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The Honda 1.6L VTEC Engine, Steve Fox
By Steve Fox
At this year's AERA EXPO 2003, which will be held at the Las Vegas Convention Center April 23-26 2003, the exciting sport compact performance market and the potential that it has to offer will be highlighted. In that spirit, AERA is building a high performance Honda 1.6L DOHC VTEC engine that will be stroked out to a 1.9L engine. This engine will be raffled off at the end of the show on Saturday, April 26. Videos of the various machining and assembly operations will be available during the show, too.
Part I of our two-part Honda "Race Rocket" engine will focus primarily on machining operations. Obtaining an engine core was the first priority in this engine build. A lot of thought went into the core selection process as well as considerable discussions with machine shops and experts in the sport compact business.
The 1.8L DOHC VTEC engine is one of the most popular engines for doing any kind of modifications and improving horsepower. However, obtaining an 1.8L engine core can cost in excess of $2,000. After talking with Alan Davis of Eagle Specialty Products, Southaven, MS, AERA decided to use the 1.6L DOHC VTEC engine, graciously donated by Eagle.
The 1.6L B16A DOHC VTEC Honda core typically runs less than $1,000. You can still make many modifications to get the desired performance while producing a good quality street engine. Here’s the initial processes we followed to begin rebuilding this popular powerplant.
The engine was torn down at AERA headquarters by the technical staff of Dave Hagen, Mike Caruso and Steve Fox, who said the core was in very good shape and very rebuildable. Generally, most Honda cores are in good shape, at least those that are take-outs resulting from auto accidents. After the engine was dismantled, it was sent to be cleaned and pressure tested.
Perry Crabb of Axe Equipment in Council Grove, KS, handled the cleaning process of the cylinder head and block. When he received the cylinder head it was still complete so Crabb sent it to a local machine shop and had them disassemble the cylinder head.
According to Crabb, there are five essential elements in the cleaning process.
- Good temperature. When cleaning engine components, you must have a minimum of 160° F. The cylinder head and block were cleaned at 170° F.
- You must have a properly configured "manifold" system as well as spray nozzles that are not restricted. The manifold system that Crabb refers to is the cleaning solution supply lines that hold the spray nozzles.
- You need a good drive system for your turntable. To get good cleaning results, the table must turn properly within the spray chamber.
- You must use good chemicals. If the chemical solution is poor, the cleaning process will not produce the desired results.
- Correct tooling is a must. When our cylinder head was cleaned, it wasn’t placed in a basket. It was instead mounted on a stand with adjustable clamps, which hold parts for ultimate cleaning. This procedure makes sure that the head is totally cleaned with no restrictions of chemicals reaching the cylinder head.
The cylinder block was cleaned in the same manner, mounted on the turntable securely and cleaned with no restrictions to the block. Once they both were cleaned, Crabb was ready to pressure test the cylinder head.
Before pressure testing any cylinder head, you want to look for all water openings and make sure that they are plugged so that no air is leaking out of it. Also, it is a good idea to have an assortment of threaded plugs for any sensor holes that need to be sealed as well.
When mounting the cylinder head into a pressure tester for tightening, you should always work your way from the center out. That way you know that you have good clamping load on the cylinder head for pressure testing.
Crabb explains that more air pressure is not always correct when you are pressure testing. Air pressure into the cylinder head is usually 2-3 times what the cap pressure is for the radiator. The Honda 1.6L engine has a 14 lbs. cap on it so when air pressure was applied to the cylinder head, it was tested at 40 lbs.
This testing pressure emulates the cylinder head under operating temperatures. Our cylinder head was submerged into water with great success; no bubbles came through, making the cylinder head good for use.
The cylinder block was then shipped to Frank Rehlinger of Delta Custom Tools in Delta, British Columbia, Canada. The block was put under 35 psi of pressure for over an hour and did not display any leaks. Rehlinger stated that they do not like to use much more than 35 psi because of the chance of pushing the side of the block out.
We had some choices with regard to the rotating assembly for this engine. Eagle’s Davis gave us a lot of insight into the rotating assembly options.
