Help me figure out what caused this...

[awdtalon4451]

A few weeks ago I lost compression in cylinder# 3. Pulled the head and this is what I found. I did this in a WOT pull. I replaced the valve but I'm not sure as to what caused it to begin with. Also new injectors are on the way, I went with some Denso 660's

 

[delta448]

I'd say replacing or cleaning the injectors is a good place to start. From the way that thing's been torched, it looks like you ran pretty lean under boost or had excessively retarded ignition timing. Might also check out the fuel pump, filter and FPR.

Nice avatar shot BTW. Something like that might do this to a valve as well. Are you rescuing it, or is this car the replacement for it?
It is your car isn't it?

 

[awdtalon4451]

This was the only valve that was messed up. I've got it all back together I just don't want it to happen again ya know How do you go about cleaning your injectors?
I was leaning toward a dying injector. I'll be running an extra set of 450's until my 660's come in on Wednesday. Check my melted spark plug thread for pics of the plug that came off that cylinder.

 

[dan catalyst]

that looks more cracked than burnt, did you find any other pieces of it? no scoring on the cyl walls?

 

[awdtalon4451]

You can't tell from the pic but were the material is missing its very smooth and wavy. It doesn't have any clean crisp breaks or anything like that. The wall of the cylinder was actually in pretty good shape. No scratches or scoring on the walls. I couldn't find any other pieces of it when I removed the head.

 

[awdtalon4451]

I wish I could change the title of the thread, it makes me sound lazy haha

 

[talonalex92]

Take a close up shot of the valve where it broke,and of the head.

 

[awdtalon4451]

The pics I posted were the best I could get my cell phone to take. The head is already put back on the car so I won't be able to take more pics. I tried to upload the shot of the cylinder walls but its already in a another thread so it won't let me.

 

[BogusSVO]

How did the valve seat look?

With that much torched, I would excpect the valve seat in the head to be distorted.

You had to run way lean or the valve was not seating fully.

 

[awdtalon4451]

How did the valve seat look?

With that much torched, I would excpect the valve seat in the head to be distorted.

You had to run way lean or the valve was not seating fully.

Damn it!!! I didn't even look at the bottom of the seat. I only looked at the top of it

 

[BogusSVO]

Did you fluid test or vac test the seat seal before you installed it?

http://www.dsmtuners.com/forums/newbie-forum/420313-how-fluid-test-4g63-cylinder-head.html

Did you at a minumim Lap the valve in?

http://www.dsmtuners.com/forums/articles-engine-fuel/341636-how-lap-valve.html

 

[awdtalon4451]

I suspect it ran lean but I'm not 100% sure. Bogus will you pm me your number. I have that spare head I want to send to you but I'm not sure if it's salvagable.

 

[kchaazz]

A little off topic, but still relavent, any smaller pieces of that valve probably got kicked out the exhaust, so you may want to check your turbine wheel on your turbo for damage. Ive seen similar cases before and the turbine ended up fubarred...

 

[delta448]

How do you go about cleaning your injectors?

Fuel Injector Cleaning and Flow Testing - Fuelinjectorclinic

Check my melted spark plug thread for pics of the plug that came off that cylinder.

http://www.dsmtuners.com/forums/cylinder-head-short-block/430720-melted-spark-plug-wot-pull.html
Interesting.

that looks more cracked than burnt,

I certainly could see that starting out as a crack. There may even be a chunk of it in the turbine housing, or a damaged turbine wheel. It must have been ran for a little while like this though, the swirled smooth edge next to the stem screams melted to me.

 

[awdtalon4451]

Thanks for the link Delta, Ill be sending my 660's off for a cleaning just for peace of mind. As far as the valve goes I just pulled a exhaust valve out of a spare head that was recently rebuilt and stuck it in. I didn't lap the valve or anything, I feel like an idiot for not changing the seat with it :/
If the valve did melt and not crack would it still be fatal to my turbo or is it more luck of the draw?

 

[BogusSVO]

Ahhhh... I doubt you have the tooling and equipment to change the valve seat.....

http://www.dsmtuners.com/forums/newbie-forum/341297-how-replace-seats-aluminum-head.html

I would recommend that you do a quick leak down test on the cyl you swapped the valve on.

Ever cut a chunk of steel with an Acetyelne torch? The slag left from the cutting would be about the same as what happened to your valve.

It would be wise just to check the turbo.

 

[awdtalon4451]

Im gonna inspect the hot side of the turbo for damage when I get home. Keeping my fingers crossed...

 

[awdtalon4451]

Hot side doesn't have any signs of debris passing through. Cold side does look like a fin grazed something. Do I need to crack the housing open to inspect internally?

 

[dan catalyst]

looks like you got lucky with the hot side and any broken chucks of valve, so it looks like it melted and didnt break. it was most likley a crack that melted into that chunck missing out of the valve. sence the head is back together, a leak down test is mandatory to make sure that valve is seating. with your luck its prob seating just fine,, but it deff. needs to be checked asap. let us know how the leak down test goes

 

[awdtalon4451]

Mission complete!!! ...Well almost . Finished it up the install today. Its running much better than before. I think it has a decent boost leak though, probably the shit couplers that are on it. I'll find out tomorrow. Leak down and compression are next

 

[awdtalon4451]

Her she sits

 

[romeen]

Just curious what your idle vacuum is?

 

[awdtalon4451]

I believe it is around 18-20, is this ideal?

 

[romeen]

With stock cams and no vacuum leaks, yeah, that's fine (not sure what "ideal" would be, maybe 22inHg or so .

 

[awdtalon4451]

Did some research, its where it needs to be