Hey all! After months of research and collecting parts, I started to do a D16Y8 MiniMe headswap onto my D15B8 Block. Lets Start with some Background on the car:
The car started life back in 1992 as a bottom of the line Civic CX 5 speed Hatchback *With AC * when my parents bought it brand new off the lot. A Divorce, a sister, and an IRS Tax Evasion later my dad gave me the car back in late 2006. The car having sat in the city for 3 months had a dead battery *Which I replaced to get home* and it then popped its headgasket the following week*....
Car sat untill March of 2007 when I finally replaced the headgasket and had it as a spare car for a few months, now keep in mind I drive a 2007 Ford Focus SE as my daily driver and this honda was to be my project, and considering my ford was FAR faster than the Honda I had read that putting a DX/LX 16 valve head with a D16A6 Camshaft and Y7 Cam gear would give me a little bit of help, and I had noticed that my D15B8 block had 4 valve pistons (I do not know how long the CX's head 4 valve pistons, so please don't come yelling at me if you have a 92 that doesn't have 4 valve pistons) when the head was off. so in late may we Converted the car to a P06 ECU and moutned a D15B7 Head with the cam and gear and found the car to be a bit more lively, along with an intake, header, test-pipe and exhaust. but after running an 18.5 at the track. *The CRX in front of me is my buddies stock 89 SI and he ran a 16.5
I was less than thrilled, and found out I was leaking compresson hard-core and found out that the valves, or valve seals were toast, so I decided "What kind of power can I get out of this little D15B8 Block." (Yes yes, I know I need an SI transmisson, my gearing sucks chunks...
I aquired a D16Y8 head with a OBX intake manifold for free (sold the OBX as it was for an automatic, and I preffer using 'stock' parts), and decided this would be the direction I'd be taking. I dropped the head off at my local machine shop and had them rebuild the head so I knew I'd have something clean to start with *HIGHLY RECOMMENDED* because when you buy a used head there is no real way to find out if the valve seals are toast, or if the valves are bent unless the head is ON the block. (the head I got for free I was told was perfect, Turns out 2 of the valves were bent)
So lets start with the common mis-conceptions of this swap, along with a shopping list so incase you are interested in doing this swap yourself you have a quick FAQ.
1) You can just use a set of D15B7/8 or D16Y7/8 headbolts
- WRONG, Because of the design of the Y8 head, the corner closest to the Vtec Solenoid isn't raised on the Y8 head, so that corner requires a Y7/Y8 Headbolt/stud.
2) I need a Y8 Distributor, and have to convert it, OR I need a Z6 Vtec Distributor
- WRONG, You can REUSE your origional CX/DX/LX Civic Distributor, the Z6 Dizzys do NOT bolt up at all, and the Y8 Dizzy will require custom wiring, or a adapter to work with your OBD1 Harness.
3) Any SOHC Vtec solenoid will work on any other SOHC Vtec Head
- WRONG WRONG WRONG You HAVE to have a D16Y8 Vtec Solinoid
Its gasket is like 3 stacked ovals, the Z6 Gasket has a triangular shape, they look VERY SIMILAR without them being off the head, and I think the D15B Vtec Solenoid may be yet ANOTHER shape.
4) You have to wire Vtec/4 wire O2 all the way to the ECU on any Civic
- WRONG My 1992 has the wiring for Vtec, and the 4 wire O2 up to the Shock-Tower, but to my understanding this is ONLY for 1992 Civic EG's, I'm not sure about the Coupes or sedans.
5) I can reuse my FPR off the D15B7/8 Fuel rail
- WRONG the Fuel rail on a Y7/8 Manifold flows MUCH better, and the FPR is mounted on the opposite side of the rail *And is off-set* so it will not work
6) I can reuse my Throttlebody off the D15B7/8
- CORRECT This has the same bolt pattern, and I have been told that certian B series TB's will also work as well.
