Hello all- i am brand new to the forum and hoping to strike gold and get some answers...here the deal:
1) Just bought a car from a dude, went to replace the exhaust and cat to pass cali smog and suprise...the parts don't fit. So then i start looking closer- engine code d15b- no numerical designator folling the "B". Called the guys at honda and they told me they aren't even pulling it up. The guy kept asking me for the number after the b like i was retarded, even though i kept telling him that there wasn't one. I owned a honda back in the day and i remember a tuner buddy of mine mentioning that JDM engines don't use a numerical end designator...that is my situation on the block.
2) The head does not appear to be vtec (somebody tell me where to look for the solenoid?), also, found out the dude had replaced the head with the head from a 93 civic cx???
3) with the above info, can anybody give me guidance on what i have, what i should do, and how i can pass smog???

-Any and all thoughts, opinions, and info would be greatly appreaciated- except for comments about how i was an idiot not to confirm this kind of **** before i got the car- already figured that one out! Thanks!

 

Is your check engine light on? Does the light work? It would come on for a few seconds when you first start the car, then turn off.

So the guy replaced the nicer head with a D15b8 head, which is nonvtec and allegedly has 2 valves per cylinder? Ouch.

 

all the d15, and d16's have the same exhaust bolt pattern, so i dont under what your saying, the d15b is simular to the d16z6 (92-95 ex/si engine), and the head you described is a d15b8.

 

Yes there is such a thing as the D15B(nothing). It should be a VTEC unless head has been changed. There doesn't seem to be any easy numbering system on the heads-- identify them by appearance and features. The CX engine was an 8 valve, I couldn't imagine someone putting one of those on looking for performance but...

The VTEC valve would be on the back of the head (intake side) on the cylinder #4 end. Don't confuse it with the EGR valve which is also near there but actually attached to the intake manifold, not the head.

What model year is the car? To to comply with emissions is based on the model year of the car not the engine. This means that (in places that are real strict about it such as California) strictly all the engine parts need to be from the same year or newer.

Like 94 said if you start at the engine, all the exhausts bolt on the same. You may have some sort of aftermarket header, which connects to who knows what as the next piece. There are two general types of stock exhausts. The 96 to 00 DX, LX (non-VTEC) used an integral manifold / cat converter. This is not what you really want due to its restricted performance and tendency to crack. Most other models have a more conventional system with cast iron manifold, front pipe, and converter under the car just back of the firewall. I think that it is legal to convert a DX to the EX undercar cat system.

 

cool- the question now becomes- can i run this **** usdm head on the jdm block and what problems am i looking at doing that? it idled lumpy (probably had something to do with shot o2 sensor/cracked manifold. MK378- you hit the exhaust question on the head- what has confused me is that it has the 96-00 integral type system you mentioned- but when i had that system out of the box at napa it wasnt even close. The one i am trying to mirror is stock as a ****- cast iron and integral. i just cant find one that goes to the d15b8 head (ie- when i tell napa i have the 1.5 ltr SOHC nonvtec engine). What do you guys think- just roll with the d15b8 head- get the parts that are supposed to worl with it, and make it work? My problem is i really need to get this thing smogged and registered soon and with minimal cash outlay or i am going to have to cut my losses. And i really don't want to do that because i have been wanting to work on one of these forever, i just didn't anticipate having this big an issue this soon. Thanks again for replying so quick and not busting my ***** about getting screwed on this- Jordan

 

Me again- i also read something about popping a d15z6(?) head on this type block to keep performance, and i have a feeling the parts would be easier to identify and source as that is fairly common usdm...might be expensive but if that would be the best budget route i would consider it...
94- you said d15b is similar to d16z6- what are your thoughts on that?

 

Again, what year is the car? Take the valve cover off and count the valves. If it's really 8 I think you're going to need to swap the head, it may be more cost-effective in time and trouble to swap the whole engine. The 8 valve was a real dog in performance and it probably pollutes more too. Also need to identify the computer and intake system in use to see if it matches the car. Swapping back to an earlier computer system is not street-legal and also likely to fail tailpipe test.

 

If the head is indeed the 8 valve we think it is, you will most likely want to find a d16z6 head and a P28 computer for it. The z6 head is 16 valve and vtec. It'll perform better and more than likely pass smog.

Again I ask, is the check engine light on? And have you confirmed that it works?

 

Ok- sorry i missed your questions. It is a 93 civic cx hatch. No engine light warning, but have not confirmed that the light is fucnctioning. I feel really comfortable doing basic mechanical, but anything electrical is over my head.

????Am i crazy for being suprised that this head and block combo as it stands right now is even working? I have always loved hondas becuase of reliability and flexiiblity- where do guys get this info- is it all word of mouth or are all the blocks and heads in the d series pretty much interhangeable????

As it stands i think i am going to have to just get an exhaust on there somehow...can't afford the time and money for a head upgrade juuuuussst yet. Apparently the guy told me he just changed out heads, so if i can get an exhaust i should be able to get some good mileage before having to do anything more...maybe i will even save enough for a b18b ; )

 

the cx i believe if i remember correctly(been awhile since i owned one), has a 1 wire oxygen sensor and has the cat on the exhaust manifold. the vx model has the same type of exhaust but has a 5 wire o2.

if you can post some pics of the ""fitment issues" your having so i can better explain thing and show you what to do.


as far as performance yea grab a d16z6 head/ intake manifold/ distributor/ ecu and install it on your d15b block, then you will need to run 2 wires from the vtec to the ecu.