Harmonic balancer tightening (crank bolt) engine in car with 4spd manual transmission

-
Peini

Peini

Well-Known Member
Joined
Dec 27, 2020
Messages
79
Reaction score
35
Location
Styria/ Austria
Hi guys,
I rebuilt my engine, a 340 small block for my Dodge Dart, and thought it might be easier to tighten the harmonic balancer to spec with the engine in the car and put it in gear since I have a 4spd manual transmission. Now that the engine is in and this is one of the last to dos before firing this thing up, I am not quite sure anymore if this is a good idea, but I cannot explain why I am uncertain about it either (maybe just a question of nerves).
First, I thought it shouldn’t be a problem since the engine makes around 340 pound-feet of torque and the torque spec for the crank bolt is definitely less.

Would be great if you could share your thoughts/ experience on that.

Thx!
Chris
 
I give a few raps with a strong impact gun and call it done.
 
So you rebuilt an engine completely and you are hung up on one bolt? Maybe a talk with a therapist could help.

“The bolt is your friend, imagine you are the bolt. Imagine you are being tightened. You are the bolt. That is tight.” - $50 co pay please.
 
Syleng1 said:
So you rebuilt an engine completely and you are hung up on one bolt? Maybe a talk with a therapist could help.

“The bolt is your friend, imagine you are the bolt. Imagine you are being tightened. You are the bolt. That is tight.” - $50 co pay please.
Click to expand...
:rofl:
 
I was working on some small front wheel drive thing with a stick and had the same thoughts. “How much torque can that little crank take?” Just your mind screwing with you, the crank see’s incredible shock loads, far in excess of the torque rating of the motor.
 
In my younger days;
I would put my big 1/2 drive Johnson-bar on there, put the bar on the frame, and hit the starter. Bam!, the bolt was loose, and the bar was on the ground.
Obviously, you can't tighten it that way, but if I could I would.
But what I have done is put a bar on the flywheel to anchor it to the bellhouse.
Using the manual trans is an idea, but to prevent the car from moving, you'll have to set the parking brake to lock it up. Which means that when you go to tighten the bolt, the torque will go into; the backing plates, then the banjo, then the springs, and you will be winding all that up until the snubber hits the floorpan, before any torque goes into the bolt. Ergo, it will take some extra swinging room for the bar.
Whereas the bar in the ring-gear eliminates all that .................... as does Rusty's method.
 
The car is your friend.

Manual trans, put it in gear (the highest you have), chock the tires on both sides. Set the parking brake.

Now the crank will have to rotate against all that immovable load which it can not.

Get you FSM out and get the torque specks. They were put in the book for a reason!

Then torque away.

I don't recall the spec but if it's in the 200 or higher range get a 3/4" drive socket and torque wrench. Harbor freight has them reasonably priced and they also have a torque measuring piece that you put between a breaker bar and the socket with a digital display. Worked great on a pinion yoke
 
Hit it with an air gun, or electric impact. Here is a different concern, did you have the balancer on when you tightened the timing cover? The balancer aligns the cover. Though I have used the dampener bolt to install the dampener, you should use a dampener installer.
 
4spdragtop said:
I fed rope into cyl #1 to stop crank/piston from moving. Worked fine.
Click to expand...
.....and you can do that, BUT, word of warning. IF the valves happen to be open when the rope comes up and compresses against them, it is possible as you're torquing that crank bolt that you "could" bend a valve against that wadded up rope. Especially if the rope just makes contact with one side of that valve. I think for changing valve seals the rope is a great idea. But I'm not so sure I'd do it to torque the balancer bolt.
 
I should have mentioned coming up on tdc for that cyl, that's what I did(half-assed followed instructions again lol)
RustyRatRod said:
.....and you can do that, BUT, word of warning. IF the valves happen to be open when the rope comes up and compresses against them, it is possible as you're torquing that crank bolt that you "could" bend a valve against that wadded up rope. Especially if the rope just makes contact with one side of that valve. I think for changing valve seals the rope is a great idea. But I'm not so sure I'd do it to torque the balancer bolt.
Click to expand...
 
4spdragtop said:
I should have mentioned coming up on tdc for that cyl, that's what I did(half-assed followed instructions again lol)
Click to expand...
If it was on something like a Chevy 350, I wouldn't sweat it. But a Chrysler with a 3/4" bolt. That takes a lotta torque. lol
 
Yes, no alignment pins on our stuff. Well, the heads do.
 
I did the balancer bolt on my asshole brother's 65 Buick Gran Sport 401 nailhead with an automatic by clamping a set of vise grips on the flexplate, rotated against the block, and torqued to 250 ft lbs. Piece of cake. My own junk I just pound it with an impact gun and call it good.
 
Why not get the correct balancer installation tool? It’s so much easier than micky mousing anything. And if you ever strip a crank bolt, you’ll never use the bolt to install a balancer again.
 
justinp61 said:
I’ve built several and never seen any pins. I always tighten the timing cover bolts after the damper is on.
Click to expand...
I would do the same thing. I just recall someone else pointed out the pins to me in the last few months.

I'm so confused!!!!

Found 2 photos... One that seems to show pin holes and one that does not?

I'm at a loss?????
Screenshot_20240524-001133.png
Screenshot_20240524-001224.png
Click to expand...
 
CRUZE 418 said:
Hit it with an air gun, or electric impact. Here is a different concern, did you have the balancer on when you tightened the timing cover? The balancer aligns the cover. Though I have used the dampener bolt to install the dampener, you should use a dampener installer.
Click to expand...
Yes the balancer was on before I tightened the timing cover and I used the tool to install the dampener.
 
Last edited:
Dana67Dart said:
The car is your friend.

Manual trans, put it in gear (the highest you have), chock the tires on both sides. Set the parking brake.

Now the crank will have to rotate against all that immovable load which it can not.

Get you FSM out and get the torque specks. They were put in the book for a reason!

Then torque away.

I don't recall the spec but if it's in the 200 or higher range get a 3/4" drive socket and torque wrench. Harbor freight has them reasonably priced and they also have a torque measuring piece that you put between a breaker bar and the socket with a digital display. Worked great on a pinion yoke
Click to expand...

Did as described some minutes ago and worked great.
Thx
Chris
 
You must log in or register to reply here.
-

Back
Top