JJ63

iTrader: (1)

I can't get my engine to go over 5800 rpms. I was told that my valve springs are too weak. They are:

Lunati
Installed Height 1.750"
Installed Pressure 115 lbs.
Pressure @1.75 115 lbs.
Pressure @1.25 250 lbs.
Coil Bind 1.080"
Diameter 1.450"

I'm running a zz4 roller cam with 1.6rr's. Exhaust lift is .540". What springs should I get? I don't have a cam card for the zz4.

Since the TPI should be shifted below 5500 anyway, is it hurting anything to leave current springs in place?

Stekman

They don't look bad, They are certainly better than any stock piece. Although, I'm sure you could do with a little more seat presssure. 130 is about the most I would take on a hydraulic roller for seat pressure.

If the TPI won't make power above that range, why do you want to rev up there?

JJ63

iTrader: (1)

Mostly I want too make sure I'm not hurting anything even when rev up to 5500.

Z69

Depends...
I chewed up my spring shims with about ten trips past the float RPM. Not sure where that exactly was since my tach was reading 500 rpm low. Had a few trips to 6200rpm (6700). Motor never made a sound. Put different springs in that are good to 7k+. Motor still pulls the same, well after I disassemble the motor and cleaned all that hardened steel out, polished the crank and new bearings. Actually needed to turn the crank, but I'm building another motor so didn't want to spend the $$.
My only clue was the valves were turning and you could see it in the stem tip wear pattern.

So you decide if it's safe.

JJ63

iTrader: (1)

I'll have my 2nd set of springs tested, I have no idea on their specs. If they're a better match, I'll use em. Otherwise as long as there isn't a performance loss, I'll stick with the lunati's and try not to over rev.

Thanks.