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

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Once as a very young and dumb PVT, I was performing services on an M577. I was going down the checklist of -20 tasks while the operator was doing all the -10 stuff.
This track had recently gotten a new engine installed, and the ductwork for the filter to turbo track was all half *** put on. I like when all the clamps face the sameway etc, so I pulled it off and was dikn around with it. The operator climbed in through the ramp and started her up. As I walked around to the back and yelled inside to shut it down, he went to a high-idle. As I climbed inside, the engine started to lope/rev/lope/rev and he cut it off, with it coming to a very unhealthy sounding stop. After looking it over, it seemed that the turbo had let go and the engine ingested the vanes. Since it was like 0miles new, everyone assumed it was a bad turbo. We eventually pulled the engine and sent it off to 3rd shop and installed a new one with no drama.
I however never did find even a trace of the clip-board and paperwork I had been using when the operator fired it up.....
 
Lustle said:
SO THAT'S WHERE THAT WENT!

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Witnessed such as this happening years ago on a friends stock flat top piston big block. He told me when he started it up it just started banging right away and he fires it up again so I can hear it. Yeah it certainly was banging. So I help him take the top off. We find two small parts in the six hole that looked almost like key stock. We see a cracked piston and dents in the head casting. The guy say's to me "now I know where that valve cover bolt went".
 
I think you are damn lucky if it didn't bend a rod and just compressed into the piston or head.
Being as small as it is you might have gotten lucky there.
 
TrailBeast said:
I think you are damn lucky if it didn't bend a rod and just compressed into the piston or head.
Being as small as it is you might have gotten lucky there.
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Come to think of it...if the part was far enough outside, and the ring lands are thin, he could have pinched a ring. Damn, didn't even consider that until I read what TB posted.

The OP needs to verify it didn't pinch the top ring.
 
Yep. We're gonna pull the intake valve and examine the valve and seat and then leak test it with alcohol. The indentations in the piston and head are very shallow, like a few thousandths, but near the edge. (And these ARE KB's...) No fracturing of eithehas been spotted so far.

The portion of the check valve that was squashed is brass; the steel tip looks uneffected. But, still, we'll take another close look at this aspect. The pistons tops come a few thousandths above the deck so we can lay a flat across the area and check for distortion.

I'm gonna go assuming the rod/crank/bearing being OK, based on prior experience with this type of incident. We'll know really fast on that!

Tnx for the good thoughts.
 
Had the intake off my race motor. Laid down shop rags in the valley to keep anything falling into the motor. Put the intake back on with rags still in there. Within to passes oil pressure went to 10 instead of fifty at idle. Then I remembered the rags. The rags had been so chewed up my motor was full of the consistency of baby poop. Other than being embarassed and doing a tear town on the motor, everything was okay. Should have seen the inside of oil pump and filter.
 
I don't think people really sit down and understand what RPM means.

I do a lot of thinking and such about engines. And try to take into account everything involved with them. And when you think about it even at idle speed, engines are MOVING. Let's say your idle is 1000 RPM (for the sake of math). That means, the crank rotates 16.6 (repeating) times every second. With a otto cycle, that's every cylinder firing 8.3 times (repeating) every second. That means in one second, there is 66.6 (repeating again) cylinder firing events.

Next time your engine is idling. Pick a cylinder. And sit there and see if you can tap the valve cover more than 8 times in one second. I guarantee you can't. You might get 4, maybe 5 taps. And that's at idle. 2000 rpm = 16 per second. 3000 rpm = 25 per second. I think you get the idea.

Even at idle. Engine are moving a crazy amount. 340 cubic inches at 1000 rpm, moves almost 600 gallons per minute of air at only 80% efficiency. Or, 10 gallons per second of air. Two and a half milk jugs. Every second. At idle.

So yeah, it doesn't take long for a very small, very "insignificant" item to really **** something up.
 
Lustle said:
I don't think people really sit down and understand what RPM means.

I do a lot of thinking and such about engines. And try to take into account everything involved with them. And when you think about it even at idle speed, engines are MOVING. Let's say your idle is 1000 RPM (for the sake of math). That means, the crank rotates 16.6 (repeating) times every second. With a otto cycle, that's every cylinder firing 8.3 times (repeating) every second. That means in one second, there is 66.6 (repeating again) cylinder firing events.

Next time your engine is idling. Pick a cylinder. And sit there and see if you can tap the valve cover more than 8 times in one second. I guarantee you can't. You might get 4, maybe 5 taps. And that's at idle. 2000 rpm = 16 per second. 3000 rpm = 25 per second. I think you get the idea.

Even at idle. Engine are moving a crazy amount. 340 cubic inches at 1000 rpm, moves almost 600 gallons per minute of air at only 80% efficiency. Or, 10 gallons per second of air. Two and a half milk jugs. Every second. At idle.

So yeah, it doesn't take long for a very small, very "insignificant" item to really **** something up.
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You get a gold star for doing the math.

Now, for extra credit, do the math at 8500 RPM, which is a real good bracket engine RPM, and then do it at 11,200 RPM which is what most Pro Stock engines were doing last year.

It will boggle the mind. Don't forget to calculate valve openings as well.
 
yellow rose said:
You get a gold star for doing the math.

Now, for extra credit, do the math at 8500 RPM, which is a real good bracket engine RPM, and then do it at 11,200 RPM which is what most Pro Stock engines were doing last year.

It will boggle the mind. Don't forget to calculate valve openings as well.
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When I worked with sprint cars I used to do that. Sit there and watch them going round. And think about RPM, valve events, displacement, etc etc. I'm sure you know how fast sprint car motors turn. Sometimes I would just be amazed that engines even ran at all.

Want even more extra credit? Figure out how much weight an engine moves every minute (not vehicle weight, rotating weight). Or how about how far a valve travels on average in one minute.

.500 lift. Moving 16.6 times per second (open and close). Equals 41.5 feet. A single valve on .500 lift will move over 41 feet. Per minute. And that's just at idle.

More to think about.
 
You can post up all that math and I'll never get tired of.

That these thing even run, as you point out, is amazing.


The math proves that out.
 
I think the most common, one is the center screw on a holley carb. It would only make noise above 2000 rpm. we were dumb and young. IT EVENTUALLY WHEN AWAY!!!! :BangHead: We found the problem when he pulled the heads off for a better set.
 
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