cheaped out on the springs why run to the limit....

921's should have been used

 

I said it before on pt.net and I'll say it here. It looks to me that the spring is not only broken but the bottom looks bent. Looks as though the spring was done in by coil bind. Does anyone else see what I'm seeing here or am I looking at it different than everyone else?

 

I would wait for install specifics before blaming the springs too although I know Comp has had issues in the past with the 918's. I ran these with a .603"/.600" lift cam for 12K miles with zero problems. The 918's were originally rated to .625" lift before they came out with their duals then they reduced its "rating" to .600" to get people to buy the duals.

 

I see what your saying....The old 918s with the blue stripe that were having the issue were breaking the tips of the valvespring. This one needs to be researched.

 

See post 15 and 20.

 

What rock have you been living under.


Also...He said they were the new 918s. I thought the new design was rated for .625 or .650 (can't remember which) and the old design was rated for .600. Either way, it a bad day.

 

Thank you, I was just about to type those exact words.

So on this engine, was preload checked? Pushrod length checked? I'd bet $100 somebody threw a 7.4 pushrod in that motor, TQ'd it to 22ft lbs and went about their merry way.

 

I'll bet you $500 I know from reading the post in the other forum where this occured that the end user didn't know the installed height of the spring. Just threw them in. I think that's what happened here and coil bind was achieved. That doesn't look like the old broken 918 problem where they'd break on the top coil. It looks all jammed up in the bottom like the coils bount up and the rockers smashed it to ****.

 

I managed to break a Patriot Gold with a Torquer v3 cam. I was just idling through a grocery store parking lot when it happened.

 

You were running a .64X" lift cam. Those take special spring and pushrod prep. Ideally, you should run shorter pushrods on the exhaust lobes and you need to make certain that your springs over your intake valves have enough installed height to keep you out of coil bind (see installation error).

 

Did not think 918s were designed for lift above .588 - .600 or so. ??

 

Touche about the pushrods. I was taking the word from TSP that the 7.4s would be fine.

 

Broke my 918 at idle in my driveway Stock Z06 cam

 

People often take things for granted, and this can and will happen again. I decided to use the tried and true TR224/224 112 in my motor (LS6) with Livernois heads and .690 lift springs not by choice but thats what they had when I got them. Sure I want Huge power but settled for a smaller cam to be easier on related parts. I don't want to be worried on my cross country trips that something is gonna snafu , I want OEM reliability and more power. OK maybe I'm a wuss but if your going with extreme parts - wheres your backup? a single spring? what I dont understand is Comp 918s with Tit retainers are a bunch more than Patriots so why do so many have them? Im kinda old school - when a SB with .450 lift was a big cam-now im thinking my 224 cam is BIG -well not compared to whats out there now buy you cant skimp -ESPECIALLY on springs and expect it to live.

 

what about the way the spring was broken in? Comp says to do a couple heat cycles on them before normal driving?