Write-Up: Removing the Crank Pulley/Harmonic Balancer

Why take the belt off at this point?  It's out of the way.

Jack the R wrote:

Why take the belt off at this point?  It's out of the way.

OK, did you get the balancer bolt loose?

My neighbor's got that impact wrench (or an earlier model). We're going to work on it tomorrow.

I've got a new harmonic balancer bolt too. I should be able to get up to the case learn part. Hopefully I can do it without a Tech 2, but if not, I know a guy who has one.

I never did a case learn when I replaced my crank sensor. Never had a problem. Maybe you'll be OK.

The DeWalt wasn't strong enough to break the bolt loose, but I scored a free air compressor and now I'm playing with an air impact wrench. How do you torque to 200 ft/lbs? I haven't found a 200 ft/lb torque stick yet.

Jack the R wrote:

The DeWalt wasn't strong enough to break the bolt loose, but I scored a free air compressor and now I'm playing with an air impact wrench.  How do you torque to 200 ft/lbs?  I haven't found a 200 ft/lb torque stick yet.

No Way, was it a 3/8" impact wrench or the 1/2"?

https://www.dewalt.com/products/power-tools/impact-drivers-and-wrenches/20v-max-xr-high-torque-12-in-cordless-impact-wrench-with-detent-pin-anvil-kit/dcf899p1


The above wrench will zip a 3800 balancer bolt off in seconds.


When I did my timing cover R&R, I marked the bolt with a straight line and two hash marks on the ID of the balancer so I had a reference to where the bolt was tightened to.  My engine builder torqued that bolt so I knew it was correct.  There are 3 power levels on the Dewalt.  I turned it up to 3 and hit it for about 5 seconds.  It tightened the bolt beyond where it was. I've used my Dewalt on flexplate to crank bolts installed with red locktite. On alternator pulley bolts, and most frequently on lug nuts. It makes short work on all of it, with ease.

How do you torque a bolt to 200 ft. lbs?  You max out your torque wrench, then put a pipe over it and lean on it as hard as you can.  For the Buick 455, the spec is 200 ft. lbs. MINIMUM.

1/2" for sure.  It's at least a few years old, but it's the big one, not the little impact driver construction guys use.

I also tried one of these - Link

I couldn't break it loose with the air wrench either, but I don't know what I'm doing with it.  At least I figured out how to reverse it.  

Just to be sure, is the torque for the 3800 bolt supposed to be 200 ft/lbs, or is that just the 455?

Jack the R wrote:

1/2" for sure.  It's at least a few years old, but it's the big one, not the little impact driver construction guys use.

I also tried one of these - Link

I couldn't break it loose with the air wrench either, but I don't know what I'm doing with it.  At least I figured out how to reverse it.  

Just to be sure, is the torque for the 3800 bolt supposed to be 200 ft/lbs, or is that just the 455?

Then there is something wrong with those wrenches.  Mine breaks everything loose, it's an amazing tool.


No, just the 400-430-455 from 1967-76.

The 3800 gets 111 ft. lbs, then 76* of rotation more.  The FSM specifies an torque angle meter (J 36660)

https://www.toolsource.com/angle-finders-c-614_263/torque-angle-meter-gm-p-149755.html

Kinda stupid to spend 728.00 though   I like the Lisle alternative,

https://www.toolsource.com/angle-finders-c-614_263/torque-angle-meter-p-67899.html

Or even better,

https://www.toolsource.com/angle-finders-c-614_263/stinger-torque-angle-gauge-p-93323.html

[quote="LARRY70GS"]

Jack the R wrote:

The 3800 gets 111 ft. lbs, then 76* of rotation more.  

I wonder if the engineers who design stuff like that are ever ashamed of themselves. Why not make it 76.005 degrees?

I'm seeing a bunch of torque gauges similar to the OTC on eBay for $8 - Link

The Lisle is on there for $34 - Link

Since being acurate to 1 degree is important, I thought I'd get the Lisle, but it's got two good reviews and one bad review. Is it also made in China?