Making sure you know what the customer wants helps make the decision easier. One option is to purchase a rotating assembly from an aftermarket source. With our Honda project we decided to go with a stroker rotating assembly (donated by Eagle Specialty Products), which included pistons and pins with locks, piston rings, crankshaft and connecting rods.
As stated earlier, the stroker kit that we are using will actually make the 1.6L a 1.9L engine. Standard stroke on the crankshaft from the factory is 3.031˝ and we’re using a crankshaft with an increased stroke of 3.334˝. However, even with the increased stroke, the connecting rod length does not change. It is still the standard length of 5.290˝ center-to-center.
We’re using an SRP piston with an -11.5 cc dish. Compression height on the piston is 1.045˝ and it weighs approximately 289 grams before being balanced.
With this piston, the compression ratio changes to 9.0:1 compared to stock, which is 10.4:1. This type of piston (lower compression) is good for use with a turbocharger or a supercharger on the engine.
The top ring groove is a 1.0 mm, the 2nd ring is a 1.2 mm and the oil ring is a 2.8 mm plus oil support spacer because the wrist pin location gets into the oil ring groove.
The other option for a rotating assembly for this project is to have the crankshaft welded and stroked to the 3.334˝ specification. Before the crankshaft can be worked on for stroking, we must clean the crankshaft and make sure that it is not cracked and is in generally good working condition.
Gary Thompson of ABS Products, Brea, CA, cleaned the crankshaft with his soda-blasting machine. This is a good process since you can blast the bearing journals on the crankshaft and not damage the journals. Our crankshaft went in very dirty and came out very clean using this process.
Once the cleaning was done, the crankshaft was sent to Randy Taylor of DCM Tech, Winona, MN, to be checked for cracks with the Magnetic Particle Inspection (MPI) process.
MPI is a process in which the piece to be checked is charged with a magnetic field that runs through that piece like water to any cracks or imperfections. When the crankshaft is magnetized, it creates a north and south pole within the crankshaft, acting as a mini-magnet. This attracts the fluorescent particles found in the indicator base solution to the cracks. When highlighted by a florescent mag light, the cracks show up as ripples in the flow of the magnetic field.
The crankshaft had the magnetic field induced by coil shot that was used first for checking the vertical plains of the crankshaft, which would include the fillets on the crankshaft. No signs of cracks in the vertical plains were found.
We then went from a coil shot to a head and tail stock shot to magnetize the crankshaft. The magnetic field is altered 90° to check the horizontal plain of the crankshaft. The crankshaft was checked from the nose of the crankshaft to the flywheel end, checking oil holes for any cracks. Our crankshaft passed both tests with flying colors.
Since the crankshaft was magnetized, we had to demag it as well. This is a very important process when checking a crankshaft for cracks. If the crankshaft is not demagged properly, during later machining processes metal can be attracted into the oil holes of the crankshaft. The demag process on the DCM machine was done through the coil and took just five seconds.
To check that the crankshaft had all residual magnetic fields neutralized, Taylor used a Gauss meter.
After checking for cracks, the crankshaft was sent to Terry Wagner at Storm Vulcan, Dallas, TX, for pre-grinding. It needed to be offset ground .330˝ to accommodate the new stroke of 3.334˝. Once it was pre-ground to specification, the crankshaft went to Jeff Gleason at Gleason Engineering Industries, Winona, MN, for the build-up of the rod journals for stroking.
Rod journal welding is a critical step and must be done correctly. It is important that the crankshaft be straightened after each connecting rod journal has been welded on. This straightening process must be done immediately following the post-heating period.
Once the crankshaft had all the rod journals welded for stroking, it was ready to go to the crankshaft grinder to be machined to the correct specs. Ed Davis, AERA Chairman, of Waterhouse Motors, Tacoma, WA, ground the crankshaft with his Peterson crankshaft grinder to a dimension of 1.7707˝-1.7717˝, which is a standard size from the factory.
The connecting rods for the original rotating assembly were sent to Ed Kiebler of Winona Van Norman, Wichita, KS. Kiebler cut and machined the connecting rods to a specified size of 1.8898˝-1.8906˝. He also inspected the small end bore for size. Once the rods had been machined, they were balanced to specification.
