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Author Topic:   400 crank
mod777
Dirt Roller

Total posts: 19
posted December 29, 2001 01:43 PM
406 - 12.5 comp - on alky - 6800 rpm max.
How long will a cast iron crank last in this motor?
Some tell me to change it out after 20 races, 'cause it's going to break soon.
Some tell me if the rotating assembly is balanced, it will last many seasons.
Some tell me to toss it now and cough up $1000+ for forged steel.

WPP
Dirt Freak

Total posts: 220
posted December 29, 2001 02:00 PM
I feel like it all depends on how much horsepower you going to run I have been thinking about running a cast crank myself

sdhnc29
Dirt Freak

Total posts: 467
posted December 29, 2001 05:10 PM
10-14 races before it cracks , if your lucky ! It does depend on horse power , but it also depends on compression ratio , and how hooked up your car is , and how loaded the engine stays . RPM alone wont break it , it's when you hook it up hard that you'll start cracking them . I'd spend a few $$$ extra for a good crank if it's in the budget .

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

WPP
Dirt Freak

Total posts: 220
posted December 29, 2001 05:46 PM
Steve There are alot of differt kinds of steel cranks from 4130 to 5140 4340 but will the differt steel forgeing be ok

sdhnc29
Dirt Freak

Total posts: 467
posted December 29, 2001 10:59 PM
I'd stick with the 4340 ! Though the 5140 and 4130 will be stronger than a cast iron crank .

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

mod777
Dirt Roller

Total posts: 19
posted December 30, 2001 09:26 AM
OK, the surface is red clay, which most nights is tacky for the heat (10 laps), then dry to dryslick for the feature (15 laps).The car is a WISSOTA modified. I think the 8" Hoosiers we run have a little better bite (we can groove and sipe) than the trailer tires the IMCA guys are stuck with. Horsepower in the very low 400's (just a guess, never dyno'd)
Mr. Hendren - can you recommend a Mfr. for the 4340 forging? I've read bad things about Scat, but what do you use? I guess as long as I'm in there, I might as well switch my
stock length rod/TRW2311 combo for a 6.0/Ross forged combo. Oh Oh, there went the budget!

sdhnc29
Dirt Freak

Total posts: 467
posted December 30, 2001 12:00 PM
Yes , I'd probably go with the new Callies Dragon Slayer crank , or a Cola . Both are very reasonably priced for the quality put into them . Both weigh right around 50lbs , I think . I doubt if you'd ever break one in you life time !! Might be a family heirloom one day !....LOL

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

FS93
Dirt Full Roller

Total posts: 52
posted December 30, 2001 08:59 PM UIN: 3107810
I must be the luckiest person on earth. The 406 motor that came in my modified has over 4 seasons of racing on it, with nothing but new bearings and rings. Balanced, 12:1 compression,on alky, guess about 6500(no tach). And I am not losing anything down the straights to other cars. running on 1/**i and 3/8 tracks. Hope it lasts another one.

charlie_two
Dirt Full Roller

Total posts: 53
posted January 05, 2002 04:13 PM
i ran the motor in my mod for two seasons never changed the bearings or rings. never felt any power loss but i also ran dry slick tracks. the motor was a 350 that had stock crank and rods(good bolts) and cheap forged pistons. all i done was assembled it. a "supposed" to be good engine builder did all the machine work to it. so not to bad considering i turned it 7000 and a little more everytime i raced it.

charlie_two
Dirt Full Roller

Total posts: 53
posted January 05, 2002 04:15 PM
also motor had 12 to 1 comp.

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