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Big end problems. Advice on what to do.

acarmody

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So my mechanic thinks I have a big end bearings problem, well #### my life. Engine was only rebuilt 2.5 years ago.

Anyway the engine has some pretty nice parts in there so lets see what I can salvage.

If it is a big-end, whats the least I can do to get it working reliably?

Can I just remove the crank, crank ground, rods ground and replace crank and rod bearings? Can I do this without removing the heads. As in can I remove the piston through the bottom f the block or is it top only?
 

acarmody

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I mustn't of heard what the mechanic was saying. Doesn't know if its big end or cam bearing.

The tapping sound is at approximately half RPM. Would that indicate cam or could it still be big-end?
 

Dr HaxZaw

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if its at half the rpm then it would be cam as it spins half as fast as your crank... either way that sucks for a motor that new
 

Immortality

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Was the oil system modified when the engine was built?
 

acarmody

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Was the oil system modified when the engine was built?

Hmm, I remember asking the engine builder about some oiling mods, don't know if he actually did though.

Do I need any specific type of engine stand for this thing, want to pick up one of these,

A341 | ESS-450 Engine Stand | machineryhouse.com.au
700


and one of these tomorrow,
A342 | AET-750 Engine Tilter | machineryhouse.com.au
700


Already have the engine crane.
 

Immortality

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Yeah, that stand will do the trick.

Use the old screw driver stethoscope trick and see if you can get a more accurate location on the tapping. If it is the crank then you can turn the engine upside down, undo the rod bolts and slide the pistons down the bore a little, once all the rods are released you can get the crank out. IF the crank is worn/damaged you are better of replacing it then getting it ground under as this can weaken then crank. MACE have brand new cranks available.
 

acarmody

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Took it to a engine builder yesterday. He doesn't believe its a big end. Likely a cam bearings or something else top end. Said if it was a big-end it would be making the noise at idle. Whereas the noise is greatly reduced at idle, just a low tapping noise. Only gets loud when a bit of RPM is introduced.
 

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Use the stethoscope method to try and track the noise down more.

Take the rocker covers off and see if everything is moving properly, could be a lifter that has collapsed. Does it have a balance shaft fitted? If so, check for the noise around the rear of the valley for noise above the bell housing.
 

acarmody

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No balancer shaft is gone and plugged at rear oil feed.

I actually have a stethoscope from Autobarn (the one that just ends in thin round steel) will use it tomorrow. I tried some pipe, but it didn't work so well, though I do believe I heard the noise louder on the flat piece under the runners on the intake manifold.
 

acarmody

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One thing I'm worried about is dialing the cam back in, I would have no way of knowing what the hell I was doing. Would dot to dot work on the Rollermaster double-row gear I have (I would obviously make new dots, not factory stuff)?
 
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