WTF is this THING in our 340 ?!?!?!?

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nm9stheham

nm9stheham

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My son and I finally got the new Hughes rockers installed and fired up about 3 weeks ago, and after about 3 seconds, there came a serious BANG BANG BANG BANG...... that was at engine speed. It sounded like a piston hitting the head or a valve.

A quick shut down, and some diagnosis (when we weren't traveling and working like maniacs) and close inspection of the valve train, it became clear something was in a cylinder jamming a piston; when turning by hand, the crank came to a stop when cylinders 8 & 5 were at TDC. I had felt a small tight spot in the rotation when we adjusted preload but this time is was a hard stop.

Well, here it is; it was on the lower side of the piston, in the small quench gap on the spark plug side of the Edelbrock RPM performer. I cannot for the life of me figure out what this is.... it has a sharp hardened point, and is split, as if it is intended to wedge into something. It is almost like a tool centering bit... could it be from the Serdi machine that was used to open under the seats??

And then comes the question of how it could be in there 1000 miles and not ever be heard......

DSCN2046 (2).jpg


DSCN2049 (2).jpg
 
That does not look like any tooling I've ever used.

Weird.

I will say this, so others may learn. An engine will swallow many things with ease. **** will move through an intake like...well...poop through a goose. I had a pretty good sized throttle body on my own engine and the neighbor just had to watch and help while I lashed the valves. He was using a 1/2 wrench that was about 3 1/2 inches long, on something and he set it on the throttle body. I never saw him do it. Neither did I see him do it. I was almost done when he showed up. I put the valve covers on, jumped in the car and checked everything out, including opening the throttle. I fired up the engine and it ran for a bit and started missing on the drivers bank. I thought WTF is going on, and it started hitting on all 8 again and I thought that is weird. About that time, it started missing on the passenger bank. I'm thinking you must be S¥€#%ing me!!! It started hitting on all 8 again. I'm standing there thinking this is insane. About then, it started missing again, and this time it didn't stop. So I pulled the fuel, killed the mag and though how does this happen running the valves?

I pulled the drivers side valve cover and didn't seen anything. Pulled the other side and there it is, the #4 intake is stuck open about 1/2 inch. I'm thinking, wtf, I stuck a valve? It's my heads. How'd I pull that boner. So I started pulling my junk apart.

In the end, after I pulled the intake I could see the end of this wrench sticking out of the number 4 intake port. Once I got it all apart, I found what really happened.

The wrench started out falling into the drivers side and went into the number 3 or 7 hole. It beat the hell out of that valve and seat, and then it blew back out of the hole it started in and blew over to the number 2 side where it went into number 2 and beat it up real good. Then it blew back to the odd side and hit the other hole. Don't know which one happened first, 3 or 7 but it got to the second hole on that side and ate it up. It then blew back into the intake and back over to the even side where it parked itself in the number 4 hole.

That was all at about an 1800 RPM idle and took no more than about 1 minute. I think very few people have an even reasonable understanding of what happens in an intake, even at an idle. When a wrench that size can move around like that, there are some serious pressure and reversion pulses in an intake.

The other thing is, check out all the cylinders. Things will visit all around.

The top picture looks like the little check needle under the accelerator pump nozzle on a Holley carb.

I still have the wrench.
 
The top pic does look like the top half of a Serdi bit. Picture it without the base.
 
Same Pic, same piece, Looks bent and folded over. Could be a Serdi bit.

That Sux..
 
yellow rose said:
That does not look like any tooling I've ever used.

Weird.

I will say this, so others may learn. An engine will swallow many things with ease. **** will move through an intake like...well...poop through a goose. I had a pretty good sized throttle body on my own engine and the neighbor just had to watch and help while I lashed the valves. He was using a 1/2 wrench that was about 3 1/2 inches long, on something and he set it on the throttle body. I never saw him do it. Neither did I see him do it. I was almost done when he showed up. I put the valve covers on, jumped in the car and checked everything out, including opening the throttle. I fired up the engine and it ran for a bit and started missing on the drivers bank. I thought WTF is going on, and it started hitting on all 8 again and I thought that is weird. About that time, it started missing on the passenger bank. I'm thinking you must be S¥€#%ing me!!! It started hitting on all 8 again. I'm standing there thinking this is insane. About then, it started missing again, and this time it didn't stop. So I pulled the fuel, killed the mag and though how does this happen running the valves?