7) I can use a P28 ECU for this setup
- EHhhhhhhhhhhhhhhhhhhhhhh I personally had my Y8 Head milled, and am using ARP studs with a thin D16Y8 Headgasket, this setup mounted on a D15B7/8 Block creates MUCH higher compression than a stock Y8 *9.6:1 CR while my setup will be running 10.8-11.1:1 CR. I STRONGLY recommend getting your ECU chipped, no matter what ECU you have your hands on and getting it tuned
- Also, keep in mind, the Z6 head is NOT identical to the Y8 head so there are programming diffrences even in the stock ECU that could cause damage if you don't get it chipped.
8) I have to use a Chipped P28 ECU for this setup
- WRONG P05 and P06 ECU's can be converted to Vtec spec cheaply ($35), and be chipped to operate the same as a P28 would, I sent my P05 ECU to Phearable.net and received it back 4 days later chipped and converted for Vtec ready to rock and roll.
9) The D16Z6 head and the D16Y8 head are basically the same
- WRONG the Z6 head has 'straight through' intake ports, while the Y8 had Tumble ports (Z6 has better top end, Y8 had more low end grunt), as well as the combustion chamber is smaller on the Y8 head which will help bump the CR a few more tenths, you can tell the difference between the Z6 and Y8 by looking at where the valves are and if the chamber is completely squared off and flush with the head, its a Y8, if its recessed a little bit, its a Z6 head.
10) I need a Z6 Oxygen sensor
- Ehhh.... If you have a CX like me with a 1 wire O2, you will need to lay fresh wiring from the shock tower (or ECU if you don't have a 92) for the 4 wire O2, if you have a DX/LX your O2 will work just fine, if you have a VX, You're gonna have to convert that to a 4 wire.
11) If I followed all the above rules I can just slap that bitch on their and away I go!
- OH GOD NO, I learned my lesson the hard way, When using a D16Y8 head, Cam, and Cam gear, your head will be off 4.75* (Half a tooth) compared to the TDC of the pistons on your B8/B7/Z6 block. You need to use either an adjustable cam gear, or Run your origonal B8/B7/Z6 cam gear on the Y8 Camshaft to remedy this problem (If your head has not been milled), otherwise your timing will never be correct.
You also need to be sure to adjust your valves (While they are cold, atleast 1 day of sitting .008 intake .010 exhaust to my understanding) before you even fire that sucker up! Over-tightened valves will burn-up quickly, its better they are a hair loose and rattly *As mine are* than super tight.
Alright Enough of that, now onto the shopping list for the swap!!!
1) D16Y8 Head - Strongly recommend a freshly rebuilt head
2) 92-00 Intake Manifold - I got an OBX one for free, but it was for an automatic only (No place to put my IACV Valve on the back of it, nor my IAT), but MANY people use the 96-00 EX Intake manifold with great success (Since I made this article, I have picked up and installed a 96-98 Intake manifold off a D16Y8, the 99 and 00 intake manifolds have cold start assist openings that need to be plugged incase you pick one of those up), I'd strongly recommend it as well because its OEM and its superior design
3) 1 D16Y7/Y8 Headbolt or Stud, 9 D15B7/B8 Headbolts or Studs, Do not mix and match these (Brand wise), I got a custom set from ARP for only $135 shipped to my door, just call them up directly and ask for 9 of the one, 1 of the other, the washers and nuts are the same for both styles of bolts), don't buy these on Ebay (too many idiots). If you are on a tight budget, Buy 1 brand new Y7/Y8 Headbolt and re-use 9 of your D15B7/B8 bolts (YES they can be re-used because they are hardened bolts, not torque to yield, but I wouldn't re-use them more than once and would RECOMMEND buying a full new set, (Honda Dealers sell them for $7 new a piece, so $70 for all 10 of the headbolts you need *9 of the B7, and 1 Y8* or $135 for ARP's)
Be aware, you need to torque these to I believe 55-60ft-lb, not the 47 origionally meant for the B7/B8 Block as with a Z6/Y8 head it recommends 52, while ARP recommends up to 60.