One thing to keep in mind, if you purchase a rotating assembly from an aftermarket source, connecting rods can be machined for a bushing, making it a floating pin instead of a press-fit pin.
Dave Clinton of Darton International, San Marcos, CA, supplied the sleeve assembly for this engine build. The cylinders had a pre-finish size of 84mm, which works well for forced-air applications such as a turbocharger. If your customer wants to use a supercharger on this engine, it is advisable to increase the bore size to 85mm.
The sleeve assembly is what Darton calls a "modular integrated deck" (MID) design. MID is a unique cylinder sleeve that, when siamesed and nested, creates a solid deck of sleeve flanges held in tension, reinforcing the upper deck area, and provides for in-field replacement. In addition, this design manages and enhances water flow from block to head to promote stability of cooling and all sleeves are of the "wet" design.
The enhanced water flow in and around the flange area is possible because of ported water flow control engineering – referred to as swirl coolant technology. This process begins with specific engineering models of respective cylinder head and combustion chamber designs, which promote increased flow of water in those areas of the upper sleeve area subjected to the most heat.
When the sleeve assembly was manufactured, it was made with a bore of 3.300˝, which leaves us with .007˝ that needs to be honed for finish size and piston-to-wall clearance. The OD size on the sleeve is 3.600˝ and has a wall thickness of .150˝. The length of the sleeve used was 5.250˝ with a flange thickness of .600˝ and a flange diameter of 4.625˝.
Before the block could be machined to accept the sleeve assembly kit, it needed to be decked parallel to the main bore. Rottler Manufacturing, machined the deck surface .005˝. This amount was taken off of the deck to clean it up and provide a nice smooth surface finish.
Once the block was decked, Rottler also went ahead and machined the block to accept the sleeve assembly. Machining the cylinder block to accept the sleeve assembly is a pretty straightforward job.
After the cylinder block had gone through the five machining steps to accept the sleeve assembly kit, the sleeves were ready for installation. We arranged the cylinder sleeves in order of installation on a clean and dry surface. We then applied a liberal amount of the special 0-ring lube supplied with the sleeve kit into all the sleeve O-ring grooves as well as the rings themselves, being careful not to roll the O-rings into the grooves, instead stretching them into place.
We made sure the block was free of all machining chips and temporarily installed the sleeves until the lower part of the flange registered on the block top. Next, the sleeves were aligned flat-to-flat to create round water transfer holes. Using a permanent marker, we marked the sleeve flange radius and a corresponding point on the deck of the block for each sleeve.
We removed the sleeves and cleaned carefully above the O-ring register with acetone. We were careful not to come in contact with the O-rings when cleaning with the acetone. Using the applied adhesive and brush supplied, we applied a light coat of compound around the perimeter of each sleeve and flange area, but did not coat the O-ring area itself.
Using the previously recorded witness marks, we installed the sleeves, tapping them in using a brass or aluminum mandrel. When installing sleeves, make sure that they are installed back in their previous position.
After sleeve installation, we pressure tested the block using 25 psi to make sure that the 0-rings were not leaking and there were no register problems with the block.
The above installation procedures, along with machining processes, are all listed in a very detailed procedure manual supplied by Darton with all its sleeve assembly kits.
Once the cylinder head was pressure tested, it was sent to Brice Harmand of Newen, Inc., San Diego, CA, for the valve seats to be machined. Harmand did a professional three-angle valve job on the head and also lightly blended the seats for better flow through the valve pocket area.
Not much flow work, if any, will be done to the cylinder head because this head from the factory is one of the best stock flowing heads out there. Some of this work could be done if a customer would like to have port work performed, but after talking to some other import enthusiasts, we determined that any work done to the cylinder head would not significantly improve our engine build performance. One individual experienced with this engine actually stated that there could be a chance that horsepower might even be lost if any port work was done to the cylinder head.
