YardstickThere is an old adage that you don't race dynos and flow benches. Manufacturers of test equipment use different standards and test procedures that will affect the results. This brings me to the yardstick. You need some type of gauge, and engine dynamometers are the ruler used. Flowmaster has had a SuperFlow SF-7100 engine dyno since 1993, and it's been my toy since 1988. This dyno was state-of-the-art back then and used the latest in computer controls, temperature controls, and the latest correction factors to create very repeatable numbers. When testing exhaust components we are sometimes looking for numbers as small as 1 or 2 hp. You can check with any engine-dyno manufacturer and they will tell you that an acceptable repeatable is at or below 1 percent. Well, as the power levels increase, that 1 percent can be a very big number. Through refinement we were able to hold the repeatable of our dyno to 0.3 percent.
Well, time marches on, and dyno technology does too. Our SF-7100 used electronics that were designed back in the early '80s, and it was starting to give us trouble from time to time. SuperFlow released its SF-902 system several years ago with complete NSE (new-style electronics), a completely digital data-logging and control system. This is a major advancement from the old analog controls. SuperFlow makes an electronics package to upgrade the 7100. It's tough to beat the hardware of the 7100, and the new electronics brings us right into the 21st century. With this comes a whole new set of testing parameters and computer controls that takes the operator out of the testing loop. This is where I had a little trouble. Turning the controls over to a computer after having run engine dynos for over 20 years, I wasn't very happy. This is one of the ways that SuperFlow has been able to raise the level of repeatability of their engine dynos. It takes the operator's opinions and decisions out of the picture. It brings the engine up on load and to full-throttle the same every time. You basically turn the engine over to a computer. For an old dog that can be very tough. What do you mean a computer knows how to run an engine better than I do?
Well, we got everything up and running with SuperFlow's help, and we tested some new exhaust components this past week. We had the data on the same engine and same components with the old system. This gave us a chance to put the dyno through its paces. It came through with flying colors. The test-to-test repeatability was better, and we were able to run all our testing without one hiccup. One other thing, with the new testing parameters and the operator being taken out of the loop, I believe we should be able to compare dyno tests from other SF-902-equipped shops. This will bring up the level of all dyno shops running this type of system-and give everyone better numbers to compare.
Leak PathQ I was looking at articles posted on the CHP Web site, in particular the article on the Squeaker Mouse 355 by Henry De Los Santos. In the article is a picture of the balancer with the caption "prior to mounting, Jun applied a small bead of silicone inside the balancer to ensure a solid, leakproof assembly." Can you help me understand this? I can't tell from the picture where the silicone is placed. The caption says inside the balancer. If "inside" means the machined surface inside the keyed hub, that doesn't make sense to me, because the balancer hub presses on the crank snout. I could be wrong, but this doesn't sound like a place that would leak. If "inside" means on the outside of the keyed hub of the balancer, that doesn't make sense to me either, because isn't the oil seal on the timing-chain cover supposed to keep oil from leaking past the balancer? What am I missing? Thanks.Richard MouselVia e-mail
A Oil leaks are one of the worst warranty claims for the automakers. They spend tons of money every year stopping weepers. In the Gen II small-block back in '92, Chevrolet deleted the keyway from the damper hub and relied on the press fit and damper bolt to retain the hub. This was done to prevent the oil-leak path from the broached keyway slot in the hub of the damper. The crankshaft still had the machining for the woodruff key. Now move to the Gen III small-block released in '97, and the damper and the crankshaft have no grooves at all. To help our old-school small- and big-blocks not leak, a small dab of silicone applied into the keyway of the damper hub before installing it will help block the leak path. You don't need to coat the entire inside of the damper hub, because the press-fit surface of the damper and crankshaft will prevent leaks like you mentioned. You weren't missing much-hope this explains what we were trying to get across.