4) D16Y8 Head gasket, 3 layer metal OEM gasket is ideal, I wouldn't use any other kind of gasket as thinner and you risk bumping your CR to nearly dangerous levels, thicker (Most likely not a metal gasket) and you risk the reliability of your setup
*edit* I used a Egay Headgasket before posting this, it failed Immediatly
, Turns out you can get an OEM D16Y8 Headgasket from HONDA for only $31!!!, call your local Dealership and pick up this part, last time I checked it was $60 at autozone for a Felpro brand one, OEM FTW!!!
5) A spare wiring harness is a big plus. A 92-95 EX/SI Harness is completely plug and play if you own a 92 Civic, or just a clip for the Vtec plug and 4 wire O2 Plug (my CX has a 1 wire O2, if you have a DX/LX you don't need that), I bought a 92-95 EX/SI Harness, but at the last second decided to keep my stock harness since I KNOW it works, and just laid fresh wiring for the O2 and Vtec solenoid.
6) This stuff:
Jack, Jack stands, good selection of tools (I have ALOT more tools than I took a picture of, but the basic kit gets the point across) Coolant, Oil, Oil filter, Injector cleaner (Since its all gonna be apart, now is a GREAT chance to clean the **** out of your injectors by gently dipping the tip in some injector cleaner and gently wiping it off) Rags, Simple Green (Nice for cleaning crap off of stuff),.
7) This Stuff:
Y8 Spark plugs, (I recommend NGK's) Spark plugs Wires *OEM, or generic is really fine unless you plan on running an aggressive ignition system, I got Z6 iridium plugs and 10.2mm wires as well as a accel HEI Super coil and will be screwing with my timing quite a bit (Turned out the plugs are the same for either head, but after further research Honda Ignition systems are plenty strong on their own, and you are better off just buying new Non-irdium NGKs and OEM wires and keeping your stock coil, I learned the hardway, but I now have all the heavy duty stuff incase I go that route), a new Alternator belt (Mine was pretty much shot, and I am running a UDP Crank pulley), O2 sensor (Again, if you have a DX/LX you don't need this), D16Z6 Timing Chain THIS IS THE RIGHT BELT, If you are doing a Y8 swap on your B7/B8 bottom end, USE the D16Z6 belt, it fits perfect, and tensions perfectly Don't listen to anyone else!!! None of this Z1 crap, its a D16Z6 Belt!!!), Water Pump (Because its only $35 and if it fails you're expletiveed, you might as well replace it) Some Vacuum tubing is nice to have in case you have to change anything around, some T's would be a good idea also. (I almost assure you that you will need a good selection of it, if you switch to a D16Y8 intake manifold it will become a necessity)
8) Cute assistant:
I have ALWAYS used my trusty Haynes manual when I am removing the head from my car, and if you don't own one, I'd buy one before even popping your hood (For 88-95 honda civics, you only really need ONE bit of information out of the 96-00 manual which is the valve gapping *Which is posted above earlier*, but the basic procedure is as follows:
1) Drain the oil out of the car - You are gonna have to do ANOTHER oil change shortly after the swap as well to ensure you have all the coolant you are about to spill into your oil out of your engine
2) Drain the coolant - (Small Wingnut on the far pass side of the bottom of the radiator)
3) Bust out the Masking tap and Permanent marker, This makes life SO much better for re-assembly, unplug connectors one by one from the head and intake manifold, being sure to label every single one as you remove it (MAP sensor, TPS sensor, etc etc) If you swap your MAP and TPS by accident when re-assembling and have a chipped ECU you can Fry it very quickly and easily completely by accident.
4) After the oil and coolant have drained, carefully remove the coolant lines from the intake manifold and head, do this carefully, and be sure to CHECK where the Coolant lines go, because some of them loop back, and around etc. Specifically the D15B7 has an extra coolant and vacuum line because the MAIN coolant rail behind the block has 2 outputs instead of the 1 my B8 block has.
5) Label and remove all vacuum lines from the intake manifold and Head, again makes life that much easier.
