hey guys..... i have a 94 gsr motor with eagle h-beam rods and wiseco 9.8to1 pistons and it only has 40miles on it and it makes this funny rattle from like the top of block, bottom of motor area...... what would make this happen?

 

damn it I ment top of block bottom of head....

 

Just when cold or all the time? What prep was done on the cylinders/block? Forged pistons need more clearance due to expanding more from cold to hot than cast ones. This can make them rattle when cold. Of course loose wrist pins could do it too or worn or tapered bores.

The ones I have heard with forged pistons have a light rap or slight knock that goes away as it warms up. If that is not what happens, I would be concerned about clearances in bearings.

 

If it does it when the motor is cold, then it is normal. This is the forged piston 'purr". The pistons are smaller in the cylinder due to the heat inside, and when the engine is a normal operating temp, the pistons expand due to heat to the correct bore and seals up.

If it does it ALL the time, then check timing, make sure your piston/valve clearance is good (should be since you are at 9.8:1 CR).

 

FIRST OFF CHECK UR CYL. WALL TO PISTON CLEARANCES THEN CHECK IF UR PISTONS ARE SILICON OR NON SILICON BASED SOUNDS COULD BE MANY THINGS