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193 Posts
Discussion Starter #1
Here are some manuals I have found online. Thought they might help someone out there.

This thread is for online Honda .pdf manuals and links to pages that have other related info.
88-91 Civic Service manual in .pdf
92-95 Civic 5G (92-95)/
96-98 Civic
This link is from the same site but it has listings for crx's 1st-4th gen. (or something like that)and the 5gen civic from above all in .pdf
Place has alot of manuals. Great site too. The manuals are in English. Site is mostly in Spanish.

# ACCORD Workshop Manual (1991-1993)
# CIVIC Workshop Manual (1984-1987)
# CIVIC Workshop Manual (1995-1997)
# CONCERTO Workshop Manual (1990-1994)
# CRX Workshop Manual (1988-1991)
# CRX Workshop Manual (1988-1991) - (PDF)
# CRX VTEC (i-VT / SIR) Manual (1989-1991) - (PDF)
# PRELUDE Workshop Manual (1988-1990)

Integra manual:
http://ftp://g2ic:[email protected]/Acura-Integra-G2.pdf

7th Gen D17A2 (EX) ENGINE BLOCK OIL PAN Diagram
6th Gen D16Y8 (EX) Intake Manifold
6th Gen D16Y8 (EX) Crank and Piston Set
6th Gen D16Y8 (EX) and B16A (Si, del Sol DOHC VTEC)Valve Cover

more links:

Heres some Helms pages. Vacuum Diagrams for the 92-95 b7 and z6.

Not .pdf but more info.
Honda Wiring Diagrams:

Some of this info might be somewhere else on but I figure while your here.

These people have written some good info. so I thought I would share the booty of knowledge.

DIY Valve adjustment on a cx (8valve):

Here's a little something for the ZC owners

"Haynes Service and Repair Manual - Rover 216 & 416

The DOHC ZC came stock in a couple of Rover products which were sold only in the UK. This is the EXACT same engine as the popular JDM ZC which people are installing in their CRXs today."

Part numbers list for the ZC.

87 Civic Sedan/HB/Wagon Factory Service Manual

90 Acura Integra Factory Service Manual

1G CRX Microfilm Diagrams

989-000 Supercharger Kit - Civic, CRX Si only 88-91
989-100 Supercharger Kit - Civic, Del Sol 92-95
989-110 Supercharger Kit - ZC 88-98
989-200 Supercharger Kit - Civic 1.6L SOHC VTEC 96-98
989-201 Supercharger Kit - Civic EX 99-00
989-210 Supercharger Kit - Civic CX, DX, LX 96-00
989-250 Supercharger Kit - Civic Si 99-00
989-300 Supercharger Kit - Civic Si 02-03

989-035 Boost Upgrade - CRX Si 88-91
989-135 Boost Upgrade - Civic 92-95
989-235 Boost Upgrade - Civic 96-00
989-275 JR Boost Timing Control
989-755 JR MAP Controller
902-116 Oil Cooler Kit - SOHC 92-00
989-220 Short Shifter Kit - Civic 88-00
989-750 VPAC

193 Posts
Discussion Starter #2
Head I.D. numbers

Here's some info I accumulated while the sight was down:

Thought I would start a thread to list head id #'s for the D-series. Please contribute your numbers to help other members out. Also, If I have made any mistakes please let me know. Send Engine type, Year, & Head Casting number.

D15b2- PM3 DX
D15b6- PM8 CX
D15b7- PM9 DX
D15b8- PM8 CX
D15z1- PO7 VX
D16a6- PM3 Si
D16z6- PO8 EX
D16y5- PJ2 VX
D16y7- P2F DX
D16y8- P2J EX
D16b5- ??? * GX

* Still needed

Numbers coming after the first three digits are possibly cam types.
For now, I will leave up only the first 3 digits (ie16y7- P2F) of the head casting #'s. As soon as I can get more info in the next few days I will add any relevant numbers coming after the first 3 digits.
For example, on my D16y7-P2F the complete series of #'s is actually P2F-HA-3 .

