98TA_vert

ok its starts off my buddy gets some head work done at local machineshop they did a little port work and installed a set of comp 918 springs with comp steel retainers w/ hd locks and comp moly pushrods hes running a lunati cam .595/.595 242*/242* @ 050 112LSA, ls6 intake, LTs, he gets the car running and in about a week and a spring breaks, cracks a guide and beats up the seat but the piston was unharmed.

Do to the obvious failure he pulled the head take back to the machine shop to get it fixed. He said he didnt over rev it i figured he was bullshitting me he and he really over revved it and it broke. He gets to the machine shop they start to take the head apart and the guy calls him over and says u aint gonna believe this, all the springs except one had hairline cracks. He goes back to get the other head there all cracked, so comp sends him a replacement set. Valve seat and guide both replaced they do good for about 10k mi

He spins a rod bearing pulls the engine while its out comp calls and and says we have a redesigned spring just send us your old springs back so he gets it back together with the new crank and redesigned springs and a lifter goes bad. He gets a set of LS7 lifters, after he's got the valvecover and rockers off the head he notices a comp steel retainer broke in half and replaced them. so he check for coil bind and where the rocker tip was riding on the valvestem both ok and both dowels are intact in the block.

A week later drops a valve. Cause= broken retainer
This time the head is destroyed broke the cylinder wall and destroyed the piston, he is so disgusted he is thinking about putting the car back to stock
are we missing something or is it a horrible run of luck?

chrs1313

iTrader: (24)

why would you keep running the 918 springs after you had so many problems with them...either cracked or retainers etc...they are a bad design i would have went with duals after i found the heads with hair line cracks but that is me...to answer your question that is bad luck...

ArcticZ28

iTrader: (14)

Sounds like a horrible string of luck, but I would really check the valvetrain geometry on this next go-around to make sure everything is good to go. What kind of heads is he running? Could they possibly be a bad batch with incorrect geometry as well? I'm just th rowing out guesses here b/c I'd like to believe it's not just bad luck.

98TA_vert

I tried to talk him into it cause i have duals with ti retainers on my setup, but the place that did the heads told him the 918s would be good.

to artic z28
they are stock off his car (98 z28)

he even intentionally set the rev limit to 6000 just so nothing would break while his wallet recovered from the first few ordeals

93redBIRDman

iTrader: (9)

I still dont understand why people would even think about buying the 918's after how many obvious problems they've had and supposedly "solved." Boggles my mind...

ArcticZ28

iTrader: (14)

It's b/c there are an exponentially greater amount of good experiences with them.

hammertime

iTrader: (1)

+1 for the geometry. What kind of head work has been done?

After milling, valve jobs, etc., a non-adjustable valvetrain has some limitations on pushrod length vs. lifter preload vs. the proper wipe pattern at the valve tip. If the rockers are traveling near the edge of the valve on either side, a whole world of trouble awaits.

Since these are stock '98 heads, they can't be worth fixing when 241 & 243 heads are available at a reasonable price. Starting over with a better head and paying attention to the valvetrain geometry should avoid any other issues.

Otherwise, sounds like somebody must have broken a mirror as they stepped on a crack and tripped over a black cat, all while walking under a ladder. Sorry about the bad luck!

93redBIRDman

iTrader: (9)

Well of course there's going to be more people happy with them than not happy, or they wouldnt be on the market. What I'm asking is why would someone buy a valvespring set when LOTS of people have been breaking them under 3k miles? No other spring has had this many failures, so why buy them...

ArcticZ28

iTrader: (14)

B/c odds are much much higher that they will work than not and Comp is a great company. I'd still use 918's, as would others (obviously).

93redBIRDman

iTrader: (9)

Well to each their own, but I'd never buy a spring set that people are having problems with. Simple as that...

There are many other companies putting out legitimate spring sets at a competetive price. I bought the PAC springs (basically the old 918 spring before they had problems) instead of the 918's for this reason exactly. Of course you will "probably" be okay buying 918's, but why risk you're entire motor when there's no reason to at all? Get a different spring set for the same if not cheaper price.

again, why would anyone buy a set of springs that people are having negative issues with when you can buy others that are just as good and possibly cheaper

ShevrolayZ28

iTrader: (4)

It's breaking so many parts. You guys sure the cam timing is right?

1999ssls1

iTrader: (71)

Are you sure the lifts only 595 with a 242 duration? You may want to take that in consideration.

98TA_vert

yea its a crappy lunati cam, i wasnt around when he put it in he said he installed it dot to dot ill have to ask him if they milled the bottom besides the port work. didnt think about that, doesnt really matter now since its all garbage but what the hell for the sake of knowing he would have had plenty of room had his pistons flycut