Hi guys, can anyone help me identify what head/block I have. My car is a 1993 Civic Hatchback auto. The block says D15B no numbers after that. The head says PM3-12 9|4 which I'm guessing is a 1995. On the right hand side of the head it says 2| 1|6. Any help is appreciated.

 

https://honda-tech.com/honda-civic-d...-here-3210150/

 

So would that mean mine is a 1995 D15B7 head. But how does that explain the D15B block?

 

Most likely, unless it has a carburetor.

People mix and match heads and blocks all the time.

 

Thanks for the info. So the D15B block is a jdm motor off a ?

 

Honda D engine - Wikipedia, the free encyclopedia

 

So it could be either one of these? Found in:
1988 Honda CRX 1.5X (rare)
1990 Honda Civic 25XXT Formula (Japanese Market)
Honda Civic Ferio MX (Japanese Market) EG8
1998–2001 Honda Capa GA4 (Japanese Market)
1988-2001 Honda Civic SH4 EF1

 

Or
Found in:
1992–1995 Honda Civic Vti (Japanese Market)
1992–1998 Honda CRX DelSol (Japanese Market)

Since the head is obviously not the original one.

 

The block also may have been mated to a D15B VTEC head.

 

Yep

 

Any way to tell exactly which one?

 

I don't think so.

 

Thanks for the help Ron.

 

Just curious, what would be the benefits if any of doing a d15b7 head instead of the original b15b?

 

Probably nothing.

 

Well it will need a rebuild soon. I'm debating in rebuilding this motor or going with a d15z1. I'm mostly looking to get the best mpg I can get. Would anyone know the differences between the motor I have and a z1?

 

That is something you can find fairly easily by searching. In a nutshell the Z1 is meant for max fuel efficiency.

 

I understand is made for fuel efficiency but my question was how does it compare to the motor I have.

 

90hp compared to 102hp new

~40-45mpg compared to ~30-35mpg

But that is assuming a non california Z1. The california Z1 is more in line for MPG as the B7.

 

Now that you have an answer that hopefully gives the info you were looking for, my question to you now is why you chose NOT to search these things on your own. It may sound like I'm picking on you but I'm honestly just curious seeing that you've been on this forum for many years.

 

My JDM D15B had dual carbs.
I just swapped in my original fuel injection manifold and distributor and everything worked.

 

I did search and I know the differences between horsepower. I wanted to know how did my motor compare in MPG to a Z1. I was just curious why anyone would put a B7 head on a B15B block and if that made any difference in MPG. Your answer "probably nothing" was not what I was looking for. So I though I would ask again.

 

No worries, vague questions receive vague answers. But now I can see what the disconnect is on both our ends.

You have to understand "D15B" is really a generic engine designation. It comes in many forms but the most common version people know is the VTEC version. What you have in your car really can't be confirmed until you open it up because like "RonJ@HT" stated:

The biggest most important difference in the D15B VTEC block is the crankshaft that is used. It shares the same stroke as any other 1.5 crankshaft but it has the bigger rod journals that is shared with the 1.6 VTEC crankshafts (and maybe all D-series 1.6 crankshafts? Not sure, I've never bothered to look that far into it). Then comes the use of the same length 137mm rods used in the 1.6 engines and it's unique piston. None of this can be confirmed until you remove the head because on the exterior all you get is "D15B" for the block markings. Maybe someone has actually deciphered the serial number break down like they've done on other engines but who knows.

So for your question as to why anyone would put a D15B7 head on a D15B block? Because they can. Because that's stock. Because that's equivalent. Because it came like that from the factory. Take your pick, at the end of the day, it's still a DX. Realize that just like ZC = 1.6L, D15B = 1.5L. The block doesn't care what head is on there. And because people swap heads around at will, the block REALLY doesn't care what head is on there. I will say there's an off chance maybe you actually have the D15B VTEC block and in that case, you have a higher rev capability because of the rod to stroke ratio but that's about it. Now as for the effect on MPG I'd love to know if anyone has actually ran that particular combo and see what the difference is with the better rod to stroke angle. To be honest though I doubt anyone here has done it and compared. I can see myself doing it just for ***** and giggles (yes I have everything needed to make an equivalent setup and I do actually intend on doing it some day).


I think the CA Z1 is more comparable to the B8 (8 valve) in terms of MPG and the FED Z1 gets a couple more than ~40-45mpg. Of course condition, driving habits, hills, etc will all play into the real world MPG...

 

THIS, that is what I was looking for, thank you for that answer.

 

Glad I could help LOL

I think the general misconception is that all D15B engines are the same. My first car had one, 91 Civic STD 4spd DPFI etc. I swapped later on to a different engine but since the D15B was out, I figured I'd open it up for fun. Once the head was off, I could see that the pistons inside were flat top with PM3 designation. That's how I learned that D15B blocks are literally that, a block stamped with D15B.