OST-035: Silver Blaze

[oldeskewltoy]

from another forum Wrote:I enjoy reading the detail in your threads but not being an engine builder guy I probably understand less than half of what you're saying...:confused:

What is the purpose/benefit of the multiple angles on the valve seats? Radiusing the openings for better flow?

Does the type of spark plug used during chamber volume measurement vary the reading? Or is something else used to plug the hole during measurement?

I use an epoxy filled spark plug with the ground electrode removed. This gives me a consistent measure. Yes - a "colder" plug will often times have a bit more room around the positive electrode, effectively increasing the chambers volume.

multiple angle valve seats - Air flowing past with minimal eddy currents. A steep angle on any of these faces and tiny eddy currents can cause poorer flow.

I've recently heard about a 7 angle... yes 7 angle valve seats... can't find a pic, but here is a 5 angle.... http://www.d-series.org/forums/attachmen...5angle.jpg

now if your machinist has the capability, this is what is often the top of the line for flow past the valve, it is a radius valve job - http://rennlist.com/forums/attachments/9...t-pic3.jpg the only flat surface on there is the small area where the valve contacts the seat, the rest is a radius