I've encountered several U20 cranks that had developed cracks. It could be
that this is what they are talking about needing to weld up. I always
Magnaflux a crank before I have any machine work done on it.
If they are planning on only sleeving one cylinder, then it would have to be
bored out to match the other ones. If they are oversize, then it will be,
too.
Gordon Glasgow
Renton, WA
www.gordon-glasgow.org
> -----Original Message-----
> From: owner-datsun-roadsters@autox.team.net
> [mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of
> Davesmbox@aol.com
> Sent: Friday, May 12, 2006 4:54 AM
> To: datsun-roadsters@autox.team.net
> Subject: U20 block and crank question
>
>
> We have a roadster new comer here in Ma. The machine shop told
> him his U20
> block and crank were no good.
> I gave him a spare block and crank I had with the understanding
> that he pay
> me what its worth when he is done with the rebuild.
> Here is the problem. They told him my crank was no good and has
> to be built
> up with welding and recut. I thought that was a technique
> reserved for cranks
> which oversized bearings are not available or large 18 wheel truck cranks
> with a million miles on them. As far as I know this crank hasn't
> been previously
> cut so it should be machinable to fit an oversized bearing. Are
> we missing
> something or are we getting bad advice from the shop????.
> The block. One piston was frozen and had to be driven out. They
> told him
> the block needs to be SLEEVED and he still needs oversized
> pistons. Ok as an old
> Triumph owner (that used a sleeved engine) I thought the main reason an
> engine was sleeved was make the sleeve and piston changeable OR
> if oversized
> pistons were not available. But why bore in a sleeve AND still
> need oversized
> pistons????? Are sleeves even out there for the U20???
>
> Is this machine shop just giving us some bad advice?
>
> Thanks for any input,
> DAVE
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