you are currently running. If there is 20W-50 oil in the pan, a quick way to trim oil pressure would be to try either 10W-30 or 5W-20 weight oil. This reduced viscosity will make a difference and may allow you to get by without having to tear apart the engine. If the current viscosity oil is 10W-30, then it's clear that the oil pump is working too hard. Assuming there is no restriction between the oil pump and where you tap into the engine for the gauge, the only way to repair this problem is to reduce the bypass spring load used in the pump to establish pressure. The best way to do this is to change the spring and then bench-test the pump assembly by driving the oil pump with an electric drill motor with the pump pickup submerged in oil and the outlet blocked so the bypass spring has to open. This way, you know the maximum cold idle oil pressure. This is a lot of work but the only way you'll be able to know for sure what the pressure will be in the engine.
Oil is Still Well
Chuck Habrack, Raritan NJ: I just read your Oil Is Well answer in the Mar. '10 issue. I worked in a motor shop (Tony Feil Competition Engines, now closed) for 13 years building mostly big- and small-block Chevys. I agree with some of your answer. We would restrict oil to the top end on engines with a roller cam and rockers using either a shaft or stud mount. We also installed a breather between the lifter bosses on a small-block so only oil would return via front or rear and epoxy a plate to cover the large drain-backs above the cam on big-blocks. Most of our big-blocks and high-end small-blocks used an external Weaver spur gear pump. We would scavenge oil from the rear of the oil gallery and not let any oil drain back past the crank. On internal pump motors, we would do our best to keep return oil from hitting the crank. I fully agree that too little spring oiling is bad. Yet dumping excess oil on the springs has no advantage. On dry-sump motors, we used tubes mounted inside the valve covers with -3 lines and bleed jets to limit the oil on the springs. Shaft rockers with positive fulcrum feed used a spray hole. In short, with full roller engines (lifters and rockers), we would direct more oil to the crank and sump. In an endurance engine that turns 5,000 to 8,000 rpm, lube for the crank and rods becomes even more important. Another reason for positive valvespring oiling is to ensure cooling the springs on engines running negative crankcase pressure.
This is the Champ steel pan for LS engine swaps into Chevelles, Novas, and first-generatio
LS Chevelle Swap
Mark Shirley, Orland Park, KS: I have a few questions concerning the engine I will be putting in my '66 Chevelle. I recently purchased an LQ9 from GM. I thought (and was told by the salesman) what I was buying was a new engine. After some part number searching, it appears I purchased a GM remanufactured LQ9. Will this motor be OK for a mild performance build? I have never purchased a remanufactured engine, and I am looking for the thumbs up or down. Secondly, if this engine gets the green light, I plan to leave the cathedral-port heads on and install a decent cam, full-length headers, duals, a TKO-600 trans, and a carb to start. As my budget allows, I'm planning on installing the FAST EZ-EFI system. I want to build a reliable engine with somewhere around 350 rwhp. Which upgrades will I need to achieve this? I was considering an '01 LS6 cam-or perhaps you have an idea. I also read that the pushrods are the weak link. I would like your suggestion on what components, cam, pushrods, and valve-springs to use (if needed) and their part numbers to facilitate this upgrade.
Jeff Smith: I called my pal Ken Casey at Burt Chevrolet in Englewood, Colorado, for the inside scoop on these engines. The LQ9 is the higher-compression (10.1:1) version of the LQ4 (9.4:1). Casey says the remanufactured engines have an outstanding warranty, which is exactly the same as new replacement engines: three years or 100,000 miles. Plus, if there is a part- or assembly-related problem, GM will replace the engine, including the labor. Of course, to keep the warranty, you can't change cams or cylinder heads, and we're not sure if the warranty holds true if you run a carburetor. But frankly, word on the street is that these engines are incredibly reliable, so I think you made the right choice.
