Do I REALLY NEED to torque the crankshaft bolt to 304 ft lbs? (1 Viewer)

[LS1FJ40]

Starting this tonight, finishing tomorrow. Do I really NEED a torque wrench? I've heard others say they tightened it until they felt it was good and tight. Is there any risk of breaking it if I use a 3/4" breaker bar with a pipe over it?

 

[Douglas S]

Think about what happens if you don't get it tight enough and it backs off.

 

[retrofive]

#yes you do.

 

[jfz80]

So you of all folks are doubting mr t's recomendations now?!?

You could get crafty with all that math and physics if you want. Seems there was a recent description of reaching 300ft pound with x length pipe and y number of pounds applied.

 

[Fosters]

if you don't...you run the risk of the crank walking...and also the oil pump drive walking and toasting the timing cover

 

[SARguy]

Starting this tonight, finishing tomorrow. Do I really NEED a torque wrench? I've heard others say they tightened it until they felt it was good and tight. Is there any risk of breaking it if I use a 3/4" breaker bar with a pipe over it?

I have done both of my 80's this past year. I went out and bought a 3/4" torque wrench. When I torqued it down, I was shocked. It took a 4 ft cheater on the end of the wrench, and I almost blew the veins out of my forehead flexing all my muscles in my whole body, past their limits to get it to 305 ft lb. NO WAY, NO HOW dare to do it by feel. It wont be enough. I saw a post earlier today showing someone torquing the crank bolt by strapping down the harmonic balancer. Ive seen posts where the rubber mount inside the balancer is torn apart and destroyed it by doing it that way. The jones video shows the right way to do it. Follow it without taking any shortcuts and you will be fine.

 

[Red Merle]

I have done both of my 80's this past year. I went out and bought a 3/4" torque wrench. When I torqued it down, I was shocked. It took a 4 ft cheater on the end of the wrench, and I almost blew the veins out of my forehead flexing all my muscles in my whole body, past their limits to get it to 305 ft lb. NO WAY, NO HOW dare to do it by feel. It wont be enough. I saw a post earlier today showing someone torquing the crank bolt by strapping down the harmonic balancer. Ive seen posts where the rubber mount inside the balancer is torn apart and destroyed it by doing it that way. The jones video shows the right way to do it. Follow it without taking any shortcuts and you will be fine.

Can you link the "jones video"?

I want to do this too, but I was really wondering how people got the nut back on tight.

 

[LS1FJ40]

Ok. I stupidly forgot to get a torque wrench. Can't find one that goes to 304 ft lbs. HF has one that goes to 300.

I saw the crazy math to get to the 304 with a cheater bar.

I'm just used to the 3FE man. This newfangled technology and stuff is difficult! I much prefer to just piss in the gas tank and pour beer in the crankcase and go! Albeit slowly.

I'll just do the rest of the tuneup stuff tonight. Deal with the oil pump cover and crankshaft seal next weekend. I'll have a 3 day weekend.

 

[fjc-man]

You could always rent a torque multiplier and use a torque wrench in the 200 ft lb range to do it correctly. Bill

 

[Notch]

I saw the crazy math to get to the 304 with a cheater bar.

All ratchets and tq wrenches are "cheater bars". 300 ft/lbs is 100lbs on a 3ft bar...or 50lbs on a 6ft bar. It's pretty damn easy to figure out since everyone has a calculator on their phone. Push your bathroom scale against a pipe, this isn't a NASA project. The exact number isn't important since this is an indirect measurement of bolt stretch. Just clean the threads and get it really close to 304 and you'll be fine.

 

[LS1FJ40]

All ratchets and tq wrenches are "cheater bars". 300 ft/lbs is 100lbs on a 3ft bar...or 50lbs on a 6ft bar. It's pretty damn easy to figure out since everyone has a calculator on their phone. Push your bathroom scale against a pipe, this isn't a NASA project. The exact number isn't important since this is an indirect measurement of bolt stretch. Just clean the threads and get it really close to 304 and you'll be fine.

That makes sense. Thanks.

 

[LandCruiserPhil]

Bigger challange for most is how to hold the crank while you set torque. It also much easier to do it from the bottom on a lift.

 

[JaketheSSnake]

I used a 14mm impact socket on a torque converter bolt wedged against the bellhousing when i torqued mine. 300 is probably good enough, the hf is probably off by that much lol. I used a 250lb wrench and set it 150 and then eyeballed the swing to 200 and then 250 and switched to my breaker bar for the last swing. I'm more worried about the antique wrench I used being accurate instead of my eyeball method lol. It seemed to go really easy. Then again, my 280lb ass pulling on a 2ft cheater bar definitely helps lol

 

[drowssap]

 

[LandCruiserPhil]

 

[JaketheSSnake]

View attachment 1340486

It worked and I've done similar things on other vehicles without issue.

 

[LS1FJ40]

What exactly does this show? Does the plate and tube hold it from rotating while you crank on the crank shaft?

 

[nukegoat]

I dont know what you weiners are complaining about. Make a thing to hold the pulley then put a 24" breaker bar on it. From 2 feet you just need 150lbs of force or more. If you cant row 150lbs for a single rep then you suck.

 

[bloc]

Assuming the factory had the bolt at 304, the crank pulley is keyed, and that the stack of parts under the edge of the bolt flange wouldn't change, I just marked where the bolt was before loosening and tightened it back to that point.

This wouldn't work for torque-to-yield (stretch) bolts.. but it made sense in my head in this case.

One of the very few instances I let myself deviate from the FSM

 

[drowssap]

It worked and I've done similar things on other vehicles without issue.

I bet you did....I am sure you got away with it....not slinging mud at all, just making sure to let people know that your advice is very very wrong.