Question on crank bolt torque

[spstan]

I want to remove the crank bolt on a 1975 Chrysler 440. Does anyone know the torque specifications? Cause my race car driver neighbor claims it can be removed with a breaker bar and socket. I was thinking of buying an electric impact wrench but I don't know how much torque the wrench should have. What' s the better option?

Separately, I was thinking of removing the 6 small "ring" bolts first. Will I still be able to rotate the engine with the crank bolt? I mean the crank bolt remains functional when the pulley attached by the ring bolts is removed? Thanks Paul

 

[Justin Plant]

If the engine is still in your car, put the socket and the bar on the bolt. Hit the key, the starter will bust it loose in half a second.

 

[spstan]

If the engine is still in your car, put the socket and the bar on the bolt. Hit the key, the starter will bust it loose in half a second.

Justin; you've tried this with success? I saw it on Youtube but everyone I've talked to cautions me against it. Paul

 

[CBODY67]

BEST to position the breaker bar so it canNOT rotate any more! Might have worked on some cars, but probably not on all. Think of that long breaker bar rotating as fast at the starter spins the motor. A prescription for many damaged parts IF the socket stays engaged, to me.

If you watch the YT channel "I Do Cars", he uses a 3" breaker bar FIRST and then the electric impact after that, once the bolt is broken loose. With the engine on an engine stand. He usually tries his impact wrench first, but 95% of the time, ends up using the breaker bar first.

I vote for the "long breaker bar".

 

[Justin Plant]

Justin; you've tried this with success? I saw it on Youtube but everyone I've talked to cautions me against it. Paul

dozens of times, A 90 yr old mechanic taught me this trick. Hondas, it will not work on Hondas

 

[Big_John]

I'm going to suggest you buy the impact and do it that way.

Yep, a breaker bar on the ground would work, and I'd do it in a pinch, but from what you've posted it's easy to see that you aren't real experienced.

You are going to have to re-install that bolt too... The usual procedure is a couple "ugga-duggas" with the impact as it's not a critical fastener that needs to be torqued to spec.

150ft/lbs is what the bolt is supposed to be tightened to, so figure it's going to be more to break it loose. Look at what they sell, pick one accordingly, and then buy the next stronger one.

And yes, you can remove the lower pulley without removing the bolt.

 

[66furys]

Dumbass that I am at my elevated age, I will chime in here. I was marking my damper with timing marks using a ratchet and socket. Then, fired the engine up to use a timing light to determine initial, centrifugal and vac advance before pulling the OEM distro. Well, as you may have already guessed, I forgot to remove the ratchet. When I started, I heard a noise, and the engine spit. I had left the wrench on. It hit the water pump pulley, and when I got out of the car, there was wrench, bolt and washer on the ground. Would NOT recommend this. Take a normal breaker and hit it with a two pound maul, and it will easily come loose, if you hit it in the right direction. Also, you can pretty easily get it up to over a hundred with the same technique....and neither the impact nor hammer will do the measuring for you, but I am a big believer in snug is good enough, even on the harley bolts that vibrate loose. Been doin this a long time and my hand has not failed me yet on torque. Certain critical bolts like crank and rod and head should be torqued for sure. At the shipyard, they use a slug wrench on the big boys with a sledge hammer. And, on some nuc jobs, they have a hole in the stud, tighten down the nut to a marginal torque, then heat the stud, and turn the nut a certain number of computed turns to stretch the stud. No sweat. Hammer

 

[66furys]

Sorry to come back again here. I am at the point on the old 383 that am thinking timing chain and gears...or sprockets. I want to find an install tool for the crank bolt, harmonic damper. When mine was laying on the ground, I forgot to measure, and the tool has to have these threads....about 3/4 fine SAE.....anyone know the size, so I get the right tool. thanks