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4,377 Posts
Discussion Starter · #1 · (Edited)
Maybe this will help with those trying to see what is involved in swapping a D-series head, or use it as good reference material while doing a swap.
Mini-me Compression #'s
Thanks to HondaTuning
and pee_wee

Z6 /Z6 Block - 9.13:1
Z6 /y8 Block - 9.21:1
Z6 /A6 Block - 9.95:1
Z6 / ZC Block - 12.03:1
Z6 / D15 - 10.10:1
Z6 / Y7 - 9.62:1

Y8 / Z6 - 9.45:1
Y8 / Y8 - 9.61:1
Y8 / A6 - 10.33:1
Y8 / ZC - 12.61:1
Y8 / D15 - 10.52:1
Y8 / Y7 - 9.96:1

Threads from our members:
D16Y7/Y8 MINI-ME WRITE UP (56k, maybe not)

This is a write-up of my y7/y8 mini me. done Bauleycivic style, though with less detail.

This swap was performed using a 1996 D16Y8 head which was mated onto a 1997 D16y7 block. I also swapped my pistons and rods for those from an 89-91 D16A6 for more compression.

pictures of my particular y8 head:

What you need to buy:
New coolant and oil
d16y8 head
d16y8 head gasket
new head bolts

1. drain the engine of coolant and engine oil
2. disconnect all coolant hoses, sensors, throttle cable, exhaust manifold and bracing from the y7 head (leave the y7 intake manifold attached--it makes the head easier to lift)
3. remove the spark plug wires and valve cover from the y7 head
4. unbolt the distributor from the head, and lay it aside, it's unnecessary to remove the dizzy from the engine bay
5. remove the 10 head bolts
6. double-check to make sure nothing else is still attached to the head, and then remove it from the block

now make sure the block is nice and clean, and if you are going to replace your internals like me, this is the time to do it, just drop the oil pan, and remove the rod bolts and pop the pistons out of the top of the block.

oh yeah, next time you hear someone talk about the bottom end of a d-series being unstable, take off the oil pan of a y7 and you'll notice a solid piece of aluminum, at least 3 inches wide tying the main caps together. :thumbup:

FIRST MAKE SURE THE #1 CYLINDER IS AT TDC by rotating the crank usign the crank pulley bolt and that the cam is adjusted to straight up position.

1. spray the y8 head gasket with copper spray and put it in position, then replace the two spacers in the block.
2. lay the head on the block carefully, making sure everything goes on smoothly
3. torque the head bolts following the factory sequence
4. reattach all of the various sensors, timing belt, coolant and vacuum lines, and whatnot to the new head.

Also, at this time, replace the P2E ECU with the P2P from the EX trim level civic.

NOTE: we did not change the timing belt on my car as it was in near-perfect condition. that is why i have omitted this information from the write-up

Making it all work: this is the tricky part as there are a wires that will need to be either rerouted, spliced, eliminated, or disregarded.

1. The throttle body is a possible point of difficulty, the easiest way is to use the Y8 throttle body and y8 IACV on the head. In order to do this with the y7 wiring harness, you will need to take two spade connectors and connect them to the two prongs on the male side of the IACV connector, the connect these two wires to the three-wire female plug on the y8 wiring harness, being sure to disregard the orange wire. You will need to swap wires A12 and A14, and then disconnect wire A13 from the plug at the ECU.

2. To wire VTEC, you will either need some pigtails or you can just run two wires through the firewall, to the ECU, one coming from the VTEC solenoid and the positive wire from the VTEC pressure sensor. Be sure to ground the negative side of the VTEC pressure sensitive to somewhere on the chassis. Route the VTEC solenoid wire to socket A8 and the pressure sensor to socket C15 (at the ECU)

and i believe that is that!

and here are the pictures:


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4,377 Posts
Discussion Starter · #2 ·
y8 head/IM on a d15b7 block INSTALL NOTES

Ok, I attempted this swap last weekend and I finished up around 10pm. I tried starting the car, but there were problems (wouldn't start). I got really scared because this is my only car and after fooling around with things for a half-hour I decided to put the b7 head back on. I now know what the problem was and to avoid embarrassement I won't say what it was... But I will give you guys a write-up so you can see what to expect in the swap. I will attempt to do it again sometime later when I have time... ok, here's the write-up:

This is for a y8 head/IM/TB on a 94 civic DX sedan (d15b7).

Ok, credit goes to BaileySi (i think his name was) for providing the initial write up for a z6 head on this block. I will list the differences.

1. The b7 distributor WILL work on the y8 head. No need to use the y8 or z6 distributor... one won't fit, the other has different plugs.

2. The throttle cable won't attach properly onto the manifold unless you modify the small bracket it mounts to. A temporary solution which sort of worked for me was to move the bracket over by one bolt to the left and just use the remaining bolt hole to attach it. A little less secure, but like I said... temporary.

3. Intake temperature sensor... just remove it from your old manifold (on the back near the bottom) and let it hang. I can't guarantee it won't give you a bad idle, but at least it won't throw a code.

4. Purge control solenoid - located on the back/right of the b7 manifold... or on the fuel rail of the y8 manifold. You'll have to use the old one which has a matching plug to your harness and either mount it to the firewall or just let it hang temporarily. Also, since it uses a SMALLER vacuum line than the y8 one does, I ended up connecting it to the cruise control nipple on the back of the manifold. The larger connection on the front of the manifold will have to be plugged.

5. Fuel rail + fuel pressure regulator - these will have to both come from a y8 or y7 manifold. Your b7 or z6 fuel rail won't work. You won't even be able to drill a hole to try to mount it because it has a divit where the hole needs to be.

6. Fuel line to the fuel pressure regulator - you will need to extend this since the FPR will be on the opposite side. Just buy longer hose.

