Timing belt snapped

[Inline Sex]

I was taking my gf to work, turned the car on, idled for about 60 seconds and then SNAP. The engine shut off quickly and I didn't hear any crazy sounds.

I have 2 questions:

What are the chances that there was interference damage?

If I take the valve cover off would I be able to see any damage that may have occurred from the top side, or do I have to pull the head regardless?

Forgive my newbiness.

Thanks!

[ttrousdell]

same shit happend to me. i was at 1000 rpm when it went. i didnt know what happened and thought it was fuel problem. opened the oil cap and saw a snapped rocker arm. Dispite the fact you were only at idle there will be interference damage and you bent a few valves im sure

[scottinAZ]

I have 2 questions:

What are the chances that there was interference damage?

If I take the valve cover off would I be able to see any damage that may have occurred from the top side, or do I have to pull the head regardless?


Thanks!

1. 100%. there will be bent valves at the least. Pistons ALWAYS win this fight. Unless the engine stopped INSTANTANEOUSLY. valves are fucked.

2. Maybe. check for excessive clearance on the valves. these will be the bent ones.

Congratulations, you just inherited a boat anchor formerly known as your cylinder head. Take it off, get the valves replaced, have it surfaced, and you are good to go.

If the damage is more than a few valves, get a replacement head off one in the scrapyard, have it remanned, and replace.

[KillaCams]

Any idea when the belt was last done? I only ask because i'm curious why your first assumption is the t belt. Did you try to crank it again after?

Your chances of interference damage is anyone's guess, the probability is high. Although i've seen timing belts snap on Hondas (also interference) and demolish the engines, and others not a dam thing happened, it's all chance i guess lol being it happened it idle i would think there would be little to no damage, but without pulling the head there's no sure way of telling.

You could get away with pulling the cap and rotor to check the belt for slackness. You probably won't see any damage with the valve cover off.

[Inline Sex]

Well actually the belt wasn't my first assumption. My first assumption was a rod. The timing belt hasn't been done in 1,000,000 +/- miles, I already had the parts but haven't gotten around to do it due to lack of workspace. I had a 77 530i that threw a rod and it was a RACKET. The way the motor just stopped without much violence, and the fact that the belt hasn't been changed since 1959, I think it's a pretty safe assumption that it's the belt.

So, maybe the best solution would be to buy a known good head that doesn't need to be surfaced (I just had a head surfaced and pressure tested 3 months ago and it cost $170, i've seen good heads for a lot less on r3v) and just do the head gasket and call it good. Sound about right?

[jlevie]

Unless seriously bent, you won't be able to tell if there are any bent valves by pulling the valve cover. With a new belt installed a compression (wet & dry) and leak down test should tell if there is leakage past the valves. That could mean bent valves, or just a worn head. But since the head would be coming off in that case for rebuilt it doesn't matter which is the case.

If the engine was idling, there is a decent chance that none of the valves are bent. It all depends on where the pistons and valves were when the belt broke.

Soapbox mode on.

I hope you realize that this was a completely avoidable event. Timing belt changes (and other scheduled maintenance) is not something that can be ignored or deferred. It has to be done on or before the scheduled point. Failing to do so results in hard failures and much greater expense for repairs.

With respect to E30's, unless you get a car that has a clear and verifiable maintenance history you should assume that none of the maintenance has been done and immediately execute all maintenance items so as to establish a zero point for future maintenance. With the youngest E30 being 19 years old and the average one have more than 100k on it the minimal list for the engine and drive train should be:

Timing belt, tensioner, camshaft seal
Water pump & thermostat
Radiator & all cooling system hoses
Fan clutch
O2 sensor
Plugs, ignition wires, distributor cap, and rotor
Oil & filter change
Valve adjustment
Transmission and differential fluid change
Brake system (and clutch if a manual) fluid flush
Cooling system flush & fresh coolant

[jlevie]

So, maybe the best solution would be to buy a known good head that doesn't need to be surfaced (I just had a head surfaced and pressure tested 3 months ago and it cost $170, i've seen good heads for a lot less on r3v) and just do the head gasket and call it good. Sound about right?

A used head always must be checked for warp and many will need a skim cut to get back into spec.

[MR 325]

You'll definitely have 2+ bent valves and a lot of time a rocker will break.

If you do the head, you MUST resurface the new one.

Or, I do have a good M20 for sale... I'm just sayin.

[Dj Buttchug]

yo if you need some help getting it fixed. new valves n machine work i can help you out.

buddy of mine has a full machine shop. local as always

shoot me a pm

[CabrioPunk]

I want to know Blount's pricing on these parts. I need a refresh. My buddy needs his done too.

Unless seriously bent, you won't be able to tell if there are any bent valves by pulling the valve cover. With a new belt installed a compression (wet & dry) and leak down test should tell if there is leakage past the valves. That could mean bent valves, or just a worn head. But since the head would be coming off in that case for rebuilt it doesn't matter which is the case.

If the engine was idling, there is a decent chance that none of the valves are bent. It all depends on where the pistons and valves were when the belt broke.

Soapbox mode on.

I hope you realize that this was a completely avoidable event. Timing belt changes (and other scheduled maintenance) is not something that can be ignored or deferred. It has to be done on or before the scheduled point. Failing to do so results in hard failures and much greater expense for repairs.

With respect to E30's, unless you get a car that has a clear and verifiable maintenance history you should assume that none of the maintenance has been done and immediately execute all maintenance items so as to establish a zero point for future maintenance. With the youngest E30 being 19 years old and the average one have more than 100k on it the minimal list for the engine and drive train should be:

Timing belt, tensioner, camshaft seal
Water pump & thermostat
Radiator & all cooling system hoses
Fan clutch
O2 sensor
Plugs, ignition wires, distributor cap, and rotor
Oil & filter change
Valve adjustment
Transmission and differential fluid change
Brake system (and clutch if a manual) fluid flush
Cooling system flush & fresh coolant

[Inline Sex]

Thanks for all the replies. I'll figure out what to do, but first.. PARTY. Happy new year to all!

[train80]

if you have a 325e, i have all the head parts available individually. valves, rockers, spring, clips. Very well maintained engine.

[Inline Sex]

if you have a 325e, i have all the head parts available individually. valves, rockers, spring, clips. Very well maintained engine.

It's an i, but thanks!

[e30rapidic]

I have an i head in pieces if you need any valves or anything. I have a box of shit for it!

[StereoInstaller1]

Although i've seen timing belts snap on Hondas (also interference)

MOST Honda motors (historically speaking) are NOT interference.

Just so you know.