Guys,

So was driving around 40 mph in 4th gear, and the timing belt broke, and car immediately shut off, and I was able to coast to a nearby gas station.

Had the car towed home, and thought I'd do some looking around...pulled the #1 spark plug to find it smashed, which obviously the piston hit it. Other 4 spark plugs looked good no issues.

Those that have had a broken timing belt before and experienced something similar, how bad was the damage? Could I just replace the belt and spark plug and be ok, or do you think more damage has been done?

 

Oh dang

No expert, but have always heard that there is usually some form of head damage (i.e. bent valves)

Certainly more of an inspection is in order. Maybe pulling the valve cover is a start.

Anyway, some of the guys will chime-in

 

Most likely bent valves man I would guess the head need to come off and be inspected and rebuilt if necessary these aren't non interference ingines so there could even be damage to the top of the piston but I would personally pull the head and have it inspected....
I would hate to get it all back start it up and cause more damage but that's just my 2 cents...

And pulling the head is no more then a days job and a couple days at a shop to look it over

 

More then likely you bent valves.
You can remove valve cover, pull cams and do a leak down test. Pulling the cams will close all the valves.

I would do leak down before pulling the head. You may have gotten lucky, even tho the odds are you bent ****.

Good luck

I don't see Head studs or Springs and retainers in your sig so if you don't have them now would be the time to do it.

 

instead of focusing on the valves which is more than likely pretty obvious, Id ficus more to find the source of why it happened, id inspect it and examine what caused that to happen, also inspect the balance shaft belt/logs etc to determine what could of caused the timing belt to snap, is it an aftermarket belt?
also 40mph in 4th ? your rpms where probably at 2.1k - 2.5k ? our cars definitely do not like that and it's not healthy to the engine. my 2 cents

 

Will def have to look at as I get some time. Not sure why the belt would break. Has approx 15k miles at most, I'm going to suspect either the tensioner went bad or a pulley.

Car already has arp head studs, and bc valve springs.

 

Sorry, the piston can't hit the spark plug, it has to be a valve.

 

Good catch. Didnt dawn on me until you noted it.

 

So maybe the piston hit the valve, causing it to bend, then it shoved the tip of the spark plug into itself?

 

This is the plug that I pulled.

 

Do not try to turn the motor over to check compression or bother with a leak down. These motors are interference motors. That means they are not designed with enough clearance between the piston and valves when the piston is at top dead center and a valve is open. Remove the head and the damage will be obvious [ bent valves ]. The pistons may be ok if the outer edge of the pistons are not damaged which damages the ring lands and the top ring will not be free in the piston groove.

Don

 

Agree. Detonation can eat the end off a spark plug but here we know it is a belt problem. To have plug damage a valve head has most likely snapped off. I advise get the head off and see what she needs.

 

+1
Can a valve be bent enough to hit the spark plug? Ir is the valve broken off and hit the spark plug on a bounce?

 

That's a good question my guess would be it could bend and still kiss the spark plug I wouldn't even fuss with a leak down compression test spend the few hours and just pull the head and see what the damage is he might get lucky and only need to replace the valves on that cylinder since that's the one that hit it

 

The piston can hit the sparkplug if a rod lets go. Hopefully thats not what happened here.