Hey guys an girls just a quick question. When installing 1mm oversize valves with standard cams will there be piston to valve clearance issues???
Nope. But why are you putting in over size valves with standard cams? Are you getting the heads ported?
Nope. Will be the same. Valve diameter will not effect the length or duration it stays open while using stock cams.
Yeah car hasn't sold so going for more power. Thanks guys wasn't sure if the increase in diameter would protrude far enough to cause problems. Heads will get extensive porting and still weighing up wether to go for aftermarket cams. Going another full rebuild as I'm not happy with the arias pistons having thin skirts. Just not sure they will cope with the upped boost as the 2560 cores I have in the standard housings have only been running 10 psi and going up to 18.
extensive porting ,1mm OS valves and no cams is silly .. better off going porting with cams and stock valves . definitely get cams (R4+) if porting and OS valves
Wouldn't I achieve the same result with larger valves and stock cams as I would with larger cams and stock valves??? Wouldn't the increase in the size of the valve + porting have the same effect as the increased duration and lift with a standard valve??
I think if your standard intake valves are ok, its not a bad way to go using stock cams, stock intake valves, 1mm over exhaust valves and a mild port job with gasket matching. This really frees up the head flow to match stock cams, good idle quality and off boost response and wont choke the motor up top. Extensive port work means you should be looking at thorough port and gasket matching, upper and lower plenum . AMS manifolds and aftermarket cams + gears, dialed in correctly.
Exactly. What I'm trying to acheive is to increase the flow into the cylinders as much as possible without changing the cams, substituting lift and duration with increased volume and flow
in that case, only oversize your exhaust valves, make sure they are blended well and dont get too much porting done
inlet are big enough as it is. you are throwing your money away increasing them. no benefit without more work. cams, manifolds, big port work etc
If you need to replace all the valves then you may as well put in the oversized inlets as well. This is what I did as the price of ferrea oversized valves was the same as stock sized and opening up the seats to take all the new valves was an extra $85. Then if you decide to put in big cams later you know the valve train is ready to take advantage of them. Remember, there is no such thing as getting used to power, you will always want more!!!!
you must have got deal of the century on your valves Karl, i can get stock valves for around 16each. ferrea are 36ea approx
its all a cost thing, to do all the valves, porting and cams is probably 2.5k worth. mild port work , reco heads and OS exhaust valves is less than half. for 400hp approx at the wheels i think its an overkill spending 2 grand on the heads. 500+ id go all out
If its a cost thing ...reco the heads and put $500 mild cams in ..better than half a head job I'm not going to agree with the inlet valves being too big for the exhaust valves after looking at the VQ heads ..they have the same ratio difference of inlet /exhaust valves..(actually looks like a slightly bigger ratio)..
i guess you stick to what you know in this game. Everyone has a differnt idea of what should be done at certain power levels. Ive outlined what i think is the best setup for a smallish budget From the flow testing i have done the intake side flows fairly well standard, exhaust does not. thats pretty clear cut to me
Which cams are $500???? The car makes 250kw atw now with standard fuel pressure and stock injectors at 14 psi. With what is planned I don't think it will be a problem to get an extra 100+hp atw. It was tuned fairly conservativly as it ran out of injectors fairly quickly hence the 250kw
