Crankshaft Nut 440 cid

[MarPar]

What is the torque spec of the big nut (i think it's 1.25"--is it?) on the end of the crank? the manual only shows the spec of the dampener bolts.

i was about to turn my motor over by hand and noticed that the nut is loose!!!

im not talking bout the bolts that hold the dampener down, im talking bout the big nut in the middle. and also, should i be concerned that this nut is loose?? i mean obviously i am concerned; hence my question so i can tighten it down, but is there an underlying problem i should be worried about because it came loose?

thanks y'all...

 

[62 Dart Convertible]

Hi Mate

The manual usually refers to this as "Crankshaft bolt" and it is torqued to 135 ft/lb.

Perhaps it wasn't torqued up properly last time installed.

 

[MarPar]

Hi Mate

The manual usually refers to this as "Crankshaft bolt" and it is torqued to 135 ft/lb.

Perhaps it wasn't torqued up properly last time installed.

Howdy 62, i see it says "crankshaft bolt" in the manual, but it also says that it's a 3/4-16 bolt. the one im referring to is a 1 1/4" inch bolt. i figured the "crankshaft bolt" the manual refers to are the ones around the big nut im talking about...

 

[IQ52]

Yep, it does say 3/4-16 for the crankshaft bolt, because, the threads are 3/4" in diameter with 16 threads per inch and it will have a bolt head of 1-1/4". Please, don't torque the 5/16x18 bolts with the 1/2" heads, that hold the pulleys on, to 135 ft-lbs.

 

[MarPar]

Yep, it does say 3/4-16 for the crankshaft bolt, because, the threads are 3/4" in diameter with 16 threads per inch and it will have a bolt head of 1-1/4". Please, don't torque the 5/16x18 bolts with the 1/2" heads, that hold the pulleys on, to 135 ft-lbs.

This Sir, is exactly why i asked!! lol thanks IQ, i knew something didnt add up.

im wondering why it backed out?? is there some other underlying cause i should look into? also, when i try and tighten it, the fan blade moves, im assuming im turning the motor over? (sorry im still a newbie at this kind of thing). it's turning pretty easily, and i figured it would take a lot to turn a motor over by hand...

 

[Meep-Meep]

Normally you can lock the flywheel with a big blade screwdriver or prybar so you can get on that bolt with a big *** pipe extension or an actual torque wrench. Why it came loose is probably what 62 said - someone didn't tighten the dog crap out of it.

 

[MarPar]

Normally you can lock the flywheel with a big blade screwdriver or prybar so you can get on that bolt with a big *** pipe extension or an actual torque wrench. Why it came loose is probably what 62 said - someone didn't tighten the dog crap out of it.

Thanks Meeps. i have both; a 3/4" torque wrench (harbor freight, but better than nothing lol) and a big olde prybar. ill get it to 135 lb/ft no problem then...

 

[Cranky]

And if you're worried about it coming loose again, clean the threads good and put a dab of red loc-tite on it.