The stock LQ9 cam specs out at 196/207 degrees duration with 0.467/0.479-inch lift and a 116-degree lobe-separation angle. The stock SAE power numbers are 345 hp at 5,200 rpm with 380 lb-ft. If you added a set of 13/4-inch headers, the power would improve slightly, although the cast-iron manifolds are very good for near-stock engines. Back in the Apr. '07 issue, we ran a test on a junkyard LQ4 6.0L ("480 HP for $3,775"). Right out of the box with a production cam, a GM Performance Parts single-plane intake, a Holley 750-cfm carburetor, and a set of Kooks 13/4-inch headers, the engine made 425 hp at 5,600 rpm and 439 lb-ft at 4,400 and 406 lb-ft at 2,200 rpm on Ken Duttweiler's dyno. Then we added a GM Performance Parts Hot hydraulic roller cam (219/228 degrees at 0.050 with 0.525-inch lift and a 112-degree lobe-separation angle). The bigger cam pushed the power up to 483 hp at 6,000 rpm with 450 lb-ft at 5,000 rpm, and torque was still 399 lb-ft at 2,200 rpm. This is awesome power for a near-stock 364ci short-block and would have a nice little lope to the idle as well. The GMPP Hot cam is PN 12480033. The cam PN is actually a kit that includes a set of LS6 valvesprings, which is why the price of the kit is around $500.
The stock production pushrods are a little on the spongy side, so a good replacement would be Comp Cams' 0.080-inch-wall-thickness Hi-Tech pushrods. The standard length for the 6.0L engine would be 7.400 inches (PN 7955-16, $115.75, Summitracing.com). I think you will be extremely pleased with the conversion in your Chevelle. Get it running by spring 2011 and bring it to our Engine Swap Drags event. As for the swap, I'm not sure if you will be using power steering. If so, you can get a conversion kit from Kwik Performance that will allow you to run an aftermarket accessory drive and clear the steering box. You'll also need a different oil pan. Perhaps the most affordable pan might be one from Champ Pans. The steel pan PN is LS1000 ($255.64 from Champpans.com), and it needs a separate pickup and oil filter adapter that bolts the filter directly to the pan. Most other aftermarket pans require a remote-mounted oil filter that adds to the overall price of the pan. You'll also need a motor mount swap kit. Generally, these are sold in conjunction with headers. As far as headers go, there are several companies making swap headers, such as Edel-brock, Hooker, Hedman, and several others. It would be worth the effort to check into the positive and negative aspects of each of these headers to make your decision. One thing to keep in mind is how far the header collectors hang down below the car. Not all headers are tucked up tightly against the floorpan like they should be. It's worth the effort to check into this.
Chevrolet; Englewood, CO; 800/585-4604; burt.com
Champ Pans; Eau Claire, WI; 715/834-7748; champpans.com
GM Performance Parts; Warren, MI; 800/577-6888; gmperformance parts.com
Kwik Performance; Springfield, MO; 417/ 955-1467; kwikperf.com
We spotted this sleeper at Firebird Raceway at the starting line while the Junior Dragsters were running.
This is the wiring schematic Mike included with his question. The only thing missing is a
Mike Tafaro, Douglassville, PA: I'm building a street/strip Nova for my brother while he's away making license plates, and I can't get the engine to start all the time. Usually, she just gives me the starter click and won't turn over. The motor is an SBC 383, around 10:1 compression. The starter is a Powermaster Ultra Torque, has been bench-tested, and works as it should. The battery is a brand-new Diehard Gold rated at 795 cold cranking amps (CCA) and is fully charged. I have a kill switch mounted to the back of the car and a junction block under the hood to provide power for the fuel pump, ignition, fan, and a small air compressor for the rear shocks. The battery ground goes to the body near the passenger side rear wheelwell. The battery positive connects to the switch, and the hot side of the switch runs to the starter and the junction block. The alternator is wired directly to battery hot, and I have one strap from the engine block to ground and another from the fender to the subframe of the car. Everything works: the lights, compressor, pump, and so on-but the car just won't start. Electrical has always been my weak spot, and any help would be appreciated.
Jeff Smith: The good news is this is an easy fix, Mike. I had the same problem with a '55 Chevy that I built way too many years ago. The problem is a weak ground circuit. You cannot rely on the body of the car to act as a suitable ground for the starter circuit. What makes this problem a head scratcher is that all the other circuits in the car-like the electric fuel pump, lights, and small compressor-appear to operate normally. This is because these components require far less current to operate-the most might be the electric fan at around 20 amps. According to Kevin Bennett at Powermaster, the instantaneous current flow before the starter begins to turn can be as high as 800 amps. Once the starter begins to spin, the current demand stabilizes between 200 and 250 amps. As you can see, the instantaneous current demand is so high that without a decent ground, the resistance is excessive and the starter just clicks. Also, Bennett says, "Keep in mind that as the input voltage to the starter drops, the amperage draw goes up. (Yes it's counterintuitive, but it works that way.) Therefore, bad cables and/or weak batteries create a situation in which the starter will pull more amperage."