6) get under the car and remove the bolts that hold the intake manifold Bracket to the engine, just by (I think above) the oil filter, now would be a good time to put the new oil filter on as well (Trust me, you don't need it anyways, and its a PITA to try to remove the bracket from the Intake Mani from the topside, you will cut the hell out of your hand trying)
7) remove the Dizzy from the head, and put it aside (B7/B8 Dizzys work on Y8 Heads, I don't care what anyone else says, worked PERFECTLY, also go ahead and replace that O ring as its maybe a $1 and helps keep oil in your head and not on the ground)
8) remove timing chain covers *Both upper and lower* and loosen the timing belt tensioner slightly, and remove the timing belt from the head. (You will need to replace your upper cover with one from a Y7/Y8 if you plan on covering your cam gear, i have not yet done this, but my car is not a daily driver)
9) Remove the valve cover from the head, and refer to haynes for proper procedure to remove the head from the block (There is a certian ORDER to remove your headbolts, if you do it incorrectly you can warp your head or block), again ensure EVERYTHING has been disconnected from the intake manifold and head, be slow and careful when doing this. I typically leave the intake manifold on the head when removing it as the bolt on the bottom center of the intake manifold is a HUGE pain in the ***. (Don't loose the Dowl pins that go between the head and block to help line the head up, you will most likely need these on your new head)
10) Pull out the the Oil Jet that will be in your block just above the top middle Headbolt hold between pistons 2+3
You can see it in that picture as that little pin-hole above the headbolt hole, grab a small screw, and gently hand thread the screw into the oil jet and remove it, it will come right-out. this part is not built into your new engine head.
11) Take a look at your crappy old head
You can see how bad mine looks, the valves were chipping, and I think I had a small crack on my #1 combustion chamber between the 2 intake valves.
12) Sit back, and have a drink.
I hope this has been informative to everyone, and I hope an Admin can move/stickey this in the write up section as it was VERY hard to find out how to do this swap with a complete write up with do's and don'ts
And until next time, here is a picture of a co-worker of mine!
CHAPTER 2: RE-ASSEMBLY!!!
Alright, now that you are ready to bump you stock CX's 70hp up a notch, it is time to re-assemble it all.
Again, I recommend removing the intake manifold bracket attached to the block, as well as attaching the intake manifold/TB to the head prior to mounting the head for ease of reaching the lower intake manifold bolts.
When Switching to a D16Y8 intake Manifold *mine was completely bare* I switched over my Throttle body *MAP and TPS sensors*, EACV (IACV) *The thing toward the firewall that has 2 coolant lines going to it*, IAT, and Purge Control Solenoid* you will discover a few things.
A) The IAT no longer has a home *The little white prong thingy that was screwed into the back of your old intake manifold* You can just drill a hole in your intake plumbing and screw/RTV it into place and you may have to make the wires a bit longer for it to reach, but I currently have mine just mounted off of one of the large Vac lines off the top of the Y8 Intake Manifold and it hasn't given me any problems yet.
B) The Purge Control Solenoid *2 small Vac lines, 1 to the manifold, 1 to the canister* no longer has a mounting point, Mine is just hanging, but it seems fine IMO, I may mount it to my firewall later with some longer Vac lines.
C) The EACV (IACV) Won't Fit because of the casting on the Y8 Manifold. We took an angle-grinder to the back of the intake manifold and carefully hacked off the casting tabs that were in the way of my B7 EACV Valve.
Back to the head:
Remove the Plastic guard behind the cam gear on the head *You will have to remove the cam gear for this, we used VERY large channel locks with a rag over the gear as to not damage it when removing it* and replace it with the one from your CX/DX/LX head so your timing chain cover will mount correctly.
I used ARP studs for my setup, put the 1 Y8/Y7 stud in the corner closest to the passenger seat *Vtec Solenoid corner* and the other 9 in the remaining spots, Make them tight/snug with an hex key socket and then lay down the gasket (I used copper spray on both sides of my HG for a bit of extra insurance).
At this point go ahead and remount the head/intakemani/TB and torque the nuts per the Haynes/chiltons manual. Be aware ARP Studs for this setup require a 12 point socket, not the typical 6 point you'd normally use. ALSO do not mount the head with the sparkplugs already in it so you get the most accurate torque possible when doing the head bolts/studs
A few quick notes, the D15B7 Throttle body is the SAME SIZE as a D16Y8, so just reuse your Throttle body.
