D16A1 engine swap, part 3
I normally would not dedicate a whole chapter to the clutch install, but
this was no ordinary clutch install! Instead of using the stock 1989 Integra
flywheel, I chose to use one from a 1991 CRX Si. The flywheels are pretty
much (famous last words) identical. The main advantage of using the 91 CRX
Si's flywheel is that it has a larger friction surface for the clutch disk.
In addition, clutch availabilty for the 1989 Integra was poor. I overlooked
a couple of "minor" measurements that ended up setting me back over a day.
In the end, I got it worked out. I hope someone learns from my mistakes...
Here is a look at the rear main seal. When I had the new one pressed on,
my buddy had made me a special .030" thick aluminum spacer to move the rear
main seal back a little. We did this because the old seal had worn a pretty
significant groove into the crank. I wanted the seal to be riding on a "fresh"
part of the crank. I figured that there would be no way that moving the seal
such a small amount could interfere with the flywheel...
I was wrong! As soon as I put more than 10 ft/lb of torque on the flywheel
bolts, the flywheel would barely turn. Honda did make the clearance
that tight. I wanted to keep the rear main seal spacer in there (for the
reasons stated above). So, I opted to have .040" machined off of the
"shoulder" of the flywheel. This shoulder simply locates the flywheel onto
the back of the crank. It was over .220" deep, so removing .040" was not
After machining the flywheel, it bolted right on and I figured that
I was on my way. Here is a look at the Action clutch's pressure plate.
It is a dual-diaphram design and offers plenty of clamping force. It's
also makes for a pedal that is very stiff.
Here is a look at the Action clutch disk. It is a 6 puck unspung design
that uses Miba metallic friction pads. This clutch will easily hold 400hp
and 250 ft-lbs of torque. That's way more than I need, but it's better to
have a clutch that is overkill than to have one that gives you no room for
This picture shows the big problem that I ran into by using the 91 CRX
flywheel. The hole in the center of the Integra flywheel is about .150" larger
than the hole in the center of the CRX's flywheel.
The hole in the center of the flywheel is a receiver hole for the transmission's
input shaft. Since the hole in the CRX flywheel was smaller, the tranmission's
input shaft would not fit inside. Because of this, the transmission would not
bolt up to the engine. Why not just push the bearing out of the CRX flywheel?
The center of the flywheel supports the mainshaft and keeps it from flexing
too much under load. Leaving a gaping hole in the center of the flywheel
would be a big compromise to the transmission's life.
This is when my buddy (aka The World's Greatest Machinist) saved the day. I
was not able to simply use a bearing with a larger inner diameter because all
of the bearings with larger inner diameters were also thicker. I needed a
bearing that had the same outer diameter and thickness of the CRX's pilot
bearing and the same inner diameter as the hole in the Integra's flywheel.
He made me this custom pilot bearing that had all of the correct dimensions.
The material is graphite-impregnanted silicon bronze. It does not require
He overnighted me the bearing and I had it the next morning at 10AM. I
pressed it in, bolted the transmission up, and was on my way. The white
marks on the flywheel are indicators for where to mount the pressure plate.
I had the whole rotating assembly balanced, so it was important to assemble
everything the way it was assembled when it was balanced.
Back to main