7. Fuel line to the fuel rail (from the fuel filter) - I tried using the one from my engine (b7) and it doesn't fit properly. The cap that goes on the end doesn't screw onto the fuel rail all the way. I ended up using a large washer in between the fuel line fitting and the cap to take up the slack space. This seemed to work as I wasn't getting any leaks when it was primed. I didn't investigate using the y8 or y7 fuel line and cap since I didn't have one.

8. Use your original fuel injectors... y8 fuel injectors have different plugs.

9. Charcoal canister - my car has three connections coming out of it. The canister designed for the y8 head has only two. My guess was to plug up the line that originally went to the b7 throttle body. The y8 throttle body doesn't have this vacuum connection.

10. MAP sensor - not sure if these need to be swapped but they have different numbers printed on them. i swapped mine just to be sure, but either one will fit your harness.

11. Coolant lines - This one I'm unsure about. The b7 intake manifold has one extra coolant fitting that the y8 im doesn't. I wan't sure about what flows where so I was guessing which line to plug up. However, on the y8 head, there is a large coolant port with a smaller port coming out the top of it. This is located near the VTEC solenoid. I decided to try and plug up the small port. Since my car didn't run for a long period of time, I can't be sure that was the right thing to do.

12. The bracket that supports the manifold against the block will no longer fit if you put the y8 manifold on. I had to remove it in order to get the whole head/manifold to seat well on the block. This MIGHT cause some stress issues for longetivity's sake so you might want to look into getting a new bracket machined to support the manifold's weight. However, my setup fit well so there won't be any immediate problems, if any at all.

Finally, just to confirm the original write-up: I used the y8 timing belt. Worked fine. I removed the oil control jet in the d15 block. I had to use new spark plug cables meant for the y8 head. This is all I could remember... so far.

As you can see, figuring out all this is what took me so long (10pm!! good thing we had an outdoor light to plug in). When I couldn't get it working right, I panicked because I needed my car the next day to pick up my girlfriend from the airport.... but, after careful thought, I know what my mistake was, and it wasn't anything I listed above. (It's got to do with spark plug wire order!!! DAMN!!! spilled the beans!!! I'm so ashamed)

If you need any help email me and I'll try to help if I can. Thanks to everyone on this board for answering all my previous questions!
My car: 94 Civic DX sedan (mostly stock!)
y8 Mini-me coming soon

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4,377 Posts
Discussion Starter · #3 ·
[FAQ] D15 SOHC VTEC Mini-Me: Massive Write Up


Additional Links on Mini-Me's:

Welcome to my D15 SOHC VTEC Mini-Me Writeup!
This is a write-up based on a 1992 D16Z6 head being bolted onto a 1993 Civic LX with a D15B7 block. Like Spade’s SOHC Upgrades thread, this is a continual work in progress. If you are thinking about doing a mini-me swap on your 92-95 Civic using a D16Z6 head, then this is the place to be. I will do a complete walkthrough of the mini-me, including a shopping list of parts, tools needed, how to perform the swap, important things to look out for, what to expect when you finish, and ideas for future modifications. These instructions are for 92-95 Civic D15B7 DX, LX mini-me’s, but most of the stuff can be applied to CX’s and VX’s as well. If you have a question about doing a mini-me on a non-OBD I car, you can PM me and I’ll see if I can help. Well…enough already let’s get to it!

1. What the exactly is a “mini-me”?
A “mini-me” is an informal name for a D-Series SOHC VTEC head mated to a D-Series SOHC non-VTEC block. Most mini-me swaps consist of D16Y8 or D16Z6 heads onto USDM D15B, D16A6, or D16Y7 blocks. JDM D15b VTEC heads will work as well.

2. Why should I do a mini-me swap?
I chose to do a mini-me swap after reading up on them and hearing that they put out a fair amount of power for how cheap they are. It is widely believed that this combination, with a thin D16Y8 head gasket, will produce a near 11:1 CR. However, after calculating the compression using the d-series compression calculator, I only came up with 10.1:1. To bump the compression a few more tenths, you can remove the middle layer from the Y8 head gasket. Theoretically, a stock mini-me with a Y8 head gasket should put out about as much power as a D16Z6, give or take a few horses. The raised compression makes up for the difference in displacement.

2. Okay, what parts do I need to buy?
For a Z6 mini-me swap you’ll need four basic things: a D16Z6 cylinder head (including valve cover, distributor, spark plugs, spark plug wires etc), D16Z6 timing belt, D16Y8 head gasket (D16Z6 works well also, but Y8 is a better, metal gasket) and P28 ECU (make sure you get an auto ECU for an auto, manual for manual).

IMPORTANT: Several places on the net and several people on Honda-Tech say that the VX (D15Z1) timing belt is the one to use for this swap because it is for a 1.5L VTEC. THIS IS INCORRECT! When I did the initial head swap, I used a VX timing belt. The VX timing belt was WAY too tight, and whined when the engine was at high rpm. I unfortunately did not discover this until the entire head was assembled. The VX timing belt has 103 teeth, where as the Z6 timing belt has 104 teeth, and the B7 belt 106 teeth. I was finally able to replace the VX timing belt with the Z6 timing belt, and the Z6 timing belt fit much better and didn’t whine. THE D16Z6 timing belt is the correct belt to use with a B7 block / Z6 head combination.

Note also: The D16Z6 and D15B7 spark plug wires are NOT interchangeable. You will need D16Z6 spark plug wires with this swap. Also, 96-00 Civic HX spark plugs are a bit colder than the Z6 and will work better with the higher compression.

You can use your stock intake and exhaust manifolds with the mini-me. All d-series manifolds are interchangeable. However, both the D16Z6 intake manifold and header flow much better than the D15’s…so if you can pick them up for a real cheap price, then definitely go for it. In addition to the main things, you’ll need little things, coolant and wire (to wire the VTEC solenoid and oil pressure to the ECU).

