What could cause this?

[jkrueger]

Second plug from the right from the #4 cylinder. These are from the right bank. The left bank is darker (richer). This is from a chevy LM7 in my coupe. Basically an iron block LS engine. This a brand new engine, less than 100 miles on it. I haven't reved it higher than 4500 rpm. I was driving at 65 mph and the engine was turning about 1600 rpm, when I heard a pop and the car lost power. When I pulled over I couldn't keep it running and it stalled and would not start. About 20 mins later when my wife showed up with the trailer, I was able to start and keep it running long enough to get it on the trailer.

Once back at the shop I pulled the plugs and did the finger over the plug hole compression check and the #4 cylinder has no compression. I also took the valve cover off and checked for valve movement and it seems to be moving well. The exhaust valve may be down a little compared to the #6 cylinder. It is hard to get an accurate measurement.

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6188_zps0fa323a5.jpg

video of valve train
http://www.25tires.com/25tires/My_Albums_Videos/Pages/Videos.html

JC

[Bob Cowan]

That's physical trauma. Something hit the electrode and bent it. That's a Bad thing. If you have a bore scope, you can look in there and see what's going on in there.

You'll probably have to pull the head off and see what's what.

[jkrueger]

Yeah the head is coming off tomorrow.

[tirod]

No compression. Hmmm. Like my logsplitter motor, it might have broken off a valve head . . . less than 20 hours, I'm not too happy with Honda. Unlike a Briggs, you can't pull the head, you pull the crank and piston out the bottom. That means taking off the plastic cam shaft and rubber belt drive.

Hey, it could be worse! And, you don't lay on the fender paint to work on it!

I suspect the "pull the motor" decision matrix is percolating to an answer about now. A borescope would answer some questions.

[tcoon]

Oh man that's awful! I feel your pain. Bent the crankshaft twice on my challenge car last year, had to pull the engine 3 times in 6 months. Good luck.

[skullandbones]

If you aim a flashlight into the plug hole you may see deep enough into the cylinder to see a bent valve if you rotate the crank as you go. If the valve did that damage to the plug, it should be visible. Those inspection cameras work great sometimes (I have one) but they don't always go around the corner where you need to see the evidence. I hope you lucked out and only have head work to get you back on the road. Good luck, WEK.

[loeffler1]

Havn't seen anyone complain about Ford engines!!! Sorry, could not resist. Probably the Chevy is not happy in it's Ford home. Seriously though, I would not be a happy camper. Is this a rebuilt engine or is it a crate engine from Chev? I certainly would be on the horn to whoever built the engine or to the Chevy people. This should not happen to a new engine, especially when not abusing it. Is there any warranty on the engine? With less than 100 miles on it, it sounds like someone screwed up. Good Luck with the repairs.

Bill

[jkrueger]

Bill, you got it right. Somebody screwed up when they built this engine. To answer some questions, it was junkyard motor that we took to a reputable engine builder in upstate NY to build. We have been in contact with him and showed him the pictures you see below and he has said that he will take care of it, because his shop did screw this one up. They timed the cam wrong and every intake valve was hitting the pistons. As far as the timing is off I'm amazed it ran at all. I am expecting all new intake valves and push rods. Fix the damaged head and piston. All new rod bearings, and maybe main bearings (I haven't pulled a cap yet), new head gaskets. I am glad he talked us into forged pistons and rods and nitrate hardening the crank. If it had stock powered metal rods and cast pistons I think the engine would be toast. The rod journals still look new as well. A lot of metal in the pan and oil and a couple of big pieces too. There is no obvious wear anywhere else in the engine, so that all had to come from the bearings I would think.

Here are the pics

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6195_zpsbefe7ea7.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6196_zpsa8ee31d6.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6202_zps4dd65b2c.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6204_zpsc65f5fc3.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6207_zps46079a5b.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6210_zps67604b29.jpg

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6212_zpse082ea87.jpg

[jkrueger]

Two more pictures

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_6213_zps3d39da59.jpg

Somebody didn't read the instructions on timing this gear set!

http://i250.photobucket.com/albums/gg253/jkrueger485/Daytona%20Coupe/IMG_2661_zpsea90eb9e.jpg

[vnmsss]

Yikes!! I am really sorry this happened to you! It's great the shop is standing behind their work, and will be fixing it though. Still a lot of work for you, and it has to be seriously disappointing to put in all that time and effort only to have to take it apart and do it all again. :(

K

[tcoon]

Oh my! That really looks ugly! Glad the shop is standing behind their work, but I am not sure I would want them touching that engine again! Putting the cam 30 deg out of time is inexcusable! Good luck on the rebuild. Looks to me like pretty much the entire bottom end should be replaced as well, may have tweaked the rods with all that contact...

[tirod]

How could the builder have rotated the motor by hand to check and lash the valves?

I suppose things can heat up and grow enough to use up .050-.080 clearance, but wow. Definitely wonder how it got past the clay checking point - or was the chain removed after and things changed?

Things that make you go Hmmm?

[Mike N]

Putting the cam 30 deg out of time is inexcusable!

If the crank key was at 12 o'clock the dot on the cam key looks like it would be only be one tooth off. I can't imagine that the engine would run if the cam was 30 degrees out of phase.

[jkrueger]

If the crank key was at 12 o'clock the dot on the cam key looks like it would be only be one tooth off. I can't imagine that the engine would run if the cam was 30 degrees out of phase.

Mike, that is how they did set. The problem is that TDC for #1 is with the crank in the position shown in the picture. The instructions for the timing set say to set the cam gear dot to the "0" on the teeth scale and NOT to the "0" on the keyway. So it is 3 teeth off.

The builder wants the engine back so he can clean it up and replace what needs to be replaced. He is setting up the shipping arrangements.

We have decided to give him a chance to fix his problem. But I will double check his work this time. Lesson learned. So far he is doing all the right things to fix his mistake.

This just delays things for us, but if we can get the engine back in a timely fashion we should still have enough time to de-bug the car before the One Lap of america race in May. I still have a lot of little things to do on the car to finish it up to keep me busy, plus all the work on our farm to fit in.

JC