Mine got zipped on with an impact wrench many years ago, same bolt.  Not going to worry about it now.


I think it is relatively easy to lock the flexplate, use a torque wrench to 111 ft. lbs, then mark a reference line on the bolt and figure out what 76* is and tighten it that much more.

90* would be 1/4 of a full turn. A little bit short of that.

But I might hit 78 degrees!

Or you might only get 75*

Why can't it be 144 ft/lbs (for example) instead of 111 +76 degrees?

I finally managed to get the bolt out.  My neighbor looked at the air compressor and gun and confirmed everything was set up right.  I hit the bolt for a solid minute and didn't budge it.  I had to fall back on the starter motor trick and that did it, after four tries.  My neighbor was watching and was alarmed at how much the engine was pushed up by the starter motor trying to break that bolt loose.  I hope I'm not in for new motor mounts now, I'm sure that's not good for them.  He thought the pry bar (the end with the socket) might have smacked the inside of the sub frame too.  I haven't inspected that area for damage  yet, but I noticed the brake lines are helpfully located in that area when I installed the pulley puller.  

Once I had the bolt out, I noticed a slight discrepancy between the old bolt (bottom) and the new bolt (top) -  

Back to NAPA to match up that bolt.

What a hot mess. Sorry for your troubles.

Par for the course it seems, although I was hoping this wouldn't be one of those jobs that drags on and on.

Found a video about changing the crankshaft sensor.  I think at one point he said the rpms were off by 300 without a case learn, but it ran.  A couple of the commentors were not so lucky though.

Has anyone had this problem mentioned in the comments -

Quote :

When you install the sensor, there is usually an adjustment screw which holds the sensor in place.  This is so to cure any impact of the balancer upon the sensor when the harmonic balancer spins.    If you do not check for spacing, you will ruin the sensor in short order.

Further down I found this -

Quote :

btw, the 2 previous GM 3.8s I replaced crank position sensors on never had a case learn on them and they went years with no problem so I been told the case learn is really for older cars with the older style ECM.

What about the thread locking compound on the sensor bolts (white) and on the harmonic balancer bolt (orange)? The YouTubers aren't replacing it.

Jack the R wrote:

What about the thread locking compound on the sensor bolts (white) and on the harmonic balancer bolt (orange)?  The YouTubers aren't replacing it.

RTFM he he.

Even if the manual did not call for threadlocker I'd at least use Loctite Blue. That thing popping off for that reason (loosening in service) would be, well, catastrophic.

NAPA says they no longer stock the harmonic balancer bolt. The hunt for what should be a very common part continues . . .

Regarding the FSM, it leaves a lot to be desired. Usually the forum or YouTube are more useful.

Looking at the FSM regarding the crankshaft balancer bolt, it says to see "fastener notice" in "General Information." There are sections about fasteners in General Information, but not a "fastener notice" section. In the "Metric Fasteners" section, it says not to use thread lockers or sealant unless the FSM specifically calls for it. The FSM does not call for thread locker or sealant on the CPS sensor studs or on the crankshaft balancer bolt. Even though they had/have something on them when I pulled them

I have never used thread locker on a crank bolt. Just torqued it to spec.

LARRY70GS wrote:

I have never used thread locker on a crank bolt.  Just torqued it to spec.

The GM ones I've seen came with a red dry threadlocker actually under the washer at bolthead. The NAPAones I've seen are naked. Given the direction the crank spins I doubt you'd 'need' threadlocker, but the presence on the OE bolt would have me using a little loctite blue on say a NAPA bolt. Blue does not require a torch to loosen/disassemble.

albertj wrote:

LARRY70GS wrote:

I have never used thread locker on a crank bolt.  Just torqued it to spec.

The GM ones I've seen came with a red dry threadlocker actually under the washer at bolthead.  The NAPAones I've seen are naked.  Given the direction the crank spins I doubt you'd 'need' threadlocker, but the presence on the OE bolt would have me using a little loctite blue on say a NAPA bolt. Blue does not require a torch to loosen/disassemble.

I know some guys will put some RTV under the washer. Had the director of my club tell me he does that.