Sport Compact Car - July '98
Project 200SX SE-R
by Mike Kojima
[Put into HTML format by Mike Mager]
Building the bottom end, part II.
PHOTOGRAPHY: Les Bidrawn
The Mustang GT in the next lane showed all the classic signs of a confrontation about to happen. Although I moved over to let him by after he approached within inches of my rear bumper, the driver was still not a happy camper. The hard stare was a bit much, but being slow to anger, I ignored him. Then he started to act really obnoxious, boorishly revving his 5.0-liter pushrod motor, jockeying back and forth with the arrogant confidence of a muscular bully kicking sand in the face of a 98-pound weakling. Assessing the threat, I noted a Borla exhaust, some sort of 17-inch wheels and a lower ride height.
Normally, I don't succumb to the temptation of a challenge like this, but the late night interstate traffic was non-existent, and I knew the road ahead well. Suddenly the Mustang reared-up and started to sprint away. No time to activate the nitrous system. A quick flick of the wrist put my compact 2045cc, high-tech four-banger in third gear and the fat part of the SR20s powerband. The enemy had gotten the jump on me, but there was still a chance for redemption.
The SR20 screamed as if I had given it the spurs, and started to reel in the galloping Mustang. The higher pitched note of the high revving four cylinder was drowned out by the basso-perfundo roar of the V8, as we approach striking distance. In a desperate attempt to stay ahead of my hard-charging Nissan, the driver revved his steed way past its 5000 rpm power peak. As I approached the Mustangs door, I stuck it into fourth gear, and feathered the throttle back to draw even with it. The driver was a comical sight. His mouth was wide open, and his eyes were bulged with amazement at seeing his car get spanked by an econobox.
After savoring the moment, I put it to the wood again, pulling a few car lengths on the driver. Backing off the gas, I flashed the brake lights to further demoralize the fallen giant, and slowed back down to cruising speed. With his head hung low, he avoided eye contact cut across four lanes to exit the off ramp. Perhaps, he'd will think twice before picking on the next econobox that he comes upon.
In the last installment (SCC, June '98) we had Clark Steppler and Jim Wolf of Jim Wolf Technology tweak the SR20's bottom end with their meticulous machine work. Now it's our turn to get busy by prepping the block for assembly.
Before assembling an engine, it's important to prep it first. Good prep work can make the difference between an engine that runs hard, and one that succumbs to an early demise.
After professional machining, blocks get internally dirty. Metal chips and honing slurry can be found everywhere. Even if it's not apparent to the naked eye, the block becomes heavily contaminated. Generally most automotive machine shops leave honing oil on the block to keep the bores from rusting. This must be thoroughly cleaned before reassembly.
For convenience, we placed the block on an engine stand so we could rotate it. We then used a de-burring knife (available at and any industrial supply store) on every sharp machined edge that we could find. Deburring can help to eliminate potential stress risers that might form cracks. However, you must be careful not to nick any gasket or seal surface while doing this.
Next, we removed the oil galley plugs that are positioned around the outside of the block. (The are removed using an Allen wrench. At this point, you must remove all traces of the old sealer from the plugs and the blocks threads.) Once this was done, it was time to start washing it.
We doused the block thoroughly with Motul's Moto-Wash. This powerful, grease-cutting detergent cuts oily grime, and most importantly, contains rust inhibitors to help protect the freshly machined bores. If you've prepped a block before, you know that the bores can rust in a matter of seconds if they get wet. We then worked the block over with a stiff nylon bristled brush, rinsing with plenty of fresh, clean water and repeating several times until the block was spotless.
Next, we used Moroso's engine brush kit to clean out all of the oil galleys with Moto-Wash. We couldn't believe the stuff that came flowing out of the oil passages. (The engine was always meticulously maintained, with frequent changes of high quality synthetic oil.) Cleaning the oil galleys is an essential step that is usually overlooked buy the amateur engine builder. If you could have seen the dirt and sludge, you would think twice about forgetting this step.
As a final stage, we cleaned the cylinder bores. Through the machining process, bores are contaminated with honing slurry that's a gritty, nasty mixture of oil, fine metal particles and depleted abrasive grit that sloughs off the honing stones. Since we want to avoid pistons abrasion so our new rings seat properly, and last a long time, we must get rid of it all. We used clean, soft, 100 percent white cotton cloths, saturated with Berrymans carb cleaner to decontaminate these critical surfaces. We wiped the bores in the direction of the cross-hatching and repeated until the white cloth remained white after a wipe. Then we immediately sprayed some Motul Protect (a powerful, rust-inhibiting oil) on the bores to protect them from rusting while the block awaited assembly. Finally, using an air compressor, we thoroughly blew off the entire block to remove all remaining residue.
From there, we washed the crank, rods and pistons in clean, virgin solvent, using a soft bristle brush and some elbow grease to dislodge any dirt or oil residue. Like the block, all oil passages were given a though brushing out and were blown off with compressed air. As a last step, the crank and rods were given a thin coating of Motul Protect, and wrapped in plastic to keep them clean until assembly time.
