Dave,
When I had my U20 rebuilt three years ago the machine shop told me my crank
was scored (it was). I had taken it apart before bringing it to them for the
rebuild so I knew that was true. It was scored because the PO had oil-starved
it (at least once) and the reason it needed the rebuild was because of this oil
starvation - and that had caused one of the main bearings to break loose from
excessive wear. I had no doubt the crank needed to be either replaced or
"built-up". There was no scoring on the journals. My brother is a mechanic
and told me that since the crank on a U20 is forged and not cast, it can easily
be built-up by welding (and is worth it!). (Side note: if you ever have the
crank out and lightly tap it with a wrench it makes the nicest "ting!" - just
like a bell, you'd ever want to hear.) Since there was no other reason to go
oversized bearing or rings, etc., I opted to have the crank built-up. So far
no problems and I still have this nice "real" racing
engine - eyelashed valve cutouts, etc. My brother also told he the history of
the engine (U20)was that it was a Mercedes-Benz inspired/designed/licensed
engine. I don't know if that's true, but it's an interesting piece of history
for a car that has lots of influences from other cars of that era. ANone know
if that's true?
I opted to keep as close to "original" as possible - I'll do oversized
bearing later, if necessary. I sometimes like to think of my Roadster as a
"well-built" MG, if there is such a thing...ha, ha! Of course my fiance just
calls it my "Stuart Little" car and leaves it at that.
Perry Smith
'68 2000
Davesmbox@aol.com wrote:
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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