Bullman Posted December 17, 2003 Share Posted December 17, 2003 Hi I have obtained a standard crankshaft for my 1700 supersprint,it has had a number of holes drilled into the ends of the web/conterbalance?Holes are about 8mm in diameter,there are 3 holes on each web/counterbalance only on the middle two throws of the crank.Can anyone inform me is this for lightening purposes or for balancing?Does this not weaken the crank in anyway?Would it be best to obtain a crank without drillings?I intend to have the crank nitro carburised but am concerned that it may bend during the treatment process due to the machined holes.Any suggestions greatly received.Thanks Bullman Bullman Link to comment Share on other sites More sharing options...
Peter T Posted December 17, 2003 Share Posted December 17, 2003 No this is normal, holes are drilled in it when it was balanced and when it was made, as long as it is crack free and has not been machined more than 20 thou your ok. Founder Member of The Twisted Prop Club. Link to comment Share on other sites More sharing options...
R2D2 Posted December 18, 2003 Share Posted December 18, 2003 You can find that "Tuftriding" a crank can allow some movement to take place but this is less likley to happen on a used crank. I have tuftrided more than 10 crossflow cranks over the years and never had one move but it can happen. If the movement is small most good engine builders can straighten them out and it is worth checking the run out with a dial gauge before you bolt up the mains. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now