The Big Picture
Why do P29 pistons from D16A or ZC engines raise the compression ratio of a D16A6 when the bore and stroke are the same and the stock compression ratios are so similar?
Compression ratio is affected by every spec in your rotating assembly; you have to look at each and every spec of the motor to accurately calculate your compression ratio.
First, the deck height tells you how much rotating assembly you can fit in your bottom end. The ZC and the A6 share a deck height of 212mm. This deck height is made up of 43.5mm of crank (87mm stroke divided by 2), 137mm of connecting rods, and the rest is piston compression height and piston to deck clearance. The PM7/P29 piston's compression height is 29mm to the 29.5mm of the A6. So far, the A6 is in the lead.
The piston-to-deck height on the ZC is at .040 inches to the A6's .020 inches. The A6 is still in the lead.
It is until you get to the piston crown and combustion chamber volume that you'll find the reason why the PM7/P29's make so much more compression. The ZC's combustion chamber volume is 43.5cc to the A6's 38cc. This, combined with a bigger piston-to-deck gap, leaves a whole lot of room that needs to be filled up for the ZC to show similar compression to the A6. Honda took care of this by endowing the ZC with its legendary 7.2cc domed pistons. The A6, however, got stuck with a set of -3.4cc dished pistons. The difference in the piston crowns (10.6cc) is enough to make a 43.5cc chamber and a 38cc chamber put out approximately the same compression.
Now, with this knowledge fresh in your mind, what happens when we put a set of 7.2cc-domed pistons in a 38cc chamber? The compression goes up, way up actually, to about 11.3:1. Check out the budget D-series build we did in the May '06 issue of HT (p. 60) for more info on a build like this.
I just bought a wideband O2 sensor and I'm not exactly sure how to hook it up. Do I leave the stock narrowband in its bung and add another for the wideband? Do I get rid of the narrowband altogether? Wouldn't that throw a check engine code?
There are a few ways you can go about this depending on which wideband controller you are using along with your engine management tools.
If you're running a stock ECU, you have two options. The first is to use both O2 sensors simultaneously. The wideband would be used only for readout purposes and the narrowband would be used for ECU input. The other option would be a narrowband output on your wideband controller. Most wideband controllers have two analog outputs; one is a 0-5 volt output for wideband and one is a 0-1v output for narrowband. The Innovate Motorsports wideband controller we use actually has programmable outputs to do with what you please. In the case of a stock ECU, you'll want to run the narrowband 0-1v output into the ECU and the 0-5v output into your wideband gauge. This would negate the need for two O2 sensors.
The thing is, since you are installing a wideband, you're probably not using a stock ECU, and if you are, it's surely modified. If you couldn't tune with your ECU, what need would you have for a wideband?
If you're running a chipped stock ECU, the software used to chip the ECU will almost always be able to disable the O2 sensor making the narrowband input unnecessary. Aftermarket engine management systems like the AEM EMS will usually be able to accept wideband inputs anyway, so if you're running one of those you've got nothing to worry about.
I personally run an Innovate wideband acting as my wideband and my narrowband with my Hondata S300. So if you're asking what I would do, there's your answer.
How do I get my shift linkage off? I took the bolt off of one side, but I can't seem to figure out how to get the other side off. There is a little pin or something like that holding it on-does it come out?
This pin is the archenemy of every Honda guy on the planet. I don't know one guy who has ever done an engine swap in a Civic or Integra that hasn't cursed this pin to hell for being the most stubborn part on the whole car.
I've seen many a tool used to try and press this pin out, the most prominent of which is a Phillips screwdriver. Unfortunately, the pin is hollow, so it will usually get pretty mangled by the 4 sharp points of a male Phillips head. A viable option for the budget-minded Honda enthusiast is an appropriately sized Allen wrench. This method works well because the Allen has more surface area than a screwdriver does. But if you hit the Allen wrench on the wrong side of its 90-degree angle, you'll end up with a pancake for a thumb.
