Dropped exhaust valve

[Dalton]

Is there no chance of the short block being good?

 

[wsuwrhr]

Is there no chance of the short block being good?

There is always a chance. Depends on the rpm it dropped, how long it ran after, if you tried to restart it before you gave up.

Piston has little chance of being any good, but your rods and block could be. Hopefully the head is.

Got to take the head off and see sir. Don't be scared, it is too late to be worried, the damage is done now.

Brian

 

[Dalton]

There is always a chance. Depends on the rpm it dropped, how long it ran after, did you try and restart it before you gave up.

Piston has little chance of being any good, but your rods and block could be.

Got to take the head off. Don't be scared, it is too late to be worried, the damage is done now.

Brian

It still ran ok, just less power and more vibration, i probably ran it 20 minutes after I noticed it just to get back to the launch ramp. Taking the head off now.

 

[wsuwrhr]

It still ran ok, just less power and more vibration, i probably ran it 20 minutes after I noticed it just to get back to the launch ramp. Taking the head off now.

Oh my.

You made your bed at that point.

Less power and more vibration. Noted.

 

[wsuwrhr]

Taking the head off now.

Those are the pictures that matter.

Bring the affected cylinder all the way down in the bore and get a good look all around the bore.

You are local to Socal right?

Brian

 

[Dalton]

Those are the pictures that matter.

Bring the affected cylinder all the way down in the bore and get a good look all around the bore.

You are local to Socal right?

Brian

I'm in havasu, for a bit

 

[wsuwrhr]

I would gather if you ran it under power, with no ungodly noises, then the valve either broke into a million pieces and went out the exhaust port, or more likely, it is embedded in the piston top.

 

[AzGeo]

Dropped Valves Matter ! .............. really matter

 

[rivrrts429]

20 minutes lol

I've caught them within seconds. Some easy and some bad. Never gone 20 minutes though so I'm intrigued with this one.

Need to find out why that one let loose and whether or not the others haven't. Hopefully you can find the broken end and it didn't find itself elsewhere.

Keep us posted...

 

[Dalton]

On the other sides exhaust flapper the rubber is missing, was thinking this sides rubber was missing also maybe causing reversion? But this side has all the rubber. Here's a good valve from the same side. I'll prob have the head off tomorrow.

 

[wsuwrhr]

Plan on replacing all the valves regardless of what you find.

 

[Dalton]

Agreed

 

[28Eliminator]

#7 ?

 

[Dalton]

#8

 

[28Eliminator]

#8

Bummer... head is probably hammered too. Sorry man, been there [emoji53]

 

[obnoxious001]

That's not actually a "dropped valve", it's broken. If there was no water problem on this side of the engine (which could definitely cause breakage due to thermal shock), it may be from exhaust temperature in that cylinder, or perhaps even fatigue from age or something.

It will be interesting to see, if the head is hammered I possibly may have a single one down in Parker, depends what you have.

 

[mjc]

I have a set of heads that just need a valve job if you need.

 

[RaceTec]

Depending on what you find and Barry can help you out with the head, if you just need a single piston we can help you out...
We can even match weight so that there is no balance issues... Just have Barry get me all of the details.

 

[Dalton]

Wow thanks guys, I messaged Barry a while back before I took anything apart and he actually predicted a broken valve with very few details. I stayed at BJ's a little too long last night but will get this cylinder head off today.

 

[wsuwrhr]

That's not actually a "dropped valve", it's broken. If there was no water problem on this side of the engine (which could definitely cause breakage due to thermal shock), it may be from exhaust temperature in that cylinder, or perhaps even fatigue from age or something.

It will be interesting to see, if the head is hammered I possibly may have a single one down in Parker, depends what you have.

It may have dropped, before it got tagged. Just sayin

 

[Dalton]

 

[Dalton]

 

[Dalton]

Thoughts on my valve colors?

 

[Jimmy]

No good there mate.
What's the bore like?

 

[wsuwrhr]

Valve colors look decent. #2 looks a little hot to me. Bore looks like a nice ding and pushed in at 7 oclock or so in the picture, Near the bolt hole. Deck looks damaged at 8 oclock. Is that just an optical conclusion?

Head looks beat up but savable from the pictures. I would definitely have it mag checked.

Id get a real good look at the bore if I were you when you tear it down the rest of the way.

Brian

 

[wsuwrhr]

Where is the valve head?

 

[wsuwrhr]

Wipe the bore with a paper towel or rag and retake the picture.

 

[Dalton]

Where is the valve head?