I however, wanted to make sure that the swap ran perfectly once I got it running so I picked up a few general maintenance things as well, such as a new distributor cap and rotor, new water pump, new spark plug wires, and a new valve cover gasket.

List of Parts:
D16Z6 Cylinder Head (Including distributor cap, valve cover, plugs/wires, VTEC solenoid, etc)
D16Z6 or D16Y8 Head Gasket
D16Z6 Timing Belt
Wire and plug for VTEC oil pressure switch

D16Z6 Intake Manifold
D16Z6 Exhaust Manifold
*If you remove your manifolds, make sure you get new gaskets

Water Pump (for the block you are using)
Spark Plugs (HX D16Y5)
Spark Plug Wires
Valve Cover Gasket
Distributor cap and rotor

I spent about $550 total when all was said and done. I paid $200 for the head, and $85 for the ECU. Random stuff kept adding up after that. $550 is comparable to a full Z6 swap, but remember this included a new timing belt, head gasket, etc.

3. What tools will I need to do the job?
Well, 95% of the job can be done with a 3/8 inch ratchet, 10-19mm sockets, and a set of screwdrivers. However, you will need a torque wrench so that you can torque the head bolts down correctly, and you will also need access to an air wrench when you do your timing belt to get the crank pulley off. You will also need wire cutters, and some electrical tape for the wiring part.

4. Okay, I got all of the parts and tools, now how do I swap the heads?
Alright first what you’re gonna need to do is remove the cylinder head.

Here are the step by step instructions on how to take your head off (Taken from helms. I recommend you have the actual manual in front of you because it includes detailed pictures and diagrams):
1. Disconnect the negative terminal from the battery.
2. Drain the coolant.
3. Relieve fuel pressure (take the gas cap off)
4. Remove the air flow tube (intake)
5. Remove the fuel feed hose and charcoal canister hose from the intake manifold.
6. Remove the throttle cable at the throttle body.
7. Remove the throttle control cable from the throttle body (A/T only).
8. Remove the fuel return hose and brake booster vacuum hose.
9. Remove the engine wire harness connectors and wire harness clamps from the cylinder head and intake manifold (Basically any hose or plug that’s connected to the intake manifold or head, needs to come off)
10. Disconnect spark plug wires at spark plugs and remove them from the distributor.
11. Remove the engine ground cable on the cylinder head cover.
12. Remove the power steering belt and pump (Do NOT disconnect the hoses)
13. Remove the power steering bracket (4 bolts)
14. Remove the emission vacuum hoses and water bypass hoses from intake manifold assembly (included in step 9)
15. Remove the radiator upper hose and heater hose from the cylinder head (included in step 9)
16. Remove the water bypass hose from the thermostat housing.
17. Remove the intake manifold bracket.
18. Remove the self locking nuts and disconnect the exhaust manifold and exhaust pipe A.
19. Remove the exhaust manifold bracket.
20. Remove the PCV hose, then remove the cylinder head cover.
21. Remove the timing belt upper cover.
22. Loosen the timing belt adjusting bolt 180 degrees to release the belt tension.
23. Push the tensioner to release tension from the timing belt, then retighten the adjusting bolt.
24. Remove the belt from the cam pulley (gear)
25. Remove the cylinder head bolts, then remove the cylinder head (loosen bolts starting from the outside, then coming in).

VERY IMPORTANT: If you have a D15 block (or any D-series block with an oil jet for that matter), you need to make sure that you remove the oil jet between cylinders 2 and 3 when you do this swap. If you don’t, you won’t have VTEC. I forgot to pull the oil jet out the first time. You won’t get a code, your ECU will say your solenoid is fine and everything is working great but VTEC will not actually engage. Make sure you remove the oil jet. I took a screw, screwed it into the oil jet, and then pulled it out with a pair of pliers.

After you’ve pulled the oil jet, you’ll need to sand down the block surface so that no gasket is left caked on the block. (You won’t have to worry about this anymore because hopefully you’ll be using a Y8 metal gasket). If you get shavings in the cylinders, then fill the cylinders with warm soapy water and float the shavings out. You’ll do this by turning the crank over a few times with a 17mm until all the water is out. Make sure that there is NO liquid in the cylinders or head bolt holes when you put the head back on (If there is, you can crack your block when you torque down the head bolts). If you are using the manifolds from your stock motor, all you’ll need to do is unbolt your intake manifold (with throttle body) off of your old head so that you are ready to put it on the Z6 head. It’s only 8 bolts.

Now, let’s put your new head on (Taken from helms. I recommend you have the actual manual in front of you because it includes detailed pictures and diagrams):
-You can reuse your D15B7 head bolts with the D16Z6 swap…they are the same size
-Always use a new head gasket
-If you are using your old intake manifold with the new head, make sure you use a new intake manifold gasket, same goes for throttle body. If you removed it, you need a new gasket.
-Cylinder head and engine block surface must be clean (no water or dirt…even in the head bolt holes)
-Turn the crankshaft so that No. 1 piston is at TDC.

