GR wrote:
After the heads are cast they go from the foundry to the machine shop where they are machined with a CNC machining centre. From there the valve inserts are fitted and the valve guides. Then the heads are ported and the valve seats cut. The chambers can then be milled to size.
Looking good! I gether from the above that the porting is still a manual task or do you have access to some funky 5-axis machine that can reach into those ports?
Speaking of porosity, my MX-5's head has plenty or aero-bar style holes in the cam bearing surfaces. Not pretty but no problems for the last 110,000km.
Again speaking of porosity a mate of mine used to work in a die casting plant making bits for Aus assembled fords, holdens and whatevers. They were so screwed on margin they couldn't afford decent machines or decently trained operators. They had a station at the end of the line where the Devcon was applied before the castings went off for machining. So your brand new (in 1995 it was) Ford transmission was swiss cheese and Devcon, same with your water pump housing etc. etc.
If all the production heads are like the one above, they'll be better than some car companies turn out.
PS. I wish I'd won the $106 million last Tuesday, I'd buy a couple of engines each from GR, MR, DR and DrM and put them back to back on a dyno, then flog them for a while, strip them down and do a wear assessment & crack test, then publish the result. It certainly would have been a way to clear up who can piss higher.
M