1075 Wiseco Piston to Cylinder Wall Clearance?

I did a rough measurement and this was the bore numbers.

The very TOP: 71.80 MM
The very BOTTOM: 72.00 MM

so the bore has a taper?

I work in thousands usually.
Thats 2 tenths of a millimeter. or almost 8 thousands of taper!!!!

Dr. Gamma wrote: I work in thousands usually.
That's 2 tenths of a millimeter. or almost 8 thousands of taper!!!!

I always tried to keep no more 1 or 2 tenths of taper from top to bottom in my finished cylinders..

So im good at 2 tenths then.

4TheKZ1000 wrote:

Dr. Gamma wrote: I work in thousands usually.
Thats 2 tenths of a millimeter. or almost 8 thousands of taper!!!!

So im good at 2 tenths then.

No, You have 2 tenths of a millimeter, not 2 tenths of a thousands.

My dial bore gauge is in thousands. thats why I work in thousands when measuring cylinders.

It does sound like the initial re-bore was badly done.
You need to find the bore clearance at the widest point.
If it's within limits you may be able to get the bores squared up, honed and re-ring the pistons .

Thanks for the help guys.

I will call the machine shop/guy on Monday and ask him about the tapper.

I will probably just run cylinder up to him and have him check it while im standing there.

I found the original Wiseco piston box and it had the clearance on it. 0.0020 in - (0.051 mm) as ZED said it was.

Keep us posted....

The cylinders will develop a taper from the pistons rocking near the bottom of the stroke. It gets much worse in big two strokes. I never bore with a taper.

ZERO wrote: The cylinders will develop a taper from the pistons rocking near the bottom of the stroke. It gets much worse in big two strokes. I never bore with a taper.

In my experience the point of max wear is just a little down from TDC. You suggesting the max wear point is at the bottom?

OK, This is going to hurt.

I am a complete dumb ass. The truth of the matter is I'm just dangerous enough to create a thread like this.

The cylinder is 100% healthy with no problems. The skirt clearance to cylinder is 2.1 thousands on 3 cylinders and 2.2 thousands on the other. The ring gap is spot on.

I now realize that the measurement is on the SKIRT OF PISTON and not the top of piston..

My friend was quite nice and didn't ride me on it.... :blush: :blush: :blush: :blush: :blush: :blush: :blush:

If I wasted your time, I hope the good laugh your having right now makes up for it.

Live, learn and dig hole - insert head......... :woohoo:

OH MY ........ it could be worse I guess.

Thanks Ganmma and Zed........and others

Hey! No problem and happy to help no matter what.
As long as the ZED is not dead is ALL that matters :lol: