Ok I have a VE auto that I am going to do some performance work on,the reason why is just funny.I got broken studs (who dont) plus i need to rebuild my vtcs,so i am just going to take the complete top end off and do some work (easier to drill the studs out for one) here are my questions thoguh.

#1 Have any of you planed any material off the heads to raise compression? if so, how much did you take off them? also have any other problems with the engine fitment after they were decked?

#2 have any of you ported a VE engine and possibly have dyno results or at least what you think you gained from it?

So that about sums that up,I plan on porting and polishing and take some material off the heads to raise my compression up some,just wondering what sort of gains I will see.Also going to keep my auto but have the valve body done and new TC.

Please no naysayers,not saying anyone on this board is like that but you never know,if for some reason something cannot be done please explain why.I build racing snowmobiles and motorcycles so I do have the know how to do any of this,just looking for input from someone that possibly has done this sort of work before or knwo someone who has

Thnx in advance.

BJ White

 

If you can find it, read the Sept 2004 issue of Popular Science. There is a guy in there who had been modifying heads, by putting grooves in the hemisphere where it combusts, which increases turbulence in the A/F mix. They compared a standard engine to his modified one and they saw 10-42% more efficient burn, his modifications actually lowered the operating temp by 16 degrees. So... I think there is some power or fuel efficiency to be gained from his modifications.

People have ported both the intake manifold and the head, I do not know of anyone who has ported the exhaust outlets, nor do I know of any dyno results to show the differences from the porting.

Brian

 

Thnks I know there has been the same thing used on certain heads for the yamaha banshee (4 wheeler) using angled grooves cut into the combustion chamber,I will try to find this article to see a picture of how it si done. Thnx for the info

BJ White

 

problem with shaving the heads is getting the cam timing back to spec. There are no adjustable cam gears for our cars. Plus the intake cam gear has a big VTC attached.

 

Jeff I was thinking of that and that si the reason I asked if anyone has done it before. Wanna make sure I dont ruin anything becasue of the VTC and no adjustability. Was thinking though that a bit off the heads wont hurt it to bad as long as there is no valves hitting,kinda depends on how much slack the adjuster will take up too though.So many variables. I have seen stock setups take 20 thou off a 2.2 GM (warped head.. typical) and they ran perfect after with no woes from the timing.

I am only planning on possibly taking 10-20 thou off depending on the squish and combustion chamber.

BJ White

 

I think a clean up cut to make the head flat again would not do much. Enough to significantly change the compression ratio would. Probably have to dig though the Nissan service manual to see what the limits are.

 

was that an OHC or push rod 2.2

i dont think it matters as much on a push rod motor