*Engine/ IV/EV/cc/cr

D16A1 30mm 27mm 43.8 9.5:1
D16A6 29mm 25mm 38 9:1
D15B1 29mm 25mm 38 9.2:1
D15B2 29mm 25mm 38 9.2:1
D15B8 29mm 25mm 38.2 9.1:1
D15Z1 27.5mm 23.5mm 25.3 9.3:1
D15B7 29mm 25mm 38 9.2:1
D16Z6 30mm 26mm 34.6 9.2:1
D16Y5 30mm 26mm 32.8 9.4:1
D16Y7 30mm 26mm 34.6 9.4:1
D16Y8 30mm 26mm 32.8 9.6:1

*Engine & Chasis codes :

'88-'89 Integra 1.6 D16A1 DA_
'88-'91 Civic 1.5 Wagon 2WD D15B2 EE2,EY3
'88-'91 Civic 1.6 Wagon 4WD D16A6 EE4_
'88-'91 CRX 1.5 DX D15B2 ED8_
'88-'91 CRX 1.5 HF D15B6 ED836
'88-'91 CRX 1.6 Si D16A6 ED936
'90-'91 Civic 1.6 EX 4dr D16A6 ED4
'88-'91 Civic 1.5 3Dr/4Dr D15B_ ED_
'92-'95 Civic 1.5 CX/DX/LX D15B_
'96-'00 Civic 1.6 CX/DX/LX D16Y7 EJ6_
'93-'95 Del Sol 1.5 S D15B7 EG1_
'93-'95 Del Sol 1.6 Si SOHC D16Z6 EH6_
'96-'97 Del Sol 1.6 S D16Y7 EH6_
'96-'97 Del Sol 1.6 Si SOHC D16Y8 EH6_
'90-'91 Civic 1.6 EX 4Dr D16A6 ED4_
'92-'95 Civic 1.6 EX/EX-S D16Z6 EH9,EJ1
'96-'00 Civic 1.6 EX D16Y8 EJ8_
'98-'00 Civic 1.6 GX D16B5 EN164
'96-'00 Civic 1.6 HX 2Dr D16Y5 EJ7_
'89-'91 Civic 1.6 Si 3Dr D16A6 ED736
'92-'95 Civic 1.6 Si 3Dr D16Z6 EH33_
'92-'95 Civic 1.5 VX 3Dr D15Z1 EH23_

1488(1.5) 1984-1987 Civic/EW1 Engine/HON1.5-PEO PEO
1488(1.5) 1985-1987 Civic - F1/12 Valve EW1 Engine/HON1.5-PEO1 PEO
1488(1.5) 1984-1987 CRX /8 Valve Roller rocker arms/HON1.5-PEO2 PEO
1493(1.5) 1988-1995 Civic,CRX/D15 Engine/HON1.5-PM PM
1590(1.6) 1992-1995 VTEC/D16Z6 Engine/HON1.6-PO PO
These could be of use.

Hope it helps someone out.

Found this interesting. Gives bore sizes.

And heres something cool:
Specs for Selected Hondas models in Japan
DA-series Honda Integra Specifications (1989-1995)

