Symptoms of a Bent Valve??

[DARK-5.0]

Well I really think I screwed the motor up tonight. For those who don't know I got my motor running last week, had it dynoed and took it to the track. It ran the strongest it ever has. Well leaving work today I hear this grind and then chattering like a roller rocker came loose. So I coasted down the hill at idle and pulled into a parking lot. I had it towed home and then started tearing it apart. Well I took the intake off and pulled the valve cover off, I noticed that my jimmy rigged oil breather had fallen down into the valvetrain. Basically, the breather wouldn't fit in the filler neck because it hit the air intake track. So I used this industrial tape that we have at work and taped a deep socket that fit the grommet perfect, to the breather. It fit perfect, the deep socket slid into the breather and the socket fit snug in the grommet. Well after even dynos and track time, it had to be when I'm putting around that i guess the tape wore off and the socket slid through and fell onto the roller rockers. It idled for maybe a minute like that. But now I pulled the cover off, checked everything out. No damage done to the roller rocker or anything. But now it runs like complete crap. It just bounces around from like 500rpms to 2krpms. And it chokes which is why I think its a bent valve.
What does everyone think. Is there any hope for me.


Jeremy

 

[Slow5.0]

Meybe broken valve spring keepers, I broke one on stock heads in april this year

Here is the links

http://forums.stangnet.com/showthread.php?t=457808&highlight=keepers

http://forums.stangnet.com/showthread.php?t=459837&highlight=keepers

 

[wytstang]

A bent valve would cause a miss would it not? How do the plugs looks?

 

[Joes95GT]

I have never had experience or know anyone who has experienced a bent valve, but I'll use a little bit of (what I like to call) "common sense" and talk through this.

A valve is just a lid connected to a long stem. If something is bent, it would be bent in the stem. If the stem is bent, the valve spring, the valve spring pocket, and/or the valve spring keeper will not look the same as the rest (I.E. cocked spring, spring sitting too far over to one side of the pocket, spring closer to coil bind at one side than another).

Go through and check the obvious. If that doesn't help, it sounds like you might have to pull the heads and pull all the valves out.

Joe

 

[SorsCode]

As Long as it doesn't look like anything like that your fine. I had an AFR 165 take a crap on me.

 

[Slow5.0]

Hollty **** SorsCode dude, is that with AFR's

 

[SorsCode]

Hollty **** SorsCode dude, is that with AFR's

That was with a 58CC AFR 165 at around 1500-2200RPMS

 

[Joes95GT]

Save that piston! It belongs on the trophy shelf. The heads don't look bad. They should weld right up...

Joe

 

[SorsCode]

The head is fixable 435 bucks. but of course I don't want that head back on my car. Not to get off subject. But its been to AFR twice. Piston has already been to the machine shop and got cleaned. its hangin in the garage.

 

[greenlantern]

Wow. Thats scary lookin. I can't believe a $1300 head did that. Did you everfind out what caused it.

 

[HazMat404]

i bent/broke a valve head off on my stock heads. you will have HEAVY miss with a bent/broken valve. my cylinder was completely dead compression wise and im sure a bent valve would do the same. it would also be tapping the piston more than likely so if you dont hear a nasty tapping sound, its probably not that. might have to pull the heads to see whats up. doesnt sound too good tho

 

[DARK-5.0]

Well I don't hear a tapping noise. But I'm gonna do a compression check tonight. I turned it over by hand it seemed smooth until I got to that #1 piston. It still turned through but there was def. stress on it. I guess I'll have to wait and see what the compression check says. If its just a pushrod or lifter, will that effect the compression test, it shouldn't right.

Jeremy

 

[wytstang]

It might affect the compression test seeing as how a lifter(if collapsed) or pushrod(bent/broken) will not let the same amount of air in because the valve is unable to open all the way.

 

[DARK-5.0]

Well without taking the head off, whats the best way to eliminate the valve?

Jeremy

 

[HazMat404]

compression test for sure. if there is anyting major on that number its defiantely a head

 

[wytstang]

The only way would be to hook up an air hose and use a fitting to tread it into the spark plug hole and see it air leaks through the top (lower intake) I did this once with my first car '72 Duster 340 and found out my valve seals where bad(through the carb.). I hope you know what I mean?