Newold1 wrote: ↑
Mon Jan 15, 2018 3:56 pm
I am not going to spend anytime defending my reading or questions, no need the OP has answered 4 of the 5 quite well in his second post.
Iam also very glad to hear from the OP that a bent valve was the only real significant damage. With the intake side this is more prevalant because the intake side tends to let go and drop the valve with the piston near the top of the cylinder piston travel and hence tends to bend the valve , drive it up and leave it stuck in the guide ABOVE a point where it drives into the piston and causes catastrophic engine damage. If the exhaust spring breaks it drops the exhaust valve into the cylinder generally close to the bottom of piston travel in the cylinder leaving the entire valve out of the guide fully into the cylinder with the piston traveling up and you can imagine what happens from there!
I was pretty sure when he posted the pics, I knew the spring and the approximate age. I knew this because this was the exact spring I and many others in the aftermarket started having serious problems with back starting about 2008 right after it was introduced and I was having my own issues with this spring on LS builds. I also saw the same type of problems from an early aftermarket same basic spring from a large industry valve spring manufacturer.
I would like to say at this point Comp realized the failures and problems and changed the manufacture and design of this spring and since then the scope , reason and magnitude of this past problem has been eliminated in that part number to my understanding.
The real reason for this problem in this beehive spring as well as some others in the industry stems pretty much from how the spring wire was wound during manufacture. If you take one of this period years particular beehive spring and stand it up and look down the top opening of the spring you will see that the center of the top opening in the spring at the retainer opening you will see that the center of the bottom opening in the spring is not directly under the top opening center. You might ask, why does this matter! It matters because as the spring is compressed the top of the spring is off center with the bottom of the spring and as the compression distance increase the wire of the spring section at the break points is being bent back and forth horizontally as the valve stem going down in the guide tries to align the two openings. Obviously valve spring wire tends to end and twist as it compresses but not in this fashion. That type of unintended bending moment at that point heats the wire and weakens it. Just like bending a paperclip wire back and forth until it breaks. I as well as hundreds of other LS aftermarket beehive spring head users and other beehive valve spring users had this breakage show up and had lots of damage and grief. Why does it not happen on all beehive springs is because not all beehive springs are made with this defect. This is backed up by the millions of beehives that are in use today in millions of vehicles. I don't think you will see this issue with any of Comps beehives today and other major spring manufacturers also eliminated this condition and beehive spring usage in the aftermarket in general is much better today than back then.
If you are using beehives today in your builds and performance uses, just take the springs and do this top down look. If you see this top to bottom misalignment-STOP-send them back if you can or can them and get another good set of beehives. I won't go into the long detail of how this problem was identified just let me say a few good valve spring experts and some good spintron testing found and proved the problem.
To the original poster if you choose to stay with a beehive spring for your application then check the new ones and make sure they don't suffer out of the box with this problem. If it were my call I would switch to a good conical spring or a nice set of straight doubles. JMO
Sweet reply, I've got another simpler reason they can fail.
If installed with a goodson valve spring mic, the small retainers go inside the mic"s counterbore. The valve spring mic is designed to have the retainer on top of the mic not down in it, this ends up giving you a 1.6xx" installed height instead of a 1.8" installed height, the larger softer coils move first and coil bind, leaving the smaller coils to compress and creating torsion at the beginning of the first small coil,
Ask me how I know..... it still makes me sick, broken rod, piston was an aluminum ball found upside down in the broken cylinder/block, broken head(chamber and cam tower) broken camshaft, broken rocker arm, valve stem even broke the cast Alu valve cover.... this was on a little Ford 2.3 ministock race motor,
I was young and I though I lost a plug wire, as I had once before, kept running it, it quit like the ignition was turned off , I was coasting to the infield clutch in, decided to let the clutch out to try and get it to start, and it made terrible clattering noise,
Pulled the valve cover at the track, found a mess,
Pulled the head at home at around midnight to find the cylinder entirely broken out and the piston upside down and the chamber with a hole the size of a quarter.
So, make sure they actually get installed at the recommended height.
I think I used the 29615 springs, then I went to 29618 and never had a problem with them at the correct installed height.