1. Install the intake manifold and tighten the nuts in a criss-cross pattern in 2 or 3 steps, beginning with the inner nuts.
2. Install the exhaust manifold and tighten the nuts in a criss-cross pattern in 2 or 3 steps, beginning with the inner nut.
3. Install the exhaust manifold bracket.
4. Install two dowel pins, head gasket, and cylinder head
-Apply clean engine oil on the bolt threads and washer contact surface
-Always use a new cylinder head gasket
-Turn the cam pulley to TDC before installing
5. Install the bolts that secure the intake manifold to its bracket but do not tighten them yet (optional, I decided not to do this because the intake manifold bracket is a bitch to get to)
6. Tighten the cylinder head bolts in two steps, working your way from the inside bolts to the outside bolts.
-Step 1: 22 lb ft
-Step 2: 53 lb ft
7. Install the exhaust pipe A on the exhaust manifold.
8. Tighten the bolts for intake manifold bracket (again, optional)
9. Install the exhaust pipe A on its bracket
10. After the installation, check that all the tubes, hoses, and connectors are installed correctly.
11. Adjust the valve timing.
12. Apply liquid gasket to the head mating surface of the number 1 and number 5 or number 6 cam holder then install the cylinder head cover (you can neglect this because you need to leave it off for the timing belt install)
13. Install air intake.
14. Fill radiator with coolant.

Alright, we’re getting there. Now all we have left to do is the timing belt, and the VTEC wiring.

COMPLETE timing belt and water pump replacement thread by Poison, GREAT info:

Lets do the timing belt first (Taken from helms. I recommend you have the actual manual in front of you because it includes detailed pictures and diagrams):
1. Remove the splash shield
2. Remove the power steering pump (should already be done)
3. Remove the A/C compressor adjust pulley with bracket and the belt (with A/C), then remove the alternator belt.
4. Remove the P/S bracket (should already be done)
5. Loosen the alternator adjusting bolt and pivot nut, then remove the belt.
6. Remove the cruise control actuator and the P/S tank bracket.
7. Remove the engine support nuts. Loosen the mount bolt and pivot the engine side mount rubber out of the way.
8. Remove the cylinder head cover (should already be done).
9. Remove the timing belt upper cover (should already be done).
10. Remove the special bolt and crankshaft pulley (you NEED an air gun for this).
11. Remove the timing belt lower cover.
12. Loosen the timing belt adjusting bolt 180 degrees to release the belt tension (should already be done).
13. Push the tensioner to release tension from the belt, then retighten the adjusting bolt.
14. Remove the timing belt from the pulleys.

I recommend that since you are replacing your timing belt, you go ahead and replace the water pump as well. It is not that expensive, and is only a few bolts. If the water pump fails, you can kiss your motor goodbye so it’s a good thing to get.

Okay, now that you’ve taken the old timing belt off (and hopefully put a new water pump in), lets put the new timing belt in (Taken from helms. I recommend you have the actual manual in front of you because it includes detailed pictures and diagrams):
1. Install the timing belt in the reverse order of removal; only key points described here.
2. Position the crankshaft and cam pulleys at TDC.
A. Set the crankshaft so that the No. 1 piston is at TDC (top dead center).
NOTE: Align the groove on the teeth side of the timing belt drive pulley to the lower arrow pointer on the oil pump.
B. Align the TDC marks on the cam pulley with the pointer on the back cover.
3. Install the timing belt.
4. Loosen the adjusting bolt, and retighten it after tensioning the belt.
5. Rotate the crankshaft (w/ 17mm socket) about 4 or 6 turns clockwise so that the belt may fit in the position on the pulleys.
6. Adjust the timing belt tension.
7. Check the crankshaft pulley and the cam pulley at TDC.
8. If the cam pulley is not positioned at TDC, remove the timing belt and adjust the positioning.

Make sure you adjust the tension the alternator and A/C belts, as well as the power steering belt. Look over everything and make sure it all looks good, because you’re almost done.

5. I’m done swapping the heads, now how do I make my VTEC work?
The P28 ECU plugs right in, you all you’ll need to do is wire the VTEC up. First, you’ll need to get an engine plug from a junkyard for the VTEC solenoid oil pressure.

You’ll need to run the blue wire (or whichever color is from the plug) to pin D6, and then run the black ground wire from the plug to anywhere on the motor. You then need to run the green wire from the VTEC solenoid to pin A4.

THAT’S IT! YOU’RE FINISHED! Make sure you’re not throwing any CEL’s, if you are, go back and check your work.

6. How much faster will my car be once it is done?
Well, my car definitely felt much better overall. The lower end will be a bit torquier, and your car will pull much better in the higher RPM’s (5000+). I feel the most difference on the highway, having the extra HP is very nice when you need to merge. I don’t have any quarter mile times from my mini-me, but I will post them as soon as I run it. The one downfall to a mini-me is the long transmission. The DX transmission is much longer than the EX, and the VX/CX is even worse. I did some calculations, at 7200 RPM here are your shift points with respective transmissions (using 195/50/15 tires, stock tire size):

CX/VX Transmission:
46 - 85 - 140 - 175

DX/LX Transmission:
37 - 68 - 102 - 132

EX/Si Transmission:
35 - 60 - 91 - 126

The gear ratios were taken from Mista Bone's tranny page. Emerika stated that the EX transmission shaved 7 tenths of a second off of his quarter mile time in his hatchback, you DEFINITELY want to get the EX transmission

7. The mini-me is nice, but I want to make it even faster. What mods should I consider?
The number one modification you should do is the EX transmission. You can pick one up in the Honda-Tech classifieds or in a junkyard for about $200 bucks. They are worth their weight in gold. The usual intake/header/exhaust combination works very well. Exospeed, ZEX, and Skunk2 make very good SOHC VTEC camshafts that will add a good bit of power as well. If you want to take it even farther, you can use D16A1 Integra pistons (P29) that will put your compression way into the 12’s.