D16A1 FI DOHC 1590cc


Model Model/Type Year Size
Eng. Type E/Type Disp. Bore


D16A1 FI DOHC 1590cc


ACCORD 76-78
EF Carb. SOHC 1599cc

CIVIC 74-79
EB-2~3 Carb. SOHC 1237cc

ED-3~4 Carb. SOHC 1488cc

CIVIC 80-83
EJ-1 Carb. SOHC 4 PORTS 1335cc

CIVIC 80-83
EM Carb. SOHC 1488cc

CIVIC 84-87
EV-1 Carb. SOHC 1342cc

CIVIC 84-87
EW-1 Carb. SOHC 12 Valve 1488cc

CIVIC Si 86-87
EW-3/4 FI SOHC 12 Valve 1488cc

CIVIC 88-91
D15B1/B2 FI SOHC 16 Valve 1493cc

CIVIC Si 88-91
D16A6 FI SOHC 16 Valve 1590cc

CIVIC 89-91
D15B6 FI SOHC 8 Valve 1493cc

CIVIC 92-95
D15B7 FI SOHC 16 Valve 1493cc

D15Z1 FI SOHC 16 Valve 1493cc

CIVIC 92-95
D15B8 FI SOHC 8 Valve 1493cc

D16Z6 FI SOHC 16 Valve 1590cc

CIVIC 93-95
D15B7 FI SOHC 16 Valve 1493cc

CRX 84
EV-1 Carb. SOHC 1342cc

CRX DX, HF 84-87
EW-1 Carb. SOHC 12 Valve 1488cc

CRX Si 85
EW-3/4 FI SOHC 12 Valve 1488cc

CRX HF 88-91
D15B6 FI SOHC 8 Valve 1493cc

CRX 88-91
D15B1/B2 FI SOHC 16 Valve 1590cc

CRX Si 88-91
D16A6 FI SOHC 16 Valve 1590cc

CRX 93-95
D15B7 FI SOHC 16 Valve 1493cc

del SOL S 92-95
D15B7 FI SOHC 16 Valve 1493cc

del SOL S Si 92-95
D16Z6 FI SOHC 16 Valve 1590cc

del SOL 94-97
D16A2/A3 FI SOHC 16 Valve 1590cc

del SOL 96-97
D16Y7 FI SOHC 16 Valve 1590cc

del SOL Si 96-97
D16Y8 FI SOHC 16 Valve 1590cc

5,217 Posts
useless info

Connecting rod info:

Engine Designation, Stroke, Con-Rod Length, R/S Ratio

D16A1,A6,Z6,Y5,Y7,Y8 90mm 137mm 1.52
D15B1,B2,B8,B7 84.5mm 134mm 1.59
D15Z1,D15B VTEC 84.5 137mm 1.62

Throttle body size

Designation, Size (in mm):

b16a SiR-58
b16a Sir2 / b16a2 / b16a3-60
h22a / h23a-62
f22 / f23-60

Oil pumps

D16A6 Oil pump flows 46.4 qt/[email protected]
D16Z6 Oil pump flows 47.6 qt/[email protected]
D16Y8 Oil pump flows 35.3 qt/[email protected]

Compression ratios

Head + Pistons = Compression
Z6 Z6------------9.2
Z6 Y8------------9.27
Z6 A6------------9.7
Z6 ZC------------11.58
Z6 86-87 A1------11.27
Z6 88-89 A1------11.58
Y8 Z6------------9.51
Y8 Y8------------9.6
Y8 A6------------10.06
Y8 ZC------------12.11
Y8 86-87 A1------11.77
Y8 88-89 A1------12.11
A6 Z6------------8.66
A6 Y8------------8.73
A6 A6------------9.1
A6 ZC------------10.7
A6 86-87 A1-----10.44
A6 88-89 A1-----10.7
A1 Z6------------7.89
A1 Y8------------7.94
A1 A6------------8.24
A1 ZC------------9.5
A1 86-87 A1------9.3
A1 88-89 A1-----9.5
ZC Z6------------7.89
ZC Y8------------7.94
ZC A6------------8.24
ZC ZC------------9.5
ZC 86-87 A1------9.3
ZC 88-89 A1------9.5

193 Posts
Discussion Starter #6
D-series Camshaft removal
D15b1/b2/b7, D16a6 Rocker arm bolt sequence for removing the camshaft.:
D15z1, D16z6 Rocker arm bolt sequence for removing the camshaft.:
D16y5,7,8 96-98 Cam removal
Valve adjustment/inspection for D16y7, D16y8

D16 Camshaft Comparison

How Camshafts Work
by Karim Nice

Online articles dealing with Camshafts
Thanks to:

Cam installation articles:
Engine Tuning: Droppin' ZEX-tasy
We show how to install a cam.
By Import Tuner Staff
If computing camshaft specifications wasn't hard enough, Honda had to toss VTEC cam profiles into the mix. This has made cam designers re-think all that they have learned in order to set up added horsepower in VTEC trim.

