oem springs are barely enough as is. one money shift and you've bent all your valves. If you have to take it apart upgrade it. With even a slightly stiffer spring now you arent bending valves.

Ferrea beehives are really nice but the seat pressure is around 110, which is on the high side of what you want.

Supertech beehive springs are 75 on the seat and have the same open pressure as the 95lb dual springs. They are really the way to go.

New stock springs are 55 on the seat, the last used set i tested with over 100k were right at 50lb on the seat. 50lbs on the seat at 9k rpm is borderline asking for a failure.

 

I agree if your taking it apart just do it right, I use bc dual springs seat pressure 84lbs if I could do it over again I would have pulled the head and replaced valves also this engine is very easy to work on not to much more work. I hear some story's of ap1 and ap2 valves separating and if your using 2 step the exhaust valve's get really hot.

 

I had a valve drop on a stock motor after a tune. Destroyed the head and block. Stock valve train, ap2 with 40k on the motor.

 

ah so many mixed experiences...im thinking about staying with an oem ap2.

 

Listen to Wadzii, he knows his stuff.

 

Yes, updgrade.

I don't know if I'd go as far as a full port polish though, just upgrade.

Build it right or build it twice.

 

If you're gonna do springs/retainers...def do 1pc Valves at the same time.

I've knocked the tulips off OEM 2-pc valves just from boost and high seat pressures. That was on B-series with 5mm Stems, but dropping a valve is basically game over if it happens at high rpm...

IMHO, if the head comes off...you do the entire valvetrain, skim the head flat .001"-.003" ona sunnen, kiss all the seats lightly and put studs in it...now you know it's solid. Personally, Id do cro-moly, or a only coated Ti retainers...I've seen Ti retainers that got so thin with mileage(Ti gauls against steel) that only the inner spring was holding the valve in the head. Obviously that was like 40k miles...but still. A valve dropping is one of the most catastrophic failures ina engine. If you lean it out, u might need a sleeve, piston and some small parts...worse case u drop whole new block in. Drop a Valve...whole new build time. Intake sucks the debris into the other cylinders...shoot all the junk thru the turbo, the broken rod is pounding holes in yer oil pan...shits ugly.

Do the valvetrain if it's apart...these cars are too easy and cheap to work on.

 

B-series has 5.5mm valve stem just like s2000. The only time you knock oem valves apart is typically from valve float or bounce. If you need to upgrade due to too much power (cylinder pressure slams the exhaust valve shut and bends the valve.. This starts to happen over 800-900hp) you need to go ahead and put 6 or 6.6mm stem valves in the motor. Stock valves work really well for 90% of applications.


The only time the retainer will gall against the spring is if they dont fit together correctly or you have a ton of valve float. With modern designs it's not an issue.

 

wadzii what you are saying makes a lot of sense. i thoink its a good idea to spend a few hundred more on supertech beehive springs and retainers. i really want to get all the right parts before installing my turbo kit.

 

How long have you had the BC duals in there, any problems with roller bearings splitting?