This seems to be the hardest question to get a definitive answer to so after doing a search and coming up with almost nothing I'm hoping someone who actually knows the answer will respond.

According to Wiki, the sohc zc motor is similar to the d16a6 with the only difference being the cam shaft timing. Does this mean the camshaft is the same and it's simply timed more aggressively or does it mean the cam is lobed and timed differently effectively giving you a little more horsepower?

The reason I ask is that I have a zc swapped into my 91 crx si that I race in ChumpCar and the motor blew so I'm replacing it with another zc because the motor is pretty competitive in my opinion. The problem is that it is technically a motor swap so I need to declare what I've done so as not to incur penalty laps.

To my understanding the motors are virtually identical with only the cam timing changed to gain horsepower. Can someone give me the exact specs of both motors, please!

 

It's not the timing of the cam, it's the actual cam.

If you check out this site, you can see the differences between d16a6 and the ZC SOHC cam size.

http://www.norcalcrx.org/tyson/SOHC_Cam.html

 

the sohc zc non vtec is the same motor as a d16a6 except the zc has a more aggressive camshaft to put out a lil more power but other than the cam they r identical motors

 

I've read that the a6 and MPFI ef SOHC zc have different oil pumps. The MPFI ef SOHC zc pump having a smaller gear but larger port.

 

DOHC ZC has a different oil pump i believe is confirmed.

but no reason to lump the SOHC ZC in there.

please make a distinction whenever talking about "ZC" oh which engine youre talking about.

 

https://honda-tech.com/forums/showth...ht=zc+oil+pump

That's the thread I was referring to. If I am wrong I'll delete.

 

i guess my memory is fuzzy.

it still needs to be said, you need to specify which "ZC" engine. there are many types of even SOHC ZC, "ZC" is not specific enough.

this is the reason ppl like the OP get so confused.

 

Well he did specify in the title about the sohc, so I mentioned the sohc. And yes, I understand there are many different zc engines. I'll edit my post.

 

Finally some very helpful answers! According to the camshaft chart posted its only the 'Actual' lift that is different between the cams. Are you positive that the cam timing is the same?

And it's definitely the Fuel Injected sohc that I have.

Thanks for the oil pump info to, it may be wise for me to check that out as well. Has anyone tried making the oil channels slightly larger to get more oil where it needs to go. I have a little info on this but am not ready to mess the engine up by botching the job.

 

why are you determined to believe the camshaft has a different timing? the chart doesnt represent just 1 measurement, by 1 person, 1 time. i wouldnt publish it if it werent true and verified.

the timing of the carbd cam is different, THATS the odd one with different timing AND lift. because the fuel injection is completely different.

the wiki on D series is absolute crap. nobody should quote that, and the thread here on HT that reposts it ought to be straight up deleted.

 

I'm not doubting the veracity of the chart you posted, so settle down!

I'm simply asking if the horsepower gains can be solely attributed to the difference in the 'Actual Lift'. All the numbers of the ZC and D16A6 are exactly the same except for the actual lift. It seems like a big horsepower gain from such a small difference.

 

i believe the exhaust manifolds that came with SOHC ZC non VTEC's were like Z6's and all later D series, 4-2-1 cast design. not our north american 4-1 choker.

taking that off and putting a later OEM 4-2-1 alone makes a lot of power with the D16A6.

so no, its not just the cams that are being accounted for in the published horsepower numbers. its a well known fact, verified by countless dyno's that the HP number for the D16A6 is underrated.

the difference in lift alone is probably not even producing much power gains anyway.

thats why i always suggest replacing the stock manifold to ANY 4-2-1 design as the first engine mod.

 

We put on a very inexpensive 4-2-1 header and I can tell you that the motor is quite peppy.