1.5 instead of 1.6 in '90 CRX Si?

Yesterday the timing belt broke on my '90 CRX Si. I'd replaced it
previously at 60K, and was planning to do so again soon, as I just
passed 115K about a month ago. Amazingly, it looks like I got lucky, as
my shop checked all the valves after I had the car towed there, and
everything was within spec and working properly.

Now the weird part (which I now remember discussing with my previous
shop the last time the timing belt was replaced). After getting all the
necessary parts, when my mechanic went to install the new belt, it
didn't fit - it had one tooth too many. After scraping away a layer of
grease to read the codes on the block, he discovered that the engine was
actually a 1.5L one instead of the 1.6L engine that's supposed to be in
'88-'91 CRX Sis. Our first thought was that someone had done an engine
swap before I bought the car (I'm the second owner), but when my
mechanic called a dealer he knew and ran the VIN by him to look up, the
dealer said that some '90 CRX Sis had been fitted with the 1.5L engine
instead of the 1.6.

Neither of us had ever heard of this before, and after some Googling on
both the web and Usenet archives, I can't find anything corroborating
it. Has anyone here ever heard of a factory-installed 1.5L in a 90 CRX
Si before? I have to admit I'm skeptical, and think the chances of the
original owner (or the dealer I bought it from) installing a DX engine
to replace a blown Si engine are greater.

Dave

 

FWIW, the Chilton's manual for the CRX Si, 1986-1991 supports what you found.

Specifically:

1986 and1987 = 1.5 liter = engine ID #s EW3 and D15A3
1988-1991 = 1.6 liter = engine ID # D16A6

 

I had a 1989 CRX with a 1.4 engine.

 

ALL 88-91 Civic/CRX Si/EX come with a D16A6 1.6L.