Someone told me that i needed vavle springs if I'm running high boost on a single cam. Is this true? I plan on going about 300hp. I was just going to try and use a stock head but, don't want to be floting any valves.

 

your not going to hit 300 safely on a stock d head. port and polish and upgraded valvetrain is your only hope. something like 70% (i think that is it, might be off) of all your power is in the head. if you go to autozone and buy the top end gasket kit it comes with Viton valve stems. get new valve springs and you should be ok.

 

Agreed.

http://forums.evans-tuning.com/viewtopic.php?t=2860

RotaryGeek = pwnt. Stop making blanket statements about topics you clearly have no actual, practical knowledge about.

 

On the valvesprings behalf I would like to note that not only do stiffer valve springs fight valve float but they also increase your valves seat pressure which disperses heat from the valves to your head better. For this reason I purchased some aftermarket springs not to rev the ---- out of my d16 but to have a cooler running valvetrain.

 

Coating your valves is a plus for fighting preignition due to your exhaust valves getting red hot.

 

that's a very good point. you generate alot of heat compressing air, especially when you are talking about "high boost" and getting heat away from the combustion chamber will help alot to increse/release power. new exhaust valve guides are also almost a must as your d is probably pretty old and they are out of spec. so make sure the machine shop checks that out. the intake valves should be okay but have them checked anyways, they will help dissipate some heat too. i hope you also plan on having a valve job done a 3 angle or even 5 angle( if you gots some moneys) would not be a bad idea at all.

also, if you want to make 300 hp, i would recommend checking out the articles section of theoldone.com. I looked through their porting articles and some other stuff. with my head i slightly opened up the short turn radius of the ports and matched the ports with the gaskets. in the combustion chamber i opened it up just a tiny bit around the edges of the valves to increase flow at high rpm. i also smoothed out the "ridges" around the exhaust valves. i then went back and sanded everything with 40, then 80 grit and polished the exhaust ports. you dont need to polish the intake or combustion chambers. also on my pistons, i smoothed out the corners and sanded it all with 80 grit finish. all work was done w/ a 90 psi max 40 gallon air compressor and a right angle die grinder with various dremel bits. i kept it at about 15 to 25 psi and just figured out what worked best w/ diff attatchments.

read up, alot of extra power can be released in the head, but don't over do it, larger is not always better, higher flow is better.

 

thanks alot. I am just going to try the stock head for now and see what happens. I am on a very low budget and am trying to get this done pretty soon. Once I get it running I may get another head and port it and slap it on later down the road. I've got some friends with h22's in there hatch's that think there hot ----. They think a d cant touch them. :P

 

well you can show up those h's with a stock d and 10 pounds with no problem, just be careful with that tune.

 

ya I know, I got a zc-t25 now. I was going to run them but 15psi killed the hg. putting on a new one this weekend and turning the boost down.