No Free LunchQ We've all seen the ads claiming that replacing your engine-driven cooling fan with an electric motor-driven fan will result in a net gain of up to 20 hp. If it takes 20 hp to drive a cooling fan, where does the power to drive the electric motor come from? If an electric motor provides free horsepower I think I'd like to drive my torque converter with a 300hp electric motor and power it with a generator driven by a 3hp gasoline engine. This should provide plenty of power to the rear wheels and phenomenal fuel mileage as well!Mark PoteBullard, TX
A Maybe you're on to something here. Put a couple of generators under my hood and hook up two 300hp engines, one to the front wheels and the other to the rear! Instant 600 hp on tap! By the way, have you ever seen a 300hp electric motor? It's huge and weighs around 2,200 pounds. And what about the regenerative voltage controller for a paltry sum of $6,137? Oh, by the way, it takes 500 volts and 480 amps to spin that puppy. Let me know of the 3hp generator that will put out that kind of power! Let's talk about electric fans now.
As the title says, there is no free lunch. The horsepower gains from an electric motor-driven cooling fan is when the crankshaft isn't driving the fans-and the fans are off. As in drag racing, if the engine is cool when you come to the line you can run down the track with the fan off. If you're running down the freeway at a constant speed, the air through the radiator will keep the engine cool andthe fan isn't running. You have a wonderful device in your car called a storage battery. This allows you to run the fans and accessories beyondthe output of your alternator and recharge your battery when cruising at freeway speeds.
I'm pretty sure that you knew all of this, but I thought that it was an interesting question. There have been some really far-out concepts running around on the Internet.
It's All About TorqueQ I was wondering what I should go with for a carb and stall converter for my small-block-powered Monte Carlo. My current setup is a 350-cid small-block with an 800-cfm Edelbrock Thunder Series AVS, an RPM Air Gap intake, 882 iron castings with 2.02/1.60-inch valves, a Summit cam (0.488/0.510 inch max lift and 234/244 degrees duration at 0.050 inch tappet lift), 1.5 roller rockers, TRW flat-top pistons with two valve reliefs, stock rods, an Eagle cast crank, and a Moroso oiling system. My converter is currently a JEG's 2,300- to 2,700-rpm 12-inch that for some odd reason only stalls to 1,800 rpm with me foot-braking it. I know that the carb sounds big, but I tried a 750 Edelbrock and lost some on the top side. Also, should I go with a 1.6 rocker or stick with the 1.5? Right now the best I can get out of it is a 13.70 at 102.08, which is coupled with a 2.26 60-foot time. Let me know what you think. Thanks.James FullerVia e-mail
A When it comes to stall speed, torque is king! As you mentioned, JEG's rates its converter at 2,300-2,700 stall. If you put a H.O. 502 big-block Chevy crate engine in front of that converter I guarantee you it will stall to 2,700 rpm. That engine produced over 500 lb-ft of torque way down low at 2,200 rpm! Your little 350 with the Summit camshaft, 882 cast-iron heads with 76cc combustion chambers, and flat-top pistons barely has 9:1 compression. This is a recipe for poor slow-speed torque. I bet on the engine dyno that your 350 doesn't even have 300 lb-ft of torque at 1,800 rpm. A 12-inch converter is very tight, and you would be better off with a JEG's 10-inch (PN 555-60401), which would let your engine get into the meat of the torque curve. The converter should range 2,700-3,000 rpm, based on the torque your engine produces. It features a dual-bolt pattern for ease of installation. These converters are designed for moderately modified engines, not for nitrous, turbos, blowers, or big-blocks.
Yes, an 800-cfm carb is too large for your engine. However, with the Edelbrock AVS-style carburetor it meters the amount of air that the engine needs by an air valve on the secondary side of the carb. This air valve opens based on airflow demand and keeps the velocity up on the intake side. If you do the math on your engine, it only requires 719 cfm at 7,000 rpm, and this is based on 100 percent volumetric efficiency! Your engine with its stock iron heads is probably at 85 percent VE at peak rpm. You should be able to tune in the 750-cfm carb and get better drivability and similar top-end performance as with the 800-cfm carb.
For now the 1.6 ratio rockers are just going to raise the effective lift and duration of your already too large camshaft. Until you increase your stall speed-and we haven't even talked about gearing yet-we would stick with the 1.5. Converter alone isn't going to move your Monte. Those late-'70s/early-'80s cars had terrible gears, to the tune of 2.56! As it appears that you're trying to have fun at the dragstrip, we would at least have 3.42 or 3.73 gears in your car.
Hope this has given you enough to think about and get your combination in order. With the proper gears, converter, carburetor, and rockers, we could see high 12s in your future.