Brian Benson at Dakota Parts Warehouse, Rapid City, SD, donated Ferrea valve springs, intake and exhaust valves, valve spring retainers and valve spring seats. The exhaust valve is a 25° flo stock size valve and made of a super alloy. Overall length of the valve is 4.035˝ (102.5 mm), head diameter is 1.102˝ (28 mm) and has a stem diameter of .2145˝ (5.45 mm). The intake valve is a 25° Super flo stock size. Overall length of the valve is 4.029˝ (102.35 mm); head diameter is 1.299˝ (33 mm) and it has a stem diameter of .2153˝ (5.47 mm).
As mentioned above, you can see that the exhaust valve is a flo stock valve and the intake valve is a super flo stock size valve. Super-flo valves often referred to as under-cut and/or neck down, actually reduce the stem diameter in the port area. This increases flow over straight stem valves, or flo valves, considerably with no adverse effect on reliability.
Titanium retainers, precisely machined on CNC-machines from aerospace quality titanium, are being used for this engine build. These 7° retainers are fully heat-treated, finished to exact tolerances, adding strength, yet offer a 40 percent weight reduction over conventional steel retainers. Please refer to the Figure 1 to match the specifications listed for the retainers: A) 1.110˝ B) .899˝ C) .675˝
Valve springs used are processed with premium-grade alloy and feature special thermal treatment. Valve spring seat pressure is 90 lbs. at 1.325˝. Coil bind on the valve spring is .787˝ while the spring has a maximum net lift of .531˝.
Ken Barton of QPAC, Lansing, MI, will micropolish the crankshaft as well as the camshafts used in this engine build. Micropolishing consists of rotating a work piece at relatively slow speeds, applying an abrasive cutting media to the part while oscillating at lower amplitudes and higher frequencies.
If the time spent to polish the journal varies or the entire width of the journal is not polished evenly, the surface finish can vary from one area to another on the journal. If the surface finish is not right or the geometry is off slightly, the bearings will suffer the consequence when the pieces are put into service.
It should be noted that it is simply not enough to micropolish parts and make them as smooth, round and straight as possible. Smoother is not always better in every case. Ideal surface conditions must be developed based on a thorough understanding of the conditions under which the component functions, coupled with a reasonable approach using a competent micropolishing source possessing metrology laboratory equipped with surface analyzers, roundness gauges, metallurgical microscopes and precise size measuring equipment.
In Part II of this article, we will cover the rest of the machining, including finish honing, balancing and the engine build specifications as well as provide some dyno number results for this engine build.
AERA Expo Presentations
The plan for the AERA 1.6L engine build is to have each company performing machining operations document their procedures on videotape. Each of these tapes will be edited to produce a complete tape that will be shown on the show floor during the AERA EXPO 2003. Along with these tapes, there will be a roundtable discussion with industry experts on these engines on the last day of the show. Here is the schedule of seminars covering this engine during the EXPO.
Thursday, April 24
Lower End Machining
The lower end of the Honda engine was machined with precise and accurate equipment. Basic machining processes were performed with some modifications to get more power and increase durability. The videotape will address:
• Cylinder block machining
• Connecting rod machining
• Crankshaft machining
• Engine parts
Friday, April 25
Cylinder Head Machining
The cylinder head will be where most of the work takes place. Basic cylinder head machining procedures along with some port modifications for better flow throughout the engine will be followed. As with the lower end, the procedures, equipment and parts used will be of the highest quality and accuracy. The videotape will address:
• Pressure testing cylinder head
• Valve seat machining
• Machining for bigger valves
• Valve guide replacement
• Camshaft bore machining
• Cylinder head port modifications
• Valve refacing
• Surfacing cylinder head
• Cylinder head assembly
• Engine parts
Saturday, April 26
9:00 a.m.-9:55 a.m.
