Timing

Later EJ25 engines were interference so I would check the compression in case you bent valves.

Do you have compression on the # 3 cylinder ?? If not your probably going to be pulling the head and having the valve on # 3 cylinder fixed . You might want to start changing your timing belts at the recommended intervals of 50,000 miles

Olds403 is dead wrong, but the other respondents are correct: you bent a valve. Sorry. That said, t-belts on the 2.5 SOHC motor are always good for 10 years.

I ran a compression check on the 3-cylinder. Zero compression. My only question now is what a bent valve cause 0 compression or is there a possibility that it has knocked a hole in the top of my piston? I am going to have to take the head off either way so I guess I will see. As far as the remark about the timing belt. This engine was recently rebuilt and the timing belt had less than 2000 miles on it. Trust me I am a stickler about maintenance on my vehicles. I appreciate the feedback though fellows and or ladies if any commented

If the valve cannot seat you have no compression. Sort of like inflating a balloon with a hole in it. Piston damage is possible,

Weird that a new belt snapped...or did a tensioner or pulley fail? If you had normal power then the timing was set ok; pretty hard to screw up on the SOHC anyway. Just pull the head when you're in there and, as you say, you'll know. Doubt that you perforated a piston. Check those pulleys and tensioner carefully; your water pump is probably ok, as they're very robust.

I have pulled the head off. The funny thing is that at least from what I can see there does not appear to be any valve damage. The piston does not appear to be damaged other. However there was an extensive amount of buildup on the Piston surface and I'm wondering if it just was not letting the valves sit down into the valve seat. I have another set of heads luckilyperiod and a brand new set of gaskets and head bolts of course. I am going to do a little more inspecting of the block and the piston and try to figure out if maybe a piston ring broke. I agree the timing belt should not have snapped so soon. I am absolutely certain that the timing was accurate. As I had been driving it around 4 weeks with no problem. All of the tensioners appear to be good nothing broken. I think the belt was just defective or it got too cold and just snaps. I don't know I will let you guys know

Hmmm.... I'd have the head checked carefully by an experienced machinist, as it's cheap once pulled. Good luck.

Carbon build up on the piston would have nothing to do with the valves seating or not. If a valve is bent even a tiny bit it won't seat and would leak compression.

Indeed.

it ended up being a bent valve of course. i replaced the heads and all is now well.

Great.