ZEX is one such company that has mastered the SOHC VTEC grind. Overshadowed by the mighty DOHC engine, the single-over-head model has always been thought of as an inferior powerplant. ZEX has brought new meaning to the SOHC engine with their new billet camshaft. The company claims that the cam is superior to all other drop-in cams so we decided to give the cam the 2NR torture test..................

Power Tech: Camshafts
Lift your Performance to New Heights
Text Michael Ferrara

Among all the components that make up an engine, the camshaft plays the most significant role in determining the behavior and character of the engine. As for the engine's behavior, most OEM camshafts offer idles that are smooth and polished. A radical aftermarket full-race camshaft may produce an idle that is rough and raw. As for character, one camshaft may regulate an engine to produce massive low-end torque, while a different camshaft in that same engine may soften up the power production at the low end while allowing the engine to pull strong up to redline. Understanding the function, design, and limitations of the camshaft will allow you to maximize your performance experience.

Function of the Camshaft

The four-stroke process that occurs in your car's engine is as follows: intake, compression, power, exhaust. While the crankshaft's position, crankshaft's stroke and rod length ultimately determine where the piston will be in the cylinder at any given degree of rotation, it's the camshaft that determines the position of the intake and exhaust valve during all four strokes. An engine's camshaft(s) is/are responsible for the valve timing in the engine. Proper valve timing is critical for any four-stroke automotive engine to operate at maximum efficiency. When the valves open, how high the valves open (lift), and for how long they stay open (duration) all determine the performance characteristics of the engine. In the performance symphony, the camshaft is the conductor of valve events. It orchestrates which instruments play (intake or exhaust valves), when they play (opening and closing events) and how loud they play (valve lift). Whereas OEM conductors (cams) offer a classical sound, aftermarket cams can really make your engine rock.

The Band of Power
As mentioned earlier, the camshaft will determine an engine's character. The engine's character in terms of power production is often termed the "powerband." Where does the engine begin to make power? Where does the engine begin to fall off in power production? Is the power delivery flat and consistent or aggressive and peaky? These questions are answered in the description and understanding of the engine's powerband. Some powerbands are narrow, while other are deemed broad. Some are peaky, some are flat. An engine that makes appreciable power from only 6000 to 8000 rpm (a range of 2000 rpm) would be considered to have a narrow powerband. A comparable-sized engine that makes power from 3000 to 7000rpm (a range of 4000 rpm) might be considered to have a broad powerband. More so than any other internal components of the engine, the camshaft and its complimentary valvetrain components will establish the powerband of the engine.

The Ideal Cam
So how do you get the perfect cam? The cam that has tremendous low-end torque, a 10,000 rpm redline, an idle like mom's car and a powerband from idle to redline doesn't exist. Fortunately, an aftermarket performance camshaft that optimizes the rest of your performance combination to provide the performance that you desire probably does exist. Dollar for dollar there is a good chance that aftermarket cam(s) may be the best performance investment that you make.

Lift, Lobes and Symmetry
For every action, there is always a reaction. From a performance standpoint, the faster a valve opens and reaches full-lift, the better. Why? Horsepower is directly related to how much air and fuel can be stuffed into the cylinder. Air and fuel can't get into the cylinder unless the valves are open. Camshafts that quickly open the valves are said to have an aggressive lobe profile. Unfortunately, the laws of physics govern the maximum amount of possible valve acceleration or "aggressiveness." If the camshaft profile tries to accelerate the valve too fast, excessive wear or valvetrain problems can occur. When returning a valve to its seat, a camshaft once again cannot do this too fast or the valve slams into the valve seat (sometimes valves even bounce off the seat). Most modern cam designs optimize valve acceleration rates by designing camshafts with asymmetric lobes. This style of lobe lifts the valve faster than it lowers the valve. Quite simply, asymmetric lobe designs can be utilized to maximize the performance available while increasing the durability of the valvetrain.

