ludesleep

Im finally gonna send my head to get a full valve train upgrade after debating on it for a couple days. I keep reading where people say you don't need it but they pretty much are as clueless as I am. Should I dish out an extra 700bux for this or should I save it and buy some nice turbo cams for my new valve train.

stackz

do you mean port and polish?? as for the valvetrain itself, unless you get higher lift cams or plan to get a fuel management system that knocks out the factory rev limit then your stock valve train should be fine. Just because you'll have a turbocharger doesn't mean anything if you don't exceed stock rpms the valvetrain is set to sustain. 7000rpm is still 7000rpm and whether it be stock or turbocharged, the valve springs don't care. You MIGHT need to upgrade the valves themselves to higher grade units IF you run a LOT of boost due to maybe the higher operating temperature in the combustion chamber but I doubt that's really necessary.

If you meant port and polish then that will always benefit with a turbo (doing the valvetrain at the same time only adds to the port and polish). Porting the intake and exhaust on the head basically opens them up a little more and allows more fuel/air to enter the combustion chamber. Polishing helps smooth the tracks on the intake and exhaust and get rid of unwanted turbulence...thus speeding up the flow. There are other things that can also be done such as port matching and bowl blending etc but for port matching you should take the gasket along with the manifold you want to run and have it all matched up exactly all at once. When you blend the bowls on the valves (seats and bowl area) you reducing the turbulence in that area which does not get polished with the runners (intake and exhaust). Other options are cutting the seats for larger valves and 3 or 5 angle valve jobs. Then there comes the whole other area of milling the head if you want higher compression or o-ringing it if you really want to run high boost/nitrous/methanol or what-not.

Think I might have missed something or another but this is pretty much some basic things that you can get done to your head...and yes, the rates on each of these vary per shop and depending on how much and/or what you get done sometimes you can get a deal cut.

psileepR

i say unless you are gonna rev the hell out of your car are get some high lift cams dont worry about getting a new valve train... stackz is right ... OEM valvetrain will hold up fine.

spend that money on headwork (pnp) to improve the efficiency of your motor. it should help spool your turbo a lil quicker

ludesleep

well I have a fully built bottom end and Im looking to run around 400hp+ at the track. When I started this project I wasnt counting on it taking this long. My son was just born into the world and I kinda need to start raping things up and finish. Im sending my head to KMS for a full titanium valve train upgrade...and really dont want to drop another 700 on porting and polish. Im kinda hurting for money and it would help. Im going with .5mm oversized valves on a h23 head...from looking at the ports they cant get much bigger and I just dont see 700bux of porting there...

psileepR

talk to Rocket at EF-1 about turbo cams... great guy

im unsure if he is making cams for your application

http://www.ef-1.com

ludesleep

i do plan to rev 9-9,500k ...since im going bigger valves..can the ports still flow it?

int3gra

Im sure you could mildy port and polish the head yourself, but try it if you have a spare one laying around

stackz

I hope the only things you'll be "raping" are on the track...

If you're going to go past the factory redline then you'll be safer using aftermarket valve springs with a higher seat pressure of at least 20% over stock. As for going with bigger valves without porting the intake and exhaust ports on a turbo engine...you're just robbing yourself in the short and long run man. Exhaust flow is what drives the turbo. bigger valves dumping into smaller exhaust runners will cause a flow restriction and in turn allow less of the available exhaust gasses you are creating out...to drive the turbine. Simple as that. Also, bigger intake valves won't matter much since you can still only spill so much down the intake runners until you open them up to match the valves.

money is always everyone's concern and when people get impatient and only have enough money at the time to do half the stuff they SHOULD...that's when they cheat themselves. Put the money aside and forget about it COMPLETELY! then once you've got the other half of the money...remember about it and get your head properly worked and all at once.

I know I know...you're about to bust a nut to get the valvetrain but dammit dude hold that chud and wait a bit.

Plus, the time you wait will allow you to properly shop around some more for good shops/prices and get a better understanding of exactly what you need. Personally, I don't think you'll need titanium valves for 400hp (ching ching$$) but hey, if you wanna be able to say you have them then go for it. call up Crane or compcams and see what their prices are on their valves and I think you'll be happy as they have quite a selection of valves and springs that won't take you to the bank...

ludesleep

if i do get oversized valves..does that mean my pistons need modified too?

stackz

depends on how big the factory piston notches are. If they are "just" machined to spec you might have to re-notch the pistons to compensate. Get some silly putty and put on the pistons then torque the head down with a gasket and turn it all the way over, take the head back off, and see if the putty is completely pressed down that you can see the piston.

if it is then you need to notch or you'll be slapping the pistons with the valves.

MotorMatrix.com

dont sweat the port and polish if you are looking only for 400hp. i made over 650 on a stock port head. upgrading the valvetrain is the way to go regardless of if you rev past redline. you dont want to take out a built bottom end over having a stock head. also, even if you are only revving to stock rpms the way a turbo car goes thru the rpm so rapidly you can still break a valve. so my advice is forget the pnp it wont add any safety to the motor and youll make 400whp easy with the right turbo.