For more info on SOHC upgrades, click here -

Shoutouts to:
Sander and Steve of Mixed Motorsports for all of their help :thumbup:
MistaBone for knowing everything and helping me whenever I had a question
Spade for all of his knowledge
Poison for his awesome timing belt / water pump writeup

Comments/additions are welcome
1993 Civic 4 Door
Mini-Me Powered
D15 Block and Tranny
D16Z6 Head
2320 lbs of pure slowness

· Registered
4,377 Posts
Discussion Starter · #4 ·
Building a D16z6 CRX
Thanks to teamimports

PARTS NEEDED: So here's the list of the parts that you need and options if you're just gonna use the vtec block for Dx,Hf or Si model:

92-95 D16Z6 (9.2:1)or D16Y8 sohc vtec block (bigger intake/exhaust ports and higher compression 9.6:1)
4g Si intake manifold and throttle body note: Dx and Hf manifold will bolt right up too if you don't want the hassle of converting your harness from dx, hf to si but Si manifold is much more desirable performance wise
4g left/driver side engine mounting bracket and rubber mount
4g stock Si/Dx/hf tranny and mounts note: again preferably 89-91 Si model for performance reasons. will explain later...
4g axles
4g Hf or Si distributor
4g Si engine harness for Si intake manifold/ecu or Dx engine harness if you're gonna use Dx manifold/ecu like wise on Hf models.
5g or 6g Ex/Si/Vx distributor wires note: 4g wires will work too with slight mods
5g or 6g Ex/Si exhaust manifold or headers note: 4g exhaust manifold or headers will bolt-up too but slightly touching the oil pan
4g stock clutch kit and flywheel or better , same year as your tranny * more clutch upgrade info below
external vtec controller and a 4wire 30 amp auto relay * more info below
5g or 6g fuel pressure regulator
4g coolant hoses and heater hoses
4g or 5g alternator belt depending on what year alternator you'll use. 4g has 3 rib belt while 5g has 4 rib belt
Tools needed:

Honda factory manual for torque specs and wiring diagram
breaker bar and flywheel stopper or just air impact to take off the crank pulley
torque wrench
lot's of metric wrenches and sockets
butt connectors or electric tape
turn signal bulb and holder with 2 wires ( to check the vtec activation)
Dremil tool or skill saw with metal blade
Preparing the engine:

Assuming that you already have the engine pulled out of your car, your vtec block is already cleaned up. Install the new intake manifold gasket and then transfer the intake manifold and then torque the nuts at 17 ft.lbs
Transfer the Si or converted Dx to Si harness to the vtec block. On 96+ block , ignore the (CFK) crank fluctuation sensor located inside the timing belt cover and the knock sensor at the back of the block. Tip: Don't forget to bolt the ground wire of the engine harness to the thermostat housing or else your engine start
Replace the 5g left/driver side engine mounting bracket and rubber mount from the 4G block. Trim the timing belt cover on the front side of the engine underneath the transferred 4G bracket to clear the timing belt cover to the mounting bracket. In order to do this you have to remove the crankshaft pulley and then torque back the crank pulley bolt to 134 ft.lbs.
5g block have the radiator fan switch at the thermostat housing compared to the 4g which is at the back of the block . You could either just extend the two wires blk and yel/green and then connect it using the 5g connector for the fan switch at the thermostat housing or on" 92 block only", there's a hole plugged up by a bolt on the same spot where the 4g switch is located. Just transfer the 4g switch to the 5g block but be careful not to break the two prong connectors and put high temp sealant before installing it
Replace the 4g fuel pressure regulator ( rated at 35-41 psi ) with 5g pressure regulator ( rated at 41-47 psi ). Don't forget to do this upgrade or else you won't have the extra fuel to compensate for the extra air once the vtec activates. This will bolt up to the 4g fuel rail plus with the help of an adjustable clamps 'coz 4g fuel return line is bigger than 5g return line.
Preparing the clutch and transmission:

Si and DX has the same gear ratio from 1st gear to 5th gear except for Hf model which is designed for fuel economy. And one of the significant differences between models are the final drive gear ratio. Si has 4.250 best mated for higher revving powered engine and better acceleration, cruising speed of 3,400 rpm at 70 mph. Dx model has 3.888 , little better gas mileage compared to Si but will slightly hurt your acceleration, 2,500 rpm at 70 mph. Hf has 2.954 (49 st) 3.250 (california) , has the best gas mileage but I don't think you want to swap to 5g vtec and put Hf tranny just for the gas mileage
If you have an 88 model or tranny, you need to use the same year clutch disc, pressure plate and flywheel to either stock from the Honda dealer around $180US for the clutch kit ( or Clutch masters, etc) and 'bout $25-30US to resurface the flywheel. . 88 Si/ Dx tranny has different # of teeth on the spline (21) compared to 89-99 (20).
If you have an 89 and on tranny , you could upgrade it even if with just a stock 92-99 clutch disc, pressure plate and flywheel. If you use the 92- 99 clutch upgrade , you have to use the 92-up flywheel . This is a good clutch upgrade if you're on the budget and not only it's larger in diameter which means more friction material, better heat dissipation and stiffer springs in the hubs to handle torturous aggressive launches and shifting. It didn't show any signs of slippage at the time especially when "squeezing" considering the fact that it was pulling low 13's all day. Tip: while you're at it, change your throw out bearing because eventually it will cause you some problems if you did not replace it.

