Stroke to bore to rpm redline

Message

Sandstorm · #1 Post by **Sandstorm** » Sat Jan 21, 2006 1:55 am

I am very dumb when it comes to motors, I'm honest.. I learned alot about these three measuments today. DAB was telling me a bout the 5000ft rule today. If you times bore by stroke and max rpm you can't exceed a certain number of travel feet per minute or something like that or a piston will shatter no matter how well it's made. The number for a 95mm piston Falicon rod at 63.2mm and our redline comes to around 4800. This is on the borderline of okay. Ideal is around 4500 or so.. The higher the number the faster parts will wear out especially a piston.. OEM engines stay around the 4500 mark for reliability.. So if you stroke and bore you better know what the final number comes out to be. If the number comes out to high you must lower the max rpm range.. The 06 YFZ has the same bore and stroke as the Falicon w/ 432/95mm piston, but the YFZ's redline is lower so the total of these three comes out lower and therefore is more reliable and less wear..

cannondale27 · #2 Post by **cannondale27** » Fri Feb 10, 2006 7:27 pm

Sandstorm I have talked to a few and the smart guys know about this.Can you or anyone find the exact rule?Is it 5000ft?Some of these guys swear by this rule.I never heard of it before this either.But want to know more.Thanks.

timbomoose · #3 Post by **timbomoose** » Fri Feb 10, 2006 7:41 pm

Will write the formula down.All books say anything at 5000 is grenade time.Poweroll wants no higher than 4000 which is extremely safe. 4500 is a good safe #.I'll get the formula.

Sandstorm · #4 Post by **Sandstorm** » Fri Feb 10, 2006 10:07 pm

Yes 4500 is a good safe number.. Stroke x bore x redline. 5000 is the majic kaboom number.. I am gonna lower my redline by 500rpm or so..

cannondale27 · #5 Post by **cannondale27** » Sat Feb 11, 2006 12:52 am

Man I have learned alot in last few years about motors.11,000 for me also.Thanks.

Cdale_racer_669 · #6 Post by **Cdale_racer_669** » Sat Feb 11, 2006 5:14 am

what units does the bore and stroke have to be in? mm?

cannondale27 · #7 Post by **cannondale27** » Sat Feb 11, 2006 10:37 am

Good question.

claas900 · #8 Post by **claas900** » Sat Feb 11, 2006 3:46 pm

..This will help with mm to sae. here

Sandstorm · #9 Post by **Sandstorm** » Sun Feb 12, 2006 2:01 am

I don't know how he caculated it..

theJeStEr1340 · #10 Post by **theJeStEr1340** » Sun Feb 12, 2006 9:55 pm

Timbo.. what is the total stroke on my crank? (it is one of your strokers)