I pulled the drivers side valve cover and didn't seen anything. Pulled the other side and there it is, the #4 intake is stuck open about 1/2 inch. I'm thinking, wtf, I stuck a valve? It's my heads. How'd I pull that boner. So I started pulling my junk apart.

In the end, after I pulled the intake I could see the end of this wrench sticking out of the number 4 intake port. Once I got it all apart, I found what really happened.

The wrench started out falling into the drivers side and went into the number 3 or 7 hole. It beat the hell out of that valve and seat, and then it blew back out of the hole it started in and blew over to the number 2 side where it went into number 2 and beat it up real good. Then it blew back to the odd side and hit the other hole. Don't know which one happened first, 3 or 7 but it got to the second hole on that side and ate it up. It then blew back into the intake and back over to the even side where it parked itself in the number 4 hole.

That was all at about an 1800 RPM idle and took no more than about 1 minute. I think very few people have an even reasonable understanding of what happens in an intake, even at an idle. When a wrench that size can move around like that, there are some serious pressure and reversion pulses in an intake.

The other thing is, check out all the cylinders. Things will visit all around.

The top picture looks like the little check needle under the accelerator pump nozzle on a Holley carb.

I still have the wrench.
Click to expand...
Good story YR.... and yeah, I 'lost' an intake bolt once while changing a bent pushrod. Found it in the #3 cylinder!

Hmmmmmmm.... we DID pull the accel pump nozzle off to clean out some gummy gas after sitting..... my son is checking right now to see if it is gone.... back with you in a moment....
 
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yellow rose said:
All the serdi tooling I have seen is flat.

The above pic looks like the piece is round and looks like it is fractured.
Click to expand...
The bits I'm thinking of have a flat oval base with a slot cut in it. The point protrudes off the base. From seeing them I assumed the slot was to adjust diameter of cut, and the cutter determined angle. Don't know though, I'm not a machinist. The 2 pics don't look like the same piece though. pics are deceiving though. And yes, things have a bizarre way of moving through an engine. Seen it more than once on our circle track engines.
 
EUREKA! YR gets the prize! We looked under the pump nozzle.....no check valve! :rofl::drama:

It must have stuck to the gummy underside of the nozzle screw, pulled up and out, and dropped in the carb throat unseen.... I never would have recognized it in its 'compressed' state. Explains why we did not hear it for the first few seconds of running; it took that long to drop through the valve. I think we will be checking that too.

Aside from a matching dent in the head and piston, it looks like we skated by on this one. I did not let it run for more than a few seconds.

Ah, gear-heading.... you gotta love it.

Edit to add: Hold it...... I got to looking at this again and the piece seems too big for the check valve. Checking again....:drama:
 
yellow rose said:
That does not look like any tooling I've ever used.

Weird.

I will say this, so others may learn. An engine will swallow many things with ease. **** will move through an intake like...well...poop through a goose. I had a pretty good sized throttle body on my own engine and the neighbor just had to watch and help while I lashed the valves. He was using a 1/2 wrench that was about 3 1/2 inches long, on something and he set it on the throttle body. I never saw him do it. Neither did I see him do it. I was almost done when he showed up. I put the valve covers on, jumped in the car and checked everything out, including opening the throttle. I fired up the engine and it ran for a bit and started missing on the drivers bank. I thought WTF is going on, and it started hitting on all 8 again and I thought that is weird. About that time, it started missing on the passenger bank. I'm thinking you must be S¥€#%ing me!!! It started hitting on all 8 again. I'm standing there thinking this is insane. About then, it started missing again, and this time it didn't stop. So I pulled the fuel, killed the mag and though how does this happen running the valves?

I pulled the drivers side valve cover and didn't seen anything. Pulled the other side and there it is, the #4 intake is stuck open about 1/2 inch. I'm thinking, wtf, I stuck a valve? It's my heads. How'd I pull that boner. So I started pulling my junk apart.

In the end, after I pulled the intake I could see the end of this wrench sticking out of the number 4 intake port. Once I got it all apart, I found what really happened.

The wrench started out falling into the drivers side and went into the number 3 or 7 hole. It beat the hell out of that valve and seat, and then it blew back out of the hole it started in and blew over to the number 2 side where it went into number 2 and beat it up real good. Then it blew back to the odd side and hit the other hole. Don't know which one happened first, 3 or 7 but it got to the second hole on that side and ate it up. It then blew back into the intake and back over to the even side where it parked itself in the number 4 hole.