Sport Compact Performance Roundtable Discussion
Saturday’s program will go over the possibilities of adding performance enhancements to the engine as well as dyno testing of the engine. Such examples of performance enhancements available include nitrous oxide, turbo or supercharger, aftermarket fuel injectors as well as fuel management systems. The roundtable discussion with industry experts will cover the engine build as well as provide time for questions.
|THE SPORT COMPACT PERFORMANCE MARKET
The Sport Compact Performance market consists of small, medium and some sports cars with small-displacement engines (typically less than 3.0L and more commonly 4-cylinders). From 1997 to 2001, the market for import and compact performance products skyrocketed by more than 430 percent, growing from $295 million in retail sales to more than $1.59 billion. Although the numbers for last year are not yet in, experts at the Specialty Equipment Market Association (SEMA) predict that sales potentially grew by 50 percent over 2001, pushing the market’s size to more than $2.25 billion.
With numbers like that, who wouldn’t want to take part in the fun? Before you jump in "fast and furiously," be aware that this market, if nothing else, is about understanding your customer. And because of the rapidity of change, it also requires flexibility.
According to SEMA, growth in the market is expected to come from females (expected to comprise at least 25 percent of the market by the end of this year), older drivers (those aged 26-30 will make up a larger share of the market) and a more ethnically diverse public. More African-Americans, as well as Latino enthusiasts, will contribute to this diversity as their general populations increase throughout the country.
The biggest player in the game currently is Honda, holding 45.2 percent of the market with the Civic, Accord and Acura Integra models as the preferred vehicles. However, the redesigned 2001 Civic hasn’t impressed tuners and consumers, according to SEMA. In addition, the 1.7L engine that gave the Civic its Ultra Low Emissions Vehicle (ULEV) status is difficult and expensive to modify, so the popularity of the car with enthusiasts may be in jeopardy. Because most enthusiasts (60 percent) purchase their vehicles used, it will take a few years before that marketplace shifts. But equipment manufacturers indicate that the three vehicles threatening Honda’s status are the Ford Focus, Toyota Celica and Nissan Sentra.
Engine Upgrade Options
Since 1994, sales of vehicles equipped with a turbocharger have declined or have been completely phased out by their manufacturers. In some cases, turbocharged 4-cylinders have been replaced by a 6-cylinder motor. This limited supply of turbocharged vehicles will continue to provide the automotive aftermarket an opportunity to produce forced air induction products for the newer cars.
Although by far the largest product category in the market is exterior modifications, engine modifications are the second-largest segment in the niche. The products that typically compose this segment include ignition coils, sparkplug wires, turbos and superchargers, cold air intakes, nitrous, headers, cat-back exhaust systems and engine hose kits. Internal engine modifications are also included such as cylinder sleeve skirts, rods and piston changes. Sales in this segment of the market were expected to top $220 million last year.
The Internet has been both a blessing and a curse to engine builders faced with Sport Compact customers. The market is seen more as "do-it-for-me" rather than "do-it-yourself." Today’s typical high performance customer may be very knowledgeable about the benefits promised by sophisticated fuel and ignition systems, but they know little about the internal workings of an engine. Be prepared to spend time educating your customer and explaining how things work.
|WHAT DOES AERA’s VANGUARD OFFER?
The Vanguard Group is AERA’s "Under 40" crowd. Led by a dedicated committee of young business professionals, the Vanguard Group was formed to get more individuals involved in engine rebuilding. Vanguard offers networking and problem-solving opportunities to younger members of the engine building community.
The Honda 1.6L VTEC engine featured in this article will be raffled off during the AERA EXPO 2003, April 26, 2003, at the Las Vegas Convention Center. In addition to the Honda VTEC, Vanguard members also will raffle off a Snap-On tool cabinet. Tickets for both drawings are only $5 each. Winners need not be present to win.
Proceeds from the raffles will benefit the Engine Rebuilders Educational Foundation (EREF). EREF establishes scholarships and provides grants to those who desire training in the field of engine rebuilding.
Vanguard’s presence will be seen on the EXPO Show floor as well as on the race track. The "Bullring" at Las Vegas Motor Speedway will be the site of Vanguard’s "Night at the Races" on Saturday, April 26. The event is open to everyone, but tickets are required. For information about any of these events, contact AERA at 888-324-2372.
This article was written by Steve Fox, a member of AERA’s Tech Support Staff, with the help of many leading industry manufacturers.