silverZ98

iTrader: (6)

im running those springs on my stage 2 pp heads and tsp 237/231 cam, now for 12,000 miles and 2 trips to missoui that is 18 hours each way from me and have had no problems, i let car warm up fully before i mover it and have since day one,

note: i have the crane springs because the pp ones wasnt out when i got my heads
Eddie

2 SLOW

i believe alan says to use the shims to up the seat pressure, that was prob. what is wrong.

Paul F

iTrader: (2)

There could be the cause of your problem. With no shims you were not running enough seat pressure for a cam that size. With the older model Crane springs you should have had them set-up at about 1.770-1.780 for about 145lbs of seat pressure and about 375 open pressure. The newer Cranes with the yellow and blue stripe need to be installed at about 1.715-1.725 for the same pressure.

If you don't have enough spring pressure for a given cam it could be floating or bouncing the valves and that will lead to spring failure. We've been running the Cranes since the first sets were available. At well over .600 lift and 7200 rpms we never had a single failure. Hopefully that trend will continue.

Fireball

iTrader: (21)

you are probably right. I know thunder spec'ed to set up the old springs to 1.77 installed height for .610 lift. Now that the material has changed...they are telling me to shim to 1.720

Thats .080 shim over factory install height

LOL...this was less than 1 minute after Pauls post

2 SLOW

i believe alan is sending me a .030 shim for the f13.. does that sound right paul/fireball?

Fireball

iTrader: (21)

are you replacing all the springs?

If so you'll get the new ones with teh blue and yellow stripe. If thats the case you wanna run .080 of shim

Paul F

iTrader: (2)

I agree 100%.


Paul

Fireball

iTrader: (21)

also don't forget new valveseals

Rokko

iTrader: (2)

I think you should do the whole lot asap. If one went then the others most likely are not be far behind.

SloppyRob

Wow, i didn't know i should have shimmed the springs. Where can i get the necessary shims for my cam?

BLK02WS6

iTrader: (2)

Fireball,
Did you put the springs on my heads, or did J? I don't think I have stripes on mine, I think they are the old ones. I got the springs/seats/retainers from Joe and the cam too - he didn't say anything about needing shims. Should I have shims on mine with .588 lift? Engine doesn't see over 6,500. This post has me worrying, but with 70 passes on the motor I must be in pretty good shape.

Fireball

iTrader: (21)

You have the older cranes. The new ones with the stripes were just released last week.

You are not shimmed and it would require pulling all the springs and valve seals to put shims under there.

BLK02WS6

iTrader: (2)

But should I be with my setup??

Fireball

iTrader: (21)

I'm not an expert in this field and I'm drawing alot of information from Thunder...

but they like to set them up tight...

Lets say this...I have the new duals...and with a .612 lift they want me to run them at 1.720 (.080 shim on stock heads). For the old springs they recommended 1.770 (.030 shim)

Paul F

iTrader: (2)

Bret the older Cranes aren't as critical as the new ones are on the installed height. Like Fireball said we like to set them up a little tight. We like to run the springs about .050-.060 from coil bind for best performance and longevity.

So to answer your question: Depending on your cam specs we would like to see a .030 shim under your springs, assuming you are running stock heads and valves. If you cam is on the milder side then you are probably fine like you are. Hope this helps...



Paul

SloppyRob

So for my setup that the spring failed I should have been running with a .030 shim? I ordered another set of cranes so i'll see if there the new or old ones. I should use the appropriate shims when i install these? My cam specs are 228/230 .576/.593 112 lsa. Also, where can i get shims, do they have to be custom fabricated?

BLK02WS6

iTrader: (2)

I have LS6 heads, they have been shaved .014 and have stock LS6 valves and spring pockets. The cam is a 228/232 with .588 lift - don't know the lobe type, but I don't think it is too aggressive. I have the titanium retainers and Crane seats that go with the 832's. Just looking for a warm feeling that I am not in danger - judging from the 70 passes I have on the engine and how good it runs, I think I am OK.

SloppyRob

Thats basically the same setup as mine....832's, Crane seats, Ti Retainers and the cams are similar. I think i'll be shimming my setup when i change out the springs.

taqwache

i wouldnt be so fast to go out a buy a patriot spring, i have personaly seen those break also. i would bet that the installed height was off like TR said.

Fireball

iTrader: (21)

I'm sure the sponsers sell them, but these are the shims you need

http://store.summitracing.com/partde...CCA-4753&N=120