Drop vavles, cam

[ironhorse]

Originally Posted by ArKay99

What Raid and Ivan said. Remember, the LS7 rocker ratio is 1.9:1, so the ramp is more severe. Couple that with a 7k red line and a bigger cam, the valve springs are going to take a beating. There were a lot of documented spring failures in the earlier LS7's...then sump issues...supposedly all fixed in 2009. If you are going to road race the car, I would suggest looking into improving the sump system.

Ther rocker ratio is 1.8 on LS7, there are documented dropped valves from 2006-up through 2011. Due in most part to bad or worn valve guides, or bad valve train geometry by some...Bad needle bearing end caps in LS7 rockers from jan 2007-late July 2007, bad batch...caused needle bearings to end up in oil pan.

[ArKay99]

Originally Posted by ironhorse

Ther rocker ratio is 1.8 on LS7, there are documented dropped valves from 2006-up through 2011. Due in most part to bad or worn valve guides, or bad valve train geometry by some...Bad needle bearing end caps in LS7 rockers from jan 2007-late July 2007, bad batch...caused needle bearings to end up in oil pan.

Oops, thanks for the correction! I meant 1.8:1, that one got by me. Over on the 'other' forum, I had read about some spring failures as I looked into LS7 issues before I bought my 09. It's been a while. I had also read about that batch problem.

[BJC99Hardtop]

Originally Posted by the machine

I have posted this before but it deserves repeating...

It is critical with an LS7 to warm up the motor before beating it. The tollerances on this motor are very close and designed to only be correct when the engine is at opperating temps. Metal expands when it heats up and aluminum moves much more than cast iron.

I never rev higher than 3000 RPM until the engine oil reaches 100 degrees. Do not go by water temp as that is controlled by the thermostat to get hotter sooner.(the hotter water helps warm up the metal) The metal in the engine needs to soak the heat to expand into it's design specs. The metal temp is better represented by oil temp than water temp, and there is no metal temp guage.

I have been following this advice since the first time I read it a couple of years ago. The oil temp is always displayed on my DIC. It is interesting how long it takes for the oil to go from 75 degrees to 100 degrees. I usually wait for 150 degrees before 6K RPM shifts!

No problems so far, but I keep the warranty up just in case. At $400 per year bumper-to-bumper, that is cheap insurance.

[ironhorse]

Originally Posted by ArKay99

Oops, thanks for the correction! I meant 1.8:1, that one got by me. Over on the 'other' forum, I had read about some spring failures as I looked into LS7 issues before I bought my 09. It's been a while. I had also read about that batch problem.

Hey Bud, glad to help...

[Mang]

Last month a valve dropped from my buddy's 2006 Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 was a only few cars later on the production line, with 35K miles also completly stock, both of our cars share the same defects which came along, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang

[ironhorse]

Originally Posted by Mang

Last month a valve dropped from my buddy's Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 is only a few VIN later produced, with 35K miles also completly stock, we share all the defects which came along with our Z06, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy

available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang

Check with Lingenfelter, I believe they have access to the original guides...See if you can speak with Graham Behan, cheif engineer at LPE...Also, if the Ti Valves are coated properly with the Molyb, then bronze guides will be fine...See bold on your post ...

[MEATHEAD1]

I do not drive my vette much right now but looking at the shop doing the work vrs me right now the shop has me beat 2 yr 24 warranty, for 7500, cam head work port polish headers and a tune, doing the work I would save a little money but no warranty. Very hard not to let them do the work.

[MEATHEAD1]

Originally Posted by mulinjohe

you need to determine if your car is an early or late 07.

It really does not matter what year, from what I have been told and have seen at the shops, it would be in my best interested to do the job on the heads. The great upside is better flow and power. For a little more cash its worth it

[ArKay99]

Originally Posted by Mang

Last month a valve dropped from my buddy's 2006 Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 was a only few cars later on the production line, with 35K miles also completly stock, both of our cars share the same defects which came along, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang

My old LS1 sucked a washer into the number 7 hole, crushed the piston, gouged the head, and cracked the cylinder wall. When I contacted Lingenfelter to purchase my semi-long-block, they told me they could replace the sleeve, for about $400... wasn't worth it for an old LS1, but an LS7 might be worth it. If you go that route, check the block all aroud the sleeve very carefully... a buddy of mine that does engine rebuilds found a crack in the block near the crack in the sleeve. He could have welded it, but it was already a lost cause...

[jaymsu]

So to sleep better at night, I need Valve / Guide / Spring replaced on heads?
(I'm not looking for any HP increase from head work)

If I were to get some reputable shop to do this work, how much should I expect to pay for the work? (head refresh and install)

[HyperX]

You need new valves. I am getting mine done this Friday. Going with Stainless Steele ones. Since my heads are going to be done and engine opened up, I am also throwing a mild cam and other things.

I have researched this issue for two years now and was initially very weary about modding my Z. Since my warranty just ran out, I am doing something to get a peace of mind.

[clogan]

Originally Posted by MEATHEAD1

Its the valve guide I seen first hand one that was getting ready to go and one that has. As far the year and Gm they filed bankruptcy. So no deal for replacement for me under warranty.
This a very serious problem modded or not.

Yup. My showroom stock 2006 had defective valve guides. Luckily I detected it at 38,000 miles, before anything catastrophic happened. Last month I replaced my cylinder heads with stock heads that had been overhauled by WCCH to replace exhaust valves with stainless steel, and replace stock sintered metal guides with bronze. Cost me 4 grand. but at least I avoided a valve drop, which most likely would have resulted in a blown engine. Some say 50% of all LS7 engines have defective guides. GM's official position is that the numbers are very small, and limited to those produced prior to a certain date. The truth is perhaps somewhere in the middle of these two extremes.

Here's an easy test that every owner of an LS7 should perform: remove your spark plugs, and inspect the threads (yes, threads) for oil. If your plugs have oily threads, there is a strong possibility that your valve seals, and your valve guides, are defective.

[mx11vette]

Has anybody looked into or actually used an available kit that gives you phosphor-bronze valve guides and all the tools required to replace your guides yourself? HorsepowerTV.com has a video showing how its done.

[MEATHEAD1]

Originally Posted by mx11vette

Has anybody looked into or actually used an available kit that gives you phosphor-bronze valve guides and all the tools required to replace your guides yourself? HorsepowerTV.com has a video showing how its done.

I looked into this and its not my first time doing heads.
Goodson is the one place to look for the kits, but when it comes right down to it, if you mess up,,,,, well you know. If you let a CNC machine shop mess up its there cost. jm2cents

[Krooze]

The thing about you are told is enough sufficient for you, but this is not the situation that always follow. if you really want to upgrade then you should check this list.
Fuel cells, Oil ,Hose fittings