A lot of attention is lavished on Honda's ubiquitous B-series engines. Different configurations of B16 and B18 four bangers constitute the majority of the Honda aftermarket. The engine is Honda's equivalent of the Chevrolet small block "mouse" motor: Robust, powerful, and everywhere.
If the B is the mouse motor, the H series must be the "rat" motor. Found under the hoods of Preludes since 1992, the biggest difference between the H and B engines is sheer size. The H22 and its non-VTEC stable mate, the H23, are bigger in every dimension, with bigger bore sizes, longer strokes, bigger dimensions, bigger valves...just about everything.
The most important size difference may be the torque numbers. The Integra GS-R's B18C has a torque output of only 128 lb-ft of torque at a lofty 6200 rpm. By contrast, the H22A found under the hood of the recently departed Prelude pumped out 156 lb-ft at a lower 5250 rpm. This number and engine speed difference make the H-series engines more tractable on the street, with on-demand torque, unlike the peaky B series.
But what if you want this beefy torque curve without the Prelude wrapper? More to the point, what if you want this torque in your Civic chassis? How exactly do you put one of these engines into a Civic? These questions and others will be answered in this four-part series, where we will build an H22A, adding higher-performance parts as needed, and then plant the sucker into an EG Civic Si hatchback.
But let's not get ahead of ourselves. The first step in putting the engine into the Si was to put the engine together. For this, the experts at Holeshot Racing in Fullerton, Calif., were tapped. These guys know Honda engines...it's all they do. If you find a Nissan or Mitsubishi part in the shop, it's because somebody accidentally dropped it. All over the facility are various Hondas in different stages of repair, from mildly tuned street vehicles to all-out fiberglass-bodied dragsters.
Interestingly, what you won't find under the hood of any of those dragsters is an H series engine. Despite apparent built-in advantages--such as a closed deck from the factory and a bigger bore and stroke--chief Holeshot wrencher Aaron Bonk tells us that the H is rarely used in drag engines. Part of the reason is the way the cylinders are lined. The sleeves in the H are much thinner, which don't allow for the flexibility in boring that one can take advantage of with a race-prepped B series engine. Because of this, the cylinder walls can't take the ultra-high boost levels found in modern front-wheel drive dragsters. Bonk points out that while an H engine can comfortably produce between 600 and 700 hp, there are B engines that are putting out close to 1000. Luckily, for our street-driven Civic, such high-horsepower concerns are irrelevant, however interesting they may be.
Whenever an engine swap is being performed, it's a good idea to take advantage of the engine being on a stand to perform whatever internal modifications one might be interested in. In this case, a mild internal build will be coupled with some high-tech valve work before the engine is finally assembled and put in the car.
No Guts, No Glory Like other Honda VTEC engines, the bottom end of the Prelude is hard to improve upon. In fact, some of the best "aftermarket" components can be pulled straight from Honda's Japanese parts bin. There, the Prelude Type-S puts out 220 hp at 7200 rpm and 163 lb-ft of torque at 6500 rpm. It does this through the use of higher compression, better intake and exhaust flow, and more aggressive cams. Using these parts on an American model Prelude is simple and relatively affordable.
Our engine utilizes a stock crankshaft, which is already counterweighted and balanced straight from the factory. Connected to the crank are Type-S rods and pistons. The pistons raise the compression level from 10.0:1 to 11.0:1. But just because they're from the factory doesn't mean that Honda skimped on the good stuff. Floating wrist pins are part of the package, rather than the pressed-in pins found on many factory pistons. This bit of engineering helps reduce friction a little, maybe resulting in a half horsepower gain. It's a lot of trouble to go to, and it's nice to see such attention to detail, even where most people would never look.
For the most part, however, the bottom end remains stock. The only other modification of note is the disabling (but not removal) of the twin balance shafts in the block. Although the engine will idle a little rougher, the reduced parasitic drag one gets by disabling the shafts results in slightly higher horsepower. Again, it's a matter of degrees, but Bonk tells us that most people won't miss them, and that the extra power is worth it.
In Part 2, we'll be putting on the head, complete with a modified valvetrain. After that, we'll be installing the engine in the car itself, a task not unlike fitting a size-12 foot into a size-10 shoe. Finally, we'll do some computer tuning to make the engine happy in its new home, along with dyno testing to find out just what the difference is between the H swap, and the more common B. Stay tuned.
Source
Holeshort Racing
(714) 772-VTEC
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Because of the way that the H22's cylinder liners are installed by Honda, the usual "cross hatch" hone job is not used. Instead, a special tool (that looks more like a cloth than a honing tool) is used. The result is this smooth finish. |
The stock H22 crankshaft is a sturdy, forged, counterweighted piece. Five main journals ensure rigidity and longevity. |
Honda goes a step farther than many manufacturers with its cranks. As these small holes show, not only are they counterweighted, but also they're balanced from the factory. |
These pistons are from a Japanese-model Prelude Type-S. The higher-domed pistons have a compression ratio of 11:0, a full point higher than the pistons found in U.S. Preludes. |
The Type-S pistons feature floating wrist pins, a touch that reduces friction losses slightly. It's another bit of attention to detail rarely found in cars like the Prelude. |
The rods are also from the Japanese Prelude Type-S. |
The H block would at first seem like a good choice for turbocharging because of its closed deck. However, at high boost levels, the thinner cylinder liners are not able to take the pressure. |
A feature standard in VTEC engines is the under-piston oil spraying system. This small network of pipes sprays high-pressure oil underneath the pistons to cool them, reducing the chance for detonation. |
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Before final assembly, the main bearings are laid in the journals. |
With the bearings in place, assembly lubricant is applied. |
With the bearings coated, the crankshaft is laid in the block. |
These thrust washers are inserted on either side of the number four journal. Their job is to prevent the crank from moving laterally. |
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The bearing caps are numbered one through five. It is important not to mix them up; serious damage to your engine could result. Also, note the arrow pointing to the front of the engine (the pulley side). Again, don't get the caps backwards. |
All the bearing caps are first placed by hand... |
...then gently tapped into place. Don't worry if they aren't completely snug, since they'll seat when you tighten the bearing caps later. |
This O-ring on the bottom of the bearing cradle could be the most important O-ring in the H22 engine. It seals the oil passage that sends lubrication to the bearings. Without a good seal, it will fail, and your engine won't get the oil it needs to work. |
The cradle is tapped gently into place, after ensuring that the O-ring is installed. We did mention that, right? |
The bearing bolts are coated with assembly lube, and then finger tightened into place. |
The bearings are torqued twice. This ensures that the caps will be evenly torqued, and that the crankshaft itself doesn't get warped. If the crankshaft spins freely after assembly, that's a good sign that everything has gone smoothly. |
Piston rings are carefully fitted next. Be sure to follow your shop manual's instructions when installing the rings. |
The rings are compressed, and the ring compressor is slipped over the cylinder. Then, the piston is tapped into the cylinder. |
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The rods are connected to the crankshaft from underneath the block after the pistons have been installed. |
Even though they won't be hooked up, it's a lot easier to just leave the balance shafts in the block instead of trying to remove them. So, in they go. |
The rest of the assembly is straightforward, straight out of the shop manual. All the pulleys and pumps were reattached in preparation for installing the head, which we'll bring you in the next issue. |