There is no magic brand of springs.
Isky, PAC, PSI, Manley........ There are tons of quality springs out there.
The key is using the correct one for your application.

I'll say it again....... IMO, you got excellent life out of the springs you were running.
You waited too long to replace them.
I wouldn't expect any other spring to last any longer in that application.

IMO just a "lack of maintenance" is what has caused your problems. I agree 950lbs on the nose is likely overkill for what you have. As for springs IMO Pac makes the best stuff out there. They are an OE manufacturer not to mention they make many of the springs in other companies boxes.

First off, if you have an all aluminum engine the COLD lash should be no more than about .004-.006. Of you are setting lash at .022 cold on the intake, you'll have at a minimum .035-.036 running, maybe a bit more.


Close the cold lash way way down. If it will start with .002 cold lash set it there.


I have measured blocks that grow .020 or more when hot and I suspect that in reality, you are running over .040 lash.


All that does is beat the hell out of the lifters and all the valve train. I believe it can set up harmonics that will break anything you put around your valve train.


That is where I'd start first. Also, I think it was Mr. Porter who was talking about how frequently you need to change out springs. I agree with that.


Start by getting the cold lash as tight as you can. If you can get the passenger side VC off quicker and easier, then set the lash at .004 cold, get the engine to temp and check 1-2 valves when hot. Adjust the hot to get as close to .020 running as you can, even if that means .002 cold lash.

FWIW on my Cuda the cold lash was almost not measurable(hard to squeeze a piece of tin foil). On cold days, IE below the upper 30's the car would not start as the valves were still open.

Here's the basic gist of what I do for street motor combos like this where a solid roller is going to be used, and relatively long service intervals are desired.
In my mind, this automatically means that some amount of power will be sacrificed for longevity.

I run really slow lobe profiles designed for high endurance applications, like marine or 24hr road racing. Something that will operate at a sufficiently high rpm(for the application) with a moderate spring pressure.
Then couple that with a high end endurance spring, set up so it ends up somewhere near .100-.150 from coil bind at full net lift.
While setting up the springs in this manner can cost a bit in terms of the upper rpm limit of the valvetrain, it's much less stressful on the springs, and they just last longer.

I would have selected lobes that would have operated to 7k with no more than 650lbs open pressure, and then used something like a PAC 1396 spring set up at 2".

And even like that, I wouldn't have told my customer it was "good to go" for 10,000 miles.

Pac has been good for me
Doug

Like Fast68 said, I think you just went wayyy too long without changing springs! Your cam must be a much more aggressive profile than the one that Fast68 spec'd for me b/c my springs are only 220# on the seat and 600# open.
I change mine out at freshen ups (usually in the 3-4k mile range) and never even check them. I don't want to be tempted to reuse them. I've sent my Isky Red Zone lifters back twice for a checkup and had them returned w/ a note saying no work needed. They are not the EZ Roll bushed lifters...those weren't available in 2006 when I built mine.

What's the rest of the combo if you don't mind me asking? Any timeslips?

i called John at bullet cams and he wanted to know valve spring install height and diameter......my engine builder had all my specs so i went and visited him......turns out my springs are comp cams 944-16...double spring...id.1.120...od.1.575...install height 1.950....seat load 190lbs@1.950....open 747lbs@1.200....coil bind 1.100....so i gave John the specs and he recommend PAC 1244 springs
Part# PAC-1244
Description High Frequencey High Lift Dual Spring for Roller
Mass (g) 142.0
Outer Spring I.D. (in) 1.120
Outer Spring O.D. (in) 1.570
Inside Spring I.D. (in) 0.780
Install Load (LB) 190
Install Height (in) 1.950
Open Load (LB) 710
Open Height (in) 1.250
Coil Bind Max (in) 1.035
Lift Max (in) 0.800
Frequency Outer (CPM) 32630
Frequency Inner (CPM) 32965

my engine builder set the lash cold at .006 intake and .008 exhaust.....then i brought to his sons place and we ran it up to 180 degrees....shut it down pulled the covers and set the lash at .022 intake and .024 exhaust.....we did some pulls and was happy with the results......got it home and the next day when it was ice cold i check the lash.....turns out the lash on the intake was .003 and the exhaust was .005.....so engine grows .019

wow....Al.....what are you running?.....whats your lash hot?

since i went with the roller cam i haven"t been to the track.....this rebuild is....

keith black aluminum 4.50 bore/4.50 stroke block/scat crank/oliver race streel rods/ diamond pistons..11.5 to 1 compression[ pump gas]/stage v heads 2.40 titanium intake/1.94 stainless valves with custom port and polish from tim banning[FHO]/stage v roller rockers/bullet roller cam duration @50 intake 283/exhaust 284/lift intake 696/exhaust 682/isky ez roll 904 dia solid roller lifters/smith .120 push rods/milodon gear drive/milodon 9 qt pan with dual line with swing gate pickup and hole for steering/tti 2 1/4 primary/4 inch collector headers/msd distrib and 6al-2 box/ray barton single plane 4500 manifold/pro-systems 11.50 dominator/built 727/PTC 3500 stall convertor/gear vendors/dana 60[was 4.30] now 3.73 gears/ss springs /pinion snubber/frame connectors/mini tubbed/20 gallon fuel cell/batt in trunk/8 point cage

first all new build ran 10.38@129....it had a solid cam[specs?] with schubeck composite lifters[which all failed and unglued]indy tunnel ram with two pro-systems 10.50 dominators[which washed all the cylinders down]/4500 stall convertor/4.30 gears/2 1/8 primary...3.5 collector tti headers....roadrunner weighs with me in it....3900lbs

The PAC 1244 and Comp 944 are the same spring.
At least they were when Comp first started marketing the PAC-aloy series of springs.
"PAC-aloy"....... Get it?
At some point they started getting some of the springs sourced from different vendors and stopped using the PAC-aloy name at that time since not all of them came from PAC(some were, some werent).
You say your motor has been together 10 years?
Those could be PAC springs, bought as Comp 944's.

And........ FWIW....... I've seen a fair number of broken 944's.

A few others were;

1243 / 943
1245 / 955
1246 / 946
1247 / 947
1248 / 948

my builder said that today but i didn't put two and two together PAC-aloy.....no my motor was rebuilt like April 2015....ran it for 10,000 miles before i dropped the valve.....when it was new it lasted 12,000 miles with a solid cam with comp 919 springs

so basically the comp springs and pacs are the same or the pacs are better then comp cams springs?

YOU RAN A 8.91@150......whats your combo if you don"t mind?

If you got 10,000 miles out of those springs you did real good....... I wouldn't blame the springs in that situation at all.

I would just change them out sooner this time....... Hopefully before one fails.

yep my fault/lack of maintenance....didn't realize....does anybody sell a valve spring compressor to pull the springs while the heads on.....years ago they did sell them......dont see them anymore

Not that I am aware of.

If anyone has something for a Hemi it's probably LSM.

But the pressure isn't the whole story.
They can retain nearly 100% pressure right up until the point of failure.

They need regular replacement....... Whether they still test good or not.

thats good to know.....thanks for that

George,I am amazed your valvetrain lasted that long!! My spring pressures are similar to chips.