stock bottom end and rpms

house

house

the Fat kid!
Joined
Apr 23, 2006
Messages
3,783
on my dodge 12v i wont be able to afford to pull it apart to balance and lighten stuff till 09 season, how many rpms safely can a stock bottom end see and last all season?
 
Mine's ran 4,500 for most of last year just fine... Can you afford to throw a fluid dampener on it?
 
The dampener will help with the resonance issues, in my humble opinion 4,500 and down you should be ok any time above that you're running risks directly proportional to the amount of time spent there...
 
I personally think it is a crap shoot over 200,000 miles. I would strongly suggest new bearings in the bottom end. If the motor was maintained then not an issue, but putting 650+HP and turning 4500 rpm would make me nervous.
 
zstroken said:
I personally think it is a crap shoot over 200,000 miles. I would strongly suggest new bearings in the bottom end. If the motor was maintained then not an issue, but putting 650+HP and turning 4500 rpm would make me nervous.
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it was well maintened for the fist 220k, the owner was a mechanic at the chrysler dealer and used it to tow his race cars to the track and was 100% stock
 
I can tell you from experience the between 5k and 5.3 k that the crank shaft is very unhappy EVEN with a fluid dampner.
A high mileage motor should be fine if it was stock, the major problem would be with rod bearings beat to death with tons of timing and cylinder pressure.

IKE
 
Mine has a wicked vibration that starts at 3900ish, so I always chicken out and let off. I don't pull so I don't need those rpm's anyway, but I wonder if a good fluid dampner would help?
 
B18B1LS1 said:
Mine has a wicked vibration that starts at 3900ish, so I always chicken out and let off. I don't pull so I don't need those rpm's anyway, but I wonder if a good fluid dampner would help?
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You sure the vibration isn't your nerves watching the tach wrap that far?

:hehe:
 
When I bought the pooler the odo showed 231,000. I turned almost 5500 coming off the line for darn near 2 years before we pulled the old motor out . And we still didn't have any major trouble with it. We just wanted to put the new full bilt motor in to try to get some hooks on it.
 
satburn said:
You sure the vibration isn't your nerves watching the tach wrap that far?

:hehe:
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Very possible, all those red lines scare me! I better try again LOL
 
I heard that there was harmonic resonance (sp?) at around 4100 and **** hit the fan at that rpm. That being said i was also told you are ok either above or below 4100.
 
We pull the stock fan off and replaced it with an electric one...We also did away with the factory air and got the shorter belt.
 
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