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> It Was Going So Well, Then Something Broke
Mblizzard
post Nov 16 2013, 04:02 PM
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Well just got my carbs sorted. Went for a drive and something has come unglued in the bottom of the engine. Huge loud slapping like a rod banging. Very rpm related. On the 3 4 side. No damage to the plugs. Still runs but it is clear that something is very broken. Will check valves tomorrow but I am betting the case has to be split.

Any thoughts on easy things to check or where to start? (IMG:style_emoticons/default/headbang.gif)
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914_teener
post Nov 16 2013, 04:14 PM
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The printed venturi's broke?
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bulitt
post Nov 16 2013, 04:23 PM
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You say you got your carbs sorted. Possible they are running too lean resulting in a detonation and bent rod? Check condition of your plugs.
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Mblizzard
post Nov 16 2013, 04:36 PM
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QUOTE(914_teener @ Nov 16 2013, 02:14 PM) *

The printed venturi's broke?


Nope they are perfect!
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Mblizzard
post Nov 16 2013, 04:37 PM
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QUOTE(bulitt @ Nov 16 2013, 02:23 PM) *

You say you got your carbs sorted. Possible they are running too lean resulting in a detonation and bent rod? Check condition of your plugs.


If anything plugs looked slightly rich.
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Mblizzard
post Nov 16 2013, 04:47 PM
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QUOTE(scotty boy @ Nov 16 2013, 02:03 PM) *

Pull off the valve cover. You might get lucky



I have not been lucky with this car yet!
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struckn
post Nov 16 2013, 05:35 PM
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QUOTE(Mblizzard @ Nov 16 2013, 02:47 PM) *

QUOTE(scotty boy @ Nov 16 2013, 02:03 PM) *

Pull off the valve cover. You might get lucky



I have not been lucky with this car yet!


At idel check to see if you're blowing any gas out, also pull a plug wire off each plug one at a time and if the rpms don't drop when you pull the plug wire off of one of them you may have dropped a valve seat.
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infraredcalvin
post Nov 17 2013, 01:53 AM
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Check for big exhaust leak near the heads. I had a smog injector plug unscrew itself on my turbo, sounded like a mechanical slap, turned out to be a $.50 plug...
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jimkelly
post Nov 17 2013, 05:05 AM
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sounds like a very loose valve rocker.


Attached image(s)
Attached Image
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Dave_Darling
post Nov 17 2013, 11:26 AM
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I've had that particular version of the sound a couple of times. In each case, it was a dropped valve seat... Hopefully this ain't one.

Pop the valve covers off and take a look.

--DD
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Mblizzard
post Nov 17 2013, 02:17 PM
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Initial look with a bore sope ghrough spark plug says #4 position broken. Too much oil to see clearly. Will drain oil and look again before dropping it. F#%k.
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messix
post Nov 17 2013, 03:00 PM
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QUOTE(Mblizzard @ Nov 17 2013, 12:17 PM) *

Initial look with a bore sope ghrough spark plug says #4 position broken. Too much oil to see clearly. Will drain oil and look again before dropping it. F#%k.

piston?
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Mblizzard
post Nov 17 2013, 03:09 PM
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QUOTE(messix @ Nov 17 2013, 01:00 PM) *

QUOTE(Mblizzard @ Nov 17 2013, 12:17 PM) *

Initial look with a bore sope ghrough spark plug says #4 position broken. Too much oil to see clearly. Will drain oil and look again before dropping it. F#%k.

piston?


Yep. Auto correct and being pissed are not a good combination.
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wndsnd
post Nov 17 2013, 04:01 PM
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Real sorry to hear that.

But at least it is a good time of year to pull the engine and have at it.

You will be back on the road for spring!
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Dr Evil
post Nov 17 2013, 04:45 PM
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Yikes, crappy luck. It could have been worse, like internal.
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Cap'n Krusty
post Nov 17 2013, 05:12 PM
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Sorry to hear that. Pistons usually break because valves hit them ..................... Occasionally they go because of FOD, like a nut or bolt falling in.

The Cap'n
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euro911
post Nov 17 2013, 05:38 PM
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Mblizzard
post Nov 17 2013, 06:36 PM
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QUOTE(Cap'n Krusty @ Nov 17 2013, 03:12 PM) *

Sorry to hear that. Pistons usually break because valves hit them ..................... Occasionally they go because of FOD, like a nut or bolt falling in.

The Cap'n


Could not see any FOD looking in but the valves seem to be ok. This was a new build on the top end with new jugs, pistons, valve guides, and such. I am wondering if I got a bad piston?
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rick 918-S
post Nov 17 2013, 07:03 PM
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Be sure to check the rod on that cylinder. I have bent them during collision.
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Mblizzard
post Nov 21 2013, 08:44 AM
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Pictures are not of good quality but this is what I see looking into the #3 spark plug hole. Looks like the piston is cracked completely across.

Attached Image

Attached Image

Any thoughts? Does not look like a valve came into contact with the piston and there is no debris that would suggest a dropped seat. Spark plug was not damaged when removed.

I have to think the piston was flawed.
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