Mark2009

I think you should do the proper wiggle test with a dial indicator.

What you, the shop, and some others are doing now is little more than guessing, which I don't think is a tool you'll find in any good machinist's toolbox.

Also the oil consumption theory has been well debunked on this particular issue on this particular engine, so the shop is engaged in even more guessing.

175rgr

I just pulled the car in the garage about an hour ago, I'm going to let her cool down and throw a dial on it. I know its not the most preferred way but I'm going to remove the rocker and leave the spring on it just for an idea, that's all I can do until my new comp LS valve spring compressor shows up, my old knockoff brand cracked.

As far as the tune being conservative, my tuner is out of town till the end of the August so I cant pull the tune yet, I called the previous tuner and he says its on 18 degrees of timing, so its not pushing to hard.

Michael_D

You'll just be wasting your time until you can get the springs off. You really need to "feel" the movement of the stem and when it contacts the guide wall.

175rgr

Michael, i updated the OP with a new video, i know what you mean by "feeling" the valve contact the guide wall and I could still feel it even with the spring on, especially in the "upward" movement toward the intake manifold.

Also, every other valve had no noticable movement with the exception of cylinder number 4 Intake valve and cylinder 8 intake valve. All others felt completely solid. cylinder number 8 had about .06 - .08 movement in both directions a little better than number 4.

Mark2009

You cannot get a meaningful measurement with the spring installed.

ATC399

Could not disagree more..

Jasonoff

Cool...

MyLS1Hauls

Before I removed my heads this spring, I "wiggled" all of my valves with the springs still on. I found 4 intake valves that moved more than the rest, so I marked them. Didn't bother with a dial indicator...was just "visual". I was removing the heads regardless, and was just curious. Sure enough, those valves were all at .005" clearance. Take it for what it's worth. I don't recommend people diagnose worn guides like this, but like I said, I was planning on having the guide bores measured anyway.

My "partially rebuilt" heads lasted 20k miles, before they needed to be redone. My cam has .675" lift, and I run stock rocker arms with PM guides. When I had them rebuilt this spring, I used PM guides again. From what I have personally seen, I feel that the valve guides are a wear item, and need to be treated as such.

ctsv510

So you had heads redone with new PM guides that wore out in 20k miles?

erikszr1

toast, first video says it all. no need to measure anything. mine was the same way. like you, I didn't even remove the rocker arm. I saw play, 3 hours later both heads were sitting on the bench.

175rgr

Regardless, from what I have seen those 2 being that loose is enough concern for me. Ill add the full specs of the motor/cam and heads to the original post along with my course of action.

I just purchased American Heritage Stage 4 heads and they should arrive by next Friday. I have to drive this car daily between now and then so hopefully nothing happens in that amount of time. American Heritage is accepting my current heads as a core and i will pick up new factory MLS gaskets from the stealership tomorrow. No need for head bolts it has ARP head studs already in it.

The car may have lasted another 5k miles or another 70k we will never know, id rather bite the bullet now and be done with it than sacrifice a 6 - 10k motor down the road.

I agree that you cannot get exact information because the springs were still installed but the fact that just two valves were in this condition and they moved as much as they did compared to the rest is enough for me to get the issue addressed.

Thanks for everyones input on the deal, ill get some videos of the valves when i remove these heads before i send them off and be sure to post them up.

MyLS1Hauls

I detailed it in another thread. Car had 7k on it when the heads and cam package was installed. This was a couple years ago, and things have changed a bit today with the way the heads are repaired. Only the 3 worn guides were replaced and all seats recut. Fast forward to this spring. Car had 26k on it, and I found most of the intake guides worn and a couple exhaust. Had all guides replaced with OE type PM, new OEM sodium exhaust valves installed, and stock intake valves. All seats recut. I expect to get another 20k out of the heads. I do NOT expect them to last indefinitely...they should, but I know better.

Mark2009

Did you or someone measure them later?

RedZ4me

So PM guides can go as high as 20,000, some stock LS7's have very high miles (plenty don't), and lots on here using bronze guides.....so we still don't have a perfect fix

175rgr

I dont think you can draw any conclusion from his situation, he didnt replace all of the guides the first time and he didnt state which ones were bad and which werent when he took it apart the second time. There are so many variables in the LS7 "fix" its insane. All I know, the movement that is posted in my videos regardless of spring tension on them or not is not normal IMO because the rest of the valves do not exhibit that behavior. Also, on my old 820 rwhp c5z I never seen this movement at all in those LS3 heads.

I will measure mine when i remove them next week for an "accurate" wiggle test with no springs attached.

What I do know, is American Heritage gave me his word that I wont have to worry about LS7 valvetrain woes any longer. If after I spent my hard earned money with him I have guide issues I expect him to stand by that word as an respectable person would. Only time will tell.

After the new heads are installed EVERY oil change I will pull the valve covers, remove rocker tension and "wiggle" the valves, recording everything very accurately. If I find anything abnormal you can bet it will be posted here. Its a small thing to add to an oil change routine and I have no problem doing it.

American Heritage

That's the thing with OEM type PM guides, they are soft and will wear just like the bronze guides do.
It took some time for us to find a hardened PM guide that could stand up to the side loading of the LS7 valves (w/stock rockers). The oem PM guide is somewhere in the low 20's or high 10's on the Rockwell hardness scale (c scale). The hardened PM guides we use are in the high 30's low 40's on the Rockwell harness scale (c scale). Alot harder than the factory style PM. We have some testing on this we will be publishing as soon as we get it all the data back from the the facility's we contracted to do the testing.
Valve guides are a replacement/wear item but they should be replaced every 60,000-110,000 miles (application dependent), not every 2,000-30,000 miles.

MyLS1Hauls

Good info. Are you concerned about harder guides eventually wearing or galling the valve stems? I know the valves are coated (exh is chromed, and the int is CrN), so the surface hardness is up there.

American Heritage

No not really, the hardness of the valves and hardness of the hardened guides are very close. From all our experience they appear to be very compatible with one another.