By using a 4g Si/Hf (they're the same), you need to modify the mounting holes on top and bottom front of the distributor. Ignore the third hole because you only need two bolts to hold the distributor from not leaking any oil and to align the distributor to stock ignition timing as shown on the pix. On 96-on block , the 4g distributor will just bolt right up without any modification

There's lots of ways to activate the vtec. You could use a tachometer with shift light from Autometer w/ relay($125) Msd rpm switch ( $55) with Rpm module or module selector w/ relay($59) , Field SFC vtec controller ($250) or just plain ol' toggle switch ($2) but might fry up the vtec solenoid.
You don't nead to hook up the oil pressure switch for the vtec by the vtec solenoid if you're using the 4g ecu.
Here's the wiring diagram for MSD rpm switch part # PN8950 and an MSD module selector part # PN8670 with 30 amp 4 wire automotive relay:
Red wire-------------------------- 12 V source
Black wire------------------------ ( - ) Ground
White wire----------------------- ( - ) side of the ignition coil or splice/connect to ecu pin location B15 or B17
Yellow wire---------------------- # 86 on the relay note: for 4 cylinder, you have to cut the two loop wires
30 amp relay
# 85 ------------------------------- 12 V source
# 86 ------------------------------- Yellow wire from the Rpm switch
# 30 ------------------------------- 12 V source
# 87 ------------------------------- to vtec solenoid (green/ yellow wire)
# 87a ------------------------------ not used
Diagram for the Field SFC vtec controller for 4gcivic/2g crx application: vtec controller ECU pin location

Red wire ------------------------splice/connect to A15(yellow/black)
Green wire ----------------------splice/connect to B15(white1)
Dark Blue -----------------------to vtec solenoid (green/ yellow)
Yellow --------------------------not used
White/green -------------------- not used
Purple --------------------------cut/connect to B16 ecu side (Si/Hf = white/red , DX = yellow/red )
Light Blue ----------------------cut/connect to B16 engine side (Si/Hf = white/red , DX = yellow/red )
Orange --------------------------cut/connect to C11 ecu side (Si/Hf = white1 , DX = orange)
Brown ---------------------------cut/connect to C11 engine side (Si/Hf = white1 , DX= orange)
Black ---------------------------( - ) ground

Now after you've dropped in the engine like just dropping in 4g engine. You'll notice that the driver side mount is a lil' off and tilted to the radiator side of the engine bay. Don't be alarmed becuase it is normal. The mounting holes for the bracket is not perfectly in favor to 4g bracket even though it bolt right up. Install the 4g axle and torque the spindle nut to 134 ft. lbs. Double check all fluids (oil, tranny oil, coolant), ground wires on the tranny and valve cover.
To determine if the vtec controller works, set it at high RPM like "5200 RPM" at the module selector or Field SFC vtec controler and then take off on second gear instead of first. Or barely use 1st gear like shift at 1500 rpm and then pop it on 2nd right away and then floor it. It's gonna lag a lil' bit and might even die but the key here is the floor it all the up to 7,500 fuel cut off. You'll feel a slight pull or G's from 3,500 to 4,400 (lower cam profile)and then drop but once it hit 5,400 rpm (high cam profile) you'll feel another set of G's if the vtec controller works. Sohc vtec low cam profile power starts dropping at around 4,500 to 4,600 rpm so if your vtec is not working , you can tell if the engine is not making anymore power beyond 5k rpm. Good luck and enjoy your vtec powered civic or crx

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Discussion Starter · #7 · (Edited) Timing Tech (Updated!!)



D14/D15/D16 (90-94 Honda Concerto)​

Head Milling information:​
From the thread "Head Milling"​
For every .012 milled there is a 1* degree retard​
Thanks to Belette for the pic.​

HondaTuning Magazine:​
Keeping Time (Timing Belt install)​

Setting Ignition Timing​

How-to install a new cam gear without removing the timing belt.​

cam timing ?? degree's per tooth​

by LuckyH​
"Here you go, aftermarket cam specs for all us civic owners"​

another great thread from​
Camshaft Tech by Kommon_sense​

cam in b7 problems!!​

y7/8 cam gear install​

SOHC non-vtec cam?​

anybody verify a jdm d15b cam for me?​


D16z6 &D16y8 Crower cam specs​
Scroll down to page 29.​

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Discussion Starter · #8 ·
Ignition timing/Cam Gear timing/Timing Belt Questions

Many thanks to:

and others who have contributed information to threads that have been added here.

Advancing my timing question

1) Igntion timing.......advancing the ignition timing beyond 2-3 degress of stock setting may require a higher octane gasoline to prevent pinging/detonation

2) Cam timing...........advancing the cam timing will trap MORE air/fuel mix in the cylinder at low-mid rpms. The result will be higher combustion pressures. This may require a higher octane gas also. You can advanced the cam too far and damage the vales.

3)worst case issue........advancing the cam timing without readjusting the igntion timing afterwards will equal a combo of 1) and 2) and you can hurt parts.

Tunning with a zex 53900
Originally Posted by OZ Racing
either way you still see a power gain on NA setups..

mine is at 2 deg retard @ 18 BTDC

I thought advancing your timing on stock would produce power gains....but retarding does as well?
Originally Posted by transzex
1 degree retard, 19 BTDC ignition timing for NA.

you're missing mista's point. there is cam timing, and ignition timing. two separately adjustable timing points.

mista is saying run -1deg on the cam gear, and 19deg BTDC on the ignition timing.

yep, exactly.

The Great Half-Tooth debate
"You walk 1/2 way into a forest, are you 1/2 way in or 1/2 way out???"

1/2 tooth off cam gear? d15 to d16?
testing this week will be a Y7/Y8 cam gear with a A6 cam in a D15B7 motor,
Why you ask????????
It is known that the cam timing error is 4.75 degrees (1/2 tooth) on the cam install.......
Everyone is saying the Y7/Y8 stock gears are indexed 5 degrees off th 88-95.
End result is less than .25 degree difference. You get more than that error from the crank keyway slop.

installed a6 cam in b2 problems need help.
the D15 block is shorter in height than the D16, thus causing a half tooth error in the cam indexing.
This is why you have to index the D16 motors with the 7 o'clock pointer.
360 degrees / 38 teeth cam gear = 9.5 degees
cam spins as 1/2 crank speed, so 9.5 degrees / 2 = 4.75 degrees, or a half tooth.
From the same thread:
Originally Posted by slowdxracer
hey just a quick question. i am planning to do the same thing he is doing but my engine is a d15b7. does the 5 degress advance or retard apply to my engine too? thanx
It is 4.75 degrees, and yes the same applies for the D15B7.
The motor I figured all this crap out on!!!!!!
D15B7/A6 crack monster........
a6 cam in a d15b7 head, will it work?
The only dynograph I know off that shows the power difference of both cam settings.
From Sept 1999.......

