camelpower

Heads were machined and tested everything was perfect new comp cam pac dual springs installed
300km motor had a ticking sound thought it was a lifter at first but when we pulled of the heads this is what we saw this is one side but 2 intake valves where crushed opposite each other cylinder 5 and 6 rockers where is perfect condition so we decided to go with a set of btr springs and see what happens

SG4247

Retainer failure.

it happens.

Lucky the valve is not in the cylinder.

Here is mine, on a different platform.

The experts say this is from constant high RPM valve float. This had 1500 miles on it, since new springs, retainers and new valves were installed.

My opinion differs somewhat. I had 2 of 12 retainers failed. The 10 look fine.

Yours looks like lock pull through. Maybe mechanical failure of the retainer parent material. Could have been a manufacturing defect or a problem with the raw material quality. Where as mine looks like the spring end is chipping away at the retainer like an air chisel.

camelpower

Damn they were brand new spring kit did 2 dyno pulls one street pull then the retainer said good bye

SG4247

Brand new does not mean good.

I feel the same way. The other failed retainer allowed the valve to drop and the valve/piston and banged up everything.

Your retainers look like Ti. My company buys and processes more Ti than anyone in the U.S. We only use virgin titanium in our parts, and they must have the very best fatigue life possible. I know that much of the titanium used in manufacturing in Asia is recycled. We have found that there is fatigue risk with recycled Titanium, and that it is not worthwhile to buy it.

Dale1990

If those are the OE Ti intake valves, did someone maybe forget to put the lash caps on those? That will lead to the tips being smashed within a few hundred miles.

TRSCobra

I've seen this countless times whenever people neglect to reinstall the lash caps on Ti intake valves.

Twinscrew

This^^^^^

grinder11

I know things have a cycle life, and agree new doesnt always mean defect free. This is one of the main reasons my PAC duals have been in place for 10 years, 52,000 miles. I'm kinda reluctant to replace them, even though I have a brand new (that word "new" again) set of the same PAC duals on the bench. I don't recommend people going 50,000+ miles on performance valves with a performance cam. But my cam is only a .603"/.608" lift, so that helps spring life. Anyway, what amazes me is how the one wiped out retainer still held on with just a "finger" of material still keeping the valve in place!! Care to divulge who manufactured the Ti retainers on these engines? If this did happen due to eschewing the lash caps, you cant fault the manufacturer. I also realize the pics are of 2 different engines. It does appear the first engine was run without lash caps. Those Ti stems wont last without them. Not everything GM did with the LS7 engine was wrong

camelpower

So not putting lash caps on the ti intake valve tip is responsible for this i see

but last question before i blame the machine shop that did my heads do the lash caps come installed from the factory on the oem heads ?

Undy

Yes, they were installed at the factory and MUST be installed after any machine work on the heads if they're OEM TI intake valves. Check the remaining valves to see if they were installed. If not, that's the smoking gun on your machine shop's gross screw-up.

Dale1990

If the shop wants to argue, here's a page out of the Factory Service Manual noting the cap ("rocker arm wear pad") needs to be installed - Step 8, Item 234 in the diagram.




Edit: Different pic. The procedure is copied in a couple different places in the manual.

camelpower

Problem is iam from dubai and we have been looking all over the place for the factory ti intake valves to replace the damaged ones and iam really hesitant of going the ss route so for now the car is just sitting in the shop untill i can find 2 ti intake valves

Undy

I'd be suspect of the remaining valves too!

Texasthunder

Who installed the heads after they were machined?