Pistons urgent help please

[njames]

Hi,
Sorry for my lack of experience but Is it possible to identify weather these are stock ecotec or l67 pistons?, as I have a spare ecotec bottom end I could just use to save this drama but I was told this engine was a l67 so different compression, cylinders 3 and 4 walls have a burn or score mark the whole length of the cylinder (see photos) can someone tell me what this is and if it’s bad I can’t feel and indentation, I also have other cylinder wall score marks can’t feel any of them and piston 6 has some weird scratches/chips out of the top right on the edge (see photos) I need advice on how bad it is/what it would need to be repaired.
Car overheated and seized but cooled down and ran again without overheating but head gasket was blown and I had to drive an hour to get home would bearings also be fucked? any advice would be appreciated thanks

 

[losh1971]

The cylinders and pistons will be fucked now that it seized. It will probably need a rebore to remove the scoring, if extremely lucky a hone might clean it up but pistons will need replacing regardless. You could fit a set of stock size SH pistons and new rings, if a hone gets the marks out but probably a lot of effort considering the price of a complete SH Eco.

 

[EYY]

There's been something foreign in that cylinder to cause those marks.

Use a stock ecotec bottom end or find a good second hand l67. They're never really the same once they've been overheated unless you hone/rering etc. or re-machine depending on damage.

 

[njames]

Yeah thanks for the responses, I’ve got a spare ecotec bottom end, can anyone tell me if the pistons in the photos are from an l67 or ecotec, it’s probly going to be cheaper to use the same as what’s in the photos? as the ecu has already been tuned for that compression

 

[njames]

Engine number is vh835837 if that helps with identification

 

[EYY]

Won't make enough of a difference to matter unless it's tuned to the very edge imo - there isn't a massive jump in compression. Apparently can get away with 10psi pulley with the ecotec bottom end without a retune as long as you use premium fuel. Of course, retune is the best way to go but not always viable where costs are involved.

 

[njames]

Thanks for the help mate

 

[losh1971]

Since you will have the engine out it would be a good idea to remove the sump and reseal it with the good RTV. Probably also be a good idea to replace the rear main seal plate. It will save a lot of hassle later, if it can be done without the engine in place. @EYY knows the name of the good sealant to use on the sump.

 

[Immortality]

One piston is totally fucked with the bit chipped out of the ring land area as that will allow hot gasses to pass and burn the piston.

I'd be checking the charger for damage, as already mentioned a foreign object has been through there.

Stock ecotec will not handle 16psi boost for long, the cast piston in the ecotec are weak and will break if it rattles under boost. Personally I'd find a 2nd L67 and start again to make use off the good bits you already have.

 

[njames]

Thanks for responding mate, I think this engine that’s fucked was an ecotec to start with and just had l67 top end. pistons look exactly the same; they have different numbers stamped but being an idiot not sure if this means different batch of pistons or different compression.

Was never planning on keeping the 16psi pulley that’s just what was on it when I bought it. I’m thinking more like 10psi, do you think that would be reliable on a stock eco bottom end with wta intercooler and mace stage 2 cam?

Not sure what I’m looking for with charger, I can’t see any scuffs or scratches on the rotors, it does look like it had some sort of coating on the rotors that had basically all come off except for a few patches?