I had a built-up/welded up stroker crank made for my nitrous bike -- and it
didn't last well at all. I heard poor things about the welded up process
after going that way. It wasn't a huge increase in displacement - about 18cc
per cylinder, and that would be out of about 70 or 80 mm stock. Whatever - it
wasn't the way to go for my engine. I then spent big (no, HUGE!!) money to
get a billet stroker crank made for me. At that time my engine builder said
he looked hither and yon and could not find an American firm that would take
the job, and I have to presume that he did his homework and really did check
'em all out, including that one on the west coast (unh, is it something like
Marine Crankshafts - or something?). We ended up getting the crank from
Farndon, a firm in the British westlands. They quoted 6 - 8 ---and delivered
in about 16 MONTHS! At a very high price, too. The thing is running now, but
we have not sprayed when it's running, so I don't know if this one will live
or not.
Further deponent sayeth not.
Jon a/k/a SSS
On Feb 20, 2011, at 1:34 PM, Larry Mayfield wrote:
I have been toying around with an idea for a new motor for my Sunbeam. But it
would require a destroked crank to meet the displacement goals. I have been
searching around for such cranks and they are pretty rare. Some are apparently
used in a Nascar class somewhere which has a displacement limit. I know about
off set grinding to either stroke or destroke abit. But, even with a brand
new crank, I would not be able to get there. So, my question... I know cranks
can be welded up and reground. But how much can that be used? If I wanted to
take a crank down with a stroke difference of say 1/2 inch? That seems like a
LOT, lol, as it would require a 1/4 inch or more of buildup on the inside of
the rod throw. Even if I started with a 289 ford crank it would still be a
lot. And is that even doable with a cast crank? I would expect it to be ok
on a forged steel or billet crank, though.
I'd like some responses from folk who have actually had something like this
done. Suggestions of changing motor blocks etc are not what I am looking
for.
And I am just fiddling around now. The Sunbeam may never run again as a race
car..and that would no doubt please a LOT of people, lol...
mayf
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