While we were working on the block, the head went back to DPR for some more work. The last time that DPR worked on project SE-Rs head, Dan hadn't re-contoured the exhaust valves very much. He felt that reversion at low port velocities could be a problem with the OBDII system. Since the engine was relatively insensitive to cam timing adjustments in the last installment of the project, we theorized that reversion was not as much of a problem as we initially suspected, and asked Dan to rework the valves for maximum low lift flow.
DPR Technician, Tom Fujita, then opened the bowl area of the ports and laid back the combustion chamber wall slightly near the exhaust valves to unshroud the valves further. This is meant to aid the flow in the area where the combustion chamber wall comes close to the valve by moving it further away from the valve, clearing the flowpath. Tom then milled another 0.010 off of the head to bring the combustion chamber volume back down to our original starting point of 43cc. Finally, Tom lightly hand-lapped the valves as a touch-up measure, and carefully cleaned and reassembled the head, paying close attention to shim thickness to maintain proper rocker arm geometry. A few issues ago we described the head porting and assembly process in detail so we will not get heavily into it in this issue.
Due to a heavy business travel schedule, we were not able to assemble the motor ourselves in the palatal, climate-controlled comfort of the SCC garage. As the assembly of any high performance engine is a delicate procedure that requires great care, we turned the project over to our friends at HMR America. HMR is a race-prep shop owned by Howard and Richie Watanabe. Howard and Richie have extensive backgrounds in race prep and engine building, with a winning history in everything from Class 7 off-road trucks to Formula Atlantic cars, so naturally we felt that our engine was in good hands.
Howard Watanabe, HMR's designated engine builder, carefully measured the bearing and piston-to-wall clearances using micrometers and bore gauges. A good engine builder never takes the machine shop's word for it, and spends a great deal of time just measuring things. It is important to use high precision tools for these measurements. Calipers are only accurate to about 0.001 inch, but micrometers and dial bore gauges are generally good to 0.0001 inches, so beware when your engine builder whips out calipers to measure your critical internal engine clearances.
Once he established the fact that the engine was properly machined, Howard carefully assembled the motor with speed and meticulous precision. One of the interesting things about real racing pros is that at a casual glance, they seem to be working slowly, but when you go away and come back a short time later, it is amazing what they've accomplished in that short time. (Just visit the garage at any CART event, it is strangely quiet, with the mechanics calmly working on the cars. Only with careful observation will you notice how fast the work is progressing.) Soon the head came back from DPR and in no time Howard had the engine back together.
As a side note, it's critical to remember to replace the oil galley plugs that were removed during the cleaning stage. Many an engine has been ruined by omission of these plugs. If they are left out, the engine won't have oil pressure. If the plugs under the timing chain cover are left off, there will be no way to see this internal oil hemorrhage until it is too late. Howard reinstalled the plugs with Locktite (blue) to seal them.
While everything was easily accessible with the engine out of the car, we decided to block the coolant out of most of the manifold and throttle body to help keep the intake charge air cooler. Since the coolant temperature sensor is located in the manifold, we couldn't block all of the passages. However, we blocked the ones that weren't as critical to engine operation. For those readers who live in cold climates -- freezing cold -- this step is not a good idea. The hot water heats the manifold and throttle body to prevent icing of the throttle body, and reduces the formation of deposits in both the intake manifold and the throttle body. Once the hot water is stopped, the throttle body will have to be inspected and cleaned periodically. Ice can also cause the throttle to stick open.
Since we blocked the hot water out of the idle air regulator passage, we anticipated minor idle fluctuations when the engine was cold. The air regulator is controlled by ECU input, with coolant and conducted manifold heat on a bimetallic spring. Since the manifold will now heat up slower, the valve might not function as quickly but we figured that it would be worth experimenting to see if the driveabilty remained acceptable.
Because the block had been decked about 0.010-in. by JWT to reduce the quench volume, and the head had been milled for a total of about 0.030-in. since we began work on it, we started correcting the cam timing. When the distance from the cams to the crank is reduced, the difference in chain link distance gets shorter and the cam timing retards. Since we already learned that the JWT cams work the best in the stock, straight up position, we used the JWT adjustable timing gears to advance both cams 2.5 degrees to restore the correct cam timing.
With the cam timing done, Howard buttoned up the engine and handed it over to Richie for a quick install. Richie made quick work of getting the motor back in the car. When helping out with the finishing touches, we noted that not a single nut, bolt, connector or even zip tie was out of place.
We filled the crank case with 5-30 mineral-based oil to ensure proper break-in. We didn't want to take chances by having the engine not break-in correctly on slippery synthetic. We were also careful to bleed the cooling system of air after filling it with a 50/50 mixture of Nissan Long Life coolant and water, as this is fairly difficult to do correctly on an SR20.
After reinstalling the transaxle, we filled it with Motul synthetic gear oil. This is a ultra slippery gear oil that has a friction modifier package that allows the syncros to grip tightly, despite the excellent lubrication properties of the synthetic oil base stock. The friction modifier package ensures fast shifts while the slick, high film strength oil helps cushion the gears and lubricate the bearings. Synthetic gear oil also tends to be lighter bodied than mineral gear oil; by reducing viscous drag the synthetic ca, as a result, free up some horsepower . Synthetics also tend to be more viscosity stable allowing for better shifts when the oil and transmission are cold.