Easy CrateQ I am in the market for a second-gen Camaro. I want to immediately swap out the engine for a Chevy crate. I was thinking about the RamJet 350 or ZZ4 H.O. 350. I want to install the engine that will give me the least amount of headaches since I am considering doing it with a friend and we're both novices. Also, is the stock transmission capable of handling the power? John MeolaVia e-mail
A Second-gen Camaros are really nice cars. My sister had a '71 and she still hates me for selling it out from under her to get her a '67 RS/SS 350! Hope you find a really clean one to start your project with.
Sticking with a carbureted engine will be much easier than converting the car over to an EFI layout. Between fuel system, tank, pumps, lines, and the like, it takes quite a bit to do an EFI conversion correctly. Then you're into the electrical upgrades. Tasks like the charging system and wiring modifications are better left to an experienced swapper. You still want to be talking to your friend when you're done with this project, don't you?
The ZZ4 would be a great engine for a second-gen Camaro. The engine is rated at 355 hp and just a tick over 400 lb-ft of torque, which will move the car nicely. The stock TH350 transmission in most of the '70s Camaros will stand up to the ZZ4 if it's fresh. Don't expect a TH350 with a ton of miles on it or "black death" trans fluid to last more than a weekend of entertainment. Good luck in your hunt for a Camaro. And make sure you feed your friend well while doing the swap.
Brake BiasQ Would you please explain the use and adjustment of proportioning valves? Are you adjusting for less braking to the front or the back? Are you attaching it to the front and back brake line? Which do you want to lock up first? Please help! I have all the pieces, but not sure about this one thing.Doug AdkinsDurham, NC
A You need to adjust the braking bias because as the brakes are applied, the weight of the vehicle is shifted to the front wheels. When this happens, approximately 70 percent of the vehicle's weight is on the front wheels and 30 percent is on the rears. Generally, braking systems compensate for most of this weight shift in the brakes themselves. As you have noticed, the front brake rotors are usually a few inches larger in diameter than the rears. The front calipers are usually multipiston design, and the rears have much smaller friction pads and calipers. Fine-tuning the brake balance is where the adjustable proportioning valve comes into play. The valve is installed in the brake line going to the rear wheels. You want to apply as much pressure to the front brakes to get maximum braking work. To adjust the valve you want to go out on a very safe road where you can do multiple aggressive stops (50-0 mph). You will want to do braking runs that are called threshold braking. This is just shy of locking up the brakes. The valve is adjusted properly when the rear brakes won't lock under maximum threshold braking until you get to about 10 mph. When I say lock, I mean that you want the right rear wheel to just lightly skid. Obviously, you will need to do this in dry conditions, on clean asphalt, and again, in a safe place.
There is only one situation in which you would want to install an adjustable prop valve in the front brakes. This is in a drag-racing application in which you are running very small (24x4.5x15-inch skinny) tires up front and very large rear slicks. Most real drag cars have more weight on the rear wheels to aid in traction. In my super-gas roadster I've installed an adjustable prop valve in the front brakes to prevent the front wheels from locking up at the finish line. When you're in the heat of battle, and you bomb the brakes to dump someone, locking the front wheels at 150 mph isn't much fun.
Missing LashQ I know you have said never to lose your cam-spec card. But sorry, I did and was hoping CHP could help me out with my valve settings. I'm running a 350 small-block with Scat cranks and rods, TRW forged pistons, Sportsman heads that are bowl ported, a '70 LT-1 manifold, a Holley 750 vacuum carb, and a Mallory ignition. Everything is blueprinted and balanced, except for the cam valve settings. The cam is a Chet Herbert solid-roller with 0.501 inch max lift, 224/232 degrees duration at 0.050 inch tappet lift, and ground on a 107-degree lobe-separation angle. I am hoping it makes about 425 hp and 450 lb-ft of torque.