That was all at about an 1800 RPM idle and took no more than about 1 minute. I think very few people have an even reasonable understanding of what happens in an intake, even at an idle. When a wrench that size can move around like that, there are some serious pressure and reversion pulses in an intake.

The other thing is, check out all the cylinders. Things will visit all around.

The top picture looks like the little check needle under the accelerator pump nozzle on a Holley carb.

I still have the wrench.
Click to expand...

First thing I thought of was a needle!
 
Well that was a quick easy answer. We had a butterfly pin from a Kinsler stack get sucked in. Took us a while to figure out why that cylinder was running hot. We figured it got puked out on to the track. Not so, it wound up in the intake screen for the dry sump. still can't figure out how it made it there.
 
Well, here is a pix of the 'thing' and an unmolested Holley check valve. It looks like the same item; the one that got into the engine must have fractured when it was crushed and made it look like something else. Well, we do know that we indeed have a good tight quench gap!

Thanks to all for the consultation.... it sure solved the mystery.

DSCN2056.JPG
 
Pascamp said:
Well that was a quick easy answer. We had a butterfly pin from a Kinsler stack get sucked in. Took us a while to figure out why that cylinder was running hot. We figured it got puked out on to the track. Not so, it wound up in the intake screen for the dry sump. still can't figure out how it made it there.
Click to expand...
That sounds crazy for it to end up there..... sure you didn't lose 2? LOL
 
nm9stheham said:
That sounds crazy for it to end up there..... sure you didn't lose 2? LOL
Click to expand...
Nope, just one. The only thing we could ever come up with is it must have been stuck to something and fallen off during a tear down. It obviously didn't sneak past the rings or valve seals. The only thing that tipped us off was one cylinder would run really hot when we'd warm up the motor in the pits. Once the butterflies opened it didn't matter. But that extra air at idle really threw off that cylinder. We thought we had a mismatched pill.
 
First car I ever owned, slant six Cuda. Had like 150K, decided to take the head off and give it to a friend so he could do a valve job on it in high school auto shop. Pull the head, and there's a 1/4 - 20 bolt sticking right out of the piston, embedded at an angle, sticking up and kissing the corner of the intake valve. Piston wasn't cracked, bolt was securely embedded in the piston. Took a dremel cut off wheel, and cut the bolt flush with the piston top. Car ran for many more miles after that.
 
nm9stheham said:
Well, here is a pix of the 'thing' and an unmolested Holley check valve. It looks like the same item; the one that got into the engine must have fractured when it was crushed and made it look like something else. Well, we do know that we indeed have a good tight quench gap!

Thanks to all for the consultation.... it sure solved the mystery.

View attachment 1714989618
Click to expand...


Just glad it didn't bend a valve or do other damage.
 
yellow rose said:
Just glad it didn't bend a valve or do other damage.
Click to expand...
ever drop a valve on the drastrip? the valve will almost always get 2-4 cylinders, and maybe more before u can get it shut down. I`ve always lived in fear of dropping something down the intake or carb. when working on an engine, always cover the ports or cab first.
 
Similar story from my teenage days... My best bud Phil had a hot rod 65 SS Impala. I don't recall what we were doing at this particular time but we were outdoors. 3 doors away was a guy named Garner who had a Camaro with "Street Cleaner" written on the rear spoiler. So we heard the Camaro fire up and hold a fairly high set idle. Phil says, "He got his new cam in". About 5 minutes later we here it shut down, hard and sudden. Less than 2 minutes later Phils mom comes to the door, "Phil, telephone". Phil says, "That'll be Garner". So about 2 hours later we found the threaded stud that holds the breather on ( or wasn't holding the breather on ) had backed out of the carb and found its way into the #4. Valve and slug ruined. That was one sad Saturday.
Our machines, our mates and their machines, the attachment is strange indeed.
Good luck with yours
 
famous bob said:
ever drop a valve on the drastrip? the valve will almost always get 2-4 cylinders, and maybe more before u can get it shut down. I`ve always lived in fear of dropping something down the intake or carb. when working on an engine, always cover the ports or cab first.
Click to expand...


It is amazing what goes on in there.

The crazy thing was I never went above idle speed, which was about 1800.
 
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