Engine talk. Rebuild, and cam.

[jasonp]

I did notice my +1 black diamond valves had a significant bigger dish than the stock valves before i put the head on hno:. That sucks cause right there is a drop in compression.

That is why some places will take and machine some off the head..

 

[87warrior917]

That is why some places will take and machine some off the head..

Yeah..If i woulda known they were that dished before i recieved it back i woulda had him mill it down to make up for it.

 

['00 WO-YA!]

Often times the valves are "Tuliped" (dished) to reduce valve weight. A lighter valvetrain is a more stable valvetrain. With camshafts that don't have very radical lobe designs this isn't as critical but a camshaft the has rapid valve opening & closing events will play havoc on valve control. It just gives the spring a fit, this is also why titanium retainers are valuble. It's not necessarily a matter of strength but weight. A few thousandths off of the head should balance compression back out but in reality there's prolly not going to be a huge noticable real world seat of the pants difference.

 

[duneracerweston]

I don't understand what you are talking about.

This was done to a stock warrior combustion chamber. I'm not going to give spec's for my duncan.

Things to effect CC in the chamber is if you do something with the valves ie lower the seats or run a dished valve maybe un shroud the valve also you can have the head machined down.
Porting and polishing the ports will not effect combustion chamer cc's.

this is what i was talking about i when i had mine ported they un shrouded the valves some and polished to to give it a more even combustion chamber

that is why i wanted to know if it was a stock head or your ported head, gosh it was just a simple question but i have my answer...