OK, just swapped short blocks to High CR 89mm bored, 90.7 honda stroke. I have used this short block before for about 2 months. No issues, noises, nadda.

At first we had a large, loud rattle everywhere. Got louder with revs and resonated at 3500 RPMs then died off a little. When driving it sound like it came from under the car. Sounded like cards in wheel spokes.

We swapped TCTs and modified the TCT piston (made it longer) and no rattle at idle and nothing till you get to 4300 rpms then rattle just screams. Sounds more like jar of marbles now than cards in wheel spokes.

Odd thing it projects to the driver side of the car and sounds like it is coming from the under, on top of or around the intake manifold? If you stand on the passenger side of the engine bay, the sound is a fraction of what it is.

Just wanted to see if this unique sound has happened to anyone?

Patrick