Hello,
I am making the 1/4 scale Kinner K5 and just got done making the pistons. This is my first IC engine.
So where I went wrong is that I modeled the piston from the strictly IC prints. Then I made the cylinders which I ended up going .006 oversize on, so I decided to just match the pistons. I re-modeled the skirt to size, but forgot to re-size the top of the piston near the rings where it would normally be a few thou smaller for expansion, etc. La-di-da, I machined it to the model without thinking about it. :wall: Original skirt size was 1.086 with the top at 1.080. The re-sized skirt is 1.093 with the top at 1.080. The ring grooves were called to be .05 deep on the radius and I did so from the 1.080 so there is still plenty of land for the ring to seat in.
Sooo, my question is, do you think I can get away with this and have a run-able engine or am I going to run into problems with blow by or something from the top of the piston not being quite to size. I spent a bit of time on these and I'd rather put the time somewhere other than remaking them.
This engine will be run once or twice a month in the good weather months probably not at all in the cold and mostly be a display piece, so please let me know based on that.
Thanks for your help.
You can see the earlier part of the build here:
http://www.homemodelenginemachinist.com/f31/my-kinner-k5-9944/
Sorry I haven't updated it in a while. :hDe:
Greg
I am making the 1/4 scale Kinner K5 and just got done making the pistons. This is my first IC engine.
So where I went wrong is that I modeled the piston from the strictly IC prints. Then I made the cylinders which I ended up going .006 oversize on, so I decided to just match the pistons. I re-modeled the skirt to size, but forgot to re-size the top of the piston near the rings where it would normally be a few thou smaller for expansion, etc. La-di-da, I machined it to the model without thinking about it. :wall: Original skirt size was 1.086 with the top at 1.080. The re-sized skirt is 1.093 with the top at 1.080. The ring grooves were called to be .05 deep on the radius and I did so from the 1.080 so there is still plenty of land for the ring to seat in.
Sooo, my question is, do you think I can get away with this and have a run-able engine or am I going to run into problems with blow by or something from the top of the piston not being quite to size. I spent a bit of time on these and I'd rather put the time somewhere other than remaking them.
This engine will be run once or twice a month in the good weather months probably not at all in the cold and mostly be a display piece, so please let me know based on that.
Thanks for your help.
You can see the earlier part of the build here:
http://www.homemodelenginemachinist.com/f31/my-kinner-k5-9944/
Sorry I haven't updated it in a while. :hDe:
Greg