Adjustible cam timming
is the DC cam gear for 92-95 and your putting it on a 98 motor??????
1/2 tooth error.

Cam gear and timing
Z6 cam in a Y8 motor?
1/2 tooth error again.

88-91 si cam in a b2/b7 head using a y7 cam gear to correct for the half-tooth error
cam gear setting for si cam in dx?


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4,377 Posts
Discussion Starter · #9 · (Edited)
Adjustible cam timing
Thanks to Builthatch for the following post:​

DC stopped making cam gears about a year before they were bought out by AEM...DC had a firesale for old stock and that is why you can see these cam gears for such low prices nowadays, however, there is another reason they stopped making them, and this reason is detailed below. I actually made a claim to AEM about it last spring, and after a back and forth with AEM tech Robert Greene, the error i detailed was confirmed and i finally was rewarded with a CORRECTLY indexed AEM unit to replace the erroneous DC cog.​

stock Y8 gear- note keyway is offset from vertical axis, however, TDC mark and side marks form perfect cross. CORRECT for Y8​

AEM Y8 gear- exact match to OE gear, CORRECT for Y8​

DC Y8 gear- note, like the stock y8 gear, side marks are on-point and keyway is offset, BUT, note that TDC marks are 4 degs away from vertical axis of stock y8 gear, though sides match. INCORRECT for everything​

AEM Z6 gear- note vertical axis bisects keyway CORRECT for Z6​

Yet another erroneous gear. Golden Eagle piece for a y8, yet compare it to the Z6 gear up top, no difference! offset keyway, nothing...WEAK!​
New thread​
by jlacoy82​

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4,377 Posts
Discussion Starter · #10 · (Edited)
Originally Posted by builthatch
this is a correct y8 gear- notice the keyway is about 4 degrees to the left of the '0' centerline and 1st cylinder TDC...
this is a stock y8 gear for reference- again, notice the keyway is about 4 degrees to the left of the "up" 1st cylinder TDC mark
this is a z6 gear, with the keyway inline with the 1st cylinder TDC mark, its hard to see cuz the mark on the gear is black as well...the edelbrock mentioned in this thread looks like this one...
this is another gear that is supposed to be a y8 gear (kommonsense's maybe?), but...its got the keyway inline with the '0' and the 1st cylinder TDC mark, just like a z6 gear-
Originally Posted by jlacoy82
So basically 88-00 and 92-00 cam gears are basically all marked for the 88-95 crowd, and even some of the 96-00 cam gears are still marked the same as the 88-00's? Is that basically it?
I've already read though that other thread on cam gears, and came up with nothing searching HT. Are the newer 96-00 Edelbrock gears marked correctly for a y8? Or are they like the golden eagle ones they mark 0 at the "valley" in the teeth, and not at the "peak"??
yes. you need to compare it to this VVV and see how the keyway is lined up with the teeth to see if it is for a 88-95 or 96-00

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Discussion Starter · #11 ·
Camgear. Worthless, as I've read.
As Bone Mentioned, a camgear does have a decent effect on SOHC power curves ... I did the Dyno Pulls below to find out what cam gear setting had on my mild D16Z6 ... A picture is worth a thousand words ....
Blue curves: D16Z6 engine, modified Z6 exhaust manifold, cold air intake, 2.25'' mandrel bent exhaust, HiFlow Cat, Zex 59300 cam, Y8 intake manifold, B18b throttle body,stock fuel and ignition maps, Cam - 0, Ignition timing at 18 btdc
Red curves: D16Z6 engine, modified Z6 exhaust manifold, cold air intake, 2.25'' mandrel bent exhaust, HiFlow Cat, Zex 59300 cam, Y8 intake manifold, B18b throttle body, stock fuel and ignition map, Cam 2 degree advanced, Ignition timing at 18 btdc
Green curves: D16Z6 engine, modified Z6 exhaust manifold, cold air intake, 2.25'' mandrel bent exhaust, HiFlow Cat, Zex 59300 cam, Y8 intake manifold, B18b throttle body, stock fuel and ignition map,Cam 2 degree retarded, Ignition timing at 18 btdc
With a bit more fine tuning in 1/2 degree intervals I might have been able to get a bit more high rpm power.

Question about the z6/y8 cam gears...
inquiry on d16y8 cam gears
Tunning with a zex 53900
y7 and right cam gear choice ?
tuning, advice?
Cam gear difference?


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Discussion Starter · #12 ·
Honda/Acura Distributor Codes
Part No.ModelYearsEngine
TD - 01U Civic 88 - 91 1.5L
TD - 02U Civic88 - 89 1.5L & 1.6L Si
TD - 03U Civic88 - 91 1.6L ZC 1ST GEN
TD - 18U Civic90 - 91 1.5L & 1.6L Si
TD - 22U Civic89 - 91 B16A 1ST GEN
TD - 31U Accord 90 - 91, 94 - 95 2.2L
TD - 41U Civic + Del Sol 92 - 951.5L
TD - 42U Civic + Del Sol 92 - 951,5L & 1.6L Si
TD - 43U Civic88 - 89 1.6L ZC
TD - 44U Civic + Del Sol 92 - 95 1.6L VTEC
TD - 52U Accord 92 - 93 2.2L
TD - 52U Passport 96 - 97 2.6L
TD - 52U Prelude 92 - 95 2.2L NON-VTEC
TD - 59U Accord 92 - 93 2.2L
TD - 59U Passport 96 - 97 2.6L
TD - 59U Prelude 92 - 95 2.2L NON-VTEC
TD - 60U Prelude 92 - 952.2L VTEC INT. COIL
TD - 61U Prelude 92 - 952.2L & 2.3L VTEC EXT. COIL
TD - 63U Civic 96 - 00 1.6L
TD - 73U Civic 96 - 00 1.6L
TD - 73U Accord 98 - 00 2.3L
TD - 76U Accord 96 - 97 2.2L
TD - 77U Prelude 97 - 00 2.2L
TD - 80U Civic 96 - 00 1.6L
TD - 80U Del Sol 96 - 97 1.6L NON-VTEC
TD - 86U Civic 92 - 00B16A 2ND GEN & B18C
TD - 89U Prelude 97 - 01 TYPE S H22A
TD - 97U CRV 97 - 00 2.0L