Types of Engines
There are two basic styles of piston engines in production today, the overhead-valve engine (OHV) and the overhead-cam engine (OHC). Overhead valve engines rely on valve lifters, pushrods, rocker arms and a camshaft which rests in the engine's cylinder block. Examples of OHV engines include most of the domestic V8 and V6 engines manufactured over the last 50 years.

Knowing the Specs
Since we have already explored the basics of camshafts, we will now attempt to unlock the mysteries surrounding camshaft specifications. Since the camshaft(s) influence when an engine starts making power, when it stops producing power, maximum power output, fuel economy, idle quality, and engine efficiency, it is important to understand camshaft specifications. With this basic understanding, you will be better able to select the camshaft(s) that will keep you ahead of the competition.

Lift and Duration
The basic function of a camshaft is to open and close the engine's valves. On many applications, a single camshaft controls the opening and closing events of all the valves in an engine. Other applications may implement as many as four camshafts to control the valve events. Regardless of the number of cams, the rules that apply for single camshaft engines also apply to those with multiple camshafts. The most well-known camshaft specifications are lift and duration. Most manufacturers give specifications for lift at the valve, instead of at the camshaft. On some applications that don't use a rocker assembly these two lifts may be the same. If you need to convert from lift at the camshaft lobe to lift at the valve, use the following equation.

Valve Lift = Lobe Lift x Cam Follower Ratio

Lift is nothing more than a measurement of the maximum distance the valve is opened. Assuming all other specifications remain the same, choosing a camshaft with more lift will increase the flow of air and fuel into an engine and the flow of exhaust out of an engine. As a result, more power can be made. In many cases, camshafts that have increased lifts over stock specifications and near stock duration will offer increased performance without making measurable sacrifices in "driveability". Everything has a limit and cylinder heads will generally reach a point where airflow no longer increases with an increase in valve lift. Before you order that mega-lift cam, please consider the following: when valve lift is dramatically increased, the possibility of valve to-piston contact, coil bind at the valve spring and valvetrain interference is also increased. To avoid bent valves, broken retainers and thin wallets, always use the necessary complimentary valvetrain components and check valve-to-piston clearance when recommended by the camshaft manufacturer.

193 Posts
Discussion Starter #7
Along with how high a valve is opened, how long it remains open also influences the performance of an engine. If you are trying to fill a glass at the sink, how much you open the faucet or valve, as well as how long you have that valve open will determine how much water fills the glass. How long you keep the faucet turned on is a simple measure of duration. The duration specification of a camshaft is measured in crankshaft degrees of which there are 720 in one complete four-stroke cycle. However, the problem with camshaft duration figures is that different manufacturers measure this duration at different valve lifts. The Brand-A manufacturer might measure duration as soon as the valve is lifted .015 of an inch off its seat until it returns to the same lift, while the Brand-C manufacturer might not start measuring until the valve is .050 inch off the seat. The result is that if we had both companies measure the same camshaft, Company-A might measure 306 degrees of duration (measuring at a minimum lift of .015"), while Company-C would measure 256 degrees of duration (measuring at .050"). In essence we have two completely different numbers for the same camshaft. Luckily, most camshaft manufacturers now provide duration figures at either a minimum lift of 1mm (Japan's industry standard measure) or a minimum lift of .050" (the traditional U.S. hot rod standard). When duration comparisons between two camshafts are being made, only compare the figures if the measurements have been taken at the same minimum lift.

Duration and Power
More lift translates into more power and torque across the powerband for most cases. In general, increased duration will shift the torque and horsepower peak to a higher rpm. All other specifications being the same, increasing duration yields more top-end and mid-range power while sacrificing low-end torque. As a result of the shifting of the powerband upstairs to higher rpms, a longer duration camshaft, when used with the appropriate valvetrain components, will also raise an engine's redline. One rule of thumb is that every 10 degree increase in duration (measured at 1mm or .050") will shift the torque peak and redline up by 500 rpm.

A Closer Look-Valve Timing
Believe it or not the explanation of lift and duration has been somewhat simplified. If we only look at lift and duration, we only know how high a valve is lifted and for how long. What lift and duration fail to tell us is when the valves are opened and closed. If we know that the complete four-stroke cycle contains 720 degrees of crankshaft rotation and the intake stroke (when the piston moves down the cylinder when the intake valve is open) makes up one-fourth of the cycle, we easily deduce that the theoretical duration of the intake cycle is 180 degrees (one-fourth of 720). If we could instantaneously open the intake valve at TDC (the beginning of the intake stroke) and have the intake charge immediately start flowing into the cylinder until the piston was at BDC (the end of the intake stroke, 180 degrees later) where the intake valve would instantaneously slam shut, we might have an engine that would run well with only 180 degrees of intake duration.

Early Intake Valve Opening
In practice, there are many advantages to opening the intake valve early and closing it late. By initiating the opening the intake valve early, the intake valve has time to get to a lift where appreciable flow will begin. On a well-designed cylinder head teamed with a free-flowing exhaust, the pressure in the cylinder when the valve is opened early may be lower than atmospheric, so the intake charge actually gets sucked in (in practice, the exhaust valve is still open when the intake valve begins to open). The benefits of early intake valve opening are very rpm dependent. At low engine speeds, extremely early intake valve opening may cause exhaust gases to be sucked into the intake manifold causing erratic idle and other problems. At higher engine speeds, this same amount of early intake valve opening will have no adverse effects since the intake manifold is not operating under a vacuum condition.

Late Intake Valve Closing
Now that we understand why we need to open the intake valve early, let's take a close look at the closing of the intake valve. The reason we leave the intake valve open past Bottom Dead Center (BDC) is inertia: objects at rest tend to stay at rest, objects (or a mass of air in the case) in motion tend to stay in motion. Since we have an intake charge in motion we can experience additional filling of the cylinder while the piston dwells (or remains in place) at the bottom of its stroke at BDC. On engine with high rod length-to-stroke ratios, the piston may dwell around BDC for 20 degrees of crank rotation before the piston starts to move up the cylinder. During this time the flowing intake charge continues to fill the cylinder. If the intake valve closes too late, the piston may pump some of the intake charge out of the cylinder through the intake valve and back into the intake manifold. This reverse flow is obviously undesirable. As you may have guessed, the optimum closing of the intake valve is also very rpm dependent.

Exhaust Valve Open Early
Since we have a good understanding of the intake side out the equation let's take a look at the exhaust side. The major difference in dealing with the exhaust side is that the average pressure in the cylinder is probably more than six times the average pressure during the intake cycle. This makes the task of releasing the exhaust gases easier than trying to get the intake charge into the cylinder. During the power stroke, the majority of horsepower is generated during the first 90 degrees or first half of this 180 degree cycle. This being the case, opening the exhaust valve early has little effect on killing power. In fact, power is usually increased since the residual pressure is released from the cylinder so the piston doesn't work as hard to push the remaining gases out when it begins its upward movement on the exhaust stroke.

Exhaust Valve Closing Late
Keeping the exhaust valve open after TDC can also have benefits. If the exhaust valve is kept open after TDC, the intake valve will also be open at the same time. When both intake and exhaust valves are open at the same time, it is termed valve overlap. The ideal amount of overlap depends on rpm. Higher rpms tolerate more overlap and the intake charge can be drawn into the cylinder due to the draft caused by the exhaust gases leaving the cylinder. When overlap gets excessive, exhaust gas can make its way into the intake manifold, diluting the intake charge. A diluted intake charge limits power production, so a careful balance must always be struck.

