Wiggle test

[joelster]

Took my heads off Sunday. Put them on the bench to do the wiggle test. Literally had to put about 50lbs of force on them to get them to move a teensy bit. FWIW, you can do the same thing to a brand new set of heads with zero miles on them. I'm sending them out to Lingenfelter this week for their port job. I figured since I'm doing a cam swap I might as well get them looked at for piece of mind.

Car has 9900 miles on it, and has been autocrossed for the past 5 years. No sustained high-rpm stuff, but lots of hard cornering. Rockers, pushrods, pistons and bores look excellent.

To clarify a "rumor" that I heard on a FB group that GM had a bunch of LS7 engines left over from the Z06 to put into the Z/28, that is false. There are stampings on my engine that say 02/04/15 at 09:23.

[ariZona28]

Very good info! Nice to see facts instead of just rumor and hearsay. What cam are you going with?

[highrevving]

Originally Posted by joelster

Took my heads off Sunday. Put them on the bench to do the wiggle test. Literally had to put about 50lbs of force on them to get them to move a teensy bit. FWIW, you can do the same thing to a brand new set of heads with zero miles on them. I'm sending them out to Lingenfelter this week for their port job. I figured since I'm doing a cam swap I might as well get them looked at for piece of mind.

Car has 9900 miles on it, and has been autocrossed for the past 5 years. No sustained high-rpm stuff, but lots of hard cornering. Rockers, pushrods, pistons and bores look excellent.

To clarify a "rumor" that I heard on a FB group that GM had a bunch of LS7 engines left over from the Z06 to put into the Z/28, that is false. There are stampings on my engine that say 02/04/15 at 09:23.

Thanks for the info! Please keep us posted.

[FASTFATBOY]

9k miles, failed



25k miles failed



There are hundreds of vids like this, doing the test with the valve springs on doesn't really tell you anything.

Boom

[joelster]

Originally Posted by FASTFATBOY

9k miles, failed



25k miles failed



There are hundreds of vids like this, doing the test with the valve springs on doesn't really tell you anything.

Boom

Those are pre-2010 Z06's correct? There was a bulletin posted my GM saying something about out of spec guides from their supplier. Fixed the issue in 2011.

My comment was more or less directed at the shops that say every LS7 is bad, even the Z/28 LS7's. Find me a YouTube video of a Z/28 engine that let go.

[ariZona28]

[FASTFATBOY]

Originally Posted by ariZona28

Keep your head stuck in the sand, it'll be fine.

[FASTFATBOY]

Originally Posted by joelster

Those are pre-2010 Z06's correct? There was a bulletin posted my GM saying something about out of spec guides from their supplier. Fixed the issue in 2011.

My comment was more or less directed at the shops that say every LS7 is bad, even the Z/28 LS7's. Find me a YouTube video of a Z/28 engine that let go.

Every LS7 has this issue, every one.

Whether they drop the valve or when they drop the valve is the gamble. I had a buddy with a stock C6 Z06 that had 100,000 miles on it and was still alive and I have seen cars with 9,000 miles drop a valve and destroy the block.

He didn't have the 100,000 mile car long, he could hear the ticking bomb.

I would bet that yours are out of GM spec, please report back. The last video I posted has a lot of info on this issue.

Good on you to pull them.

[macalot]

Originally Posted by joelster

Find me a YouTube video of a Z/28 engine that let go.

Crickets!!

[joelster]

Originally Posted by FASTFATBOY

Every LS7 has this issue, every one.

Whether they drop the valve or when they drop the valve is the gamble. I had a buddy with a stock C6 Z06 that had 100,000 miles on it and was still alive and I have seen cars with 9,000 miles drop a valve and destroy the block.

He didn't have the 100,000 mile car long, he could hear the ticking bomb.

I would bet that yours are out of GM spec, please report back. The last video I posted has a lot of info on this issue.

Good on you to pull them.

I agree that '06-'09/'10 Z06's had issues, but I haven't seen anything about '14-'15 Z/28's. Find me some concrete info about a Z/28 that was torn down and had valve issues. My heads were sent out this morning.

[silversleeper]

Originally Posted by macalot

Crickets!!

https://www.camaro5.com/forums/showp...&postcount=111


Clearly you didn't read the comments below the video by professionals that have worked on hundreds of LS7 heads, at least two well known shops/mechanics I recognized posted comments.
No one is forcing you to learn anything, but saying it doesn't exist isn't factual. It's like you are calling members here who have posted about their Z engines being ruined by this liars, that's interesting.


I was deciding between the LS7 and LSA and decided I could live with a supercharger coupler replacement and weak intercooler brick but did not want to deal with heads unless an already done by a pro, used car presented itself at a good price. Not everyone does much research prior or post purchase.
Edit: L99 AFM lifter problems and V6 timing chain issues had me rule those out too.

[4 FN 27]

Originally Posted by joelster

Find me a YouTube video of a Z/28 engine that let go.

I didn't get it on video...but:

https://www.camaro5.com/forums/showthread.php?t=419077

#918 got a replacment motor all under warranty @ 958 miles.

Run the Carfax. It is there.

Not sure what caused the issue but the #6 Piston was in the Intake Manifold. GM would not allow us to tear into the motor. And it was shipped back.

[Shark72]

⚖️ I love my Z/28. Had a 2013 1LE and a 2015 ZL1, both great cars but Z/28 is the best! No problems! No fear hear!

[FASTFATBOY]

Originally Posted by macalot

Crickets!!

You think the LS7 is immune to this issue because it's sitting in a Camaro?






The Z28's sit, very few people drive them. A miniscule percentage actually beat on them the way Z06 drivers do.

But, carry on....