civintegra

three weeks ago I broke a few valves in cyl. 1 and I have attributed it to a broken valve seat. This is the second head with a broken valve while using the crower springs and retainers I have. I am looking to get some opinions on the appropriate springs/seat pressure for revving to 9k safely but also getting as much longevity out of the head. This is a street car that will be making around 500whp

Just some info on my next setup:
84mm gsr
wiseco 9.5:1 pistons
Crower rods
ITR cams
PTE 5858
Springs/retainers/valves?

Thanks in advance..

wantboost

iTrader: (2)

are you sure that everything was clearanced right? Have you put the same spring/retainer/lock on each cylinder every time? Might want to pull the springs and check free height... one or more could be short causing excess tension on the valve seat...

that being said, an improperly cut valve seat, damaged/defective valves, valve guide problems, anything really.

are you using stock valves?

civintegra

I havent spec'd the valve springs since they were removed from the damaged head so I dont know if one or more are defective. All my valves were adjusted properly, checked again at 2000 miles, and I had 7000 miles total on this motor. I need to check the old springs just out of curiousity. The only thing that has remained constant over the last two motors I have built are the springs and retainers. I guess I will check the old ones, either they are bad or I have really bad luck.

Ill check and get back, but I am still waiting one the replacement head to show up

Oh and no I have always used ferrea valves

wantboost

iTrader: (2)

I had a set of what are either 1st gen omni or early rocket springs and retainers a friend gave me that had a few springs that broke during a tuning session.... I noticed a few of the springs were shorter than the rest. Not sure why they were but it bothered me as I was going to just order the few replacements I needed but with springs that are all different heights I knew that installed high and base spring height would be all over the place

can you send the valves back to ferrea and see if they can establish a cause for the valve failure?