Part No.ModelYearsEngine
TD - 03U Integra 88 - 91 ZC 1ST GEN
TD - 23U Integra 90 - 91 1.8L MAN/AUTO
TD - 44U Integra GS-R 92 - 95 B17A & B18C
TD - 55U Integra 91 - 95 1.8L
TD - 84U Integra GS-R 96 - 98 B18C
TD - 85U Integra 96 - 00 1.8L​

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Discussion Starter · #13 ·
Euro Mini-Me
A new addition for the international owner's of the 5th gen EG EDM LSi w/D15b2

Wiring diagram thanks to eg4:

you must add this wires:

A1 injector 1 >> brown
A2 injector 4 >> yellow
A3 injector2 >> red
A4 vtec-solenoid >> yelow-green
A5 injector3 >> blue
A6 Lambdaheizung >> orange/black
A12 thermostat >> yellow-green

B11 Cyl P >> orange (dizzy)
B12 Cyl M >> white
D6 VTEC vtec >> blau

add this pins:


OBD1 - preOBD0

A7 mainrelay pin 8 A14
A8 mainrelay pin 8 A12
A13 Engine Light B6
A20 Spülluftsteuerventil A6
A21 Zündelektrode B17
A22 Zündelektrode B15
A23 Hauptrelais Klemme 2 A2
A24 Hauptrelais Klemme 2 A4
A25 Hauptrelais Klemme 3 A15
A26 Masse A18

B1 Hauptrelais 3 A13
B2 Masse A16
B9 Hauptrelais 6 B13
B10 Geschw. Sensor B1
B16 CKP M C2

D1 Backupsicherung B1
D4 Prüfstecker B20
D9 LiMa B14
D11 Throttlesensor C7
D13 TW Sensor C6
D14 Lambdasonde C16
D15 TA Sensor C5
D17 Map C11
D19 Map C15
D20 Throttlesensor C13
D21 Map C14
D22 Prüfstecker C12

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Here is the EDM wiring diagram roughly converted to english.
you must add these wires:

A1 injector 1 >> brown
A2 injector 4 >> yellow
A3 injector2 >> red
A4 vtec-solenoid >> yellow-green
A5 injector3 >> blue
A6 O2 sensor >> orange/black
A12 thermostat >> yellow-green

B11 Cyl P >> orange (dizzy)
B12 Cyl M >> white
D6 VTEC vtec >> blue

add this pins:


A7 fuel pump (main relay) pin 8 A14
A8 (main relay) pin 8 A12
A9 EACV (IAC valve) A11
A13 Engine Light B6
A20 EVAP purge control solenoid A6
A21 ICM B17
A22 Zündelektrode B15
A23 ground *(main relay ground) 2 A2
A24 ground *(main relay ground) 2 A4
A25 to main relay and to ground 3 A15
A26 Ground A18

B1 IGP2 3 A13
B2 LG2 A16
B9 starter signal 6 B13
B10 vehicle speed sensor B1
B16 CKP M C2

D1 Back Up Power B1
D4 service check connector B20
D9 alternator B14
D11 TPS Signal C7
D13 ECT sensor C6
D14 O2 sensor C16
D15 IAT sensor C5
D17 Map Signal C11
D19 Map 5V C15
D20 Throttle sensor C13
D21 Map GND C14

Hope that helps.

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Discussion Starter · #15 · (Edited)
Wiring Diagrams/Schematics

Injector Wiring:
High horsepower boosted cars often need large injectors. Most large capacity injectors are available in peak and hold form - about 2 ohms impedance, whereas most stock injectors from about 92 on are saturated (8-10 ohms impedance). Honda engine computers require a total injector impedance of about 10 ohms so a resistor pack is needed whenever the stock saturated injectors are swapped with peak and hold.

Early model injected Hondas; 90-95 Prelude and Accord; 89-91 JDM B16A Hondas all ran external resistor packs with low impedance injectors.

This wiring diagram shows the wiring for saturated (upper), and peak and hold injectors (lower). The engine computer activates the injectors by grounding each injector in turn.

Converting to Peak and Hold injectors

Near the brake master cylinder on OBD I cars is a connector that distributes power to the injectors and a number of sensors. Verify with a multimeter which wires go to the injectors. Cut all 4 and connect the wires coming from the injectors to the resistor pack. Connect the power wire from the resistor pack to all 4 of the unused wires coming from the power connector. OBD II cars may have this connector somewhere under the intake manifold.

VTEC Wiring:

OBDO Wiring:

OBD1 Wiring:

OBD2 Wiring:

Dog in your write up I read that using a6 pistons and a y8 head gave you a 10.6:1 cr. I am planning on using a set of a6 pistons in my y8 block/head setup. I am assuming that I will have the same cr as you since the blocks are the same. My question is what are the exact specs for these pistons? The deck heigth must be different that with the y8 pistons? Every cr calculator I use tells me that I will only be running a 10.1:1 cr with a6 pistons. :confused:


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