EJ20k belt snap - all ONLY exhaust valves bent?
 

(Please see post #2 for an important update, all intake valves, not exhaust).

Hey Guys,

We have a little Sherlock Holmes episode here, basically there's an EJ20K that we had to pull due to valvetrain noise shortly after installing. I've taken the heads off just now and it seems that only the exhaust valves are bent. How is this possible? Any ideas? I thought that it'd be pretty much random? But it seems all 4 cyls, all exhaust valves.

https://1drv.ms/f/s!AqCJmE8mfh_9he4S2gxw2bV1sEnpwA

2 cylinders seem to have 1 exhaust valve each, 2 others seem to have 2 exhaust valves each.

What's more interesting - is that before putting this in we measured both compression (it was around 9-10 BAR IIRC) and leakdown (>10%) on cold...! strange!


Thanks for your ideas and opinions!
Cheers.
Eid

Wanted to give this a proper update. I forgot to mention that technically there was a crash and the cam pulley was damaged, I am not sure if that lead to the belt being snapped, or it was just how it arrived. In any case there was a possibility of things hitting each other.

We delivered the heads to the machine shop today, I will keep this updated - maybe it will be of some use to somebody.


ALSO, it was the intake valves, not exhaust..

Are the heads being machined? if so, look at thicker head gaskets to compensate.

As well as the witness marks where the valves had contact with the pistons, it looks as the pistons have had contact with the cylinder head too judging by the lack of carbon on the piston crown.