Ive always thought any grooves were bad. This only has 1500 miles on it. Head studs leaked and were getting coolant passed the head gaskets to the lifter valley. I pulled the heads the other day and found this. I can feel them, and catch a nail in them slightly.





How bad is this at only 1500 miles? What causes it? I really dont want to pull this thing out...

 

When you were having your block machined in the first place did you let the shop know that you were intending to use studs? If so did the shop use studs on the torque plate instead of bolts. Studs and bolts put different stresses on the block. As a matter of fact I had been thinking about what would cause so many people to have issues with leaky studs, and the only thing that I can think of is that people/machine shops are not using the studs on the torque plates, and then studs are being used in final assembly, and the diffence in the stresses is enough to cause problems.

Same thing with those lines you are seeing... I am betting studs were not used in the machining process and those groves are being caused b/c the stresses on the block are different with the studs, than with the bolts that were (likely) used in the machining.

 

I do not buy the studs vs. bolts for a moment. Yes they should be considered when boltiong down the torque plate but that would cause subtle differences in distorsion not a scratch and not the sealing issues guys have.

Looks to me like the scratch extends up into the carbon above where the piston rings travel, in that case I would suspect debris on the ring when the piston was slid into the bore.

 

With only 1500 miles, that sounds like the most likely scenario.

 

Did VRE assemble it top to bottom? Have you spoken to them yet?

 

Since there are so few miles on the engine I wonder if its caused by debris, are those new pistons? did you clean the ring lands out before assembly? did you change the oil after a short heat cycle after the first start?

 

This is fairly normal, they LOOK like a scratch but it is more like a scuff. If you cannot grab the line with your fingernail do not sweat it, run it. You MAY have gotten a little water in the cylinder also.

If the rings were file to fit, and were not properly de-burred that will also cause this.

David

 

They assembled the rotating assy. I bolted on the heads. I have not called them on this yet. I asked their opinion about the coolant in the oil before I pulled the heads though.

New pistons. I did the first oil change pretty quick.

I can catch a nail in there. Its not really deap, but I can feel it with my nail.

Im so fustrated with this pos car that Im about to burn it. It took 6 goddamn hours to pull the heads with the studs. Driver side was a breese but the passenger side hit the header. The header wont come out unless the motor mounts are unbolted and the engine lifted. I had to take every damn stud out.

I spent too much money on this to do it twice. Thats the only reason I could justify spending ~10k on an engine. Then coolant in oil. Now scratched cylinders. Im a ****ing dumbass for not buying a C5 and doing a heads/cam swap. It would not have cost much more if I sold my Z28, and would have been faster, and a much better car.

 

I took a few more pics.

This one looks worse. Its deeper. All my 12pt sockets are at work so I cant turn the engine over to see it better.



Another pic of the cylinder in post #1.



All the others pretty much look like this and are ok with me.



I should have all my gaskets here tomorrow. Should I keep running it?

 

It used to look like this

 

You have a cracked piston ring.
The ring was accidently broke during assembly.

 

wow, that doesn't look like 1500 miles of build up. I pulled one down at about 1000 @ a few hours of tuning and it wasn't showing any signs of wear. I'd say agree that there had to have been trash in the cylinder. how did the gaskets fail? its it possible something got into the cylinder? were they heads clean? intake? i'm sure they were but man thats a gouge, not a scratch in the 1st shot.

 

The gaskets didnt fail. You can see where the water went up the threads of some of the head studs, then followed the gasket to the lifter valley. I pressurized the cooling system with the intake off and it got wet at the head gasket where the head meets the block. I installed the studs per the arp instructions that came with them.

Nothing got into the cylinder. Im very carefull when assembling engines, I do this kinda stuff for a living. The cylinders were wiped down with lint free rags and light oil prior to the heads being installed.

The intake was pressure washed very very well to make sure it was clean. It was ported by Lloyd, then sand blasted. I made sure there were no metal shavings or sand in it. The heads got the same treatment.

 

opps, reading comprehension got me on that one.
I wasn't doubting the cleanliness of the install especially w/ the shots of the shortblock. just curious.

 

I think Sam Pace has the most likely answer. If the ring wasn't broken during assembly it was "almost" broken and then did break after some miles.

Head studs are hard to seal. I've been using grey/black RTV with 100% leak free success. The ARP thread sealant does not seem to work well for me at least. Learned the RTV trick from Ed Wright, (but he uses silicon sealant).

Things like this happen. Just bad luck it seems. School of hard knocks.

Karl