The correct way to do this is to use a punch. There are punches out there made specifically for this purpose that can be ordered through a Honda dealership or one of the major tool companies (anybody with a tool truck). These babies push the pin right out, no hassle whatsoever, and they're only about $30. Buy one and save yourself the headaches.
I've been thinking about swapping my '99 Si's stock B16A oil pump with Type R oil pump. Will it work with my block?
Fountain Valley, CA
The answer is yes, you can put an ITR oil pump on your Si's block, but it is a waste of time and money. All OBD-2 B-series VTEC oil pumps are identical, meaning the oil pump on your B16 IS an ITR oil pump.
If you're having a problem with oil starvation, there are other things you should be looking at. The most obvious is your oil level. Obviously, if your motor doesn't have any oil in it, or is low on oil, or burns oil, you'll starve for oil under load.
Assuming you have oil in the motor and you're still having problems with oil starvation, you'll want to consider a baffled oil pan. Without baffles, hard g-loads, like drag launches and banked turns, can push all of the oil to one side of the oil pan, leaving the pickup area dry and your motor starving. A baffled pan has plates welded in it to keep oil in the pickup area so it will always be there when it's needed.
If you're running a baffled pan and you're still having problems, the next step would be an Accusump. An Accusump is a pressurized reservoir of oil that acts as a buffer in the case of brief oil starvation. If the oil pressure in the motor drops below that of the Accusump, the oil in the tank will be fed into the motor.
The last step would be a dry sump system, which keeps the oil in an external reservoir and pumps and scavenges via an external pump. This is the way to go if you've got the cash and you're building a crazy race car, but most of us don't, so we'll stick to baffled pans and Accusumps.
I just finished assembling my N/A GSR motor build, and after running it for a while, my timing belt has moved about a quarter of an inch off of the cam gears. Is this a problem? The timing is still correct but the placement of the belt scares me. Could it be the aftermarket gears?
I remember the first time I encountered this problem. I had just finished building my first B-series (a turbo GSR) after having done D-series motors for a few years. When we got it done and broke it in, the belt had moved off the cam gears. I flipped out. I had never seen anything like this happen and I just knew it was something that I had overlooked, even though my buddy (who owned the motor) swore up and down that it was OK and he'd seen it "a bunch of times."
After pulling the motor back out and getting it on the engine stand, I took off all of the timing covers and pulled the belt off. Everything looked OK, so we put it right back together, put the motor back in the car and continued with the break-in period. In about 10 minutes, the belt had moved right back into place. Now my buddy's argument seemed a little more convincing, but I was still wary, so to his discontent, we pulled the motor one last time and checked everything out.
After digging around, looking extensively (in all the wrong places) for the culprit, I was about to give up. I then realized that I had neglected to put the second belt locator washer after the timing gear on the crank. I re-installed the washer, gear, belt, covers, and crank pulley, started her up, and she's still running today. Hmm, I'll bet she needs a timing belt change after all those years-this time, I'll remember both washers.
Tip Of The Hat
I just bought some new coilovers for my Integra, but they were not what I was expecting. They came with just a shock, a threaded spring mount, and a spring. Do I have to use my stock tops? How do I take them off the stock suspension? What about putting them back on?
Most entry-level coilovers will come without the upper spring perch or top hat. High-end race setups will usually come with a uniball-type mount, but that isn't until you get near the $2,000 range
Any time you remove the top hats from suspension you should be very careful. Going about this the wrong way can send a spring coil across the shop, or worse yet, into your assistant's face. A projectile spring or damper can seriously hurt or kill somebody, so do it right.
First, get yourself a set of spring compressors from your local auto parts store. Here in California (and probably the rest of the country), Autozone will rent you the tool for free, so you have no excuse not to use one. The spring compressor grabs onto two coils of the spring, and as you tighten the compressor the coils pack together, leaving room on top to get the top hat off without any preload on it.
If you can, use the compressor to put the new springs on the coilovers. Unfortunately, most linear springs are so closely wound that they cannot receive the grips of the compressor. In this case, thread the spring perch all the way down until it is locked at the lowest setting it can get to. Install the spring and the top hat, and then thread the perch back up to your desired ride height position.
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