The little Mouse is stuffed into a '62 Corvette with a four-speed and 3.70:1 gears. It runs great and pulls hard, but I would really like to get it dialed in right. Currently I set the valves at 0.022 inch of lash, because I didn't know what else to do. Chet Herbert doesn't keep spec cards on special grinds. Any help you can offer would be greatly appreciated.Joe FrinkRedlands, CA
A It's tough to guess a valve-lash setting for any camshaft. It's predicated on the clearance ramp, flank, and ramp of the camshaft profile. With roller camshafts you will find lash designs that come in as tight as 0.012 inch, and I've seen rollers with lash points as loose as 0.035 inch. Your first cut at 0.022 is a pretty good guess. We would loosen the exhaust another couple of thousandths. This is for exhaust-valve expansion. Also, most manufacturers will give you a range of +/-0.004 inch on tight lash rollers, and +/-0.010 inch on wide lash designs to adjust for testing. You can tighten up the lash, or loosen, to find the best performance on the dyno. This will give you a direction on a better camshaft profile selection.
Your guess of 425 hp and 450 lb-ft may be a little on the high side. The 425 hp may be attainable if you switch to a more current design on the inlet manifold, but your 450 lb-ft is definitely high. You're probably in the 410-420 range. This should move your little Vette with ease. Enjoy the power and top-down motoring!
LG4 RunnersQ I was very interested in the question from Bill Wivel and your response to him concerning swapping a 350 for his 305 ("Tired Monte," PQA, Nov. '06). I have a similar situation: an '87 IROC-Z with a Quadrajet carb 305, engine code H, LG4.
I want to upgrade to a 350, and all the crate engines I see in the catalogs refer to earlier years than mine. I also live in Arizona and am concerned with passing emissions. I was wondering if the same solution you offered to Bill would apply to me? I am concerned that the long-block may not fit my engine compartment without some modifications. If this would work for me, I was thinking of ordering the engine without the stock heads and cam.
I have the Edelbrock intake manifold currently on my IROC 305. I also have a Holley fuel pump, Pacesetter shorty headers, an MSD ignition, a Flowmaster exhaust, ram air, a K&N Filtercharger, and a high-performance chip. It runs great, but I probably have 50,000 miles of life left on the engine (so says my mechanic).
Anyway, if the same prescription you gave Bill would apply to my situation, I would substitute the heads with Chevy S/R Torquer heads, 76cc, '87-and-up, and of course use the same cam you recommended, with the new 350 long-block you suggested. What do you think?Edward FiliksMesa, AZ
A Bill Wivel's LG4-equipped Monte Carlo sparked more than a few questions. We got a question similar to yours from John Davies of Reno, Nevada. It seems the smog police are cracking down everywhere, and you need smog-legal engine packages for both your cars. You've got a Camaro, and John has an '87 El Camino. Let's briefly go over the original answer and add some new info to match your questions.
When replacing either an '82-87 LG4 or L69 in any of the Camaros, Impalas, Montes, El Caminos, or trucks, the base Goodwrench engine is a great one to start with; it's sold under PN 10067353. The upgrade components of an Edelbrock PN 3701 manifold and camshaft, PN 3702, will give you a great-performing, emissions-legal engine. As in Bill's case, I recommended he also install the Edelbrock TES system in his Monte. Ed, you said you already had headers on your Camaro. John, the TES system, PN 68793, will also fit your '87. El Cam. You will need to upgrade to a four-bolt, high-flow catalytic converter from either an '85 Camaro or an '85-86 Corvette.
Now let's talk about some new developments. Ed, if you would like to purchase the GM Goodwrench short-block, this is the foundation that the complete long-block is built from. You need to pick up short-block PN 12601517, which comes as a rotating assembly with no camshaft, lifters, timing chain and gears, or tin (pan and front cover). This is where you run into a little problem. In '86 GM changed the design of the small-block to a one-piece rear main seal. With this GM changed the oil pan and front cover, and they went to a one-piece oil-pan gasket. You wouldn't be able to use any of your tin on this engine. Ken at Burt Chevy says the short-block is only $300 less than the complete. You might be better off buying the complete long-block and selling off the heads to recoup some money. With the complete engine you would have a new oil pump, timing-chain set, good GM lifters that you could use on the new Edelbrock camshaft, pushrods, rockers, and tin.
Next, with the crankshaft change in '86 to a one-piece seal design, it also changed the crank-flange bolt pattern to an externally balanced flywheel/flexplate. You'll need to go back to a two-piece flexplate PN 471529.
