Well I just finished my car Monday night, tune and all and Wednesday evening out playing around at the top of 2nd the motor went kaa-poo-yaa! Last night I pulled the plugs and valve cover to reveal the number 6 plug was pretty boogered up. The valves were still in the head and didn't seem to have any problems so my guess is the head gasket let coolant into the cylinder and boom goes the piston. I'm pulling the intake and head tonight to assess the damage.

So now I'm torn between what to do.... If the cylinder isn't to beat up and can just be honed clean I will get a new piston and rod, have everything checked by the machine shop and slap it back together with new gaskets. If it's torn up I can do 1 of 2 things: 1. I've got a buddy that has a ls1 block, crank and pistons he will sell me and I will get some rods and put it back together that way or... 2. Try to find a 6.0 short block to slap all my stuff on and play for the summer and tear apart and build this winter.
The driving factor is that I would really like to get the car running again soon so I've got my toy back for the summer. I will be posting pics as I get the car further apart along with updates. Any suggestions and/or opinions are welcome. On a side note I would like to make more torque so what are some options I could do. Mods and power in sig. Thanks!

 

A 6.0 short block would improve performance across the board, torque and all. To me that seems faster than a tear down.

 

Ditto. I'd go with the 6.0L.

 

The car made 580 on bottle. A stock 6.0 short block should hold up shouldn't it?

 

Sorry man.

Did it fail while you were spraying or just N/A?

A 6.0 would increase hp/tq from the 5.7 & would prob. be the better decision. Another option, for more tq, would be a stroker.

 

It went on motor. It was odd because when I made a 3rd gear nitrous pull it blew the coolant overflow hose off but I chalked it up to the clamp being loose but I guess I was wrong.

I was thinking about getting a 6.0 and doing a 402 kit in it.

 

6.0 Block, Bigger Bore is always Better, Stroker or Not!


Sorry for the setback.

 

The 402 would definitely give you more torque. However, you were saying you wanted to get on the road quick.

 

Yeah the 402 would be a winter project for the end of this year. If the stars align just right and by some miracle my cylinder walls didn't take a beating I will put a new rod and piston back in and be on my way. Ideally I'd like to find a 6.0 short block with flat tops and just run all my stuff on it. Then winter time build it. But I'm not having much luck finding and lq9 bottom end in anything around here

 

6L would be the cheapest/quickest option (probably the LQ4). So you'd take a compression hit... but if your block is okay, you could build a 383 out of it while you use the 6L... but I'd rather build the 6L even with the weight penalty.

 

If the block is alright I've got a few friends with spare parts to help me get the ls1 back together. That would keep my costs the lowest and just pick up new gaskets. Then I could start a 6L build and take my time doing it.

 

Update:
Got the intake off to reveal the #6 intake valve tulip chilling in the head sideways. I'm guessing it broke it off some where close to 7k bounced around in the cylinder and knocked a hole in the piston. Martin said this valve train would be good up to that limit but I think since it had 2.08 valves in it the heavier weight just over did it and floated the valve. Planning to get the heads off in a day or two.

 

Update pics.

 

thanks for posting back what you found. nice looking CNC work on that intake port

 

I am sorry for your loss

 

I will have more pics of the carnage inside of the cylinder once I get the head off!

 

How big was the cam....did you check piston to valve?

What was the .050 and LSA numbers?

Sorry if I missed it....look for other signs of valve hitting pistons when it comes apart

Good luck getting it back together but its always helpful to clearly know what failed so you can eliminate that issue on the next go around (assuming its something that can be figured out).

-Tony

 

The cam specs are 235/243 @ .050 .637/.627 lift and 111LSA. I didn't check the ptv in all cylinders. But I did cut .060 valve reliefs on all pistons.

The only things I can imagine maybe the 2.08 valves were too heavy for the springs and floated somewhere around 6800. Martin@Tick suggested I used the 1207x spring for that cam with my rollers and I'm sure they should have done just fine. The only other thing I can think of is I had a friend give me a hand cutting the #6 & 8 pistons and maybe he didn't get them far enough. I'm going to give Martin a call tomorrow after the holiday and ask his opinion.

 

Got the head off tonight. The cylinder walls got scuffed up and I'm not sure how much damage they can take before you can't rehone them. So I'm not sure about the block yet. The piston definitely tool a beating and I think the rings went too. The head doesn't look too bad but where it broke around the valve guide I'm not sure it's fixable.

 

Finally got the motor out. The pieces of broken valve must have been blown back up into the intake because the # 1,3 & 5 cylinders all had damage and pieces of metal in them.

I picked up a set of forged rods and pistons with polished and balanced stock crank. I'm taking the block and new heads to the machine shop today. I picked a nitrous outlet plate so with the forged internals I will bump the nitrous up to 200-250.