To diagnose this problem, round up a digital voltmeter. First, let's test something easy like the electric fan. Turn on the fan and with it running, read the voltage at the battery. Next, read the voltage at the fan again with the fan running. You will record a significant difference in voltage at the fan compared with the reading at the battery. Electrical resistance is present in any circuit, and the voltage at the load (the fan) will decrease with resistance. For example, a 0.60-volt-or-more loss directly at the fan compared with the reading at the battery indicates excess resistance in the circuit; voltage was lost somewhere in the circuit from the battery to the load and then back to the battery on the ground side. If the original power cable is large enough, then the voltage drop is probably located in the ground circuit, since resistance can occur on either or both the power and/or ground sides of the circuit.
Next, let's isolate the circuits. Install a dedicated, fullsize ground cable that's the same size as the positive battery cable. Connect this ground to the engine and battery with another cable over to a common ground that will include the electric fan. With an improved ground circuit, the voltage at the fan should increase. If the voltage difference between the fan and the battery is now 0.40 volt or less, the circuit is close to ideal. Keep in mind that resistance increases with the length of the wire. This is why a larger cable is required when distance between the battery and the load increases. With a dedicated ground cable now in place, the starter motor will crank over just fine.
Now that the starter motor works, if your digital voltmeter has long enough leads, you could test for a voltage drop over the entire length of the ground cable. This can only be done while the engine is cranking. Place the positive lead on the case of the starter motor and the other on the negative terminal on the battery. While the engine is cranking (disable the ignition to allow enough time to read the meter), you should read no more than 0.50 to perhaps 0.60 volt. This is a great test for the internal resistance present in the battery cables in any car. Both cables can be tested this same way. Even brand-new, inexpensive cables can have enough internal resistance to cause a problem. A friend of mine once purchased a brand-new battery, cables, and starter for his small-block Camaro but experienced hard starting issues when the engine was warm. I checked the voltage drop on the cables and discovered numbers in excess of 1 volt. We installed new 1/0 welding cables and the engine cranked over like it had a 24-volt battery. The voltage drop number plummeted to roughly 0.38 volt.
Powermaster Electrical; Systems West Chicago, IL; 630/957-4019; powermastermotorsports.com
Block Filler Olds
Thomas Bush, Winnebago, WI: I had my Olds 455 block rebuilt from 462 to 472 ci when the nitrous roasted a piston. In the redo process, the Olds mavin wrencher (Greg's Olds Performance) used some amount of block filler and sleeved the cylinder. It retained its street/strip applications-using an aluminum radiator, electric fan, and electric water pump with Evans coolant in a '65 Cutlass 4-4-2. Completing the drivetrain is a G-Force four-speed, a 4.11:1 gear, and a Detroit Locker in a Moser 9-inch. I've measured the rear-wheel power at 435 hp at 5,400 rpm and 461 lb-ft at 4,100 rpm on the motor and 522 hp at 5,500 rpm and 602 lb-ft at 3,600 rpm on a 125hp nitrous shot.
Is the practice of using block filler in a primarily street-driven 455 Olds still applicable in today's rebuilds? I presume this was done for durability. Is it overkill for a car that seldom uses its slicks? I seldom hear about block fillers used anymore in automotive performance publications. In fact, my 572ci aluminum-block Hemi motor with Indy Cylinder heads in my Challenger has no filler and produces considerably more grunt that the Olds. Was the filler needed or simply a precautionary measure? Is there any downside to using it?
Jeff Smith: The use of block filler is basically intended for thin-wall blocks that suffer from unstable cylinder walls, especially when pushed to their limits in terms of horsepower. The combination of high rpm and very high cylinder pressures can and does force thin cylinder walls to move around, reducing ring seal. The most common material is a specifically designed product called Hard Blok. This is a cement-based material that has the same thermal coefficient as cast iron, so it grows at a similar rate as an iron block. Once this material is mixed, poured into the block's water jacket, and allowed to harden (usually in less than 24 hours), it cannot be removed. For race engines, the general procedure is to perform what is called a tall fill in which Hard Blok is added almost to the top of the water jacket. A short fill pours roughly half the depth of the cooling system jacket to allow for better cooling. Drag race-specific engines generally go with the tall fill, while circle track engines prefer the short fill. Summit sells the Hard Blok in a 14-pound container for $89.95 or a short fill with 12.5 pounds for a little less. You can buy two, 61/4-pound bags for $79.95. Moroso also sells a 1-gallon jug of engine block filler for $13.75 through Summit Racing. Keep in mind that this material is not a sealer. It is porous and will not seal a leak that originates from the water jacket.