Begin re-attaching all your pre-labeled lines to the head *Everything on the head is in the same position as the old head, same with the TB, the differences are gonna be the placement of things on the Intake manifold and Fuel rail (Aren't you glad you labeled everything?), be sure you remember where everything goes SPECIFICALLY on the Intake manifold as some things have changed distance and will require new plumbing.
Also, the fuel pressure regulator is going to need a much longer piece of tubing than origionally on it if you used a Y8 intake manifold. So you will need to pick up some small emission line tubing to connect the FPR to the intake mani. also the fuel return line had to be lengthened as well * I used a plastic Straight-through connector with some more tubing for it to reach*
Once everything has been re-connected, if you have a DX/LX all thats left is wiring Vtec *Many different articles on how to do this, google it, or search on honda-tech.com
For us CX owners we have to wire the 4-wire O2 as well *Will work on a small write up for that later*
that leaves us with just a few small things left, Bringing the motor and head to TDC, Attaching our Timing Chain (MAKE SUPER SUPER SUPER SURE you are at TDC on your head and block after you've tightened the tensioner back down, and be slow and careful when you are bringing them both there. After you are on TDC You can re-attach your timing chain cover and crank pully, Attaching our Crank pully (I sure hope you didn't loose that Woodruff key when you took that bad-boy off) should be fairly easy at this point, be sure to torque it correctly as I've read a few horror stories about crank pulleys falling OFF of running cars, so be sure you triple check it.
After that is done, slowly spin the crank with a 17 mil socket on the crank bolt to double check for clearances *Leave your sparkplugs out for this so you have no pressure and can feel if you are hitting a valve or not*
Again, my doodle from earlier:
I'm using a lightweight Aluminum crank pulley with NO accessories except for the Alternator, keep in mind that you WILL need to purchase a smaller belt if you are doing this I purchased the 'stock' belt and it was 3 inches too big. *The belt in my picture EARLIER is the correct part number if you are re-using the stock crank pulley*
I'll return later on this week with the final chapter in this project!
Well... Blew the headgasket AGAIN... But here are some teasers of my Epic Failure.
I'll have it running right soon enough.
After replacing the headgasket again I still had a bad miss/stutter down low and after a TON of research found that you have to use a D15B7/B8/ D16Z6 Cam gear ON the Y8 head otherwise the TDC of the cam will be 4.75* (A half tooth) off from your crank and it will run like ****, I'm changing it out tonight and will give my final verdict!
AGAIN, my cam doodle
Car is running correctly!!! (as of January 12 2008)
Overall the car moves out MUCH MUCH better, but I am still debating if the swap was worth it.
I spent about $800 when its all said and done, but keep in mind please that The head was professionally rebuilt (3 angle valve job, 2 new valves, resurfaced the head) which set me back a fair amount and I bought a number of modifications which were really un-needed (I learned the hard way so you don't have to), if you have a head which you know is in decent shape, and your using your D15B7 intake manifold/TB, and you don't need to replace your water pump *Or your cam gear for that matter if you don't have a milled head* you can do this entire project for around $350 if you get half-way decent deals.
So $350 for 50hp (realistically on a D15B7 you'd be seeing 20-30hp gain, but you also get to wind your motor up to 7200-7500RPM and get useful power out of it which is a BLAST)
MY SHOPPING COSTS:
D16Y8 head - Free
D16Y8 Rebuild - $263
Sparkplugs and Wires - $45 on Fleabay
Headgasket - $31 from Honda
ARP Headstuds - $135 from ARP
Accel HEI Supercoil - $69
AEM Tru-Time Cam gear - $44 from Ebay
Stock P05 ECU - Free
having my ECU Chipped and socketed and converted to Vtec with a basemap - $100
Water Pump - $40
Valve cover gasket set - $20 (Included plug well seals, dizzy o ring, and valve cover)
D16Y8 Intake Manifold - $40 and came with a B+M FPR GR26EAT deal, normally these go for $100
Egay Intake - $25
Megan Racing UDP - $40
Having the pulleys AC and PS shaved and balanced - $60
So effectively I have rebuilt my entire motor minus my Piston rings for that price.
