To much compression or to higher revs I reckon

ffark

that hurt
give it a bit more next time and maybe shell weld back togeather

i live by
live hard drive sideways so i always break stuff

guess ill be postin the same thing soon gonna through the blower on a stocko and fry some stuff as is been sittin around for way tooo long

Another thing is that the standard A series oil pump only supplies enough oil till 7000rpm after that you need to use an L-series rotor and spacer in an A-series oil pump.

My "good" A15 has a custom pump using the L series gears. I didn't bother transfering it onto this motor as it was always going to be a temporary measure. Perhaps a bit more temporary than even I intended. lol

1975 was a bad year for valves (and pistons)
lets get a 30 year old engine and stick some boost in it. that'll work. NOT!

and a bigger oil pump wont stop it detonating its ass out (but helps the crank live(and empty the sump faster, but thats another issue) but that doesnt seem to be your problem)

but seriously is there enough piston to see if the ring lands are smashed? going by what i can see in your pics either the ex valve failed or the engine detonated the piston ring lands out and then seized smashing the piston

ouch, i'm putting my money on too much compression...
I'm building a supercharged mx5 at the moment for a friend, it has the turbo 1.8ltr out of the BPT 4wd mazda, but i'm still dropping the compression just to be safe.
I would get the head sleeved, probably the only way you'll be able to get rid of the gouges. They look a little too deep.

Have fun, let me know how you go mate.
Ty

Those pictures of the motor look nasty.
I hope I don't have to pull my motor apart and see that.
I currently am using an adjustable waste gate but it is still boosting 10psi. I plan on reducing my boost to 5 or 6psi and I set my timing at 5 degrees advanced.
The track will be open for the season soon. Since I work there, they said I could come out and do some tuning and burnouts. As soon as I find someone with a digital video camera, I'll get something on youtube.
As for a dyno, before I do that, I still need to deal with my cold air intake. I am currently running without an aircleaner. I picked up a couple of Dodge SuperBee looking scoops which really give the car a mean look.
They kind of look like this:

Dodge Super Bee

The car is really coming together.
Next project is a roll cage.

The bent pushrods would leave me to beleive that the piston let go 1st. Even with the minimal timing 15psi is too much for casties without an intercooler. especially with the poor effeciencies of the S/C14. But I'm not crying any. apart from the financial aspect, (this short block cost me $300 to freshen up) I kinda get a kick out of building engines and then destroying them. (well I enjoy screwing the living fukc out of them, and sooner or later somethings gotta give)I'm still trawling the piston catalouges for a piston to suit my A15. the E5 piston (I think) has a lower deck height, but the smaller dish volume means that the CR would actually be higher. A mate gave me a set of 78mm ones that he used for 6 months before going to 79mm ones. They are a good option, but they also need the small end of the rod opening up to 20mm. The bloke who does my engine machining said the last A15 he did this to he made the pins fully floating, and machined circlip groooves into the pin bores. I do like the idea of floating pins, and I an almost put the circlip grooves in myself.