So I had my 95 Civic EX engine replaced almost 2 years ago by a small garage that is out of business now. It failed CA smog. It didn't occur to me that the engine was changed until the spark plug wires wouldn't fit during a recent tune up. Stupid me didn't see that the engine says VTEC while the original wasn't VTEC. So I ordered new wires for a 95 VTEC engine and problem solved.

Now my stepdad thought that since the hydrocarbons are high on the smog check that it may be running rich and it may be due to the engine coolant sensor failing. When we tried to replace it, none of the 95 engine parts looked right. I told him about the engine swap and he suggested it may be an older engine. So he found the engine # from the block and an online site says it was installed in Honda and Acura cars from 86 through 93, depending on the model. Assuming the website is correct, I lost all hope for the engine ever passing smog. Then this morning I though about how the distributor cap, rotor, spark plugs all were ordered to fit the original 95 non-VTEC engine and they installed just fine (and the rotor/cap looked the same). What are the odds it is a 95 VTEC? The engine was stamped ZC7406.622 if that helps. Any other sites where I can cross-check the engine?

 

That's called a "ZC" engine but it is basically a D15 block, it may have various heads including one that is DOHC. I don't think that setup is legal in California since it's an older engine than the car is and it was also never sold in the USA. If they check the numbers you'll fail before you even get to the sniff test.

For the most part, D-series parts interchange readily. You probably have the original USDM distributor, manifolds, etc-- only the block and head are JDM.