Good day guys

I have a 1993 Honda Civic 4-door 160i Luxline with a d16a7 single cam motor.

I wan to upgrade to a twincam but I don't know which engine's head will fit. Now I want to know from you guys:

Which Honda Civic motor's head will fit perfectly onto my motor without any modifications?

 

short answer, none

 

Within the first 10 minutes of searching google or using HTs search option you will find out that D-series fit D-series and B-series fit B-series. So no DOHC option for you if you keep that D series motor.

Whatever questions you may come up with may have already been asked by someone here. There are over 346,000 threads in the Honda Civic / Del Sol (1992 - 2000) section alone with over 3.2M posts. This is now a library not a help desk.

 

Slightly flawed statement.

 

In regards to heads its spot on.

 

D16A1, D16A8, D16A9, all DOHC, all not directly interchangeable with D-Series SOHC blocks.

 

I should have known from OPs question of can a DOHC head go on my SOHC block that I needed to be more specific. Not sure why I focused more on B's fitting on D's because that wasn't even a question they asked... anyway. Should of left it with not_so_jdm's post.

 

That's why I said "slightly" flawed. I knew what you meant, but people who don't and just read it might think they can grab one of the heads I listed and put it on.

 

Now I am curious... why is the first upgrade you ask about doing is swapping to a "twin cam" head?

My first guess would be for looks.

 

Because DOHC heads are more efficient than SOHC heads. This is a simple, known fact. Regardless, though, what OP wants to do isn't possible.

 

Since the subject is present.... I have never understood this. I can piece together more flexibility as you can adjust each cam separately but that doesn't automatically make it more efficient, or maybe it does...

Can you tell me why the DOHC more efficient? What makes it more efficient?

For the life of me, this has eluded me.

 

Because the intake and exhaust events can be tuned/timed individually. The only way to do that with a SOHC would be to have custom cams made with different angles between the intake and exhaust lobes to test until you find the best one (which can be different from motor to motor), and that would be comically cost prohibitive. Also, because each cam is only riding one set of valves, an SOHC cam has to fight against two sets of valve springs, whereas one DOHC cam only has to fight against one set of valve springs, while the other cam fights against the other set.

In short, better control, and less resistance.

 

The flexibility is the key, was staring right at it with a dumbfounded expression.

I guess the resistance compounds when both springs are active on one cam instead of just doubles when separated onto two cams?

 

I don't know the exact numbers behind it, I'm just casually aware of the difference. Since there's still a belt involved tying the two cams together, I seriously doubt it's as simple as additive/multiplicative/exponential.

 

You could always weld two d series motors together

 

Great idea!