That's a great question. Could it of gone flying out the exhaust? Haven't snooped in the exhaust manifold too hard yet. The bore has what I would call slight damage, I can feel it with my finger nail though. So I'm guessing that is too much.

 

[wsuwrhr]

That's a great question. Could it of gone flying out the exhaust? Haven't snooped in the exhaust manifold too hard yet. The bore has what I would call slight damage, I can feel it with my finger nail though. So I'm guessing that is too much.

Yes sir, certainly possible, that is why I am asking. That is probably why the whole thing didn't grenade when you ran it for so long afterword.

Block is probably junk if it has any marks in it. If it is standard, and assuming you can bore it .06, that is only .03 to bore out, per side.


Bore looks "pushed in" to me, near the threaded bolt hole at 8 oclock.

 

[Dalton]

Yes sir, certainly possible, that is why I am asking.

Block is probably junk if it has any marks in it. If it is standard, and assuming you can bore it .06, that is only .03 to bore out, per side.


Bore looks "pushed in" to me, near the threaded bolt hole at 8 oclock.

Haha damn yeah it's a 468

 

[Dalton]

 

[wsuwrhr]

Haha damn yeah it's a 468

I don't know the bore size of a 468, but it would be needed to be looked at to see if it is any good. Id look up Barry(Obnoxious) here on the boards and see what he has to say, he is out in AZ.

 

[wsuwrhr]

View attachment 517052

Dang it, that is the worst place for a mark.

 

[wsuwrhr]

Dart Big M, go big or go home.

 

[Dalton]

Dart Big M, go big or go home.

Just looked them up, not crazy expensive actually

 

[wsuwrhr]

Just looked them up, not crazy expensive actually

Yep, by the time you locate a new or used OE, and have it mag checked.....

Bucks ahead.

Take your block and head to a shop first, you never know until you try.

Look around on here, might be able to find something too.

 

[BUSTI]

Just looked them up, not crazy expensive actually

Not crazy at all. I've been quoted by two reputable builders in so cal to refresh my 460 BBC and after doing all the numbers I'm just going to start new with an aftermarket block. Everything pan to heads.

If you would like any help i can shoot you my list as a starting point.

 

[obnoxious001]

It may have dropped, before it got tagged. Just sayin

Except the valve stem is still in place.

 

[obnoxious001]

The block can be saved, a good shop can install a "step sleeve" if that cylinder has too much damage to clean up, or more importantly if it's cracked. People tend to shy away from sleeved blocks, but think about it, aluminum blocks are all sleeved.

That being said, first step is to have the block carefully inspected, then make a decision.

 

[wsuwrhr]

http://www.riverdavesplace.com/foru...big-block-and-468-big-block-and-496-big-block

 

[AzGeo]

Looking at the photo of the cylinder head and it's valves with the 'lost one', I suggest you get in touch with a professional, before you put this back together .

The fact that this motor was 'driven for a number of minutes AFTER a known failure', and now we are all inspecting 'questionable readings', I am going to pass on an opinion .

Get this thing to Barry, and pay for the knowledge he has gained over 35 plus years of doing this stuff .

Don't bother robbing a 7-11, you will most likely need more like 'El Torito', or 'Chilli's' kind of gross cash to fix this thing correctly ................ HA HA

 

[Dalton]

The block can be saved, a good shop can install a "step sleeve" if that cylinder has too much damage to clean up, or more importantly if it's cracked. People tend to shy away from sleeved blocks, but think about it, aluminum blocks are all sleeved.

That being said, first step is to have the block carefully inspected, then make a decision.

Hey Barry, what's your phone number?

 

[obnoxious001]

Hey Barry, what's your phone number?

Sent by PM

 

[Dansblown73Nordic]

I ran a 468 for 10+ years with four sleeves in one side of the block. Turned 6k every time it was out never skipped a beat...

Now as far as the block im going to say you are very lucky. I had a SBC once that had a 1/4 inch stud fall in the carb. When the guy started it the stud hit the top of the piston. It split the piston like a piece of firewood. It broke the block all the way to the crank boss on the underside....NFG!!!!

 

[Oilman]

We saved ours after breaking a valve but we shut it down after it went. There is always someone that will give you a tow.
1 new piston, 1 valve and new springs cleaned up the cylinder and valve seat.
We got lucky the valve hung at high RPM and kissed the piston before it broke.

 

[Dalton]

Engine is out and at Louis Performance

 

[Dalton]

Progress...jim said I should be right around 550hp


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[Tinkerer]

bore notch the cylinders to add 25 HP

 

[Dalton]

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[Dalton]

bore notch the cylinders to add 25 HP

hellllllll no