Went to the dragway tonight. After my second pass, I noticed my valvetrain ticking a bit, so I pulled aside. A few friendly LS1'ers were helping examine and diagnose the sound...

It would idle normally, then randomly sputter for a few seconds, then stop In addition to this slight ticking. While we were listening, I blipped the throttle a little and then we heard a SNAP! The motor almost died but I shut it off anywayl. We thought for a second. Then tried to restart it with no luck. Had to get it towed home. I'm scared I've done something serious internally. The guys, who I hope chime in said it may be a broken pushrod? Could anyone else offer some advice? How severe could the problem be?

If this is the case, What are some good pushrods to upgrade to? Best prices? I have yet to search, but will right after I post this. Also, I have never done any valvetrain work. Are there any good how to sites? I plan on checking LS1Howto.com.

One last note, I'm sure as hell glad I didn't make another pass. I could have completely blown my motor. Thanks in advance...

Rick M.

 

If something really snapped I bet pushrods are the least of your worries. But I Thunder and I believe TSP sell pushrods that are a bit cheaper then the pushrods that come with the Comp Cams name on them.

 

Could anyone else offer some advice? What could have broken?

 

Pull the spark plugs, if you have a broken plug;chances are you had a bent pushrod that could have caused PTV(Piston To Valve) contact. Either way i would pull the heads(Or said head that you heard the sounds from). Hope it's nothing to serious, GL man.

 

Yes, unfortunately don't rule out a mess yet. As stated, the stock pushrods are known to bend fairly easily, especially on a missed shift and mechanical overrevving of the engine but to just snap? Can't say I've heard of too many doing that.

 

it was sputtering down and the motor starting shaking and then all of a sudden you heard a snap/metallic clank sound and he shut it off....im unfamiliar with broken internals since i havent broke mine yet but it sounded like a metal chafing sound when it started to sputter then made that metal sound

 

Did you notice your oil presure while you had it idling before the final clunk? Is it leaking any fluids? Do you have oil in the engine (check the dipstick)? Have you pulled the valve covers?

Have you had any past oil pressure problems? Have you checked the plugs and wires? Any clutch problems? Have you drained and checked the oil (for metal shavings, parts, or coolant)?

Sorry hard to diagnose over the internet...

 

I am guessing you snapped a valve spring.
If you pull the valve covers off, you can see if you did or not.

 

Well, this happened last night and I pulled a double shift today...just got home so I haven't had a chance to really check anything and don't plan on it right now in the dark. Tomorrow morning, I'm going to pull the valve covers, or cover since we only heard this sound from the driver's side. Hopefully, I'll be able to post more info about it then.

I haven't noticed any change in oil pressure - although, I did just replace my oil pressure sensor after my recent LS6 swap. I read it is normal to read slightly higher on the guage after replacing these, which I did notice...

I guess I'll also drain some oil and check for any visible shavings while i'm working on it.

I appreciate all of your comments and once I get that cover off, Hopefully you guys can help me out a bit more as I've never attempted any internal/valvetrain work. A plus is my brother, a volvo technician offered his assistance with this problem of mine too.

Rick M.

 

I pulled the valve covers. Nothing's broken. I only had enough light today to check the front four pushrods. Straight and clean. In the morning I'll check the rest, But I just don't understand what else it could have been.

Rick M.

 

something in the bellhouseing?

 

Don't eyeball pushrods, you need to pull them and roll them on a perfectly flat surface to see if they wobble. Did you kill the timing chain?

 

well the motor was still running after the snap. I also had a friend look and make sure each rocker moved while I turned the motor over by hand...so I couldn't have broken the chain, right? The snapping noise Definitely came from the driver's side. We were sure it was valvetrain but apparently not the rockers, springs or pushrods. My brother's on his way with some tools. Hoping the boroscope will open up a few doors.

 

you might have to pull the head off just to make sure that your valves and such are ok. if that is ok then i would try and re-assemble. Maybe an injector/coil gave out??

 

A coming and going ticking with a snap and no restart eh? I'd pull the front cover. Sounds to me like the cam retainer isn't right or something. Don't trust your ears, aluminum transmits sound so well, the problem could actually be anywhere. If the pushrods look good ect ect pull the front cover, you never know. I'd bet if I was a betting man that it isn't a bottom end issue.