Bending a rodney

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Ironmike

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3 questions 1: how easy or difficult for that matter would it be to bend a high quality I beam type rod?

2: if one did indeed have a bent rod, would the engine vibrate at All RPM's?

3. With heads off, wouldn't it be pretty noticeable due to valve reliefs being "off", due to twist?
 
OR a piston that has a deck height different than the rest
 
Is this the new mill you built? Does it knock know? A high quality rod? What make and at what power level? I would imagine that it would vibrate at any rpm if the rod is bent. How much of a deck height difference there could be, might only be picked up with a mic. The twist and bend may not be so obvious.
 
Ironmike said:
3 questions 1: how easy or difficult for that matter would it be to bend a high quality I beam type rod?

2: if one did indeed have a bent rod, would the engine vibrate at All RPM's?

3. With heads off, wouldn't it be pretty noticeable due to valve reliefs being "off", due to twist?
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Ok, what's the rest of the story?:D
Or is the question purely theoretical?:rolleyes:
 
Ironmike said:
3 questions 1: how easy or difficult for that matter would it be to bend a high quality I beam type rod?

2: if one did indeed have a bent rod, would the engine vibrate at All RPM's?

3. With heads off, wouldn't it be pretty noticeable due to valve reliefs being "off", due to twist?
Click to expand...

Item 3 sounds like a rod twisted, not bent. Rods usually bend in a buckling fashion (like the elbow in your arm). I can't think of a force on the piston that would tend to twist the rod without also some buckling. (But, this is Ironmike's engine... anything is possible LOL.) If the rod started to buckle sideways, then you would see/could measure one side lower than the other at the piston top. (The 'sides' being along the line of the wrist pin.)

It could vibrate due to the rod effectively being shorter and the compression on that cylinder dropping; I would expect to feel that at all RPM's. If it was severe enough to effect actual balance, then the rod is probably into the cylinder wall.

I can't make a good comment on how easy it would be.
 
Engine came off dyno 580 hp 540 tq. No issues. In car now.... idled awhile checking things and found oily plugs. No big deal, decide to go for the first blast and see smoke in my rearview. Got pissed and decided to "clear it out". Nailed it smacked 2nd and the whole friggin car is shaking. Limped home and found number 6 and 8 plugs totally fouled out, dead....

To make a long story shorter we found the headbolt tubes, done at porting had started leaking. So that's all fixed up now, went pushrods oiling only, blah blah blah.

Fired it today check for leaks.....go through a heat cycle and shutdown. Adjust valves hot button it up and go for a ride.

At 4000 rpm, the shifter was shaking so bad I thought my hand was gonna fall off. Cruising home at 2300 fairly smooth. Up the R's and she starts shaking. Neutral, clutch in clutch out, no diff.

They're are a couple variables....new aluminum flywheel NOT used on the dyno. Supposed to be internal balance type. Centerforce 900400. And a brand new McLeod p plate and clutch.

AND a 833 I just rebuilt over winter. I've done several of these and can't imagine it's something in there.

Oh yeah, plugs look great! Jesus I can't get a break.

So I wonder that first day I decided to try and clean it out, if I might have hydraulic'd a rod. Although heads were off for pushrods oil conversion and all pistons topped out the same, visually. I know cause I cleaned every grimy one. I did not measure though.

Hopes are running towards something with that flywheel....but who knows. Seems to me it would take a hell of a lot of oil in there to bend a rod. I have 67cc chambers so at least more than 67cc's.
 
Ironmike said:
Engine came off dyno 580 hp 540 tq. No issues. In car now.... idled awhile checking things and found oily plugs. No big deal, decide to go for the first blast and see smoke in my rearview. Got pissed and decided to "clear it out". Nailed it smacked 2nd and the whole friggin car is shaking. Limped home and found number 6 and 8 plugs totally fouled out, dead....

To make a long story shorter we found the headbolt tubes, done at porting had started leaking. So that's all fixed up now, went pushrods oiling only, blah blah blah.

Fired it today check for leaks.....go through a heat cycle and shutdown. Adjust valves hot button it up and go for a ride.

At 4000 rpm, the shifter was shaking so bad I thought my hand was gonna fall off. Cruising home at 2300 fairly smooth. Up the R's and she starts shaking. Neutral, clutch in clutch out, no diff.

