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View Full Version : 2002 Celica GTS bent valve???



RobUpNya
01-19-2011, 01:14 AM
I started getting a check engine light and the code refers to a misfire in cylinder 1. I had my buddy clear it and never the less... 350-400 miles later it came back with the same code pointing to a misfire in cylinder 1. One day warming up my ride I heard knocking on top of cylinder one and I looked up other forums stating that for some reason my year celica there was an issue with bent valves?

Can anyone tell me how true this is? Anyone else have this type of problem?:wacko::thinking:

Grot
01-19-2011, 01:18 AM
The only way you could easily bend a valve is a mis-shift or a broken timing belt.

It is more likely that your valves need to be adjusted.

donteatbugs
01-19-2011, 04:26 PM
bent valves come from a mis shift. you may have broken lift bolt, bad spark plugs, valves out of adjustment....

Luni
01-19-2011, 05:00 PM
7th gens are timing chains. And most the time your misfire comes from a bent valve. You can generally check by running a compression test. The number 1 cylinder would register less compression than the others.

usually if you bend a valve, youll bend 1 and 4 together, or 2 and 3 together.

And also, these cars had an issue with their ECUs and injectors and there was a TSB issued, a revised injector and ECU released to deal with a misfire too.

So, your issue may not be as serious as valves. Do the compression test and see.

Smaay
01-20-2011, 05:12 AM
The only way you could easily bend a valve is a mis-shift or a broken timing belt.

It is more likely that your valves need to be adjusted.

wrong, 2ZZ can bend valves at 8500RPMs very easily. i have been building and repairing them for almost 10 years now. I have almost seen it all

Smaay
01-20-2011, 05:13 AM
bent valves come from a mis shift. you may have broken lift bolt, bad spark plugs, valves out of adjustment....

wrong! broken lift bolts have absolutly nothing to do with misfires, you dont have to misshift to bend valves.

it could be plugs or valves out of adjustment

Grot
01-20-2011, 05:28 AM
wrong, 2ZZ can bend valves at 8500RPMs very easily. i have been building and repairing them for almost 10 years now. I have almost seen it all

I'm a 4th gen guy I was just making an assumption.

MCcelica
01-20-2011, 09:59 AM
The 2zz is an interference engine. So throwing a timing chain could bend the valves. But if that happened the engine wouldn't run at all. A misshift could bend a valve if you sent the engine clear up to the rev limiter and just dumped the clutch.

The main effect of broken lift bolts is the engine sometimes just won't go into lift.

Moral of the story is Smaay is correct as usual.

Smaay
01-20-2011, 02:50 PM
^^^^ :) the 2ZZ is only interference when lift is engaged.

donteatbugs
01-20-2011, 03:29 PM
i stand corrected, i didnt know what happens when the lift bolt break.

RobUpNya
01-20-2011, 05:28 PM
Great advise. I will have my mechanic do a compression test later today.

So far, to try to remedy the solution, I have changed the spark plugs to ngk oem spark plugs and that didn't do a thing. Thanks SMAAY! I'll do that compression test later. Now if it is a bent valve, would anyone know of a good site I can get a new cylinder head from?

austin.c
01-22-2011, 03:26 PM
When i bent my valve, i ordered new thru monkeywrench racing. had a local shop do all the head work. it wasnt all that bad to take the head off while the engine was in the car.
might be better to rebuild what u have instead of buy new. but its all your call.

Smaay
01-27-2011, 01:11 AM
just because you bent a valve, you dont need to replace the head. trust me i see bent valves in 2ZZs all the time. when i do an engine rebuild, i take all the valves out and put them in my hand drill. watch the face of the valve to see if it wobbles, if its smooth, then its good, if its bent it will wobble. a severe bend might crack the valve guide so it will need replacing, but a slight bend you only have to replace the valve and re-shim it.

as for pulling the head in the car.... i HIGHLY SUGGEST AGAINST IT! yes it can be done, but for the amount of work involved, just pull the engine. i have a complete guide on here in the stickys step by step. you cant go wrong.