The obvious disadvantage to using this material for a street engine is that engine cooling will be restricted. While that's of questionable benefit for a street car, what is less obvious is that the oil temperature will also rise dramatically because the inherent cooling effect of the water at the bottom of the cylinder walls also pulls heat out of the oil. With the jacket filled with Hard Blok, the oil temperature also spikes. For these reasons, I would not recommend this procedure for a street engine since it would require adding a large external engine oil cooler just to keep the engine oil temperature within reason. By stabilizing the cylinder wall with Hard Blok, you should see a small return in terms of better ring seal. To quickly address the other engine with the aluminum cylinder block, this Indy block is an aftermarket piece that was built specifically to handle a large dose of power. The cylinder walls are certainly thicker and structurally enhanced to improve ring seal, making Hard Blok unnecessary.
Hard Blok; Brentwood, TN; 865/457-0509; hardblok.com
OK, this photo is pointless except to remind you about the Car Craft Summer Nats, July 16-18, 2010, in St. Paul, Minnesota.
The stock LS truck intake manifold does a great job of making torque, which in a pickup is
Son of Lester
Cpl. Cole Crewes, Camp Lejeune, NC: I read the article on the Lester Scruggs 404 stroker and thought it would be a great addition to my '02 GMC Sierra 2500HD 4X4 with the LQ4. I would like to keep the fuel injection and change the bore to 4.060 to squeeze out a little more low-end power. Do you think it's a good idea? Should I keep my stock intake manifold with the stock heads? What size injectors will I need?
Jeff Smith: First of all, Cole-it's always a pleasure to hear from our men and women in the service and especially from Marines. The additional cubic inches with a bigger bore would be beneficial to adding torque. The iron block should accommodate the 0.060-inch overbore without difficulty, although it would be a good idea to have the block sonic-checked first. A minimum of 0.200-inch wall thickness after boring is preferable, but slightly under that is acceptable since you're not trying to make huge power. I'd suggest finding a spare 6.0L short-block to perform the work. That way, you could keep your truck running while you build the new engine. Then you can sell your original short-block after the new motor is in the truck. I found SRP and Mahle pistons available for your application. Both of these pistons require an aftermarket connecting rod because they use a smaller 0.927-inch wristpin versus the stock-diameter wristpin. This will unfortunately add to the cost of your buildup. The SRP piston is a 4.065-inch-bore piston (PN 279592). The Mahle pistons are an excellent choice-they're what we used in our Lester Scruggs motor-and come with pistons, pins, locks, and a complete ring package. The Mahle package PN is L922314065F04 and costs $626.95 from Summit Racing. These pistons are designed to be used with a stock stroke and 6.125-inch connecting rods. We used Scat rods in our engine. Keep in mind that these changes will require balancing the engine. Look for a piston and rod package that is no heavier than the stock bob weight. If the piston and rod package is heavier, it will require adding Mallory metal to the crank that could add $200 or more to the cost of normal balancing.
I'd suggest retaining the stock truck manifold and the LQ4 heads. It's also possible to squeeze more power out of the engine with a little work to the stock heads. West Coast Racing Cylinder Heads (WCRCH) has an excellent CNC porting process for the stock 6.0L heads that adds quite a bit of power without having to purchase new cylinder heads. On our 404ci LS engine test, the WCRCH-ported 6.0L heads were worth 24 lb-ft and 29 hp over the stock 6.0L heads. Headers would also be a wise investment to improve exhaust flow. We found a set of 15/8-inch direct replacement shorty headers from JBA (PN 1850S-1JT titanium coated) that would work. A low restriction after-cat-style exhaust would also be a good idea again to allow the engine to make as much torque as possible.
You didn't ask about a camshaft, but if you're going to improve the power a little with some tuned-up heads, a mild cam would also be a good idea. The original LQ4 camshaft specs out at 196/207 degrees of duration at 0.050-inch tappet lift, with 0.467/.0479 inch of valve lift with a lobe-separation angle of 116 degrees. The mildest cam would be the '02 to '04 405HP LS6 factory cam (PN 12565308, $264.95 from Scoggin-Dickey). Before you drop the cash, try looking on the Internet for a used LS6 camshaft. The LS6 specs out at 204/218 degrees of duration at 0.050 with 0.555/551-inch lift with a lobe-separation angle of 117.5 degrees. This adds 8 degrees of intake and 11 degrees of exhaust duration along with 0.088/ 0.072 inch of additional valve lift. This cam lift and duration bump, along with the mods to the heads, plus the exhaust will no doubt require some tuning to wide-open throttle fuel and spark curves and also the part-throttle areas. This should probably be left to a professional tuner, so it might be wise to find this person first before ordering any parts. He might be able to point you in the right direction from a parts combination standpoint and he will already have the tune-up in his repertoire of EFI maps.