They're are a couple variables....new aluminum flywheel NOT used on the dyno. Supposed to be internal balance type. Centerforce 900400. And a brand new McLeod p plate and clutch.

AND a 833 I just rebuilt over winter. I've done several of these and can't imagine it's something in there.

Oh yeah, plugs look great! Jesus I can't get a break.

So I wonder that first day I decided to try and clean it out, if I might have hydraulic'd a rod. Although heads were off for pushrods oil conversion and all pistons topped out the same, visually. I know cause I cleaned every grimy one. I did not measure though.

Hopes are running towards something with that flywheel....but who knows. Seems to me it would take a hell of a lot of oil in there to bend a rod. I have 67cc chambers so at least more than 67cc's.
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Your story telling ie info sucks. So it was shaking before and is shaking now. A bent rod will weigh the same as a non-bent rod. Sounds like a balance issue--now whether that is engine or drivetrain is impossible to tell from the above piss poor story. J.Rob
 
nm9stheham said:
Item 3 sounds like a rod twisted, not bent. Rods usually bend in a buckling fashion (like the elbow in your arm). I can't think of a force on the piston that would tend to twist the rod without also some buckling. (But, this is Ironmike's engine... anything is possible LOL.) If the rod started to buckle sideways, then you would see/could measure one side lower than the other at the piston top. (The 'sides' being along the line of the wrist pin.)

It could vibrate due to the rod effectively being shorter and the compression on that cylinder dropping; I would expect to feel that at all RPM's. If it was severe enough to effect actual balance, then the rod is probably into the cylinder wall.

I can't make a good comment on how easy it would be.
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I think it has to twist to bend.
 
If it was that bad--sure as **** it would shake on the dyno at some point the operator would notice. I can tell when I have a slight misfire and I'm no Amazing Kreskin. J.Rob
 
I'm sorry it was the Rodney that caught my eye. I would hope the clutch disc is broken. Working but way out of balance. Not what I call a super easy fix, but certainly I hope it's that over a bent rod.
 
j par said:
I'm sorry it was the Rodney that caught my eye. I would hope the clutch disc is broken. Working but way out of balance. Not what I call a super easy fix, but certainly I hope it's that over a bent rod.
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Me too! Wouldn't surprise me either
 
Mike Mike Mike! Say it ain't so. Check the balancer, remember mine went bad and it sounded like a rod. It's the whole reason I have a new 418. I'm hoping it's not a rod, that would suck.
 
superchargeddrt said:
Mike Mike Mike! Say it ain't so. Check the balancer, remember mine went bad and it sounded like a rod. It's the whole reason I have a new 418. I'm hoping it's not a rod, that would suck.
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No sound Glenn. Just a baaaaad shake. I did think of you, though. Balancer was the first thing I checked.
 
Ironmike said:
Me too! Wouldn't surprise me either
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Jezzuz! WE go from catastrophic bent rod to screwed clutch disc! One thing I do know is --OP should probably refer to the internet for any and all medical advice from here on out too. Donezo-J.Rob
 
Ironmike said:
Well if it was bent without a twist, there would be cylinder wall damage.
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Sounds like you have seen more than enough. Don't need the likes of me--unsubscribing so I don't get a trillion notices like the other cylinder head thread where your problem was solved in the first few pages. J.Rob
 
RAMM said:
Sounds like you have seen more than enough. Don't need the likes of me--unsubscribing so I don't get a trillion notices like the other cylinder head thread where your problem was solved in the first few pages. J.Rob
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Thanks!
 
Ironmike said:
Well if it was bent without a twist, there would be cylinder wall damage.
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What's the back story from before it was on the dyno?
What was done?
I just don't see bending a rod at 4k without a good reason, or smoking after a dyno run unless there is more to it than that.
 
By the way Mike,
I'm real close to taking my Dart for its first test drive (boy am I nervous and excited at the same time). Just have to connect the exhaust and a little under hood wiring.
 
No back story. Ran great on the dyno. No vibration, no problems. Head porter believes the epoxy used when tubing the headbolts finally failed allowing oil into the ports. That's all been corrected now.
 
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