Ups and Downs:
The car now has Vtec and pulls strongly up top and I have my redline set to a staggering 7800RPM, but it runs out of steam about 7500RPM (Which is still alot better than the 6000RPM redline the poor old 8 valve head had, or the 6500 that the 16 valve B7 had while neither made power over like 5K anyways).
Its torque is still very similar as to how it used to be *The car used to be an 8 valve car which had 92 ftlb of torque that peaked as early as 2200RPM, so needless to say I feel like I have the same low-end that I used to and I still only have 1.5 liters of displacement obviously*
My transmission Still sucks chunks. My 1-2 upshift doing WOT runs up to 7200-7500RPM hits at nearly 50mph, and my 2nd to 3rd upshift hits going over 80mph, so I suspect when I hit the quarter mile, I will still JUST be shifting into 3rd gear at the end of the track which kills.
so in simple terms, "It moves out great until it redlines in 2nd at 80mph where it falls flat on its face...."
Shifting into second at 7500RPM Grabs at about 4200-4500RPM, which is VERY nice as before the car was grabbing at 3000RPM which meant I had to wait a week for the motor to develop power again with the D15B7 16 valve head I used to have on it
3rd gear is useless on a CX transmission, at redline, The math says I won't hit redline in 3rd gear until 155mph (My redline is 7800RPM)
I am now feeding the car Premium fuel to reduce any kind of chance of detention, but if it was tuned for regular gas, I'm sure I could run 87 octane safely.
so the bottom line is, "Was it worth it?":
Right now, for me, quite simply "Yes and no"
For 2 main reasons:
The Up side
at the time of this swap, I had a D15B7 head on my B8 block with a hard-core compression leak. It ran an 18.5 at the track and could easily be outpaced my my Daily driver... The valves were burning up and it was on its last leg... The 8 valve head sucked, and I have NO need for an ANOTHER eco car (I own a 2007 ford focus as my daily driver, why do I need 40mpg in 2 cars when I can only drive one?)
Now I have a fully-rebuilt civic that has alot more kick, and still gets killer gasmileage because of the transmission. I plan on picking up an SI tranny, and I'm confident this car can ripoff a high 15 second quarter mile once its tuned with decent tires and an SI transmission. Right now I assume I will be in the mid 16's on my fat [175/70/13] tires
The Down side:
For another $200 I could have done an LS swap which would have had more torque and similar horsepower. I will be most likely spending about $200 on an SI transmission before this is all said and done as well... If you want cheap EASY horsepower, Buy a B18B1 off an integra and drop it in, Its a VERY VERY easy swap, and can be had for less than a grand. *Flamesuit on* Also in my opinion a B18B1 has alot more potential than a D16Z6 that you can buy for 'half the price' Yes you can buy an entire Z6 for $500, and just drop it in, but there is ALOT more involved than you think, and you might as well just buy the B18B1 for that extra $500 and enjoy the extra torque and horsepower out of the box.
When its all said and done, I don't regret it. When you buy a motor for a swap, you really have no idea what kinda condition it will be in, and you are best off having the motor rebuilt before installing it anyways, which means "If you wanna do it right" you will be spending upwards of $1600 to stuff an LS B18 into the car.
For someone who wants a little more kick out of their D15B7 or D15B8 Civic, this is a GREAT option if done economically (Ala has a D16Y8 head laying around or can get one for like $100, this would be a FANTASTIC modification and you can get it done for sub $300 and you will have replaced your headgasket and a number of other important pieces at the same time, making it well WELL worth it), I made the mistake of "Go big or Go home" on a 1.5 block.
I will RESERVE FINAL JUDGMENT until I get an SI Transmission, the car moves out much better, the motor has plenty of kick, but it is being slaughtered by my CX Transmission
Modified by Dasfinc at 2:34 PM 1/12/2008