Cylinder resurfacing the sealing surface

[Roslin]

As my engine broke 6 of the 24 head studs, and leaked a bit between heads and cylinders, i am planing to resurface the heads and the cylinder. 0.I'm (0.0019 inch) on each part should bee enough.

Then the question is how to do this operation without damaging the Nicasil coating as it ends on that small radii between the cylinder wall/ face.

I was thinking about making a very accurate fixture and mount it in the CNC turning machine, and then turn from the bore and out (radiial) with a PCD (diamond) cutting edge - what i am curious about is, wath will happened with the Nicasil coating ?? here i am thinking on cracks or it will fall off in flats on the radii.

Another possibility is to grind them in a circular grinding machine with water.

Roslin

[cnavarro]

Surface grinding machine is the way to go. Just make sure that you set up the cylinder off of the bottom deck that normally sits on the case, and do all the cylinders from one side of the engine at the same time (or all of them at the same time is even better).

We have tried to do it in a lathe and it is very difficult, but possible, to do with a very sharp insert and very light cuts (.0002"), working your way from the inside of the bore outwards, so that there is aluminum under the nikasil supporting it, so hopefully it doesn't chip.

[Roslin]

Hi Charles, Thank you for your replay.

When you tried the turning method, was that with PCD or carbide cutting edge ? I don't think is difficult to achieve equal cylinder hight, because the machine are very accurate in the replay when it is warm. but i do not know how the diamond will work in the Nicasil.

But anyway, i think you are right the grinding machine are the safest way to go.

I will bring a result and some pictures when it is done.

Roslin

[cnavarro]

We have used both diamond and carbide inserts with similar results. Actually, we've had better results with carbide and sharpening the insert between cylinders. I'll stick to grinding - it's cheaper and easier to maintain tolerances with better surface finish.