Ed, the 350 block has the same external dimensions as the 305 and will bolt right into your IROC with no modifications. As we said in the first answer, one of the best parts is that the smog police won't even know that the long-block has been touched.
Ken's Going To Hate Me!Q I have a '69 Chevelle 383 stroker, a TH350 trans, and a Moser differential with 3.73:1 gears. The speedometer is way off and reads much faster than I'm going. My mechanic tells me that he cannot change the gears in the trans to compensate. Where can I find more info on this? Thank you very much.Scott HippertDover, MN
A Years ago I had another reader write in with a speedo calibration problem. Well, I recommended then that he contact Ken Casey at Burt Chevrolet. Ken is the GM Performance Parts manager and is a wealth of knowledge. Your mechanic is off in left field. You can change out the drive and driven gears very easily on the TH350 trans. To make a long story short, Kenny sold a ton of speedo gears and gear reduction boxes to calibrate speedos all around the world. Give Ken a call at 800.345.5744, and he'll get the pieces in the mail to calibrate your speedo.
Nasty, Wicked & Wild 327Q I'm currently building-or trying to build-the most wicked, bulletproof Saturday-night-special 327 small-block for my '65 Chevelle. I need a little help ensuring all the parts I'm slowly putting together for this build will work the way I hope them to. Here is what I have so far: a casting number 3970010 four-bolt main 350 block from a late-'70s truck, a number 4672 forged (supposedly) large-journal late-'60s 327 crank turned 0.020 inch under, Scat forged/bushed 5.7-inch I-beam rods, and Speed Pro flat-top hypereutectic pistons. I'm planning on buying a set of AFR 190 heads, and fitting them with a set of 2.02/1.60-inch titanium intake/exhaust valves complete with locks and retainers that my friend got for me at a ridiculous price, a large Comp Cams hydraulic-roller cam and lifters with 1.6 Pro Magnum rockers, an Edlebrock RPM Air Gap intake, a Mighty Demon 650-cfm carb, a TH350 with 2,500-2,800 stall, and a 4.10 posi-fitted 8.2 10-bolt with a Gear Vendors over/under unit. Whew.
What I'm trying to accomplish is 475 hp and 400 lb-ft of torque on 94-octane pump gas. My titanium friend did custom-port development for Roush Racing for six years, and he is going to feather in the CNC'd ports and chambers on the AFRs, along with milling them to about 58cc chambers. I'm trying to get to 10.5- to 11.0:1 compression with the flat-top pistons so I don't mess up the quench on those beautiful heads by stuffing an ugly dome into them. Can that be accomplished with angle-milling the heads and decking the block? Is that carburetor going to be the right size? Will that four-bolt block and 327 crank be compatible (both two-piece rear main)? I'm going to have the rotating assembly balanced since I'm guessing the peak horsepower range will be over 7,000 rpm. I was told the hypereutectic pistons will handle up to 500-plus horsepower. What cam would you recommend? The block is still at 4.00 inches but is going to get machined. Any special things I should make sure the machinist does? I know it's a lot to digest, but I've done a lot of reading, and I think I can finish this build for $5,500. Please help all you can. Thanks.Matt A. SpradlingDetroit, MI
A 327s have a very special place in my heart. Back in the '70s that's all I built, and I loved the way they winded! You've gathered up some really nice components to tease that 475hp bogy. That's only 1.44 hp per cube out of a 331 on pump gas. Let's take a swing at this thing.
First, your 327 crankshaft is a forged late-'60s large (350) journal design. It will bolt right into your 010 block with no modification. Yes, the Speed-Pro pistons will take up to 500 detonation-free horsepower. However, you've got so much money in this piece, we would step up to a set of forged pistons. This would give you a level of comfort to spin this thing to the moon. We run into a slight problem getting compression. With a 0.030-inch overbore, zero deck, 58cc chamber, 8.7cc 0.039-inch head gasket, 1.5cc ring land volume, and 8cc valve reliefs, you come up with 9.91:1 compression. To get up to your desired 10.5/11:1 squeeze you'd need to clip the heads down to 50 cc. Even with angle-milling, you will not reach this volume without running into the intake valve seats. To reach the compression you wish, you will need to run a very small, 6cc dome piston. With this you will be able to run your AFR heads as received at 64cc. With these changes your compression will come in at 10.96:1. This is a very small dome and won't affect the efficiencies of the combustion chambers.
It's very cool that you have been able to pick up the Ti pieces from your friend. This will give you added valvetrain stability from the lightweight components. As for the camshaft, I would recommend going with a mechanical roller rather than the hydraulic. With all the killer Ti pieces, keep the valvetrain light with a mechanical roller. To reach your power bogy you will need a rather large camshaft for your little engine. Checking in the Comp line like you asked, we zeroed in on the Xtreme Energy Mechanical Roller PN 12-773-8. This nasty camshaft comes in at 254/260 duration at 0.050 inch lift, 0.582/0.588 inch max lift with 1.5 rockers, and is ground on 110 centers. This is a "bottom of the page" listing in the Xtreme Energy line. These duration numbers run really well in mid-build drag-race engines. They make killer torque and run well up stairs. The 1.6 rockers will kick the duration a couple of degrees, and the max lift up to 0.620/0.627 inch. With the titanium valves and components, you should be able to step up the rocker ratio.
Now that we've kicked up the camshaft you will need a few more rpm in that torque converter. 2,800 rpm would be an absolute minimum and you should push it up to 3,200. Also, the Performer RPM Air Gap is going to limit the top-end breathing of this engine. We would go with a Victor Jr. PN 2975 and a 2-inch open-plenum spacer. Yes, you will give away a few pound-feet of torque at slower engine speeds, but the single-plane will sing upstairs. Speaking of airflow, you will need a 750-cfm carburetor for this animal. Our Air Dyno says that the 400 lb-ft is very real, but the 475 hp is going to take some tuning work. Horsepower peak will be over 7,000 rpm, probably closer to the 7,500-rpm range. This is another reason to step into forged pistons.
What should you tell your machinist? Keep it simple. Check the block thoroughly for cracks and sonic-check the cylinder walls for core shift. Yes, the 0.030-inch overbore will leave the cylinder walls with enough meat, but ring seal will be very important to reach your power bogy. Make sure they use a torque plate to bore and hone the block, and leave ample material for finishing honing. Use ARP studs throughout. Line-hone the mains to resize them properly after stud installation, and to ensure a very straight housing bore. That crankshaft spinning at 7,500 rpm doesn't want to kiss any bearings.
Let us know when you get this beast together. Try to spend a few dollars and run the engine in on a dyno. We want to hear that sweet song of a 3.25-inch stroke.
Shove VetteQ I have an '85 Chevette. Yes, a "SHE-Vette," not a Corvette, that I drive daily and have done some nice mods to. I'd like to swap in a TH200-R4 transmission. Will it work behind the stock 1.6L engine? I have the TH 180 trans now and thought the swap would be better on gas mileage and performance. How about the Ecotec 2.2L crate engine from Chevy? Will that work with the TH200-R4? Thanks.Tim HeckmanScott AFB, IL
A The Chevette brings back some nasty memories! I was a heavy line mechanic for a couple of years back in the late '70s. I had a deal with the other guy that he would do all the work on Vans, Vegas, and Monzas. That left me with the Chevettes, LUV trucks, and the dreaded Olds diesel trucks and Montes. I hated Vans and Vegas, but sometimes I think the other mechanic got the better deal. The Chevettes had a very noisy rearend, and the torque-arm arrangement GM designed for these cars transferred all the rearend noise into the interior of the vehicle. No matter how you tried to set up the ring and pinion on these cars, they would always have some noise. GM even started to put a cartoon in the manuals stating, "Some noise is OK!" Well, enough of ancient history and lets get back to your question.
The original 1.6L four-bangers will not accept the TH200-R4 bellhousing. It was unique unto itself. Can you swap in an Ecotec 2.2L? Sure. However, the TH200-R4 won't fit that block flange, either. If you want to build a killer car, slip in the new 2.0L Ecotec that's in the '07 Saturn Sky Red Line! The nasty turbocharged direct-fuel-injected engine produces 260 hp and 260 lb-ft! It's the most powerful engine GM is producing, at 2.1 hp/ci. This, with the five-speed gearbox mated behind it, would be a real kick in your SHE-Vette. Enjoy!