[Land-speed] Destroking a Crankshaft...

[Dave Dahlgren]

There are lots of smaller displacemet high performance engines available 
without jumping through the destroke hoop. Very short stroke big bore 
engines seldom make much in the way of power unless you have a very large 
budget so why bother in the end?
Dave
----- Original Message ----- 
From: "Larry Mayfield" <drmayf at mayfco.com>
To: <land-speed at autox.team.net>
Sent: Sunday, February 20, 2011 1:34 PM
Subject: [Land-speed] Destroking a Crankshaft...


>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