Valve pockets/dome not square to gudgeon pin?

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Valve pockets/dome not square to gudgeon pin?

Postby ChaosAD » Thu Oct 14, 2004 9:56 pm

If the top of a piston is not square to the other pistons when a straitedge is held against the line of the dome (either a twisted rod or the hole for the gudgeon pin is not machined square to the top of the piston) then will this cause airflow problems or valve clearance problems?

Measuring the two exhaust valve pockets against a straitedge held against the edge of the bores shows that one valve pocket is 2mm closer to the edge of the straitedge than the other?

Would this be anything to worry about?
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Postby kingcorolla » Thu Oct 14, 2004 11:42 pm

Yours (4a-ge?) is a pretty non interference engine, twisted or bent gudgeons will increase piston ring, and possibly bore wear. not 100% sure but dont think this will cause valve slap. Whats your comp ratio?
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Postby ChaosAD » Fri Oct 15, 2004 4:33 pm

Its a rebuilt 4age, It will no longet be a non-interferance engine cos of the hicomp pistons and big cams
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Postby CAMB01 » Fri Oct 15, 2004 8:48 pm

if your measuring the piston with it still in the bore, then the piston has rocked to one side.
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Postby ChaosAD » Sat Oct 16, 2004 11:55 am

No, it hasnt rocked. Its turned several degrees counterclockwise!
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Postby Mr Revhead » Sat Oct 16, 2004 2:46 pm

that sounds.... odd..... :?

you did say they were "factory seconds" which makes me suspicous....
to be honest with the investment youv already made in parts and labour id be looking for new pistons....
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Postby ChaosAD » Sat Oct 16, 2004 5:08 pm

I thought they were seconds cos one of them had a dent in it, but they arent.

It could be one of two things. Bent rods, or poorly manufactured pistons.

The pistons are made by AE which is sopposed to be a reputable brand.

I bought the rods off a guy who upgraded to stronger rods, but if they were twisted the piston heights would be all up to shit, Which they arent.

Either way ive still decided to replace the cast pistons with something a bit better
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