The Bottom Line
A camshaft may look simple, but its job is no easy task. Understanding the function, design and limitations of aftermarket cams will allow you to make educated decisions about getting the right cam(s) for your car. Remember to rely on the experts. The wealth of knowledge that the major cam companies possess is incredible. While it is great to have an understanding of cams, there are enough self-proclaimed engineers in the world. Nine times out of ten, the specialist at the cam company will know more than you (that's his or her job). The value of your performance education is identifying the one out of ten instances that you may encounter. As always, remember to consider that the camshaft(s) are just one element of the performance combination. All of the parts in the combination need to work together to produce the maximum in power and reliability. Camshafts will only do there job effectively when complimented with the correct valvetrain component. Installation of the camshaft and complimentary valvetrain components must also be done correctly. Failure to do so will result in a loss of performance and the potential for component damage.

VTEC: Powerband Optimizer

Many bad explanations of the VTEC advantage have been given in the past. The advantage is simple: VTEC allows the engine to perform as if the cams were switched to a different profile at a set rpm. The low profile can optimize idle, meet emissions and provide good bottom-end torque. The high-profile lifts the valves higher and opens the valves longer to improve power at higher rpms.

VTEC does not allow for higher peak power to be made. If a set of non-VTEC cams were ground to match the VTEC high-lobe profile the same power would be made. However, the Non-VTEC cam would not have near the performance of the VTEC cam at lower rpms. Driveability, fuel efficiency and idle quality would all suffer.

The end performance result of VTEC technology is an engine that has an incredible broad powerband.
Related Diagrams:

193 Posts
Discussion Starter #8
Cam installation
This is a step-by-step procedure on how to install a cam.

Tools you will need are:

1) 12mm and 10mm socket
2) 12mm wrench
3) socket wrench and extensions
4) car jack
5) timing light
6) torque wrench
7) break-in lube grease
8.) feeler gauge, and flat screw-driver
9) Car's Handbook


First, loosen up the driver-side wheel lug nuts, and lift the car on a jack stand...
Then remove the wheel, and position engine's #1 piston at TDC.

Now remove the head valve cover bolts with a 10mm wrench or socket. Loosen up the bolts in a cross pattern. And remove the cover..

Remove the belt cover, (with the belt tensioned) Loosen up the cam gear bolt using a 12mm wrench. (turn counter-clockwise)

Using the 12mm and 10mm sockets and a socket wrench with extension, loosen up the bearing cap bolts in reverse of their tightening sequence... Loosen the bolts a 1/4 turn at a time, until you can turn them by hand... Then just loosen until they can be pulled, but do not remove them...

Now, loosen the belt tensioner and slip the belt off the cam gear. (dont pry the belt off the gear, just use your fingers to slide it off.) Since you'll be reusing the belt, Mark the relation of the belt and the cam gear, to ease on reinstall.

Loosen the distributor bolts with a 12mm wrench, and remove it. (place rags below to catch any oil that will come out).

Now, remove the vtec motion assembly along with the bolts... And/Or remove the bearing cap assembly...
Put these parts aside in a clean place, and wrap a rubber-band around the vtec rocker-arms to prevent any complications on reinstall later on...

The camshaft should be visible now. Just remove it out of the head, holding it for the cam gear and the other (dizzy) end. Place on a clean area, and remove the cam gear, cam key, and oil seal. Those will be re-used..

Next. Get your new camshaft and place the cam-key on the key slot. Place the cam gear over the cam, and slide the gear into place... (If you need to tap it in, use a rubber hammer. Dont use anything that would damage the surface of the cam gear.) Make sure the gear and cam key, are going in smoothly. If not, remove and retry again...

Now that your got your new camshaft ready to install. You need to apply break-in lube to prevent any damage during start-up. You can use any aftermarket brake-in lube, moly-base grease, lithium grease, or if your cam came with one you can use that too... Use the one that best works for you.

You want to cover the whole cam journals and bearings with the lube. Make sure everything gets well coated...