The engine started easily on the first few cranks. After letting the engine warm up, setting the timing and checking the coolant, we pinched off the crank breathers and PCV system while the oil filler cap was open and the engine was running. This forced all the blow-by to spurt from the oil cap where we could see it. However, there was absolutely no blow-by smoke coming out of the oil filler hole. This was very unusual on a brand new engine and is a sure indicator that the rings were sealing exceptionally well. Our care in machining the block was already starting to pay off. After a few more minutes of fast idle, we turned off the motor and changed the oil and filter. This ensures that any dirt, rust or metal particles that somehow missed our cleaning process can be immediately disposed of before they can do much damage.
After a quick spin, we noted that the engine felt very responsive, but it wanted to detonate with its 11:1 compression. Because detonation will quickly kill a high performance motor we retarded the distributor about 6 degrees so we could drive the car around to break-in the motor.
We drove the car 500 easy miles, and changed the oil again using Motul's Synthetic SYNERGIE 6100 5/40. This oil is 100-percent vegetable based, so it's very clean burning and bio-degradable. It also has superior film strength and is used by NISMO, Nissan's Japanese motorsports division, in it's Le Mans Group C prototype cars. Five hundred miles provides plenty of time for rings to seat with our precision bore and honing job. We noted that the break- in oil was clean, still exhibiting a light amber color. Normally break-in oil gets filthy, loaded with blow-by smoke residue and metal shavings as the engine breaks in. An engine will typically burn a lot of oil until the rings seat. Project SE-Rs engine did not burn much oil at all during this break-in period, another indication that our carefully machined block is allowing excellent ring seal.
Despite the fact that we had blocked off the manifold heating passages, driveabilty was only minimally affected, with only a slight burble noticed for a few seconds when the engine was allowed to cold soak on the coldest nights (California cold nights anyway). Previously, the manifold would get hot to the touch, nearly as hot as the valve cover. Now the manifold only warms slightly, helping keep the intake air charge cooler.
We headed up to Jim Wolf Technology to get the ECU program optimized for our high compression ratio. Steppler of JWT reprogrammed the spark tables of our ECU to reduce the ignition advance only in the areas of engine operation where the detonation occurred. Clark discovered that most of the detonation happened when the engine was at extremely light load, and small throttle openings instead of the typical, heavy load, low-to-medium rpm operation that usually causes detonation. We attribute this to the SR20s efficient, compact combustion chamber which has built-in, natural detonation resistance and to the increases of cylinder quench and good flame travel attributed to the DPR heads modified quench zone and the JWT flat top pistons. Because of these factors, Clark hardly had to change the wide open throttle parts of the ignition table.
This light load detonation, although still potentially damaging, is better than detonation at extremely high cylinder pressures. Detonation in those situations can burn valves and break pistons with the greatest of ease.
As a warning to those that are duplicating the build up of project SE-R: Do not attempt to run a compression ratio this high on pump gas without a JWT computer specifically reprogrammed to run 11:1 compression. The detonation that you will experience will quickly destroy your new engine even if it is still only light load detonation. If you retard the distributor enough to kill the light load detonation, your spark will be so retarded at the WOT parts of the map that you will lose more power than the high compression will cause you to gain.
For safety, Clark also richened up the fuel tables at wide open throttle to have the engine run at a fuel air ratio approximately 12.3:1 instead of the normal JWT program of 12.6:1. This should help keep the combustion chamber a little cooler and further help reduce any chance of detonation during extended full throttle operation.
After Clarks programming was complete we were amazed at the newfound power, throttle response and torque that the new engine made. We eagerly drove back to DPR to Dynojet the new engine.
On the long drive, we noted that at cruising speed the engine now runs much cooler than it did before. In fact, the engine temperature now fluctuates around the thermostat's opening point even with the supposedly hotter-running high compression. We attribute this to both the effectiveness of the Swaintech Gold thermal barrier coating on the piston domes and to the SR20DET piston coolers that JWT installed in our last installment. This cool running is also most likely another factor in the engine's detonation resistance.
On DPRs Dynojet, Project SE-R recorded nearly 165 horsepower at the front wheels. This equates to about 190 crank hp and a 13-hp improvement since our last feature of the build-up. The engine also produced 152 lb-ft of torque with over 125 lb-ft available from 2500 rpm on up. (125 lb-ft is more torque than the stock engine had at its torque peak.) The powerband is broad, useable and flat, with lots of area under the power curve making the little SR20 feel like it has much more displacement than it really has. Not bad for an OBDII-equipped smog engine! Because of the cooler intake manifold, the piston coolers and the Swaintech coatings, Project SE-R now pumps out the same horsepower readings run after run on a Dynojet. Previously, the engine would lose about 3-4 hp with subsequent runs due to heat soak. Look out Type R Integras. Our lighter Nissan 200SX will be more than a match for those Championship White Acuras.
In upcoming issues, we'll experiment with header designs, NOS tuning and extrude honing of the intake manifold.
Reprinted with Permission