As for injector size, my buddy Kurt Urban at Urban Performance tells me the LQ4 engines used two different injector sizes ranging between 24 and 28 pounds per hour (lb/hr). The LQ9 engines with higher horsepower ratings used the 28-lb/hr injector. Urban says that with the mild enhancements you are planning, the stock injectors should be big enough to feed 400 hp.
Kurt Urban Performance; Commerce, MI; 248/345-8169; kurturbanperformance.com
Mahle Motorsports; Fletcher, NC; 888/255-1942; mahlemotorsports.com
Scoggin-Dickey Parts Center; Lubbock, TX; 800/456-0211; sdparts.com
Sportsman Racing Pistons (SRP); Huntington Beach, CA; 714/373-5530; jepistons.com
West Coast Racing Cylinder Heads; Reseda, CA; 818/705-5454; proheads.com
You might remember Keith Anderson's Viper as the late-model class winner at last year's Real Street Eliminator event at the Car Craft Summer Nationals. Keith recently took his Viper down to Texas for a couple of fun weekends. He ran the car at the dragstrip, pulling down an impressive 10.76 at 133 mph and then impressed the crowd with a 190.0-mph run in the standing mile. Yahoo!
Here's a Muncie four-speed (right) compared with a Richmond six-speed. When you can visual
Dan Schultz, Layton, UT: Could you please explain how to figure out how much torque a manual transmission can handle compared with engine output? To handle the torque of different motors, I read that Ford's T10 transmissions used lower low gears in First gear for big-blocks compared with small-blocks. How much torque will a T10 handle?
Jeff Smith: This appears to be somewhat of a black art within the aftermarket transmission business as to how it rates its transmissions, and there is no standard within the aftermarket as to torque capacity. There are several levels of testing, and frankly the waters are a bit muddy. But what we can do is look at some basic engineering and design concepts with manual transmissions that you can use to judge the torque capacity of a transmission. A quick way to estimate torque capacity is to measure the distance between the centerlines of the input shaft and cluster gear. The greater apart the centerlines are, the larger the gears and therefore the greater the torque capacity. As an example, here are several transmission center distance figures:
This is a good place to start, but even within the Tremec T56 trans lineup, the company lists boxes that are rated anywhere from 330 to 550 lb-ft capacity, so the center distance is just one variable. As for the Super T10, Richmond Gear lists torque capacity ranges from 375 lb-ft for the 2.43:1 First gearbox down to 286 lb-ft capacity for the 3.42:1 First gear transmission.
The Richmond capacity points out that a big factor is the First gear ratio. As the First gear ratio becomes deeper (from 2.20:1 to 3.26:1, for example), the input shaft gear becomes smaller (much like a pinion gear becoming smaller as you move from a 3.08:1 rear gear to a 4.11:1). A smaller pinion or input gear offers less torque capacity than a large gear. Gear material also plays a role in this torque capacity game. There are some World Class Ford T5s, for example, that are built with 9310 nickel steel gears that are significantly stronger. This will help capacity, but keep in mind that the higher the steel's tensile strength, the more brittle it becomes, so that becomes a trade-off. Finally, the angle of the gear teeth has an effect on ultimate strength. A straight-cut spur gear, for example, is far stronger than a helical-cut gear. The problem with spur gears is they are incredibly noisy. Helical- or angle-cut gears drastically reduce the noise but at the cost of strength. The old Muncie rock crusher transmissions were stronger but also noisier than their M20 or M21 production cousins. This is a rough outline of how to judge torque capacity.
Within the manual transmission aftermarket, however, I am not aware of a standardized test procedure. Many aftermarket transmission companies rate the trans at what they compute as the torque it can handle under sustained, continuous duty. This is not any kind of impact load test. There is a big difference between the two. As an example, the next time you're at the state fair with your buddies and see one of those old-time grip strength test machines, let your friends go first. When it's your turn, hit the machine with an impact load as opposed to a continuous load-you'll win every time.
Transmission Technologies Corporation;
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This is a close-up of the mill from a Junior Dragster. These cars run in the 12s in the eighth-mile.