conrod crankpin bearing problem

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Seight-V8
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conrod crankpin bearing problem

Post by Seight-V8 »

hello all,

taking things really slow with my latest 4.6 v8 engine build.....so I'm checking as much as I can before and as i build it.

Got my engine internals back from chessman's just before xmas, after balancing.

Just checking conrod crankpin clearances with a bore micrometer, I notice that some of the conrod bearing caps don't fully seat when the bearings are installed.

Looks like maybe some of the bearing ends are just a little to long around the circ of the bearing.

Internal bore of the crankpin of the conrod also measures a little large too, so suggesting its not seating properly.

Anyone else had this problem, and is it ok to remove any material to make the bearings fit and the caps to meet face to face.

cheers

scott



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Post by katanaman »

Check your conrods for being out of round. Pretty common and can be fixed by getting them recircled.

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Post by Seight-V8 »

funny just been checking that too.....

worst I've out of round reading is 0.02, but cant find what it acceptable from the LR manual.

Anyone know?

I'm guessing this amount should be ok.

As there's 0.04mm specified on the crank mains.

cheers

scott

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Post by Seight-V8 »

narrowed it down to 2off half bearings that are a little on the big side when sat in the rod cap, so managed to get 7 out of 8 to be ok.

Will just have to carefully remove material on the two that are left to make them fit and have the correct diameter.

at least I found it before just assembling the engine....so I'm happy.

regards

scott

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Post by katanaman »

Entirely up to you but I would be sending them back. These are supposed to be precision and they seem to be far from it. Hand fit bearings went out a long time ago and this has the potential to ruin your new build. Who is the manufacturer?

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Post by Seight-V8 »

yes I have thought about sending them back, ive had them since easter and not used them.

There were supplied by real steel and are 4.6v8 OEM items made by gylco so fed mogul items.

I've just done fitted the main ones of the same make, and they have all came out with the correct diameters and fitted lovely.

So maybe just a bad batch, or bad 2off bearing shells.

Maybe best I speak to real steel first, before I attempt anything.

cheers

scott

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Post by DEVONMAN »

No way would I adjust those bearings to fit. If you put them side to side with a good one it will show that they are different and suspect.
Real Steel will probably say it's your con rods that are wrong so be ready to say that the two iffy ones are different to the rest.
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Post by DaveEFI »

I'd try the 'faulty' shells on one of the other cylinders which has proved good.
That would show if there is any difference in the shells.
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Post by Seight-V8 »

I've found a set of standard size "King" crankpin bearings, that I didn't use.

And these are perfectly sized in the bore, so definitely 2off wrong sized gylco bearings.

Not used "king" bearings before, but these where supplied by turner engineering, so hopefully OK to use.

thanks for all the help.

cheers

scott

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