Now place the new cam gently over the head, and into place... If you feel you need to apply more lube, do it now.
turn the cam gear at TDC direction, and slip the belt back into place (do not tighten yet)...

Place the bearing caps back over the camshaft, followed by the vtec motion assembly and bolts... (if you need to clean anything, use lint-free cloths. Dont place your fingers in any of the bearing surfaces or cam lobes)

Make sure everything lines up where it's supposed to. Re-check everything twice. look that the rocker arms line up right towards their designated cam lobe, and that everything fits and looks ok...
Now that you checked everything, remove the rubber-bands holding the vtec rocker arm assembly.

Tighten down the bolts in their tightening sequence. First snug them down, and then turn them 1/4 of a turn at a time until you're ready to torque them...
Torque the 6mm bolts at 16lbs... (or at car specs)
The 8mm ones just arm tightened will do.

Reinstall the distributor, and tighten the belt tensioner (make sure the belt lines up with the cam marks you made earlier, or that is at TDC).
Now that the belt is tighened, torque down the cam gear bolt...
Turn the engine two full cycles and see that everything lines up right.
Now you're ready to do your valve lash... (check your handbook or this site for direction on how to do valve lash)

193 Posts
Discussion Starter #10
Volumetric Efficiency

Does this sound correct?

Air Capacity (cfm): Since an engine is actually little more than an elaborate air pump, it’s ability to perform work—measured in horsepower and torque—is a product of its capacity to inhale and exhale air. An engine’s theoretical air capacity is a product of its rpm and displacement, divided by two (since only half of the engine’s cubic capacity is being displaced during each stroke). For purposes of rating airflow (i.e. via a carburetor), this formula is converted to a quotient reflecting cubic feet per minute (cfm) by dividing both sides of the equation by 1,728, the number of cubic inches in a cubic foot. The reduced formula for cfm:

Rpm x displacement

Note: To convert CC to inches times the CC by 0.0610237441

Volumetric Efficiency: How efficiently an engine actually pumps air, compared to its air capacity (as calculated above) determines its volumetric efficiency. Theoretically, an engine’s maximum efficiency is highest at its torque peak. This can be determined by a chassis dyno. Actual airflow, on the other hand, must be determined with an airflow meter. The relationship between the actual and the theoretical (times 100) is the engine’s true volumetric efficiency or:

Airflow cfm x 100
.....Rated cfm

Volumetric efficiency has a lot to do with performance. Gains in volumetric efficiency has a lot to do with performance. Gains in volumetric efficiency—by turbocharging, supercharging, or intercooling, for example—result in greater output.

Let’s say a D16Z6 engine with a displacement of 97 cubic inches (1590cc) produces its maximum torque at 7,000 rpm, Using the formula mentioned earlier, the engine’s theoretical cfm is :

97 x 7,000 = 196

Now let’s say the engine’s actual measured airflow at 3,500 rpm turns out to be 80 cfm. Volumetric efficiency, expressed as a percentage of theoretical capacity, can be calculated as:

150 x 100 = 76.5 (percent)

Why Horsepower is Calculated At Sea Level:

An important factor in figuring volumetric efficiency is elevation relative to sea level, at which the engine is operating. As elevation rises, oxygen levels are reduced, reducing an engine’s volumetric efficiency. The typical drop in horsepower at any rpm level is approximately three percent per 1,000 feet of elevation. To figure how much horsepower you’ve lost at a specific elevation, use the formula:

Elevation (ft.) x .03 x hp at sea level

Example: The D16Z6 produces 125 horsepower at 6,600 rpm at sea level. At 5,000 feet, that engine’s output loss—suffering from RVES (reduced volumetric efficiency syndrome) –can be calculated as:

5,000 x 0.03 x 125 = 19 horsepower

At 5,000 feet, this engine is now producing only 106 horsepower at 6,600 rpm. At 10,000 feet, the same engine is capable of producing only 87 horsepower at 6,600 rpm.

If you see any mistakes let me know.
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